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Plant science panel

Plant science

Put your questions directly to researchers 

Send questions via our online form, Twitter to @senseaboutsci using #plantsci, or email us at plantsci@senseaboutscience.org.

Ash Dieback disease, GM crops, bees and pesticides, mycotoxins in food, biofuels... Plant research is central to decisions about future energy, land use wildlife, environmental protection, pest problems, nutrition and food safety. Leading research institutions and learned societies across the UK have come together to make themselves available in a public panel, where you can put down questions and opinions for response. 

Please note: this panel is not for general horticultural advice.

Further information about the plant science panel members here

Answers to your questions below

Alison Clark
"Is there clear unequivocal evidence that omega-3 has specific health benefits?" [In reference to the recent coverage of the field trials of GM camelina.]
Bill Anderson
Alison Clark (registered dietitian): "You could not have missed all the hype over omega 3 over the years and with good reason as you have probably heard that eating foods rich in Omega-3 could help to keep you healthy. There is evidence to suggest it could be beneficial for the following.

• May protect the heart and blood vessels from disease

• Supports healthy development of your baby during pregnancy and breastfeeding

• Provides other important nutrients including vitamins A and D and protein

Because of this and other health benefits it is recommended that we eat more foods containing omega 3.

Omega-3 fats come in different forms: ALA (alpha-linolenic acid) cannot be made in the body so must be eaten in our diet. It has important functions and is needed to make other omega 3 fats. ALA is found mainly in vegetable oils (rapeseed and linseed), nuts (walnuts and pistachio) and green leafy vegetables. EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are long chain fats that can be made from ALA in our bodies. They have the most direct health benefits."

Dr Sarah O’Connor
"I've read that a serum made from a tobacco plant might hold the secret for curing Ebola, but I'm skeptical. Why would a plant contain something that can help fight Ebola? Apart from nonsense herbal remedies, can we actually get proper medicine from plants?"
Calum Eribo
Dr Sarah O’Connor "Antibodies, which are extremely important in treating lots of diseases in addition to Ebola, are difficult to make. Engineering plants to produce these antibodies is a proven easy, safe and cheap way to get large quantities of antibodies for the clinic. ZMapp, which is what the Metro article refers to, is a mixture of antibodies that are showing some promise in fighting Ebola. Tobacco does not naturally produce these antibodies. So the you're correct, tobacco doesn't normally make a compound that fights Ebola.

There are plenty of nonsense herbal remedies from plants that don't do anything except waste your money. However, there are many compounds that are isolated from plants that have clinically proven disease fighting properties. For example, Taxol (Paclitaxel ) is isolated from the Yew tree and is one of the standard chemotherapies used against breast cancer. Vincristine is isolated from periwinkle, and is used to treat leukaemia.

These compounds are very toxic- that’s why they kill cancer cells - and the plants have probably evolved to produce them as a defense to keep animals or insects from eating their leaves. However, a person suffering from these diseases can't simply eat the plant to treat their disease. Instead, the compound needs to be purified from the plant, and very often administered intravenously. So while plants definitely make substances that effectively treat diseases, there is a lot of purification and processing that needs to take place if the drug is to be effective.

Prof Huw Jones
"A friend of mine, a scientist but not in food sciences, told me a couple of years ago that what is wrong with GM crops is that they are alien to the human body. That is, on average, the crops we have been eating over millennia have evolved as we have evolved. What my friend says, therefore, is that by subjecting crops to the GM treatment we have greatly enhanced their development and that is simply not good for us."

"My response to that was that I had heard no one else saying that and that he might well have had a valid point."
Online commentor
Prof Huw Jones: "This concept has no basis in science and the crop varieties we eat today have not evolved naturally. They have been bred over relatively short time-scales for yield, disease-resistance and quality and now bear little resemblance to their ancestral wild relatives. However, there are no nutritional differences between the GM varieties approved for cultivation today and their non-GM counterparts. In fact the nutritional differences between soy and maize are far greater than can be made by adding a gene for say insect resistance to either species. Human diets are anyway amazingly diverse and rapidly changing. For instance, Northern Europeans are now exposed to many new and exciting fruits and vegetables they have not ‘evolved with’. Bananas have been readily available in the UK for only about 100 years, but are now considered a completely normal part of our diet with over five billion of them consumed annually in UK."
Parkinson's UK
"I have read a few small studies that show that broad beans (fava beans), and possibly the younger pods/sprouts, contain enough levodopa to manage Parkinson's disease symptoms. Put simply is it true? There are some experts who say broad bean usage for Parkinson's is limited as its levodopa content cannot be guaranteed. Surely some hungry entrepreneur with access to HPLC-ED could overcome this and sell it commercially?! There are a few companies selling powdered broad beans but not sure how credible."
Hannah Churchill: "Broad beans, also known as fava beans are a natural source of levodopa, which is a chemical building-block that your body converts into dopamine. People with Parkinson's don't have enough dopamine because some of the nerve cells in their brain which produce it have died. As such, supplements containing fava bean extract have been used as a treatment for Parkinson's, particularly in countries where synthetic dopamine drugs are not available.

As you suggest one of the challenges of using fava beans as a source of levodopa is there is no way of measuring the dosage accurately. Individuals may under medicate and find it difficult to effectively control their Parkinson’s symptoms or over medicate and develop side effects such as uncontrolled movements (dyskinesia) which can be very distressing. Research into the use of fava beans for Parkinson’s is still fairly limited and so as yet not recommended as a treatment for those with the condition.

As I understand it, if a commercial company extracted levodopa from broad beans and intended to sell it commercially they would be heavily regulated and need to be approved by the MHRA. However this does not seem to apply to powdered broad beans."

Hannah Churchill is the Research Communications Officer at Parkinson's UK

Professor Tom Sanders
"I've read that antioxidants can in fact be counterproductive for patients undergoing cancer treatment. Does this new study mean that cancer patients should avoid organic produce? Or are these differences in antioxidants too small to matter?"

Prof. Tom Sanders: "Some dietary supplements containing antioxidants interfere with the drugs used to treat cancer and so should be avoided unless advised otherwise by your doctor. Patients on certain types of chemotherapy are advised to avoid grapefruit juice because the phenolic materials it contains interferes with drug metabolism. There is no reason to avoid organic produce but you may need to avoid consuming certain foods such as grapefruit juice and cranberry juice with some medications. The differences between organic and conventional produced crops is really rather trivial."

Professor Tom Sanders is the Head of Diabetes and Nutritional Sciences Division at the School of Medicine, Kings College London.

Professor Tom Sanders
"The claim that '...switching to organic fruit and vegetables could give the same benefits as adding one or two portions of the recommended "five a day"' seems like a huge oversimplification. Does this study actually support even this claim?"
Theresa Cave
Prof. Tom Sanders: "The reasons why people who eat more fruit and vegetables are at lower risk of cardiovascular disease and cancer is uncertain. One view is that it is due to residual confounding. That is people who tend to eat plenty of fruit and vegetables are often people who do not smoke and drink excess of amounts of alcohol, which are known causes of cancer.

Other candidates for the protective effects are vitamin C and potassium which are supplied mainly by fruit and vegetables. Potassium helps lower blood pressure. There has been some interest in anti-oxidants other than vitamins provided by plant foods but this has mainly focused on drinks such as tea and chocolate. There is a large group of compounds called plant phenolics that have anti-oxidant properties that are found in higher levels in organic crops than conventional crops but there is little evidence that this has any effect on health. These phenolics have potentially negative as well as positive health effect. Much of the benefit of eating your five a day is that you do eat less unhealthy food such as cakes, biscuit and confectionery."

Professor Tom Sanders is the Head of Diabetes and Nutritional Sciences Division at the School of Medicine, Kings College London.

Dr Ian Bedford
"Please can you tell me whether bees or other insects collect pollen from wind pollinated crops, e.g corn/maize."
Dr Ian Bedford: "Pollen producing plants basically fall into two categories, those that need insects for pollination and those that rely on the wind. The former usually produce sticky, hooked pollen grains that stick to the pollinating insect, whereas the latter produce copious amounts of small, smooth pollen grains that freely disperse on the wind. Plants that rely on wind dispersal of their pollen usually don’t produce bold flowers and fragrances to attract pollinators. Despite this, many insect pollinators need pollen as it provides an essential source of protein for their brood, so sometimes during Spring they’ll collect wind-dispersed pollen from catkins on trees such as hazel and alder. Later in the year, when crops such as maize are producing pollen, it’s very unlikely that pollinators will collect their wind-dispersed pollen when they have so many other alternative sources that provide nectar as well."
Prof Tim Benton
"This factory farmed lettuce sounds too good to be true. What's the catch? Has anyone tried to do this before with other crops?"
Max Goldman
Prof Tim Benton: "Using LED lighting systems in insulated blockhouses and with recirculating “fertigation” systems seems do-able in terms of energy and space usage, but is likely going to be best for things like lettuces (because they can be grown on shelves) and they don’t need deep roots (like root veggies). Other modern greenhouse systems, like Thanet Earth, will be required for large-scale production of e.g. Tomatoes, Peppers. So considerable scope but not the answer to everything…"
Prof Lin Field
"Articles in the news this week have suggested that "pesticides kill birds" - but is this just correlation rather than proof of causation?"
Prof Lin Field: "The authors admit it is only a ‘correlation’ which doesn’t necessarily mean ‘causality’. However, it is strongly correlated so it could be that neonicotinoids are ‘responsible’ for the effect. I’m not really surprised that the use of an effective insecticide to control pest insects would reduce the number of birds who feed on insects, on what is already mono-cultured farmland with low biodiversity. My main point is always that controlling pests and maximising yields on land used for agriculture leaves more unfarmed land where insects, birds and other biodiversity can flourish! The so-called ‘sparing’ system rather than ‘sharing’ which in my view is less likely to work for either farming or conservation."
Dr Andrew Kiggundu
"Is there no patenting involved in this GM banana [the vitamin A enriched banana reported earlier this week]? I've seen many arguments against GM technology on the basis that companies will actually own the food that people will grow. Also, The Independent article says the 'first plants could be available to farmers and smallholders within six years.' But how long after this before the plants are able to produce useful yields?"
Alex Gardener
Dr Andrew Kiggundu: "Yes, there is no patenting in this particular project. It is all for the benefit of local communities who eat banana as a food. In east Africa cooking bananas are a very important staple food and farmers never need to buy seed because banana is propagated from suckers.

A banana plant produces the first fruit 11 months after planting. The second and subsequent fruits are generated continuously every 3 months. The plants will continue, like normal bananas, to produce several suckers (baby plants) vegetatively. Farmers can use these to expand their gardens or share with others."

Prof Huw Jones
A letter in The Independent (in response to a previous editorial) made claims about new crop-breeding technologies. What is marker-assisted selection? How does it differ, if at all, from other GM techniques? Do you know of examples of it delivering solutions in developing countries?
Prof Huw Jones: Conventional breeding improves features of crop plants by making crosses between compatible lines to combine the best features together. The resulting hybrids get half their genes from each parent but the breeder has no control over how the 27,000 genes from each parent get divided up and put together. Many thousands of plants must be laboriously tested and screened to find those with all the beneficial characteristics in the same plant.

In some cases, the breeder knows the gene or has a genetic marker for a beneficial trait. By analysing the genetic fingerprint of all the many thousands of progeny plants at the seed or seedling stage, the breeder can more easily and quickly select the individuals that possess that beneficial trait.

Unlike GM, marker-assisted selection does not increase the pool of genes that a breeder can use. It simply speeds up the conventional breeding process. It uses knowledge about genes and DNA but is not, itself, a GM technique and it does not, on its own, result in a GMO. However, MAS is often used in combination with genetic modification to follow the newly-inserted gene through different generations.

There are many examples of MAS being used for developing country agriculture. For example, it has been used to select for virus resistance in breeding programmes for common beans; and to select for virus and green mite resistance in cassava both for Asian and African agriculture see more here.

Claire Stoker
"I read that stinging nettles are 'struggling to adapt to climate change' while other species, like Holly are flowering earlier due to warmer temperatures in early spring. Is this something we are seeing with our food crops like wheat and barley? Are there some crops that are adapting better to climate change than others?"

Claire Stoker: "The UK is predicted to experience warmer, drier summers but wetter winters meaning crops benefit from wetter soils, but are then challenged with drought stress in summer. UK plants are varying in response; barley is adapting well, the rising carbon dioxide levels gave this plant a natural drought defence as higher carbon dioxide levels increase efficiency of plant water use. Wheat is predicted to begin flowering and maturing earlier, hence avoiding summer drought stress."
Prof Keith Lindsey
"I read last week that the EU has agreed a new 'GMO cultivation proposal' which would allow countries within the EU to decide for themselves whether they can allow or restrict GM crops. But what is stopping contamination of GM free countries from neighbours who do decide to grow GM crops?"
Prof Keith Lindsey: "The regulatory system in place for the approval of GM crop cultivation in the EU considers the risk associated with the growing of a GM crop, which includes the potential for pollen transfer to non-GM plants. The precautionary principle considers the worst case scenario, i.e. assesses the likely impact on human health and the environment if pollen escapes a field of GM crops. The main approach to mitigate spread of GM pollen is by managing the agricultural practice, i.e. by separating fields of GM and non-GM crops. While pollen of some species some can be carried significant distances by wind or (to a lesser extent) insects, the likelihood of a given GM pollen grain landing on the stigma of a non-GM crop several kilometres away (e.g. in a different country) is likely to be very small, but such an assessment would be part of the risk assessment process. In reality the probability of cross-fertilization under such circumstances is likely to be very low. Currently limits of 0.9% are set as the threshold limit for the maximum GM content of a crop that is considered legally GM-free or organically produced - higher levels must be labelled as GM. Note that some European countries currently do already cultivate GM crops, with no adverse effects on crop production in other countries."
Prof Lin Field
"I read in the papers about a 'bio-pesticide' made from spider venom and snowdrops. Is this a viable alternative to the pesticides we currently use? Are there other 'bio-pesticides' and how well do they work?"
Helen Reegan
Prof Lin Field: "This is about a ‘fusion protein’ containing a spider toxin and a carrier protein (from snowdrop) which has now been shown to have no adverse effects on honeybees. The question is: does it actually work against pest insects? There is a previous report that it is toxic to a range of insects when fed orally via coated leaves, but the efficacy has not been tested in the field. So I would say the jury is out.

There are other biopesticides, such as entomopathogenic fungi and other toxins from microorganisms, such as the Bt toxin, the latter is widely used in crops that have been ‘engineered’ to produce the toxin. Delivery by this route is clearly controversial where GM is not accepted."

Prof Dave Goulson
"I read an article about an new invasive species of bee that is spreading rapidly across the UK. It seems this new bee, the tree bumblebee, has a greater resistance to parasites than the traditional British bee. The article was a bit of a 'scare-story', but isn't it a good thing that we're acquiring what seems to be a better bee to pollinate our crops?"
Dan Curtis
Prof Dave Goulson: “The invading bumblebee, Bombus hypnorum, seems to actually suffer more from parasites, but paradoxically is thriving regardless. So far as we know it is not doing any harm – in Europe, this species has always lived happily alongside all of our other native bumblebee species. Bombus hypnorum is certainly keen on pollinating the raspberries in my garden, so is very welcome as far as I am concerned.”
Professor Ottoline Leyser
Every year I used to buy two small Christmas trees to light up the entrance to our porch. I buy potted trees and then move them on to the land to grow on to larger trees. I’ve been doing this for about ten years. Now, instead of buying new trees for the porch I now take a top cutting of some of the trees I’ve grown on – cut back the lower branches and plant them in the ground entrance to the porch.

After cutting the top of one tree in this way, I decided to make a lateral branch stand directly upright by caning and tying it with the hope it would form the new upright of the Christmas tree and grow on for future cuttings. I did this three years ago. However, this lateral branch still knows it is a lateral branch – it will do its damnedest to grow laterally no matter how I force it vertically. The new cells somehow know that they originated from a lateral branch, and not the central branch of the tree. Do you know how this is achieved?

Shamus Burns
Professor Ottoline Leyser: "Although people usually think of shoots as growing up and roots as growing down, a quick inspection of most plants makes it clear that while the main shoot usually does grow straight up, and the main root straight down, the lateral shoots and roots often grow at shallower angles. It has been shown that, just as tipping the the main shoot over results in its re-orienting to resume straight up growth, when side shoots are tipped over they re-orient to resume their characteristic shallower growth angle. This has led to the idea that instead of just growing up or down plant organs grow at a so-called set point angle. In some species and in some situations, it is possible for the set-point angle to change. For example the shallow angles of side shoots and roots often change as the shoot or root matures. Furthermore, if you decapitate a shoot, quite often the closest side shoot re-orients its growth to the straight up position, effectively taking over as the main shoot. What you describe for Christmas trees suggest that their side branches have particularly immutable set point angles.

We do not yet know how the set point angle is determined. Recent exciting research from the laboratory of Dr Stefan Kepinski at the University of Leeds suggests that, like the main shoot, side shoots have the same gravity response system that directs straight up growth. However, in side shoots this is off set by a system that orients growth downward. This off set system is what generates the set point angle and it is dependent on the plant hormone auxin. Hopefully over the next years we will gain some understanding of how this works, and then it will be possible to work out why in some shoots the set point angle is easy to reset, but in others not."

Dr Miriam Gifford
"Recently I have read that legumes fix nitrogen from the air if they can not obtain efficient amount of nutrient directly from the soil. What happens to levels of nitrogen fixation after supplementing legume crop with fertiliser? How much of the fixed nitrogen will be actually used by the next crop? Are there any implications of such practice?"
Dr Miriam Gifford: "Legumes interact with rhizobia (nitrogen-fixing soil bacteria) in cellular structures (nodules) on their roots. The plant-rhizobia interaction is highly tuned to the environment, so the plant makes more or less nodules dependent on how much nitrogen there is in soil. If there is a lot of nitrogen then plants don’t make nodules. If there is an influx of nitrogen (e.g. fertiliser is added) after plants have made nodules, then the plant can shut down nodule activity and nitrogen fixation. This is a resource-balancing mechanism since making nodules requires carbon, thus if nitrogen-fixation from symbiosis is not necessary, carbon is not wasted.

The biologically fixed nitrogen remains in the plant, thus would not normally be available for the next crop - unless the remnants of the crop are ploughed into the soil.

We think that if we can enable biological nitrogen fixation in non-legumes we can significantly reduce the need for nitrogen fertiliser, bringing massive savings to agriculture."

"Regarding the so-called terminator gene. I understand that plants with this gene would not set fertile seed and therefore could not reproduce. BUT: could the gene escape and be picked up by other plants which would then become infertile? I'm not so concerned as to whether it is likely but whether it is possible, in principle. And if not, why not?"

Richard Kuper
Professor Martin Warren "I'm not sure that there is a terminator gene - what this is referring to is terminator technology. Here plants have been genetically modified with a switch to allow for control of seed sterility/germination. There is always a chance that any piece of DNA can jump from one species to another - especially as eukaryotic cells contain many transposable elements. Nature has been jumping genes for billions of years - it is a natural process. However, in this case if the control elements were to transfer across they would not provide any advantage and would likely quickly be lost especially if they conferred infertility."
Dr Steve Thomas
I have read reports saying both that plant growth will increase in a warming climate, and that it will decrease in a warming climate. Which statement is true or is there not so clear an answer?
Dr Steve Thomas: "Unlike animals, once plants start growing in a particular location they are usually fixed in that position. Their success in becoming established in this location depends on the ability to be able to withstand the local environmental conditions. In the case of flowering plants this involves the successful production of seeds that will allow the growth of a future generation. Flowering plants have been very successful in adapting to widely different environments, with some species capable of growing in deserts whilst others survive in extreme cold conditions, such as those experienced in Antarctica. Temperature is one of the important environmental factors that they have evolved ways of adapting their growth to. This has been achieved through intricate sensing and response mechanisms that have evolved over a very long period of time. This allows a specific plant species to successfully time its germination, growth, flowering and seed production for that particular environment.

The large increases in temperatures that are expected to be caused by global warming are likely to occur on a much shorter timescale than those through which plants adapted to a particular environment. This is likely to result in changes in the distribution of plant species, with those that are adapted to the warmer conditions becoming established. In the case of crops, there is the need to breed new varieties that are adapted to the changed conditions otherwise yields will be impacted on."

Dr Richard Harrington
“Does any member of your panel have a comment on the study that seems to correlate a decline in monarch butterfly numbers with the planting of GM herbicide-resistant crops?"
Dr Richard Harrington: “Significant loss of milkweed, the food of the monarch butterfly larvae, would intuitively be expected to impact numbers of migrating adults of this iconic species. The paper you refer to provides convincing evidence of this and suggests that the use of herbicide-tolerant (h-t) corn is the underlying cause. Whilst there are no data in the paper showing the link between the use of h-t corn and milkweed density, again it seems intuitively likely as the purpose of the h-t corn is to allow improved weed control without harming the crop.

The prime suspect when considering monarch decline has been deforestation in the parts of Mexico where the adults overwinter. It is very interesting to see this other factor highlighted. As so often, there is no one simple single cause in the decline of a species. The work also highlights the conflict between food production and the welfare of other species on which, through complex interactions, our own welfare ultimately depends, and it demonstrates the importance of high quality studies aimed at getting the balance right.”

Professor Kevin Folta
In the news I’ve seen mention of genomics being used to find (for example) the best apple variety to grow in droughts. But does the genetic basis for the resistance to drought, for example, mean the apples taste different too?
Professor Kevin Folta: "The concepts of flavour and aroma are simply how the brain assembles information from what the plant is made from. Sugars, acids and volatile organic compounds released from food interacts with specialized sensors in the mouth, nose and throat. These receptors send the information to the brain, which then assembles a sensation of flavour. Flavour therefore has two parts: the first is based on the combination of molecules present in a food item, in this case an apple. The second is the combination of sensors ready to interpret the information.

That's why something that tastes wonderful to me might not be your favourite at all.

The particular flavour-molecules that a plant produces depends on interactions between genes and environment. My lab recently identified a gene in strawberries that is required for "peachy" flavours. If a strawberry doesn't have the gene, it can't make the peach notes. Environmental factors also play a role, as even if a gene is present, it may not be expressed well on a cloudy day or late in a season.

So shuffling genes by breeding to identify drought-resistant varieties could profoundly affect flavours, although it is difficult to say precisely how. Over the past 50 years fruit breeding has prioritized production traits, like yields, shippability, size, colour, etc. Flavour and aroma have been a bit down the line in terms of importance. That's why our recent varieties lack exciting flavours.

The good news is that as we further unveil the genetic basis of flavours and the genes that control them, we can now specifically breed for plant materials likely to possess improved flavours. I'm optimistic that the next generations of fruits and vegetables will be our best, and will spark renewed interest in nutritious fresh produce."

Legumes are said to help fertilise surrounding plants by their ability to fix nitrogen. How far does this benefit reach, i.e. if you have a vegetable patch, how far should you intersperse legumes with your other crops for maximum benefit? Can they completely replace using fertiliser?
Professor Giles Oldroyd: "Legumes fix atmospheric nitrogen through a beneficial association with nitrogen-fixing bacteria, which occur in specialised nodules on the roots of the plant. The levels of nitrogen-fixation in a legume are sufficient to replace nitrogen fertiliser for that legume crop. Legumes can benefit the growth of other plants either as rotation crops (commonly used in the developed world) or through intercropping (commonly used in the developing world). However, in these instances the nitrogen provided by the legume is rarely sufficient for all the nitrogen needs of the partner crop, and in commercial agriculture legume rotations are generally augmented with nitrogen fertiliser. Where co-planting is used the legume is planted alongside a cereal for maximal benefit. A common co-planting would be a climbing bean alongside maize. However, it is important to remember that nitrogen is only one component, albeit the most important component, of inorganic fertilisers, and legumes whether in rotation or in co-planting will not improve the phosphate or potassium content of the soil."
Derek Stewart
Many people have told me that rapeseed oil has a strange smell and taste. Is there a scientific reason behind this?
Derek Stewart: “Rapeseed has been undergoing something of a revolution in the last few years, with its health benefits being increasingly recognised through a wealth of compositional evidence, along with rapeseed's comparative benefits over olive oil. This is largely due to its significant amounts of mono- and poly-unsaturated fats. Oilseed rape plants (and all the other members of the Brassica genus, such as Brussels sprouts, cabbage, and cauliflower) also produce sulphur-containing compounds called glucosinolates.

When the oilseed is crushed and the oil and seed casing are pulped, the chemicals, such as the sulphurous glucosinolates, are transferred into the oil. Sulphur-containing organic compounds will, to varying degrees, “go off”, often due to exposure to the air, producing sulphur dioxide which is notorious for its pong! However, these compounds will all be at really low levels and pose no threat to health. (In fact, sulphur dioxide is a commonly used preservative in wine making.

The resulting smell and taste will depend on many things, such as the variety of the oilseed rape, location of growth, local environment (terroir) and climate. I would encourage you to embrace the diversity!”

Dr Richard Harrington
The cold winter, late spring and dry summer last year (2013) led to decreased threat from disease carrying aphids to rapeseed and cereal crops. What effect could this year’s wet & mild winter have on the 2014 aphid population?
Dr Richard Harrington: "There is a strong correlation between winter temperature and the time and size of early-season flights of many pest aphids, especially those overwintering in the mobile stages rather than as eggs. Correlations with rainfall are insignificant by comparison. On that basis our forecasts are for earlier (by 2-4 weeks) and larger flights than usual. Although 1.5 to 2 deg. C warmer than usual, winter temperature (we use January and February) did not break records. Rainfall did, though, and it can be risky to make predictions in conditions outside previous experience. Thus, whilst sticking to our guns, we are more nervous than usual!"
Dr Hanna Tuomisto
Is soil on organic farms better at holding water in times of heavy rain?
Dr Hanna Tuomisto: "Soil water holding capacity depends on the soil type and the soil management practices. Soil organic matter content plays a key role influencing the structure and water holding capacity of soil. Management practices that improve soil structure include application of organic matter in the soil; use of crop rotations that include deep rooted crops (eg legumes); avoiding use of machinery and grazing on the field when the soil is wet; minimising tillage; and avoiding overgrazing.

Organic farms often have higher soil organic matter content due to higher levels of organic matter inputs in the form of manure and compost. Organic crop rotations also include deep rooted legume and grass crops that improve the structure of soil. Many conventional crop farms operate low or zero organic matter applications into the soil and have simple crop rotations without deep rooted crops. However, some conventional livestock farms are very close to organic livestock farms in terms of crop rotations and organic matter applications."

For a look at the science of rooting and potential impacts on soil water holding capacity our plant science panelist Dr Robin Sen has written a more in depth blog.

Dr Robin Sen
How is the soil going to recover after weeks of floodwater? Will the worms survive? How about springtails and mites?
Dr Robin Sen, Reader at Manchester Metropolitan University: “Soil organisms together with plant communities in floodplain areas are generally well adapted to regular flooding, particularly where there has been limited or no management. However, current flooding is mainly concentrated in floodplains where the soils have been significantly altered due to urbanisation or long-term agriculture. As a result, these soils can lack the resilience to withstand prolonged flooding events following historical changes to physical, chemical and microbiological properties, along with typically reduced non-flood adapted plant diversity, particularly with regard to agricultural land.

The rapid loss of soil aeration following waterlogging drives further changes in soil properties that can trigger release of essential plant nutrients such as phosphorus and nitrogen causing a major loss of soil fertility.

Another major risk to soil life and productivity comes from the input of pollutants such as toxic heavy metals and hydrocarbons from nearby flooded urban brownfield sites and roads. Post-flooding recovery of soils is greatly dependent on a range of factors such as soil organic matter content and subsequent land management.

For more information about soil protection, consult the Soil Strategy for England report published by the Department of Environment, Food and Rural Affairs (DEFRA, 2009)."

James Dent
When the rains stops, will that be the end of it (i.e. the floods will go away)?
James Dent, Independent Consultant; Hydrology & Meteorology "No. After any flood, it will always rain again, and if the catchment is saturated, further flooding will occur. Floods will decline naturally: the steady fall in river levels after a flood is called “recession”.

The speed of the recession depends on the size of the river and the magnitude of the event. Where out-of-bank flow has occurred and flood plains are flooded, it may take some time for water to recede. In large lowland areas, decline of floodwater by natural outflow and drainage through the subsoil may take days or weeks, especially if groundwater levels are high."

Fazir Khan, Civil Engineer: "There is always lag period between the peak rainfall event and the peak flood event. The peak discharge experienced during a flood event occurs some time after the peak rainfall event. This time can vary depending on the size and configuration of the catchment from minutes to hours to even days for very large catchments that flow to flatter low lands.

There can also be an exacerbation of the flood event in areas where there is tidal impact in the lower reaches. A rising high tide can sometimes coincide with a rising flood to create very high flood depths for the duration of the high tide in a given area. High tides can therefore by extension, if they coincide with floods, lengthen the time it takes for surface runoff to dissipate and therefore extend the time of the flooding in an affected area.

In summary, flooding can be experienced for some time after rainfall ceases because of flat slopes in the discharge channels, constrictions in watercourses and outfall drains; backwater effect caused by high tides and other physical characteristics of the catchment in question."

Dr Tim Hess
Is there a contradiction between reducing flood risk and preserving environments for wildlife? (Scientifically speaking, not politically).
Dr Tim Hess, Reader in Water Management, Cranfield University: “Yes and no. Engineering rivers to increase their capacity (by dredging, straightening or enlarging the channel) generally has a negative impact on river habitats by changing the hydrological behaviour of the river from its “natural” condition - although “sensitive” river engineering can minimise these impacts.

Some actions to reduce flood risk may be compatible with preserving environments for wildlife. For example, washlands on flood plains may provide storage for flood waters and habitats for plants and animals. However, rarely is flood water clean, and high loads of nutrients and pollutants brought onto the land with the floodwater can cause significant damage to valuable wildlife sites.

Planting woodlands in the upper reaches of catchments can encourage rainfall to infiltrate into the soil rather than runoff over the surface (depending on the soil type and amount of rain) and managing peatlands to retain water can provide benefits to wildlife and flood risk management.”

Dr Tim Hess, Reader in Water Management, Cranfield University. He has over 30 years’ experience in research and consultancy in the application of hydrology in managed rural environments.
It seems there are lots of different ways flooding can happen. Are there different types of flooding?
Dr Tim Hess, Reader in Water Management, Cranfield University: “Yes, certainly. A "flood" occurs when water gets onto places which are usually dry. We can recognise five types of flooding:

a) Flooding may be caused by the flow in rivers exceeding the capacity of the channel (fluvial flooding). This usually occurs after long periods of heavy rain. It is what rivers naturally do, and is why rivers have flood plains. The problem arises when we want to use the flood plains for other purposes (houses, agriculture, transport routes, etc.).

b) Rain falling on the land surface at a rate greater than it can be moved away by natural or man-made drainage causes pluvial flooding. This occurs during intense rainfall and tends to be quite localised and short in duration. Urban areas are prone to pluvial flooding when the drainage systems become overwhelmed or blocked.

c) High groundwater levels after prolonged rainfall result in groundwater flooding. Groundwater emerges at the surface in depressions and hollows and basements of houses.

d) Coastal flooding occurs when waves overtop coastal defences. This usually occurs when high tide coincides with low air pressure and high winds (tidal surge).

e) Finally, flooding can occur due to breaches or failure of infrastructure (such as dam failure).”

James Dent, Independent Consultant, Hydrology & Meteorology: "There are several types of flooding.

a) Fluvial. Flooding caused by streams and rivers in response to rain and in some cases snow-melt. Can be in response to local rainfall events or, as in recent months to widespread heavy rainfall over a prolonged period. This latter type of event will cause major floods on the largest catchments, e.g. Thames, Severn.

b) Pluvial. Flooding as a direct result of heavy, localised, and usually short duration rainfall, e.g. thunderstorms. Floods of this type are most common in small, steep catchments, e.g. Pennines, Welsh Valleys, and in urbanised catchments where large extents of paving prevent infiltration.

c) Groundwater. Occurs in relation to major water-bearing strata (aquifers), such as chalk, sandstone and alluvial sands. Groundwater levels rise as a result of prolonged rainfall, especially in winter, where there are only small losses by evaporation. It is common for groundwater flooding to come after major fluvial flooding events. The delay in the response to aquifers to inflow and outflow means that groundwater flooded areas will remain for several weeks after the fluvial flood event.

d) Coastal/Estuarine. Costs and estuaries are at risk of flooding from high tides. This flood risk will be enhanced by the natural tidal cycle and incidents of high, persistent on-shore winds. Tidal surges are caused by the influence of low atmospheric pressure, i.e. the passage of depressions. Adverse combinations of high tide, wind and atmospheric pressure can cause significant events like the North Sea Floods of 1953".

Professor Jonathan Jones, the Sainsbury Laboratory. Professor Jones uses molecular and genetic approaches to study disease resistance in plants
I recently read about GM blight resistant potatoes in the newspapers but aren't there blight resistant varieties already?
Chris Peters
Professor Jonathan Jones, the Sainsbury Laboratory: "Yes, but existing blight-resistant varieties, for example Sarpo Mira, are not currently favoured by the market, and do not get onto the Potato Council list of top 50 varieties planted in the UK. We believe it makes more sense to add traits such as blight resistance to existing market-favoured varieties.

Also, the pathogen [disease-causing organism] that causes blight is constantly changing, and current pathogen races can overcome resistance in the most commonly grown potato varieties in the UK. Importantly, the gene we trialled, Rpi-vnt1, confers resistance to all currently circulating UK strains (and we can never have ‘too many’ resistance genes). We are cloning additional such genes"

Read more about the research here.

Howard Wheater, Emeritus Professor at Imperial College London and Director of the Global Institute for Water Security
What is the difference between ground and surface water?
Howard Wheater, Emeritus Professor at Imperial College London: “Surface water is used to describe flows in rivers and lakes, and overland flow, for example over paved surfaces. However, surface flows can be generated in part by subsurface processes, e.g. soil drainage, and groundwater discharges.

Typically, soil pores contain air and water, both of which are needed for plant growth. When the pore space of soil (or rock) is completely full of water, we have ‘groundwater’. Groundwater usually exists because of some subsurface flow barrier (e.g. a layer of reduced permeability). The surface of the groundwater is often evident as a ‘water table’: If you dig a hole in the ground to reach the water table this would be the level of standing water in the hole. Water table elevation rises and falls according to groundwater recharge and discharge. Where the water table intersects the ground surface we have a ‘spring’. And with very wet conditions, groundwater discharges can take place where they may not be expected and cause surface flows – or, alternatively, groundwater can flood basements and other structures below the surface.”

Do we need more man-made rivers in low lying areas?

“Low-lying areas don’t have enough elevation difference to support soil drainage and river flows, and hence can easily become water-logged and flood. Agricultural drainage is often used to improve the ability of such soils to transmit water. Subsurface drains would normally connect to a system of open ditches and streams. These are part of the natural landscape and traditionally would become inundated during wet conditions, and act as a temporary store of water. Improved drainage removes this storage and passes the water downstream – where it may create new flooding problems. So having more man-made rivers may help a local problem, but may worsen conditions downstream.”

What do people mean when they talk about trapping flood water on higher land?

“Various agricultural practices in upland areas can help to store water in the landscape. For example, planting trees improves the ability of the soil to accept and retain water, and small reservoirs can trap water for farm use. These practices can reduce flood risk downstream. However, other practices, such as drainage, will reduce water storage and can make matters worse downstream.”

How can we get rid of water faster?

“Getting rid of water faster may often mean creating a problem for someone else downstream. The most ‘efficient’ way would be to change the natural river system into a concrete, un-vegetated channel designed to move water fast and efficiently. But this then loses the natural ecological function of the river system.”

Forestry Commission
What will the impact of a flood be on different kinds of trees? Will trees rot?
Dr Tom Nisbet, Forestry Commission: "The impact of flooding on trees depends on the timing, duration, frequency, velocity and depth of flooding. Tree seedlings and young trees are more sensitive than mature trees, especially if flooded during the growing season. Wild cherry, beech and Norway maple tend to be the most sensitive, while willow, poplar, elm and alder are among the most tolerant. Shorter duration flooding can cause stem damage/lesions, while longer flooding leads to dieback and tree death. The more sensitive species tend to show stem damage after around 10 days inundation and dieback after 40 days, while the most tolerant species can survive >100 days of flooding without damage. Guidance on the sensitivity of different tree species to flooding is provided by FOWARA (2006). "
Forestry Commission
Should we plant more trees/forests - if this holds water in upland areas and reduces flood risk? Would this have made a difference with the flooding we’re seeing at the moment? How much?
Dan Curtis
Dr Tom Nisbet, Forestry Commission: "The short answer is yes. Trees can help to reduce flood risk in a number of ways, in addition to providing other multiple benefits to society. Since April 2012, Forestry Commission England have offered an enhanced rate of grant to encourage land owners to plant more woodland where this can assist flood risk management. It obviously takes time for trees to grow and maximise their contribution and thus needs long-term planning and co-ordination to make a difference. How much of a difference depends on many factors, especially the scale of planting upstream of vulnerable communities and the nature of the flood risk. The greatest scope for woodland creation to help is within smaller catchments (<100 km2). Location is also very important since planting trees in the wrong place can increase rather than decrease flood risk."
Paul Temple, a tenant farmer in East Yorkshire. He grows arable crops and rears beef cattle.
What happens to grassland after it has been completely flooded for 2 - 3 months?
Paul Temple: "The grass dies, soil life dies, soil structure is ruined. It will require re-seeding and will take at least 2 years to re-build what's lost. Until a newly seeded grass has properly established it remains extremely vulnerable to the weather and damage from grazing livestock. The simple reason is the lack of root mass."
Dr Phil Howell, a pivotal part of the NIAB's pre-breeding group. He has over 20 years experience in crop improvement.
Are flood resistant crop varieties being used in vulnerable areas like the Somerset levels?
Phil Howell: “Flooding risk is often managed through farming systems (rather than growing specific plant varieties): within the Somerset Levels, 70% of the agricultural area is grassland, as pasture is more tolerant of water-logging than arable crops. It is technically difficult to run specific flood tolerance field trials, although variety trials held at contrasting locations and over multiple years tell us something broadly about which varieties perform best under wet conditions.

On a positive note, British researchers have recently developed a hybrid grass which can improve the soil structure through deep rooting. This could actively reduce the run-off from upland pastures, thus mitigating the risk of flooding further downstream.”

Paul Temple, nominated by the National Farmers' Union. Paul is a tenant farmer in a family partnership in East Yorkshire.
Can certain farming methods create flood risks?
Joss Sanglier
Paul Temple: “Certain farming methods increase, for example, maize stubble on a slope left over winter. All farms, however, have an annual soil protection review – and all farmers do everything they can to prevent flooding for the obvious reason of soil and crop damage with loss of income. Farmers have been frustrated about this issue for the last ten years or so as good drainage management (at a national level) has been ignored.”

Should farmers build more ditches and why?

Paul Temple: “It's not a case of building more ditches, but of carrying out proper maintenance on existing ones. Strategic reservoirs, to give water holding capacity, should be part of a future plan to provide irrigation.”

What will the impact of a flood be on different kinds of crops and trees? e.g Will farmers have to plant something different next year? Will prices go up? (Rebecca Gale)

Paul Temple: “Flooding basically kills roots - for annual crops, in a short time; grass can manage a little longer. If the water table rises some tree roots shallow off and the trees either die or are vulnerable to wind damage.

Wet soils lose their structure and ‘growing ability’, needing either a severe drying out or deep cultivation to put this right. Flooded soils become compacted and anaerobic with soil life (critically, worms) dying. A permanent pasture that is flooded and destroyed in this way will take several years to re-establish the same root system.

In terms of the impact on crops, Spring sowing will be delayed. Prices, however, are less likely to be directly affected - unless the crop is high value vegetables not easily replaced. A final point is that any production we lose needs replacing with imports, i.e from another country where land is not flooded. Most farms have someone with generations of experience and all of them see flooding as failure!”

In relation to the application for a GM Camelina field trial at Rothamsted Research "Will the plant still produce all its original nutrients? Will it produce toxins?

Professor Jonathan Napier, Rothamsted Research "We have re-engineered the biochemical pathway to produce fish oils in the seeds of the oil crop Camelina. Our experiments to date in the laboratory and glasshouse have shown that all the traits and biochemical characteristics that we have examined in these transgenic plants are identical to wild type. No difference has been observed in seed set, size, germination and fertility. The trial we propose is to test the agronomic performance of these plants. The new biosynthetic activities are specifically targeted to the seed only and the plants are developmentally and morphologically the same as wild type. Analysis of the oil extracted from the seed of the engineered plants shows the same composition as wild type plus the Omega-3 LC-PUFAs that are beneficial for health i.e. eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)." Read more about this work at www.rothamsted.ac.uk/camelina
Prof Bill Rutherford
Since plant cells absorb UV rays, would it be possible to remove the plant cells from a plant, put them in a medium that would keep them alive, and make the entire substance into a UV blocking material to be used as sunscreen?
Alana Ervin
Professor Bill Rutherford, Imperial College London:

The green pigment, chlorophyll, absorbs red and blue light and on to higher energies, covering the solar spectrum quite well in the UV. In fact, proteins containing chlorophyll may have existed simply as UV screens before they evolved to photosynthesise.

But the pure chlorophyll pigment is a bad idea as a sun screen. It would absorb the UV and visible light but then react with O2 (the molecule not the company) and the excited O2 would then kill your cells. This reaction has been studied as a way of killing cancer cells. In the natural environment carotene molecules prevent excited chlorophyll wreaking havoc.

So Alana’s idea of keeping chlorophyll in its native cell is a better bet as a UV screen. That said, it is quite hard to keep a plant cell alive outside a plant. Algae or photosynthetic bacteria may do better since they are used to the free-living, unicellular lifestyle but even those get contaminated with other microbes or just die.

Thus I would predict that bacterial/algal sunscreen might work for a short time in principle but would be fairly smelly, possibly slimy and certainly green: a tricky prospect for the sales department.

Ian Denholm
In terms of biodiversity decline, is there much connection between meadows and arable land?
Ian Denholm: "Some plants that grow in hay meadows will also grow among crops, but the species that have fared worst in terms of population decline are mostly arable specialists with few, if any, alternative habitats they are able to grow in. These plant species have fallen victim to herbicides and modern cultivation regimes. They tend to be annuals dependent on regular disturbance of the soil and with restricted periods of germination and growth. Common Poppy (Papaver rhoeas), for example, has declined dramatically in arable land but it can also colonise field margins, roadsides and urban habitats. So it isn't under major threat, unlike some close relatives - Rough Poppy (Papaver hybridum) and Prickly Poppy (Papaver argemone) - that are less adaptable and are now becoming hard to find."
I want to know whether selenium can affect flavonoids. If so, then what is the mechanism?
Shiva Bazl
Matt Audley:

Selenium is not essential to plant growth but is essential to human health as it forms part of some important anti-oxidant enzymes. In some countries, including the UK, dietary intake of selenium is below recommended levels. Finland has even added supplementary selenium to cereal crop fertilisers, although other non-grain crops such as broccoli are known to be better selenium accumulators.

Selenium is thought to be taken up by plants through the same pathway as sulphate resulting in competition between the two chemicals (Ellis and Salt 2003) and so an abundance of one may inhibit uptake of the other. Flavonoids are most commonly known as plant pigments which add to the colour of fruits and petals. Selenium enrichment in tomatoes resulted in an increase in some flavonoid chemicals (Schiavon et al 2013) but a decrease in other beneficial compounds, especially containing sulphur, in broccoli (Finley et al 2005). The underlying mechanism remains unclear.

Dr Joan Webber
Could a genetically modified approach help tackle ash dieback in the UK?
Dr Joan Webber: In order for a GM approach to work we would first need to know the basis of resistance to Chalara (the fungus causing the disease) before any suitable genes could be engineered into susceptible ash trees. Those GM trees would then need to be tested to ensure that the resistance was stable and expressed - so GM is not a quick fix. However, resistance that is likely to be durable and long lasting usually comes from making use of many genes which all contribute to resistance, so-called quantitative resistance. In the case of ash dieback, conventional breeding for multiple-gene resistance is still widely considered to be the best strategy for achieving long term resistance.
Dr Robin Sen
"What evidence is there that glyphosate is damaging to soil and its organisms, and is generally toxic?"
Verity Newman
Dr Robin Sen "Glyphosate, the active ingredient of Roundup®, is the most popular broad spectrum herbicide on the market for weed control. It works through blocking the activity of an enzyme in a biochemical pathway plants need to produce several essential aromatic aminoacids (used in plant defences). The same pathway is also found in soil bacteria and fungi that are not the intended target of the herbicide, which are crucially important in maintaining soil structure and fertility. There is increasing evidence for persistence and non-target toxicity on soil bacterial communities and mycorrhizal fungi that work symbiotically with plant roots. Over time this could disrupt soil and plant productivity. Short-term cost-benefit analysis favours use of chemical control agents such as glyphosate, particularly in conjunction with genetically engineered glyphosate resistant crops such as maize. However, all broad spectrum herbicides have the associated issue of affecting non target species and research is happening now to find more targeted and sustainable alternatives, such as selective bio-pesticides, for the future."
Dr Astrid Wingler
Can you tell me more about phenotypic plasticity in plants: Can plants adapt to different light intensities? How does this affect leaf thickness?
Hannah Morley
Dr Astrid Wingler "Plant growth and morphology are incredibly plastic, as demonstrated, for instance, by the cultivation of small bonsai from species that would normally grow into large trees. The size and number of plant organs can vary widely depending on the growth conditions, which enables a plant to acclimate to its environment. For example, in low-nitrogen soils plants invest resources in extensive root growth to allow sufficient uptake of nitrogen. Leaf size and thickness are also affected by the environment. In low light, e.g. at the bottom of the forest canopy, formation of thin leaves with a large area (shade leaves) allows plants to harvest sufficient sunlight. In contrast, leaves of the same individual that are exposed to high light at the top of the canopy are usually thicker but smaller (sun leaves)."
Dr Robin Sen
How do we get more phosphorus and cavity prevention in soil?
Lina Pettidis (@linaolight)
Dr Robin Sen "Phosphorus is an essential element for life and is found as a mineral called phosphate rock but also in complex organic molecules such as DNA. With the cost of mineral phosphorus fertilisers climbing, alternative biofertilisers are being developed based on mycorrhizal fungi that work symbiotically with plant roots and bacteria to unlock phosphate from soil reserves. These soil microorganisms further help the plant roots absorb both mineral and organic phosphorus. Mycorrhizal fungi also improve soil structure and reduces soil cavity formation. You can think of the symbiotic fungi as being like the network of steel rods used to reinforce concrete except this root associated filamentous fungal network (See a photo of a mycorrhizal Scots pine seedling) also massively increases nutrient uptake capacity of the plants."
Dr Alan Jones
Does either Conventional Farming or Organic Farming have less effect of nutrient loss in the topsoil?
Josh Stone
Dr Alan Jones "Well-managed farming practices try to maintain soil integrity and nutrient levels. Soil organic matter, which gives the soil structure, and enables it to store both nutrients and water is very important for this. Farmers need to balance nutrient inputs (from either mineral or organic fertiliser), with the nutrients lost from soil when crops are harvested. From 1860, traditional ‘extensive’ agriculture was superseded by ‘intensive’ farming, which resulted in higher yields but caused a rapid decline in soil organic matter. From the 1950s, inorganic fertilisers were used in intensive farming to match nutrient inputs with these higher yields and arable soil organic matter is now recovering. Essentially, neither conventional or organic farming cause soil degradation, but mismanagement of soil nutrient capital in the long term does. Reducing yields by farming less-intensively is one way to prevent this, or alternatively, we can use inorganic fertilisers and intensive farming to obtain high yields without degrading the soil."
Dr Hanna Tuomisto
Between Conventional Farming and Organic Farming which would you classify as more eco-friendly?
Josh Stone
Dr Hanna Tuomisto "There is not a straightforward answer to this because the variation in farm management practices used within both organic and conventional farming systems is wide. The answer depends also on the scale of the comparison. Organic farms generally support higher biodiversity per unit of field area. However, the yields of organic farming are lower, and therefore, organic farming requires more land for producing the same quantity of products. If as a consequence natural areas are converted for agriculture the overall biodiversity benefits are not necessarily higher. Regarding greenhouse gas emissions and nutrient losses to waterways, organic farming often has lower emissions per unit of land area, but similar or even higher emissions when compared per unit of product. The optimal environmental performance might be achieved by developing farming systems that combine the best practices from current organic and conventional farming."
Professor Joachim Schiemann
Has there been any proven claims that living near GM fields are toxic b/c of pesticides? Or any other pesticides or herbicides for that matter. I've asked farmers who work directly. What does the data show?
Joni (@rose_joni)
Professor Joachim Schiemann "With the help of crop genetic improvement technologies, including GM technology, we are now able to modify traits in crop plants, as well as introduce new ones. As with plants produced by conventional breeding methods, the resulting GM crop plants will be integrated into pest management systems. Integrated Pest Management (IPM) is a broad-based approach that integrates a range of practices to control of pests, including weeds, insects, viruses, fungi, bacteria etc, in a cost effective way. One of the tools IPM uses is pesticides. So, fields with GM plants, as with fields with conventionally bred plants, are generally treated with pesticides."

"Now we have to ask which particular GM traits can be linked with the production of pesticides in the plant, or with the novel use of pesticides during the plants cultivation. These are essentially two traits: insect resistance based on proteins produced by the soil bacterium Bacillus thuringiensis (BT) and herbicide (weed-killer) tolerance against broadband herbicides such as glyphosate (HT)."

"BT crops (e.g. GM corn MON810) produce a protein toxic for specific groups of insects (e.g. the European corn borer) without effecting humans. In addition, there are hundreds of publications summarised by several meta-analyses to show that BT crops do not have negative impacts on insect populations, including bees, under open field conditions."

"HT crops are tolerant against specific broadband herbicides, which fight most weeds but are tolerated by the HT crops when sprayed on them i.e. the HT crop does not die when sprayed with the herbicide. The application of herbicides including the particular broadband herbicides is strongly regulated in Europe. Only herbicides that are proven not to have negative impacts on our health and the environment are registered to be spayed on fields, including fields with GM plants. It is important to stress that herbicides have to be applied by respecting principles of good agricultural practice."

"In short: There is no evidence available that living near GM fields is more or less dangerous than living near fields with conventionally bred crops when principles of good agricultural practice are respected by farmers, which is the case in Europe."

"This report was recently published which goes into GM regulation in Europe in more detail: http://www.easac.eu/home/reports-and-statements/detail-view/article/planting-the.html"
Dr Wendy Harwood
I just read in an article that complete genes can flow into our bloodstream from GM food. True?

View article here
Twitter Talk
Dr Wendy Harwood "A paper was published in PLOS one in July this year with the title ‘Complete genes may pass from food to human blood’. In this study the authors looked for foreign DNA in human blood samples. They concluded that the presence of foreign DNA in human blood plasma was not unusual. The highest levels of plant DNA, from food sources, were found in blood from patients with some form of inflammatory disease. Some of the DNA fragments found were large enough to carry a complete gene."

"This finding applies equally to all DNA found in our food. Our food contains large amounts of DNA and GM plants typically contain one extra gene added to at least 25,000 existing genes. The minute amounts of DNA from our food able to pass into the bloodstream do not cause us any problems. DNA from GM plants would be no different."
Dr Miriam Gifford
When feeding a plant with an ion solution in a pot with a soil medium, what chemically happens to cause the PPM's of the runoff to higher or lower than the solution going into the medium and what does it mean?
Robert Miller
Dr Miriam Gifford "When an ion solution is added to a plant in a pot there are three components that can use or change the ion solution: the plant, the soil, and anything else associated with the soil or plant, typically microbes such as bacteria or fungi. Three typical effects are (1) Some individual ions in the solution will be used up by the plant or microbes, or absorbed in the soil, reducing the ion concentration in the runoff. (2) The water in the ion solution will 'leach' out some ions from the soil, increasing their concentration in the runoff. (3) The plants or microbes will metabolise some of the ions in the solution or in the soil, creating different compounds that might then be present in the runoff, altering the solution composition. Together these effects mean that what goes in, might not come out!"
Dr Theodore Allnutt
Given that big industry makes frequent ballsups and are frequently fined for malpractice, how can we trust GM?
Andrew Martin
Dr Theodore Allnutt "GM is no different from any other new technology. It has risks and benefits. For example, many people are injured by cars every day, but we generally accept that the benefit of having cars outweighs the risks. What's more, we have the choice whether to use a car or not based on our own interpretation of the risk. Similarly, we also have a choice whether to grow or eat GMs, this is upheld by EU labelling and farm 'coexistence' regulations. In addition to this choice, GMOs are tested as far as possible for safety: at every stage of development of a new GMO crop, from the laboratory to glasshouse to field trials to commercial release, it is mandatory for risk assessments to have been completed showing that the GMO will not have unintended effects on people or the environment. Very strict laws are in place in the EU to ensure this."

"To date there have been no known cases of ill effects on people from eating GMOs. This is an impressive statistic since millions of people eat GM foods every day. There are arguments on both sides about the impact on the environment of GM crops and whether they are better or worse than conventional crops. But it can be said for certain that new GM crops will require less land to produce bigger yields and will enable farming in adverse conditions (drought, high salt etc.). It is important to remember that compared to natural environments, all agricultural environments are very, very low in biodiversity and have sustainability problems. Therefore, increased productivity using GM crops will mean that less land is required to grow our food, thereby reducing the pressure on the natural environment compared to conventional and organic farming methods."
Professor Rob Chilcot
Possibly anti-GM friends have been pointing me to a study, entitled Evidence of GMO toxin absorption and toxicity.

The article claims that:

- toxins resident within GM foods can dangerously enter (and are entering) the human organism.

- pregnant women and their fetuses had detectable levels of the toxins in their blood.

- these research findings show that GMO products contain toxins that can be absorbed by humans, and that they may cause serious side effects.

Can you comment on this article/study please, and whether it makes any sense?

see study here
Jon Moynihan
Professor Rob Chilcot "The human body is exposed on a daily basis to millions of chemicals arising from our diet and environment. Modern analytical techniques are very sensitive and can detect vanishingly small quantities of chemicals in samples. The detection of very low concentrations of pesticides in humans is a reflection of the fact that they are used in the production of many foodstuffs."

"The concentrations of pesticides found in the study you mention are thousands of times below the level required to cause any harm. The same study also demonstrates the presence of a toxin in humans which was attributed to the ingestion of GM crops. However, the toxin is also produced by bacteria (Bacillus thuringiensis) that occur naturally in our environment. Thus, it would be strange if this toxin and other chemicals that we use to grow crops were not detected in humans!"
Dr Alan Jones
What actually happens chemically on a molecular level when a plant suffers nutrient burn. Why do the leaf tips turn brown and turn downward?
Robert Miller
Dr Alan Jones "'Nutrient Burn' occurs when plant tissue comes into contact with high concentrations of fertiliser. These are typically ammonium nitrate based. The osmotic effect of these ammonium salts causes plant cells to 'leak' water and lose their turgor. A similar effect to when most common plants are exposed to sea salt. The ammonium ions in solution are acidic, these will strip tissues of hydroxide anions, causing further cell damage. The browning effects you see are caused by oxidation of poly-phenolic compounds within dead plant cells (lignin, flavonoids, anthocyanins). This is similar to when a half-eaten apple browns when exposed to air. The leaf curling is from damaged cells, which collapse and cause leaf tissues to lose their structural support."
Professor Tim Benton, UK Global Food Security Champion
Given that the world is dependant on just six of many thousand potential food plants worldwide and that we need to re-localise our food systems in a Low Carbon Economy; What potential food plants should community supported agricultural projects be trialling and learning to grow, process, store and prepare to make a strategic contribution to food security?
Rick Cross
Professor Tim Benton "I don’t agree with the premises of the question. There are about 24000 plants used for food worldwide (see www.foodplantsinternational.com). Furthermore, decarbonising the food economy is not the same as locally producing food (fruit/veg can be grown in the sun and shipped over with a lower carbon budget than if it were grown in heated greenhouses here in the UK)."

"I’d agree that we need to grow more diverse foodplants in the UK for our own food system resilience, and climate change will allow/force us to move into what may be seen as novel crops. I’d say we need more non-starchy fruit and veg and much can be grown in polytunnels or under glass. In terms of top fruit (and the scope for agro-forestry!) apples, pears, plums etc could make a comeback and even figs and apricots can be grown commercially."
Guy Barter, Chief Horticultural Advisor, RHS
There has been quite a lot off information sent out by my local allotment association, suggesting glyphosphate, particularly roundup, has bad long term affects on soil health and worm population. My understanding was that glyphosphate itself was not harmful though the liquid in which it is "hosted" is, hence warnings not to use near ponds, and suggestion it may harm amphibians. I woud be really appreciative on any comment the panel may make as to its safety.
Verity Newman
Guy Barter, Chief Horticultural Advisor, RHS "Glyphosate is produced and used in extraordinary quantities and has been for decades, apparently without significant ill effects. Many people disagree with the scientific evidence, and glyphosate is seen as very threatening by those who concerned by excessive, or perhaps any, use of pesticides. The RHS accepts the scientific evidence, but we also espouse the use of integrated pest management where cultural controls are used in the first instance to avoid and then control weeds and pesticides only applied as last resort."

"Glyphosate is in fact the only weedkiller actually approved and allowed for use in aquatic situations. However the issue of pesticides in drinking water is extremely important at the moment due to ever increasing water quality regulations. Hence the use of glyphosate in aquatic areas is strictly controlled by the Environment Agency who license properly trained operators. All other users, including amateur gardeners, must ensure that glyphosate and indeed all and any pesticides never enter surface or ground water. Where this proves impossible the pesticide concerned may lose its approval and be withdrawn."

"The proper use of glyphosate involves applying as directed spray to foliage to point of run-off and to avoid treating soil. Naturally some glyphosate reaches the soil, but it is rendered inert in the soil, and is unlikely to leach into waters. Water supplies have been identified to be at special risk from treatment of streets, car parks and other hard surfaces as glyphosate (the only approved weedkiller for these situations) is not absorbed onto soil, and can be washed into brooks, drains and so on. Gardeners should heed this and be very wary about applying glyphosate to drives, patio and paths. We suggest that on a small scale hot water is a potential alternative."

"On the matter of worms and soil organisms it is notable that farming methods of no-till or minimum till are replacing ploughing to save fuel and time, and also to enhance soil health and structure. Without ploughing to reduce weeds, extensive use of glyphosate and other herbicides is involved, and apparently soil health is enhanced by lack of ploughing, and not adversely affected by herbicide use."

"In allotment gardening glyphosate has very limited use as being non-selective it is hard to apply without damaging crops. However, it is very valuable in clearing overgrown plots as it is extremely effective against bindweed and other perennial weeds that relish arable soils and resist digging. Clearing overgrown plots is laborious and slow without the help of glyphosate. We suggest that even those who do not wish to use pesticides in their gardening consider glyphosate in such extreme circumstances."
Professor Rob Chilcott
The next generation of insecticides will be RNAi based, any worries about our genes?

See article on RNAi insecticides here
Wouter Havinga @wouterhavinga
Professor Rob Chilcott "This question is concerned with the safety of food that may contain molecules that have been designed to turn off (or “silence”) genes in pests such as insects or fungi. Gene silencing uses RNA, molecules that are similar in structure to DNA and are required for manufacturing proteins within a cell. For many years it was thought that involvement in protein synthesis was the only function of RNA. However, it was recently discovered that certain types of RNA are used by cells to control which genes (sections of DNA) get made into proteins (a process called “gene expression”)."

"The potential advantage of RNA gene silencing is that it is very specific and so can be used to turn off a single gene which may only occur in one organism. By targeting essential genes, it is theoretically possible to control the population of a single type of pest. However, it is difficult to get RNA into cells (where it can have an effect) because all organisms produce a form of RNAse; an enzyme which rapidly digests and neutralises the biological effects of RNA. This is one of many reasons why RNA gene silencing has yet to be established as a pesticide. The presence of RNAse in humans is also why it is highly unlikely that food containing modified RNA will cause any health effects in consumers."

"It is worth considering that we eat plant and animal RNA on a daily basis without any associated adverse effect simply because we digest RNA very effectively. Moreover, the introduction of RNA-based pesticides will be subject to national and international controls which include a requirement for companies to demonstrate the environmental and consumer safety of their products."
Dr Theresa Huxley, Fellow of the Institute of Food Science & Technology
A columnist writing in the Guardian has claimed that:'Over centuries, modern agriculture has bred the nutrients out of our food.'

Link to article

So the question is: is it true that the nutritional content of food produced by modern agricultural methods has declined?
Franco Henwood
Dr Theresa Huxley "I believe the absolute facts about whether the nutritional content of food produced by modern agricultural methods has declined don't currently exist."

"As far as I know there is little or no concrete evidence since in my experience the fresh produce industry has historically relied upon authorative texts such as Mc Cance and Widdowson's the composition of foods and has not routinely tested varieties."

"Likewise we don't know how micro climate and longevity of storage impacts on nutrient content, nor how husbandry or varietal clones impact on nutrient composition ....."

"There is of course the added complexity of the fact that the science behind testing has evolved over the centuries so accuracy of test results has increased."
Dr Huw Jones
I would like your comment on the following extract from

this article

"Genetic engineering is 40 years old. It is based on the naive understanding of the genome based on the One Gene - one protein hypothesis of 70 years ago, that each gene codes for a single protein. The Human Genome project completed in 2002 showed that this hypothesis is wrong."

"The whole paradigm of the genetic engineering technology is based on a misunderstanding. Every scientist now learns that any gene can give more than one protein and that inserting a gene anywhere in a plant eventually creates rogue proteins. Some of these proteins are obviously allergenic or toxic."

This is in light of your comment in answer to another question in which Dr Gia Aradottir said '..the important outcome is what proteins the genes code for.'

See Gia's original answer in Q1 here
Lucy Flint
Dr Huw Jones "Mankind has been engineering plant genomes since the move from hunter-gather lifestyles to farming-based communities. It is true that the one gene-one protein model is overly simple and that in specific cases, the situation is more complicated. For example, alternative splicing of exons from the same gene can generate different protein versions. Or different proteins can be generated from the same gene from RNA transcripts that overlap, or that originate from different reading frames or even in opposite orientations. However, these examples are understood and do not undermine the ability to reproducibly up- or down-regulate single genes to produce single proteins. This is the fundamental basis of the many biological research experiments in hundreds of Universities around the world to investigate exactly the point in your statement; gene function. I have absolutely no doubt that the constructions we inserted into our plants do not encode any other protein other that the ones intended."
Professor Julian Ma
I am an advocate of technology and have no concern about GM food and food crops, provided they are properly tested and regulated. By contrast, I am uneasy about the prospect of using GM for pharmaceutical production. My reason is that pharmaceuticals are biologically active compounds and the inadvertent consumption of these plants or plant parts by humans could easily be harmful. For this reason I suspect that accidental release of the gm pharmaceutical plant, or its pollen, or seed, etc could have very serious consequences far beyond that imagined for release of GM food crops, because this would contaminate an environment with a potentially dangerous organism. A single case of unknowing consumption of for example a plant producing a vasoactive peptide drug could cause serious harm. Given that risk, I cannot see any case for starting this programme in the first instance. Best not to make plants that are apparently benign, but in fact produce potentially dangerous pharmaceuticals?
John Turner
Professor Julian Ma "I think it is fair to say that all molecules that are "foreign" to us are potentially biologically active compounds. And that we encounter many of these kinds of molecules everyday, in our food, the environment and from animals and other people. But you are right, some pharmaceuticals might be harmful if encountered inadvertently, we know that from the many toxic plants and micro-organisms in our environment."

"The use of GM plant biotechnology is not really different to other kinds of GM (in bacteria, yeast, mammalian cells, animals) that we currently use to make biotech medicines. But that is not to say that the risk management of these technologies does not have to be considered very carefully. Risk management is carried out on a product-to-product basis, the more highly you assess the risk of your target molecule, the more carefully you have to manage that risk. Many pharmaceuticals carry little risk, whilst others (as you point out) carry more. For the latter, the risk management strategy might be to increase the containment and isolation of your manufacturing. It would be possible to use plants that do not produce pollen or seed, or use plants (like moss or algae) that are grown entirely in containment."

"It's important to realise that GM plants for pharmceutical production does not refer to just one manufacturing platform. There are many options - different plant species, different levels of containment, production in different parts of a plant etc."
Live online Q&A: What would your ideal ‘super wheat’ be?
What would your ideal ‘super wheat’ be?
Dr Phil Howell, Dr Robert Koebner and Professor Mike Bevan
UK scientists have developed a new ‘super wheat’ variety and the early trials suggest that the new wheat is bigger and stronger than modern wheat varieties. If you could create a ‘super wheat’ what characteristics would it have?

We ran a live #plantsci Q&A with scientists working in this field, full text here.
Dr Joan Webber, The Forestry Commission
I saw an article in the Daily Mail suggesting that in 10 years all of Britain's ash trees will be gone. I also have heard it said numerous times that 90 per cent of Denmark's ash trees have died as a result of the disease. The figure of 90 per cent fatality rate seems to be widely cited as the average fatality rate for this disease. Yet this figure applies to one country, Denmark, and not, as far as I can tell, to Europe as a whole. Do we know what the average death rate is for ash trees infected with this disease - i.e. the rate for Europe as a whole, not just one country.
Franco Henwood
Dr Joan Webber "Firstly, this figure of 90% of ash trees in Denmark have died from Chalara ash dieback is a mistake that has been promulgated widely in the press/media. Danish colleagues working in Chalara have made it clear that the correct version should be that 90% of ash in Denmark are affected, and not 90% dead. Affected doesn't mean that all trees will die and, in any event, the disease progress can be very slow in some trees and there are varying reports saying trees may take, 5, 8 or even 10 years before they succumb."

"It's much more difficult to answer the second part of the question - does this apply across Europe? All we can say is that many trees are affected across Europe, and the disease is now throughout most of the ash range in countries that have been affected for some years by the disease (eg Poland, Lithuania, Sweden, Norway and Denmark). So in those countries probably the majority of ash trees are affected by the disease and a high proportion, but not all, will have died as result of the disease either directly or indirectly. In the case of the latter, trees can be so weakened by the year on year effect of Chalara that they can succumb to other tree pathogens such as honey fungus (Armillaria) and these may be the final 'killing agents'."

"It's difficult to give exact figures because it would mean a huge survey effort to define the numbers of trees and then those affected/dead in all the various countries where ash is now affected by Chalara, so that's probably why there are no clear unambiguous figures for every country affected by Chalara."
Can the herbicide glyphosate be linked to to neurological disorders (learning disabilities (LD), attention deficit hyperactive disorder (ADHD), autism, dementia, Alzheimer's, schizophrenia and bipolar disorder) as described in this article?

Twitter Talk
Dr Timothy Marrs "Glyphosate cannot be linked to the neurological disorders listed. The toxicity of glyphosate has been extensively reviewed and is deemed safe to use by different organisations including the WHO (FAO/WHO, 1987; 2006). This herbicide has low or non-existent effects on how signals are transmitted in the brain. In addition to this glyphosate is poorly absorbed within our intestine, instead it is excreted unchanged in the urine. So not only does not affect how our brains work, there is also little chance of it entering our system if consumed, except in grose overdose."

"In addition to this there is no evidence of carcinogenic potential in longterm studies. There is little evidence to show that it damages the cell in a variety of in vitro and in vivo tests (FAO/WHO, 1987; Williams et al 2000; FAO/WHO (2006). Effects on fertility were not seen in multigeneration studies in the rat nor does it affect foetuses in utero."

"It is worth noting that the biochemical synthetic pathway that Roundup attacke in plants does not exist in humans."


Atkinson D. 1985. Toxicological properties of glyphosate, a summary. In: Grossbard E, Atkinson D, editors. The Herbicide Glyphosate. London: Butterworths 127-133.

FAO/WHO (1987). Pesticide residues in food - 1986. Evaluations 1986 Part II toxicology. FAO Plant production and protection paper 78/2. Rome. Food and Agriculture Organization of the United Nations. http://www.fao.org/docrep/W8141E/W8141E00.htm

FAO/WHO (1998). Pesticide residues in food - 1997. Report. FAO Plant Production and Protection Paper 145 . Rome. Food and Agriculture Organization of the United Nations. http://www.fao.org/docrep/W8141E/W8141E00.htm

FAO/WHO (2006). Pesticide residues in food - 1986. Evaluations 2004 Part II toxicology. Geneva. World Health Organization. http://whqlibdoc.who.int/publications/2006/9241665203_eng.pdf

Williams GM, Kroes R, Munro IC (2000). Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, glyphosate, for humans. Regul Toxicol Pharmacol;31:117-165.
Dr Astrid Wingler
Do non-green leaves (eg copper on a copper beech, yellow on some leylandii) offer an advantage or disadvantage in energy absorption compared with green leaves?
Guru mag
Dr Astrid Wingler "Leaves normally contain green pigments (chlorophylls) and yellow pigments (carotenoids). In addition, red/purple pigments (anthocyanins) can contribute to leaf colour. Anthocyanins often accumulate during stress, especially in cold and sunny conditions, but also during the development of young leaves or during leaf senescence, e.g. in autumn. Some plants do, however, generally have high contents of anthocyanins, giving them a purple appearance, despite the presence of carotenoids and chlorophylls. By absorbing some of the light driving photosynthesis, anthocyanins can act as sunscreen, and it has been reported that leaves with high anthocyanin content therefore have lower rates of photosynthesis. On the other hand, anthocyanins can protect leaves, especially young and senescing leaves and evergreen species during winter. This protection may be due to the anti-oxidant activity of anthocyanins, but their exact function is controversial."

"Some ornamental shrubs appear “golden” because of a reduced content of chlorophyll and the presence of carotenoids. Photosynthesis could not occur without any chlorophyll, but to what extent photosynthesis is affected in “golden” leaves depends on the light conditions. Often, only leaves of the upper branches appear yellow, and more chlorophyll is synthesised in the shaded lower leaves, thus allowing sufficient absorption of light energy."
Dr Andrew Kiggundu, Head of the National Agricultural Biotechnology Centre at NARO, Uganda
#Uganda is investing in #GMO golden bananas with added vitamin A. Pros and cons??
Joanne Pennock
Dr Andrew Kiggundu: "Are there any pros for Uganda investing in GMO golden banana? Yes, about 35% of Ugandan children are stunted, meaning that they will never archive their potential in life. Also 28% of Ugandan children and 52% women are vitamin A and zinc deficient. These deficiencies exist because most communities depend on staple starchy crops such as banana, cassava etc. In some western districts of Uganda even protein is hard to come by. Although there are fruits which grow abundantly in some places, they are only available seasonally twice a year."

"In order to prevent these deficiency problems crops are being developed with increased vitamin levels, also known as bio-fortification. The community will have the plantain materials free and can freely replant bananas as well as share them with their relatives and friends. With bio-fortified crops the government program to improve public health in rural communities can be easily realised."

"Cons… There are really no cons here except for the delays associated with regulation. We hope that the laws ensuring the biosafety of these crops will be in place soon."
Dr Jeremy Sweet
Is Pioneer Xianyu XY335 hybrid corn (maize) derived from a parental strain including genetic modification techniques and what do you think of reported reproductive and other problems as discussed in the Asia Times article of 8th October 2011? http://www.atimes.com/atimes/China/MJ08Ad04.html
Robert Saunders
Dr Jeremy Sweet "Pioneer Xianyu XY335 hybrid corn (maize) is not a GM maize, I have confirmed this with Pioneer. Where there appears to be confusion is that in China it is being used in the breeding of GM varieties because of its high yield potential. Similarly one of its parent lines PH4CV is also being used in the breeding of GM varieties as is shown in the patent reference in the Asia Times article. I am not aware whether these new GM varieties have entered the market in China and also how they are or will be marketed. Officially no GM maize is approved for marketing in China, but GM maize is being imported and controls are not very tight in some regions. Because of the high reputation of XY335 it is likely that similar/same names are being or will be used to market the new GM varieties. It is also note worthy that there is some duplication of "varieties" in China by some unscrupulous seed producers who are also selling material labelled as XY335 but of variable genetic origin."

*Further clarification

"Maize breeding is generally done by outcrossing to produce new lines, developing inbred lines of the best types with particular traits and then hybridising them to produce new hybrid commercial varieties with the required combinations of traits. This means that breeders maintain separate "pure" inbred lines which can be selected and used in breeding programmes. GM types are maintained as separate lines and are only introduced into hybrid varieties in the generation that produces the commercial hybrid seed. Thus the GM line is one parent of the commercial hybrid, the other parent being another non GM line with desirable traits. If combinations of GM events are required in a hybrid then a line is produced containing the combination of events which forms one parent of the hybrid. Alternatively two different GM lines may be used as parent lines to produce the commercial hybrid seed containing two (or more) GM events."

"In the case of Pioneer XY335 no GM line would have been used in the development of its parental lines as this would or could introduce GM into the hybrid."

"If GM is used in the breeding of any parental lines of varieties, including hybrids, then the resulting plants are classed as GM, even if the transgene is "absent" from the plant. This is because the transformation process may leave residual amounts of trangenic DNA in the plant or may induce unintended changes to the plant and these would have to be examined for biosafety."
Dr Sarah Al-Beidh
I am doing some Research into how do herbs get their different flavours e.g Lemon thyme orange thyme and I am finding it difficult to find the clear answer. I know a little bit about it that is to do with compound's (terpenoids) and volatile oils, but how did Lemon thyme become Lemon and orange thyme. Does this chemical process take place in other herbs e.g Blackcurrant, mint and many more?
Claire Forster
Dr Sarah Al-Beidh "As you rightly mentioned, terpenes are key constituents of essential oils, responsible for much of the aroma/ flavour associated with a particular plant. Plants often produce these essential oils to confer antibacterial, antifungal, and/or insecticidal benefits."

"To develop different flavours, plant breeders utilise the natural variation that exists in populations. To do this, they cross seedlings, selecting individuals that display the most desirable traits. If this selective breeding focusses on flavour or aroma, the process is likely to influence the terpene profile of the resulting generations. The process is repeated over several generations, consistently selecting the ‘best’ individuals in the population (i.e. those exhibiting the most desirable traits). For reliability and consistency, it is important that these 'new' characteristics are shown to be genetically robust/ stable."

"As terpenes are temperatures sensitive, methodologies such as High Performance Liquid Chromatography (HPLC) and gas chromatography (GC) will be used to identify, separate and quantify terpenes in plants. The terpene profile of a sample plant will be compared against those of pure terpene standards. In your example of blackcurrant mint for example, a sample of this plant would have a terpene profile similar to that produced by blackcurrants (and of course, mint)."
Dr Ellen Colebrook
How do you define or what ways can you measure plant stress in a mixed landscape or mixed cropping system?
Dr Ellen Colebrook "A plant is generally considered to be stressed if its growth, health or yield is compromised by factors such as disease or environmental conditions. To determine the level of stress a plant is experiencing, we usually measure some aspect of the plant’s physiology which changes in response to stress. One approach to monitoring plant stress in the field is by remote sensing. This involves using data collected from large areas by satellite or aircraft to analyse the light reflected from plant foliage. For example, thermal cameras (which detect infrared light) can be used to measure canopy temperature, which can be affected by stress. Another common way of measuring plant stress under field conditions is by testing the way in which light interacts with the green pigment chlorophyll in the leaf (chlorophyll fluorescence). This gives an indication of the efficiency of photosynthesis, which can be compromised by stress. A number of portable tools suitable for high-throughput use in field settings are available for this."
Dr Wendy Harwood
Curious. A video report on GM. I know 1st half is cobblers - does 2nd half have any basis?
Michael Barnes
Dr Wendy Harwood "It is important to remember that herbicide tolerant crops can be bred by conventional means as well as using GM techniques. The development of herbicide tolerant weeds is an issue for all such crops. Good agricultural management can limit the development of resistant weeds. Where there has been extensive use of any single herbicide, including Roundup, and where agricultural practices to limit the development of resistant weeds have not been effectively employed, it is not surprising to see some herbicide tolerant weeds. This would be one possible risk considered in a full risk / benefit assessment that would be carried out before growing herbicide tolerant crops in new areas."


Live online Q&A: Using GM plants to ‘grow’ medicine
Insecticides and bees
Dr Ian Bedford, Dr James Cresswell, Professor Lin Field and Professor Dave Goulson
Insecticides, in particular neonicotinoids, and bees are being widely discussed. Articles appear regularly in the media, campaign groups ask people to sign petitions to protect bees, in parliament MPs are investigating insecticides and insects, in the EU they are considering a partial ban of neonicotinoids and some UK garden centres have already stopped their sale. But what are your questions? Some that we have already received include: What is causing the decline in bee health? Is bee colony collapse disorder linked to the presence of neonicitinoid pesticides? What safeguards are there that any alternatives to neonicotinoids that farmers may use will not have unforseen consequences?

We ran a live #plantsci Q&A with scientists working in this field, full text here.
Dr Eleanor Gilroy
I'd like to know how long it takes to develop a GM crop?
Lily Geek
Dr Eleanor Gilroy "The most time consuming stage of generating a GM crop is the years of fundamental plant science research that is required to gain the desired level of understanding of the plant characteristic to be modified."

"The transformation process itself, the means by which new DNA enters the plant cell nuclei, is relatively straightforward and takes a matter of days in the lab. The length of time it takes to physically make a transgenic plant from those transformed cells is roughly correlated with the length of the life cycle of any particular crop plant species. For example, the model plant Thale Cress (Arabidopsis thaliana) has a life cycle (seed to seed) of around 6 weeks which is why it is popular for scientists to use in the lab to study plant genetics. UK crops such as Barley and Potato would take 2-4 months to transform and generate seed. Tree-like crops such as apple or plum would take several years to reach a stage where they produce seeds."

"Developing an entire crop from a single transgenic plant however would take many generations to build up enough seed to plant a whole field or many fields, not to mention all the years of testing and legislation by food standards agencies before it could be considered a GM crop."
Dr Wendy Harwood
Why are people so resistant to feed testing GM crops for longer than 90 days? Surely its commonsense that some important effects take longer than three months to show up or is it because the shorter tests make such effects less likely to show up and some people don’t want us to see them? Why was that French researcher criticised by PR operations for using the same strain of rats that Monsanto used- isn’t it double standards?
Paul Cawthorne
Dr Wendy Harwood "The key question is what testing is necessary to ensure that we can be confident of the safety of GM crops. Many scientists feel that GM crops have been subject to such extensive testing over the last 20 years that further animal testing is not scientifically justified. GM crops are currently assessed based on a comparative approach, looking to see if they are substantially the same as the equivalent non-GM crop. There has been 20 years of research using a range of techniques to compare GM crops to conventionally bred crops, looking for unintended changes in the GM crops. Such unintended changes have not been found (Herman & Price, 2012)."

"GM crops have been examined in feeding studies longer than 90 days. A review of 17 such studies is provided by Ricroch (2012). None of these studies found any new safety concerns and so did not add additional information to that obtained from 90-day feeding studies. 90-day feeding studies are the industry standard, it is important to remember that the life cycle of a mouse or rat is far shorter than that of humans. If extensive analysis of the composition of GM crops and 90-day feeding studies show no cause for concern, then longer feeding studies, with the associated delay to the approval process and extra costs, are not justified."

"Regarding the strain of rats used in the study by Séralini et al. and also for 90 day feeding studies, these were Sprague-Dawley rats. Sprague-Dawley rats are the standard lab rat for 90 day studies. They are not suitable for 2 year studies, because these rats only live an average of 2 years and are prone to spontaneous cancers. If these rats are fed a healthy balanced diet and kept for 2 years one might expect 40 to 75% to develop tumors making them unsuitable for long-term studies."

- Ricroch (2012), Assessment of GE food safety using ‘omics’ techniques and long-term animal feeding studies. New Biotechnology, dx.doi.org/10.1016/j.nbt.2012.12.001

- Herman & Price (2013) Unintended compositional changes in genetically modified (GM) crops: 20 years of research. J. Agric. Food Chem. dx.doi.org/10.1021/jf400135r
Live online John Innes Centre Q&A: Cash for ash - Will it help?
Cash for ash - Will it help? John Innes Centre live online Q&A
Professor Allan Downie, Dr Dan Maclean, Dr Joan Webber and Dr Erik Kjaer
Sequencing and analysing the genomes of the ash dieback fungus and of ash will provide the information needed to help nature recover from the current epidemic. Scientists are pooling their expertise in collaborative research funded by BBSRC, announced on Friday 8th March.

The John Innes Centre ran a live Q&A about the research effort on Monday 11th March 12-1pm: http://oadb.tsl.ac.uk/?p=371
Professor Keith Lindsey
Is there GM pollen hidden in my honey? Should I be worried?
Twitter Talk
Professor Keith Lindsey "If you live in the UK, there is virtually no likelihood of GM pollen being present in your UK-produced honey, as there are no commercially grown GM crops planted out in this country. The small-scale research trials of potato and wheat do not produce significant amounts of pollen, and any pollen produced by such plants won't travel far because it is heavy, and the plants aren't bee-pollinated. Even if GM pollen did get into the food chain via honey, the genes present in commercially produced crops (outside the UK) are typically not expressed at high levels in pollen, and do not code for toxic or allergenic proteins - toxicity tests are carried out long before crop cultivation, as part of the very strict regulatory process. Remember that the genes present in GM crops are found in nature anyway, and you eat many of them all the time, with no deleterious consequences to your health."
Dr Sarah O’Connor
Are there any plans to search for new plants hunting for new charecteristics/genes?
Suraj Rai
Professor Martin Warren & Dr Sarah O’Connor "We are continually on the lookout for new plants. In addition to the secondary metabolites that plants make, we are also on the lookout for new crop plants with desirable traits. If we find a wheat plant that, for example, grows faster, is more disease resistant or is more drought tolerant, we can breed or "cross" that plant with the standard wheat plants used to generate a better crop. In fact, the wheat that we eat today looks very different from the wheat that we used hundreds of years ago! Scientists are also looking for the genes that control these desirable properties- if we know what the genes are, and where they are located on the plant genome, we will be able to do this selective breeding more quickly and effectively."
Professor Martin Warren
Can genomics leapfrog GM in terms of usefulness to agriculture and can it be sold to the consumer as different?
Andy Barr
Professor Martin Warren "Genomics is discipline that analyses the structure and function of the genome and it is currently being used to gain a lot of knowledge through the comparison of genomes - which allows us to understand some of the larger scale phenotypic differences between plants. Through such comparisons we can learn how best to breed and/or engineer plants for useful traits and properties. Genetic modification (GM) is a technique rather than a discipline. The initial genetically modified plants and crops were contentious because the public was not fully engaged in the debate as to the usefulness of the approach. GM is being superseded by synthetic biology - but here there is full inclusion of social scientists to ensure that the subject is discussed in an open arena. The public perception is that genetic modification is not natural - but genomics tells us that nature has been shuffling large segments of DNA around for billions of years. So, getting back to the question, genomics tells us how and why plants are different and we can apply that information in a very targeted way to benefit agriculture - but this is likely to involve engineering of the genome. To try and disguise genetic engineering as genomics would likely cause more distrust. I would prefer to argue that genetic engineering is a natural process that can be harnessed for major agricultural and economic benefit."
Professor Alison Smith
Agroecological methods vs GM as a strategy for CC adaptation, CO2 sequestration, biodiversity & food sovereignty?
Joe Atkinson
Professor Alison Smith "Agricultural food production is facing an increasing number of challenges today in the face of increasing populations, climate changes, and reduction in fertile land. Ensuring security of food supply in the future - while at the same time avoiding further environmental problems and loss of natural habitats and species extinction - is going to be extremely difficult. We therefore need to use all the means we have to tackle the issues - not least because the problems differ around the world and for different agricultural products. In some cases it might be appropriate to modify agronomic practices to include havens for wildlife around field boundaries - as is encouraged for arable farmers in the UK today. In others, there may need to be more technological approaches such as modification of crop plants to withstand highly saline soils and/or particular pests and diseases. This latter approach may be conventional plant breeding - assuming that the desired trait is present in the gene pool for the plant - as well as GM to introduce novel traits."
Dr David Cooke
There seems to me to be some misinformation out there about the fungus supposedly responsible for ash die-back, chalara fraxinea. I believe the fungus is actually a sub-set of Hymenoscyphus pseudoalbidus. What puzzles me is how this actually infects the tree. Does it enter via the root system or by absorption on the leaves and shoots? Then, what actually happens next? How does it actually kill the tree?
Peter Dobson
Dr David Cooke "At the Ash Dieback workshop in London on 13th Dec two researchers from Denmark were present to share their experiences. During the coffee break I asked Lea Vig McKinney exactly this question. It is clear that the infection is airborne and there is no evidence for infection via the roots. The infection court is thought to be the leaves, leaf petioles or axils with the pathogen moving down the petiole into the twig and further into the stem from there. Girdling of shoots causes wilting symptoms. There are also some reports of infection at the base of the stem under high disease pressure. Surprisingly the infection phase of the life cycle has not been well studied. Much of the experimental work is based on wounding shoots and introducing the pathogen via these wounds."

Further information available at:


Live online Q&A: Using GM plants to ‘grow’ medicine
Using GM plants to ‘grow’ medicine
Dr Penny Sparrow, Professor Joachim Schiemann, Professor Julian Ma and Professor Maurice Moloney
Plants can be modified to ‘grow’ medicines. For example, insulin can be ‘grown’ in a GM safflower plant, which would be cheaper and more efficient than current methods. These plant-made pharmaceuticals are never likely to enter the food-chain but they fall under the same EU regulations as GM crops that are grown as food. The EU GM regulatory system is lengthy and costly, making the cheaper plant-made alternative production method prohibitively expensive.

We ran a live #plantsci Q&A with scientists working in this field, full text here.
Dr Eleanor Gilroy
I think I know what genes are, and that any protein they code for can be tested to see if it is dangerous or not. My question is, am I right about this, if not what precautions have been taken when doing GM research.
John & Shirley Homan
Dr Eleanor Gilroy "Yes you are right, genes are defined units of DNA and produce strings of RNA which are then translated into protein."

"So far no genes used in GM plants are predicted to make a protein that is dangerous to humans. Some GM crops have been developed to be dangerous to insects that eat them. Traditionally these plants would have been sprayed with a pesticide that would have killed a large number of non-target species along with the insects damaging the crops. Utilising GM means many more insects survive in the surrounding area allowing birds and other organisms to thrive better."

"GM crops and sprays are tested as vigorously as new drugs for their effect on us. After tests on their safety for human consumption more tests are performed on their impact on the environment by doing field trials. This is why it is so important that field trials are not destroyed. If they are, scientists have no way of measuring what the effect of growing GMs on the environment."
Dr Peter Eastmond
Is Arabidopsis (a small flowering plant related to cabbage and mustard that is widely used as a model organism in plant biology) the best experimental organism?
Suraj Rai
Dr Peter Eastmond "The answer to this question really depends on what biological process you want to study. Arabidopsis does most things your average plant does, and so for many biological questions it’s arguably the best experimental organism. However, it’s important to consider that there are also many things that Arabidopsis just doesn't do. For example its roots don't form symbiotic associations with mycorrhizal fungi or nitrogen-fixing bacteria like soybean for instance. Its leaves don’t employ C4-type photosynthesis like maize. Its seeds don’t contain a starchy endosperm like wheat or rice. And so on. To understand why Arabidopsis was adopted as a model organism and what advantages it holds over other plants, when it’s the appropriate tool for your question, then I recommend visiting the TAIR web site (http://www.arabidopsis.org/) and clicking on Arabidopsis thaliana. This is a route to a more comprehensive answer than I could hope to include here."
Professor Tim Benton
my Q. on GMO is whether 'new' varieties are necessary: there is a lot of CWR diversity that we are losing. Diversity, landraces + practice are vital to local food security - Does the way GM crops are produced reflect this?
Kay Evelina
Professor Tim Benton "Yes, there is huge untapped variation in natural variation in crop species and this is important to local food security. However, the environment is also changing fast and GM is, at least in theory, a faster way of providing genetic variation than waiting for natural mutation and natural selection to maintain local productivity. Theoretically, there is nothing stopping drought resistant genes (for example) being designed in to a species and then it being bred into local varieties where they are particularly well locally adapted."
Professor Dave Goulson
Please could you address the issue of bee toxicity to the neonicotinoids. What is the latest scientific opinion?
David Bracey
Professor Dave Goulson "The European Food Standards Agency recently reviewed the safety of neonicotinoid insecticides, and concluded that the three most widely used compounds, imidacloprid, clothianidin and thiamethoxam, pose an unacceptable risk when used on any crop visited by bees (e.g. oilseed rape, sunflower, maize). This decision is based on a number of recent scientific studies which demonstrate that the concentrations of neonicotinoids found in the pollen and nectar of treated crops are sufficient to have a range of impacts upon bees, including impaired ability to navigate and collect food, and reduced colony growth and reproduction in bumblebees. Concern has been heightened by recent evidence which suggests that neonicotinoids accumulate in soils and so are found in untreated follow-on crops, and that clouds of neonicotinoid dust are created during sowing of treated seeds which can kill bees and contaminate hedgerows. My personal opinion is that the EFSA stance is justified and sensible."

"However, it is important to realize that bees do also face many other threats, including a shortage of flowers in modern intensively farmed landscapes, and various parasites and diseases. Placing a moratorium on neonicotinoid use will not at one stroke solve all our bees’ problems."
Professor Huw Jones
There's food and there's genetically modified food. What's the difference?
Twitter Talk
Professor Huw Jones "The consumer can tell no difference but EU law requires food from GM crops to undergo a rigorous risk assessment before it can be imported or cultivated."

"Plants are the main source of food for Man and animals. Crop plants have been slowly improved, in one sense genetically modified, by farmers and plant breeders to give the highly efficient varieties we farm today. The early methods to develop new varieties were relatively passive, making simple crosses in the field. However, over the last century, plant breeding techniques have required more human intervention to provide useful genetic variation. Methods such as wide-crossing between species that would not hybridise in the wild, artificial mutagenesis to generate random changes in genes or marker assisted selection became increasingly used. Over the last thirty years, plant breeders have learned how to move single, specific genes form one organism to another by a method called ‘recombinant DNA technology’. Crops made by this method are what we know as GMOs and fall into EU legislation for testing and labelling. Many scientists see recombinant DNA technology as one more step (albeit an important one) in the continual development of ever better and predictable plant breeding methods."
Dr Alan Jones
Modifying croplands to increase plant reflectivity has been proposed as a way of curbing climatic warming on a regional scale. The idea is to use 'optimal breeding' or GM to 'design' varieties of a crop with more reflective properties (higher albedo). For instance where wheat is grown now, a brighter variety of wheat would be planted next season. One approach could be to make a plant grow trichomes on the leaves. Is it possible to make e.g. wheat grow trichomes?
Helene Østlie Muri
Dr Alan Jones "Small trichromes (leaf hairs) exist in wheat and conventional plant breeders are working to enhance this. These hairs are advantageous for the wheat crop, as they reduce water consumption and increase resistance to pests. Special cultivars of wheat and other crops also have waxed (glaucous) leaves, which enhance drought resilience and reflect light. By implementing crops with features such as these globally, modelling analyses suggest a Global Warming reduction of -0.2˚C over 150 years. The only disadvantage might be that widespread changes to cropland reflectivity (and transpiration rates from changes to leaf morphology) would affect rainfall patterns in these agricultural regions."
Dr Jeremy Sweet
If European publics hamper developments in research in GM, is the technology available and feasible to be developed in the parts of the world where issues of food supply already cause serious problems?
Anne Jackson
Dr Jeremy Sweet "GM technologies being researched in developed countries can have useful applications in developing/poor countries. Examples are Bt maize, to control lepidopteran pests in Southern Africa, Vitamin A enriched rice and virus resistant GM papaya in SE Asia. Future examples are drought tolerance in maize and wheat which could have applications in many arid regions, and maize with herbicide tolerance for Stryga control in sub-Saharan Africa."

"Research being conducted in developed countries into plant genetics, molecular breeding and genetic modification techniques can be used to identify and transfer useful genes ( eg pest and disease resistance) to a range crop species of value in developing countries in order to improve the performance and stress tolerance of these crops. Thus for example, the gene mapping of rice, banana and sorghum can have worldwide implications for the breeding of these crops (see http://www.nuffieldbioethics.org/sites/default/files/GM%20Crops%20summary.pdf). Several UK (eg NIAB, JIC, Rothamsted) and other EU research organisations are studying GM crops for developing countries to address production and supply problems."
Professor Ottoline Leyser
Evolution has made some pretty creatures, but I think we could do better. Do you think that creating new species ex nihilo for aesthetic or artistic reasons will be possible? Ethical?
Lee Fedorchuk
Professor Ottoline Leyser "We are some way from creating new species truly ex nihilo, but I think in the long term it will be possible. Perhaps more importantly, the ethical question you raise has been of relevance already for 100s of years. Through classical selective breeding we have created many organisms so different from those produced by natural selection that they can reasonably be classified as new species. Some of these were produced primarily for utilitarian reasons, but even for these, aesthetics has played an important part. For example maize is very different from its closest wild relative, and maize breeders over 1000s of years have selected aesthetic characteristics such as kernel colour, as well as more utilitarian ones, such as kernel size. For plants, most people are comfortable with the extremely unnatural forms we have created for our gardens. There is more controversy over similar extremes in animal breeding, where animal health is affected because, for example, we like our dachshunds long."
Professor Lars Ostergaard
My question is whether the Ampicillin [an antibiotic] resistance gene is present in GM maize and, if so, whether any consequential ill-effects have ever been looked for/identified in consumers. Finally, has the fate of that gene in the human gut ever determined/confirmed experimentally.
David Pugh
Professor Lars Ostergaard "During the transformation procedure to produce a GM plant, it is still necessary to include an antibiotic resistance marker gene, such as the gene that makes the cells resistant to Ampicillin. Although I can't comment on whether companies specifically use the Ampicillin-resistance gene in maize, I am certainly not aware of any studies that would show, that GM maize or any other GM plant product has had any ill-effects in costumers."

"What I can say is that the studies that have been done into gene transfer from the eaten plant material to bacteria in the gut have revealed that the risk of gene transfer is extremely small. Although, one can never exclude such possibilities in biology, it is less likely that pathogenic bacteria will acquire antibiotic resistance in this way compared to other ways."

"If you want to learn more, please see the following links and the references included. http://www.jic.ac.uk/corporate/about/publications/gm-debate/armg.htm"
Professor Rob Chilcott
Will pesticide residue on food reduce my sperm count? Should I go organic?
Twitter Talk
Professor Rob Chilcott Based upon current evidence, the simple answer is probably no: a diet based entirely on organically-grown produce would be unlikely to affect sperm levels.

There are a number of scientific studies which indicate that some pesticides may have “anti-androgenic” activity: an effect which interferes with the normal response of the body to male hormones. The actual quantity of such pesticides in the food we eat is subject to very strict controls and so it is unlikely that the concentration of any one pesticide would be sufficient to cause a measureable effect. In saying that, the effects of some pesticides may be additive. That is, exposure to a number of substances (at a low dose) may result in an overall dose which may be sufficient to cause an effect. However, no studies in humans have established a link between pesticide residues and male infertility.

It is worth considering that we are exposed on a daily basis to a wide variety of chemicals present in our diet and environment which may potentially affect fertility. So, sticking to organic food would probably not make much difference to our total daily intake. It is also worth pointing out that whilst organic foods may generally contain less pesticide residues, it doesn’t necessarily eliminate exposure. The type and amounts of pesticides used on all crops are subject to strict controls which are monitored and enforced by the UK’s Food Standards Agency (FSA).
Dr Sarah Al-Beidh
Is it possible to apply fertiliser to hardwood trees to make them grow faster, but still produce quality timber?
Mike Vernon
Dr Sarah Al-Beidh "A few factors need to be considered to help answer this. First, tree species vary in their 'nutrient use efficiency' (NUE) which relates to how effectively they are able to utilise nutrients. A tree's response(s) to nutrient application can therefore vary depending on the species considered. Second, environmental conditions can influence the responses of trees to fertiliser application. Research conducted on Eucalyptus trees in Australia for example, found that N& P fertiliser applied in dry weather (low soil moisture) detrimentally affected pulp yield, wood fibre length and wood density- responses not observed when soil moisture was (near) optimal. Third, what we mean by 'quality timber' is likely to depend on the end product of the wood; one reason Stradivarius violins are considered the best quality in the world is that low ambient temperatures and slow, constant growth rates produced trees with uniform growth rings and (therefore) consistent timber density. Finally consider tree age and site quality; the effects of fertiliser application are likely to be reduced in older vs. younger trees and in trees growing in soil with high nutrient availability compared to those in nutrient-poor sites."

"In principle, responsible fertiliser application in optimal environmental conditions is unlikely to be detrimental; however, it is likely to affect tree volume and in doing so may affect timber quality. Whether this effect is considered detrimental or beneficial is likely to depend on how timber quality is defined."
Dr Ellen Colebrook
Are there any ways that genetically modified plants could help reduce the warming of the earth? The consequences of the warming of the earth terrify me.
Stuart Baillie Strong
Dr Ellen Colebrook "Agriculture is a contributor to climate change through many routes, for example through the use of fertilisers (which results in greenhouse gas emissions). Any changes in practice or new technologies which improve the efficiency of, or reduce the need for, inputs such as fertilisers, herbicides and insecticides have the potential to reduce emissions. The production of crops that grow better with lower inputs, including by genetic modification, could contribute to this. Also, the growing of non-food crops as renewable sources of energy and transport fuel could off-set the emissions produced by fossil fuels and lock more carbon in the soil, helping to combat climate change. It’s possible that GM could speed up the improvement of these crops."
Professor Maurice Moloney
1) What is the percentage breakdown of where Rothamsted’s funding comes from?

2) Do many of the of the scientists there belong to environmental Groups/NGOs?

3) Do both the funding sources and the various affiliations of the senior staff there tend to skew the type of research that they are covering ?

Tim Mitchell
Professor Maurice Moloney "1) The approximate breakdown (unaudited!) is as follows:
~60% from BBSRC in the form of Institute Strategic Program Grants and competitive responsive mode grants
~10% from other Exchequer sources including DEFRA, DECC, DIfD, NERC
~7% EU
~4% Foundations such as The Lawes Agricultural Trust, Bill and Melinda Gates, Perry Foundation, Felix Cobbold etc
~12% Industrial research collaborations
~5% Levy boards and crop research agencies (HGCA, BBRO, AHDB etc)
~2% royalties, licence fees etc"

"2) Yes, but not (as far as I know) in the more extreme end of the spectrum such as GM-freeze etc. Typically, we have staff who are members of RSPB, Butterfly Conservation, Wildlife Trust, FoE, CPRE etc. However, staff are not required to divulge involvement in any NGO or political organisation."

"3) Funding from BBSRC and other research councils is for work covered in their strategic plans (e.g. http://www.bbsrc.ac.uk/nmsruntime/saveasdialog.aspx?lID=3719&sID=6953 ) and therefore the funding sources do play a role in determining which areas are studied. However, the funding bodies, including industry, have no say in how a Rothamsted scientist interprets her/his own results. The principles of academic freedom apply in Institutes just as they do in Universities."
Dr Astrid Wingler
How do plant roots actually draw up nutrients? And…can they take up nanoparticles?
Peter Dobson
Dr Astrid Wingler "Roots can take up nutrients directly from the soil. In nature, however, most plant species form symbioses with mycorrhizal fungi which, through their extensive mycelium, increase nutrient uptake, thereby improving the supply of nutrients to the roots."

"Like other plant cells, root cells are enclosed by a membrane, which in turn is surrounded by a cell wall. While the cell wall is permeable to water and most nutrients, specific transport proteins are required to take up nutrients, such as nitrate, phosphate or potassium, into the root cells. Water and nutrients are transported from the roots to the shoots in a system called xylem. On their way from the soil into the xylem nutrients have to cross cell membranes at least twice: (i) to get into the centre of the root which is sealed off by a hydrophobic strip that prevents transport through the cell wall; (ii) to be loaded into the xylem."

"Nanoparticles can, in theory, follow the same route, but they can also enter the roots through wounding. Whether or not they are taken up and transported to the shoots depends on e.g. their size, surface charge and also the plant species. There is concern that nanoparticles taken up by plants may be toxic to the plants themselves or accumulate in the food chain. On the other hand, it may be possible to use nanoparticles for the delivery of fertilisers, herbicides or pesticides."
Dr Alan Jones
Plants surviving the K-T Event that killed the dinosaurs seem to exhibit less efficiency in photosynthesis that the pre-K-T event plants. Are there any pre-K-T "super photosynthetic" plants or DNA around these days? Would Jurassic Park plants make good candidates for agricultural gene splicing?
Clint Agnew
Dr Alan Jones Much of the flora of North America may have become extinct. However, plant life is generally resilient to mass extinction events, owing to long-lived seeds and underground rhizomes. It is likely that over millions of years, the global genetic diversity of plants was able to fully recover from this event. The most photosynthetically efficient plants ever to exist are the C4 plants, which evolved carbon concentrating mechanisms around 25 million years ago; some 40 million years after the K-T mass extinction event. At times in the Earth's history when CO2 levels were lower than present, plants evolved more stomata to cope. This adaptation is not an advantage under present conditions, because it increases water use (i.e. droughting).
Professor Tim Benton
Do you think the European fear and distrust of genetic modification in food crops is dying down? It seems mad that such useful technologies should not be fully available for deployment as world populations grow, desertification increases and food-growing areas are jeapordised by climate change.
Anne Jackson
Professor Tim Benton "With new technologies, which are truly untried, the precautionary principle indicates that one should be very cautious about deployment. However, as technologies get adopted and if risks are not realised the need for precaution falls. GM crops have been around for decades now, and are grown, globally, over about 10% of the cropped area by millions of farmers big and small. They also increase farm-gate incomes (when taking out the seed-provider premium) by about USD78bn per year. Both these suggest the caution with which the EU has approached GM is not needed and the costs of not using GM are increasing (in terms of lost revenue and lost R&D); and both are being recognised in Europe. Indeed, in a recent report by the Commission concludes (p16) “The main conclusion to be drawn from the efforts of more than 130 research projects, covering a period of more than 25 years of research, and involving more than 500 independent research groups, is that biotechnology, and in particular GMOs, are not per se more risky than e.g. conventional plant breeding technologies.” (http://www.plantsci.org.uk/sites/default/files/a-decade-of-eu-funded-gmo-research_en.pdf)."
Professor Maurice Moloney, Director and Chief Executive of Rothamsted Research
Do plant breeders feel that their work, or the speedy exploitation of their innovations, can be blocked by the patents of Big Corp (Monsanto, perhaps). If they do feel it, is it just a gut feeling, or are their feelings evidence-based? If so, what evidence exactly?
Roy Marsh
Professor Maurice Moloney "In a general sense, the fact that Monsanto has a patent on a new gene does not interfere with the work of a conventional plant breeder. The patent system does not allow a patent of something that occurs naturally. The Company must have "improved" it in some way outside the plant. This means that a 'naturally occurring' plant gene cannot be blocked by a Company. Sometimes, the combination of the Company "improved gene" and the variety that the plant breeder has developed is seen to be a beneficial combination. If that is the case, the breeder and the Company have to negotiate a deal. Generally, the breeders have done quite well in those negotiations (see Pioneer Hybred, Limagrain, KWS and SES van der Have). This is because (and most people don't know this) plant breeders also have protection called Plant Breeders rights under the international Plant Variety Protection system (PVP, http://en.wikipedia.org/wiki/Plant_Variety_Protection_Act_of_1970). This provides for 20 year protection for the plant breeder for their registered varieties. Overall, the system is well-balanced and plant breeding companies have done just as well as the big companies like Monsanto. Without a plant breeder, none of the companies have access to the market really."
Professor Dave Goulson
Neonics are relatively new and there's a large amount of research on effects on bees. Is this a consequence of neonics being uniquely harmful to bees? Or are other insecticides that neonics replaced similarly dangerous (to bees)? Alternately, has less attention been placed on older insecticides such that we don't really know the comparative risks of neonics?
Rachael Ludwick
Professor Dave Goulson "Neonicotinoids have been in use since ~1994, and their use has increased greatly over time. They are not uniquely harmful to bees; more or less all known insecticides are inevitably toxic to bees. Neonicotinoids are predominantly used as a seed dressing; they are systemic, spreading through the plant tissues and entering the nectar and pollen of treated crops such as oilseed rape. They are quite persistent chemicals, remaining in the plant for months and in the soil for years. In contrast, non-systemic alternatives such as pyrethroid insecticides which are typically sprayed on the crop are short-lived in the environment, breaking down within a few days, so as long as they are not sprayed on flowering crops they pose little threat to bees."
Dr Astrid Wingler
I moved from England to Finland six years ago. Although I'm not quite north enough for the actual midnight sun, there is 24hr. daylight through June and July. When do plants respire in these conditions?
Patrick George
Dr Astrid Wingler "In contrast to animals, which need to burn organic compounds in respiration for energy supply, green plants can convert light energy into chemical energy in the form of ATP in the process of photosynthesis. However, plants cells also contain mitochondria, the organelles in which respiration takes place. Respiration is required in the non-green organs of the plant (e.g. roots), but also happens in green organs, such as the leaves. While 24-hour days are unlikely to directly affect rates of respiration in non-green organs (especially if they are underground), it is widely assumed that light suppresses respiration in leaves. This is, however, not trivial to analyse: in the light the rates of carbon dioxide and oxygen exchange between leaves and the atmosphere are not only resulting from respiration, but also (and more strongly so) from photosynthesis and another process called photorespiration. Nevertheless, sophisticated measurements show that respiration does happen in the leaves in the light, even if the rates are reduced. To what extent respiration in green organs is required for plant growth is another interesting question."
Professor Huw Jones
Should we be worried about a viral gene found in GM food?
Twitter Talk
Professor Huw Jones and Professor Patrick du Jardin "No. The natural plant virus, the Cauliflower mosaic virus, is ubiquitous in plants and derived foods, both GM and non-GM and does not pose safety concerns to human and animal health."
Dr Smita Kurup
I bought a "grow your own peppermint tea from seed" pack recently. I thought that the seeds cannot be peppermint seeds if the plant is sterile, but could they be seeds produced from a M spicata X M aquatic cross?
Richard Spencer
Dr Smita Kurup "Yes, peppermint is a hybrid of Mentha spicata and Mentha aquatica. Seeds of peppermint are set from this cross, however peppermint (Mentha piperita) is sterile so the hybrid plant will not set seed. It's not normal to find peppermint seed unless the cultivator has crossed the two required species, even then, the essential oils can vary between crosses. I think a lot of the time, M. spicata (spearmint) is sold as peppermint. I would suggest being cautious about any seed sold as peppermint. I think its best to buy the plant and propagate vegetatively (by rhizome)."
Professor Ottoline Leyser
How do you rate the chances of achieving the sustainable intensification of UK agriculture?
Professor Ottoline Leyser "Even in the UK where farming methods are well developed and yields are already high, I think sustainable intensification is achievable, especially if you consider the whole food production system from farm to fork. Improvements to reduce inputs while stably increasing outputs can be made right across the system. These include research-driven improvements to crop management and crop varieties both in the field and post-harvest, reducing waste throughout and reducing meat consumption. What are the chances of these improvements being realised? Unfortunately, I think progress is likely to be reactive rather than proactive, driven by continued increases food prices and instability in food supply."
Dr Cornelia Eisenach
In the interest of maximizing photosynthesis, can plants photosynthesize certain kinds of light during the dark cycle?
Clint Agnew
Dr Cornelia Eisenach "In the ‘dark’, blue light would make the light-dependent photosynthetic reactions work, albeit at lower efficiency. However, the ‘products’ of the photochemical work are used in a complex metabolic pathway, called the Calvin-Benson Cycle. Some of the enzymes of this cycle are ‘activated’ by light, so the cycle, in effect, does not work in the dark. The ferredoxin/thioredoxin system is responsible for the light-dependence of Calvin-Benson Cycle enzyme activity. I don’t know exactly the action spectrum of the ferredoxin/thioredoxin system, i.e. whether it would still be able to ‘activate’ enzymes under blue light, or whether it has even been tested."
Professor Keith Lindsey
Can you please tell me what proper, controlled research has been done on the safety of GM maize and soya?
Pippa Woods
Professor Keith Lindsey Companies hoping to introduce new GM crops onto the market in Europehave to submit a very large dossier of relevant evidence, which includes data on the molecular characterization of the introduced genes, their safety in terms of toxicological studies, effects on the plant, and effects on the environment. Some of these data are published in the peer-reviewed scientific literature, for all to scrutinize. The dossier is assessed in Europe by expert panels, that include in the UK for example molecular biologists, ecologists, agronomists and farmers. The advice produced by the regulatory panel (known in the UK as the Advisory Committee on Releases to the Environment, ACRE) is published on its public website (http://www.defra.gov.uk/acre/) and informs government ministers, who then consider the advice and make a decision on whether to support the application from the company at European level, prior to further action. Sothere is a large body of scientific evidence on various types of GM maize and soya available to the public, which is considered in relation to determining whether there is a significant risk to human health and the environment.
Dr Anne Osterrieder, nominated by the Society of Experimental Biology.
Can plants be supplemented via an "I.V." drip or foliar feeding with sugar or other nutrients/photosynthetic pre-cursors successfully?
Clint Agnew
Dr Anne Osterrieder "Plant cells synthesise compounds in a chain of chemical processes, also known as metabolic pathways. In each step an enzyme makes changes to a precursor, just like a machine in a factory, and passes them on to the next enzyme until the precursor has been turned into the end product. If you externally supplied nutrients or precursors, you would first need to make sure that all cells take them up. Then the cell would need to include the additional compounds into its existing pathway. Production of more end products would depend on a number of things, such as the availability of free enzyme molecules or the ability of the cell to make more enzymes on demand. I think the answer to this is: ‘It depends!’"
Dr Peter Eastmond
Saw a field of daisies in bloom last week in Oundle (UK), this can't be normal can it?
Dr Peter Eastmond "If the daisies are the common English species Bellis perennis then they would usually flower in early to midsummer. However, they are also known to flower in mild winters and it's most probable that the recent mild weather is the cause."
Dr Sarah Al Beidh
Is there any other special reason why banana leaves are so big except struggle for light?
Dr Sarah Al Beidh "The short answer is – they're big because they can be! Bananas grow predominantly in wet tropical lowlands where the growing conditions are more favourable than temperate regions. Adequate natural soils, no shortage of water, along with warm weather and almost 12 hours of daylight throughout the year enable banana trees to grow quickly and have large leaves. As you rightly mentioned, for plants growing in the shady understory of a forest, large leaves also capture as much of the available light as possible and so can make the maximum amount of ‘food’ through photosynthesis. In comparison, plants in temperate regions have to endure freezing temperatures so have developed strategies to cope. These include shedding their leaves in winter (e.g. deciduous trees) or reducing them to tough needle-like structures filled with natural ‘anti-freeze’ (e.g. pines in northern forests)."
Professor Alison Smith
Is there any evidence to support the idea that GM fruits and vegetables contain lower nutrient levels their organic equivalents? I read that a 1950s (pre-GM) apple is equal to two present day apples, is this true?
Professor Alison Smith "Some studies have shown that the nutrient content of today's fruit and vegetables are lower than those measured in the past. In the case of apples, one explanation is that the newer varieties have been bred for yield and appearance, with little attention paid to the nutrient content. However these varieties have all been established by conventional plant breeding - that is crossing two varieties together and then selecting different traits from amongst the offspring. As far as I know there are no GM apples. In fact the first major GM crop, and the one that was sold in the UK in the 1990s, was GM tomatoes - called Flavr Savr. These were modified so that during ripening, although the fruits turned red, and became sweeter as the acid was turned to sugar, they did not soften very much. This gave them a longer time to sweeten, and also facilitated processing. I think that in the UK all the fruit was used for making tomato puree. Analysis of the nutrient content - vitamin A, vitamin C, vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin) and vitamin B6 (pyridoxal), as well as elements such as Ca - showed no difference compared to non-GM fruit."
Dr Sarah Al-Beidh
Is this the beginning of the end for the deciduous tree vis-a-vis global warming & resulting proliferation of pests?
Dr Sarah Al-Beidh "In recent years, there have been a number of new pests and diseases recorded in Britain. Most of these however, have come here as a result of the international trade in plants and plant products, rather than climate change. Global warming does have the potential to affect many types of plants- not just deciduous trees. Some plants will benefit from a warmer and wetter climate while others may be adversely affected. Where climate change is gradual, plants are able to adapt; however, rapid climate change puts plants under stress and this may cause some plants to decline in areas where the climate is no longer suitable. Stressed plants may become more vulnerable to pest and diseases."
Dr Hanna Tuomisto
I want to create a "food forest" on the East Coast of the US. What methodology and resources would you recommend?
Dr Hanna Tuomisto "‘Food forest’ or forest gardening is a form of agroforestry where food crops and trees are planted together. In a forest garden food plants can be grown in many layers, including fruit trees, nut trees, berry bushes, vegetables, herbs, mushrooms, root vegetables and vines. A well designed forest garden can be nearly self-maintaining. More information about forest gardening and other types of agroforestry can be found on www.agroforestry.co.uk."
Dr Alan Jones, nominated by the UK Plant Sciences Federation.
'The Queen of the night', Selenicereus grandiflorus, is a cactus flower which only blooms one night a year. What could be the foundation of this life process (of only blooming ONCE a year during the night) from an evolutionary perspective?
David Bracey
Dr Alan Jones "White flowers suggest this species is pollinated by night-flying moths, which are the most visible flowers at night, particularly during full-moon nights. This species produces large, highly fragranced (and, therefore, highly attractive) flowers. By minimising the time spent investing in this organ, and being synchronous with other members of the species, this plant minimises the total 'cost' of reproduction and maximises its chance of reproductive success. This is essentially the basis of natural selection. Selenicereus grandiflorus, maximises pollination potential by putting all its 'eggs in one basket' in one night, monopolising pollinator activity for several hours - by sheer force of numbers. This strategy will go wrong if the timing coincides with adverse weather conditions."
Dr Astrid Wingler, nominated by the Society of Experimental Biology
Nitrogen fixing crops. Good idea as less synthetic fertiliser used, or bad idea as more Nitrogen for leaching = environmental issues?
Dr Astrid Wingler "Over half of the nitrogen added to the soil as fertiliser is lost, e.g. by leaching of nitrates or production of the greenhouse gas N2O. Fertiliser input into agricultural systems could be reduced by engineering crops, such cereals, to form symbioses with N2-fixing bacteria or by introducing the N2-fixing enzyme nitrogenase directly into plants. The higher input of nitrogen could theoretically result in increased leaching of e.g. nitrates. However, since the nitrogen would be fixed within the plants and therefore be directly available for growth, the amount leached would probably be much less than for fertiliser applied to the soil."
Dr Sarah Al-Beidh, nominated by the Royal Horticultural Society. Sarah is a post-doctoral researcher at the Royal Horticultural Society
What proportions #biochar to #compost best for clay soil s.e. england for #mycorrhiza n minilife?
Dr Sarah Al-Beidhe "When it comes to applying biochar to soil, more horticulturally-focused research in temperate systems is needed as we still have questions on its long-term effect(s) on soil health. Also not all biochar is the same - different raw materials and production processes result in biochar with different chemical and physical properties. Even fewer studies have investigated the impact of biochar on soil fauna so, whilst it’s unlikely that it has any adverse effects on soil-dwelling invertebrates, more research is definitely needed! The physical structure of a clay soil can be considerably improved by digging a 10cm layer of bulky organic matter (such as mature garden compost) into each 30cm of soil."
Professor Rob Chilcott, nominated by the Society of Biology. Rob is is head of toxicology at the University of Hertfordshire’s Department of Pharmacy and Fellow of the Society of Biology. He is also currently Chair of the UK Register of Toxicologists and
When you eat a gmo food what happens to the genes in the food in your digestive tract?
Jason Rucker
Professor Rob Chilcot "Our digestive tract has evolved to produce a wide range of enzymes which are very effective at breaking down our food into small molecules to allow absorption into our body. The same goes for the DNA within our food: it is extensively digested into its component molecules before being absorbed. Therefore, we do not actually absorb the genes present within our food (whether genetically modified or not), but we do absorb the molecules the genes were originally built from. The molecules we absorb from our digestive tract can then be used by our bodies to produce, amongst other things, new (human) DNA. Some people have argued that we do absorb genes from our food and that these can be inserted into our genome. If that were true then we would all be carrying genes from everything we had ever eaten: the human race would probably have died out millennia ago or we would currently be evolving into our favourite meals."
Paul Temple, nominated by the National Farmers' Union. Paul is a tenant farmer in a family partnership in East Yorkshire.
Animal-free organic farming seems greenest but also has the lowest yield. Q: how big a problem is low yield (aside from profit)?
Paul Temple "Low yield is a problem for one very simple reason, there are more people every year to feed and we haven't more land in which to carry out expansive farming low output agriculture. Taking the UK as a example. The recent census revealed an additional two million people now live and need food in the UK. As a net importing nation we therefore require yet more land in other countries to service demand. Producing less food simply adds tension to an already rising food market and while the wealthier part of the population can cope it creates real problems for the poorest."
Dr Wendy Harwood, nominated by the UK Plant Sciences Federation. Wendy is a Senior Scientist at the John Innes Centre.
If genetically modified crops were more widely grown, would ecosystems stand to gain or lose?
Christopher Wilson
Dr Wendy Harwood "Genetically modified crops are already widely grown; on over 395 million acres worldwide last year. If this area was expanded further the issue of whether ecosystems would gain or lose would depend entirely on what sort of crop was grown and where. It has to be remembered that GM is just a technology and it is the particular introduced trait that is important rather than the technology used to develop the crop. Some traits could impact the environment negatively and some positively."
Dr Hanna Tuomisto, nominated by Sense About Science. Hanna is a a postdoctoral researcher at the European Commission’s Joint Research Centre in Italy.
To what degree is the decline in sparrow populations down to farming methods, and what can farmers do to help?
Dr Hanna Tuomisto "A recent study suggests that urban noise may be a key cause of declining sparrow populations. Changes in agricultural practices play a role too. Farmers can help sparrows by providing feeding and nesting habitats, such as non-cropped areas, wild flower plantations and over-winter stubbles."
Paul Temple, nominated by the National Farmers' Union. Paul is a tenant farmer in a family partnership in East Yorkshire.
Is it even possible to farm organically without animal manure? Can "green manure" (plowing in pulse crops) suffice?
Paul Temple "It is possible to farm organically without livestock. However it makes more sense and improves the fertility build up required in an organic system to use livestock through grazing, feeding green crops, utilising straw and returning manure. Organic crop output is significantly lower than conventional routes, using livestock improves overall food output in the cycle, offering the chance to improve soil fertility and organic matter."
Professor Keith Goulding, nominated by Rothamsted Research. Keith is the Head of Department for Sustainable Soils and Grassland Systems at Rothamsted Research.
Can the scientific community really take on the interests of farming and the multinationals, to ensure land use and the soil health is reversed and maintained, to help support the planet and man?
David & Thea Dunn
Professor Keith Goulding (guest contributor) "As a scientific community, Rothamsted Research does not seek to ‘take on’ anyone but works with farmers and all those who have an interest in good soil management. Organisations such as ours work with LEAF (Linking Environment And Farming) and its collaborators such as Waitrose and ASDA, directly with M&S and Sainsbury’s, and with multinationals such as BASF, to translate our research on soils into practice. Current projects are exploring the role of organic matter in stimulating earthworms and good soil structure, how plants can be used to manage soils, and what simple measures of soil biodiversity can be used as indicators of soil health. The challenge for all of us in a global market is to work with farmers to help them manage their soils well while producing food at a price that people can and will pay. Rothamsted and others who have a commitment to soil health, are members of the Global Soil Biodiversity Initiative: http://www.globalsoilbiodiversity.org/?q=participants "
Live online Q&A: Environmental impact of conventional and organic farming on the land used
Environmental impact of conventional and organic farming on the land used
Professor Jonathan Foley and Dr Hanna Tuomisto
Questions were answered on the environmental impact of organic and conventional farming on the land used.
• Is organic farming better for local wildlife?
• If we want to increase yields doesn’t that mean we have to use a lot more pesticides?
• We waste so much food; do we really need to grow more?

We ran a live #plantsci Q&A with scientists working in this field, full text here: http://www.senseaboutscience.org/pages/-environmental-impact-of-conventional-and-organic-farming-on-the-land-used-480.html
Live online Q&A: Safety and regulation of GM
Safety and regulation of GM
Professor Huw Jones and Professor Jonathan Jones
Questions were answered on GM trials, super-weeds, and ecosystems.

We ran a live #plantsci Q&A with scientists working in this field, full text here: http://www.senseaboutscience.org/pages/-safety-and-regulation-of-gm-478.html
Live online Q&A: Using GM plants to ‘grow’ medicine
Genes and testing of GM crops
Professor Huw Jones
Questions were answered about the interplay between genes from GM and wild species, the identity of a species after multiple modifications, and testing of GM crops.

We ran a live #plantsci Q&A with Professor Jones about these issues, full text here: http://www.senseaboutscience.org/pages/-genes-and-testing-of-gm-crops-476.html
Live online Q&A: Using GM plants to ‘grow’ medicine
Consumption of GM crops
Dr Gia Aradottir
Questions were answered about putting animal genes into crops to increase protein content, and risk of increased incidence of allergic reactions due to novel proteins.

We ran a live #plantsci Q&A with Dr Aradottir about these issues, full text here: http://www.senseaboutscience.org/pages/-consumption-of-gm-crops-474.html
Live online Q&A: Using GM plants to ‘grow’ medicine
GM trials, super-weeds, and ecosystems
Dr Toby Bruce and Dr Wendy Harwood
Questions were asked about 'super-weeds' and GM crops - what they are, their impact on the ecosystem, and what we know about their safety.

We ran a live #plantsci Q&A with scientists working in this field, full text here: http://www.senseaboutscience.org/pages/-gm-trials-super-weeds-and-ecosystems-472.html
Live online Q&A: Using GM plants to ‘grow’ medicine
Commercialisation of GM
Professor Maurice Moloney and Professor Jonathan Jones
Questions about GM crop patenting and ownership, and the ethics of GM research were answered by Professor Maurice Moloney, Director and Chief Executive of Rothamsted Research, and Professor Jonathan Jones, Senior Scientist at the Sainsbury Laboratory.

The questions and answers from this live #plantsci Q&A can be seen here: http://www.senseaboutscience.org/pages/-commercialisation-of-gm-470.html
Live online Q&A: Using GM plants to ‘grow’ medicine
Cross pollination
Dr Wendy Harwood and Professor Huw Jones
Experts on GM cereal crops answered questions about the spread of wheat pollen, 'jumping genes', and other risks and benefits of GM wheat crops.

All the questions and answers from this live #plantsci Q&A can be found here: http://www.senseaboutscience.org/pages/-cross-pollination-468.html

     Plant Science Partners