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Title: Toxic Crops
Source:
ABC.net
URL Source: http://www.abc.net.au/ra/innovations/stories/s2967862.htm
Published: Aug 9, 2010
Author: staff
Post Date: 2010-08-10 19:00:30 by buckeroo
Keywords: None
Views: 86
Comments: 4
Toxic Crops Contact: Dr Ros Gleadow Faculty of Science Monash University, Clayton, VIC 3800 International Telephone: +61 3 9905 1667 FAX: +61 3 9905 1450 Email: ros.gleadow@sci.monash.edu.au Website: www.biolsci.monash.edu.au Website: www.abc.net.au/catalyst/stories/2891924.htm TRANSCRIPT: DESLEY BLANCH : Double food production with half the resources, that's what scientists say we will need to do by 2050 to feed an estimated 8.5 billion people. Now, climate change alone will make that a difficult job, but there's another factor that scientists are only beginning to understand. For ABC TV's science and technology program, Catalyst, Graham Phillips went to Monash University in Melbourne to find out how rising CO2 levels will affect our food security. DR GRAHAM PHILLIPS : We've constantly fought a battle against weeds, disease, pests and drought when growing crops. But the security of our food supply is being threatened by a sinister new player generated by us. The next big food issue could be how rising levels of carbon dioxide affect our fruit and vegies. Now we know that plants love CO2 so rising levels of it will affect their metabolisms and it seems almost certain that for many foods the levels of nutrition will go down and for some, toxin levels will go up. Both serious issues when you are trying to feed a world with an increasing population. DR ROS GLEADOW : We're tracking worst case scenario with carbon dioxide at the moment and we need to predict what sort of things are going to happen in the future. DR GRAHAM PHILLIPS : Carbon dioxide is crucial for plant growth. Plants breathe in CO2 and convert the gas into usable energy. DR ROS GLEADOW : Plants use carbon dioxide. It's a carbon catcher and storage system so you think if there's more carbon dioxide they would just capture and store more. But in fact that doesn't happen. Plants do grow faster at elevated carbon dioxide usually, but not as fast as you'd expect. DR GRAHAM PHILLIPS : Ros Gleadow has been studying the effects of raised C02 on plant growth. DR ROS GLEADOW : Leaves of plants grown at elevated carbon dioxide have a lot less protein than wheat, barley, rice, all of those in probably only 50 to 60 years time will have 15 to 20% less protein in them than they do now. DR GRAHAM PHILLIPS : So why would a plant have less protein in a raised carbon dioxide environment? In the process of photosynthesis, plants convert carbon dioxide into sugars using a protein called RuBisCO to capture the CO2 from the atmosphere. If carbon dioxide levels increase, plants will need to produce less RuBisCO to capture the same amount of carbon dioxide. Less of this protein means a less nutritious meal. And the plant's extra resources can then be diverted into protecting the plant. Plants protect themselves using spines and thorns or make themselves less appetising by producing toxic chemicals. Eucalypts produce phenols. DR ROS GLEADOW : In about 50 years time or even 100 years time eucalyptus leaves will have trouble supporting arboreal herbivores like koalas because the phenolic concentration will be too high and the protein level too low. DR GRAHAM PHILLIPS : Phenols are one way that plants protect themselves from animal attack but there is another way, cyanide. EMERITUS PROFESSOR HOWARD BRADBURY : If an insect comes and eats the leaf, then it immediately gets a nasty taste of bitter hydrogen cyanide so it goes somewhere else. So this is a really great mechanism for protecting the plant. And there's about 2,000 plants that use this mechanism including apples, apricots, peaches. DR GRAHAM PHILLIPS : One of the biggest worries is Cassava. This is one of the main staple crops of third world countries and it also produces cyanide. DR GRAHAM PHILLIPS : This is a cassava plant. It is a small one the big ones can get up to 3 metres. Now, the leaves can be eaten. They can be thrown into a salad as greens but the most important part of the plant as far as food goes is the root. Now that could be peeled, chopped up and cooked. It could be turned into flour or indeed tapioca. Now the reason cassava is so popular around the world is the plant is highly drought tolerant. It requires very little water and can grow in extremely poor soils DR GRAHAM PHILLIPS : These propagate really easily these plants. EMERITUS PROFESSOR HOWARD BRADBURY : Oh yes, yes they are very easy to grow and cassava from the agriculture point of view is just marvellous, that's why it's used so much. It's easy to propagate, you just cut a little bit of the stalk put it in the ground and that's it. And a week later it is all shooting. It's just amazing stuff. DR GRAHAM PHILLIPS : The trouble is its full of cyanide? EMERITUS PROFESSOR HOWARD BRADBURY : Yeah that is the problem with it. DR GRAHAM PHILLIPS : Cassava is a staple food for much of the developing world. But if it is not prepared properly it can cause a serious lifelong disease called Konzo. Julie Cliff has been a medical doctor working in Mozambique since the 1970's and has seen the effects of cyanide in cassava first hand. DR JULLIE CLIFF : In Mozambique the disease that gives us most problems is a disease called Konzo and that's a permanent paralysis. And they get that when they eat too much cassava. The first time it happened was 1981. We went to investigate it and we got a message saying it was polio. But we soon realised it wasn't polio because the symptoms were quite different. DR GRAHAM PHILLIPS : Back in the lab, Ros's group have been looking at how rising CO2 will affect the cyanide levels of cassava. DR ROS GLEADOW : We grew cassava at three different concentrations of carbon dioxide. Today's air, one and a half times the amount of carbon dioxide and twice the carbon dioxide of today, and we found that the cyanogen concentration in the leaves increased. DR GRAHAM PHILLIPS : So as we get more carbon dioxide in the atmosphere these will contain more cyanide? EMERITUS PROFESSOR HOWARD BRADBURY : More cyanide yes. The yield from the roots which is the main thing will go down. So that is the most worrying aspect. DR ROS GLEADOW : I feel sort of slightly uncomfortable with having discovered something so bizarre that the plants actually made less tubers when we grew them at elevated carbon dioxide. But they did. It is all very highly balanced in plants, the ratio of the proteins and the toxins. When you grow plants at elevated carbon dioxide the plants are more efficient so they can grow really well. And at the same time allocate more of their resources to defence. DR GRAHAM PHILLIPS : Cassava may not seem that close to home in Australia. But the principle of this research and the shocking health side effects, should really be a warning sign for us all. DR ROS GLEADOW : In Australia an important part of pastures is clover. And in Australia most of the clovers contain cynaogens. The concentration of cynaogens increases and the concentration of protein decreases in clover grown at elevated carbon dioxide. I think this illustrates the importance of really knowing what it is that we think might happen so we can plan for it. DR GRAHAM PHILLIPS : Before rising carbon dioxide and toxicity levels had been linked, Howard had been spending his retirement coming up with a simple method to remove cyanide from cassava. EMERITUS PROFESSOR HOWARD BRADBURY : Two-thousand-and-four I worked out the method and now here it is 2010 and it's not being used anywhere hardly, except the Mozambique health department has finally said yeah that's a good method. They're finally adopting it. It's taken them 5 years! DR GRAHAM PHILLIPS : So what's the method? EMERITUS PROFESSOR HOWARD BRADBURY : The method involves taking the dry flour and then you add about an equal amount of water and then mix it up. The flour all swells up. They then take the wet flour and put it on a basket in a thin layer not more than a centimetre thick and the enzyme can then attack the cyanide compound and break it down and gradually liberate hydrogen cyanide, which is a gas. DR GRAHAM PHILLIPS : Gee it's a pretty simple method for detoxifying? EMERITUS PROFESSOR HOWARD BRADBURY : Very simple, yeah. DR GRAHAM PHILLIPS : Howard's solution allows people to safely eat cassava and this knowledge will become more important if cassava becomes more toxic in a carbon rich environment. DR ROS GLEADOW : I don't want to be a gloom and doom person. I want to think: okay clover's going to become more toxic, let's develop other cultivars. If cassava's going to become more toxic, let's look at some other cultivars. Let's look at other ways we can deal with this problem. DESLEY BLANCH : Dr Ros Gleadow from Monash University in Melbourne, and that report by ABC TV's Graham Phillips. Poster Comment: Conclusion: increased amounts of CO2 in the environment reduces nutritious value for humans and can cause illness and even death.
With our changing climate could our food become less nutritious or more toxic?
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#1. To: All (#0)
What, no scientific considerations about how the world is dying? Of course your beloved non-scientific "chemtrails" are important and more relevant than crop production and health.
"we ought to lay off the criticism" -- Pinguinite, circa 2010-05-26 22:17:22 ET
---------------------------------------------------------------------------------------------------------------------------------- What happens when we convulse to death based upon EPA/FDA standards based on the increasing pollutants within the environment? Do you think they will throw a farewell reef to you as you see God?
"we ought to lay off the criticism" -- Pinguinite, circa 2010-05-26 22:17:22 ET
I ran out of smart sounding quotes
#2. To: wudidiz (#1)
#3. To: wudidiz, BUCKEROO (#1)
One of the major consequences of the 9/11 movement has been to draw enormous amounts of energy and effort away from activism directed to real and ongoing crimes of state, and their institutional background, crimes that are far more serious than blowing up the WTC would be, if there were any credibility to that thesis. That is, I suspect, why the 9/11 movement is treated far more tolerantly by centers of power than is the norm for serious critical and activist work....Noam Chomsky
#4. To: AGAviator (#3)
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