Biology News & Research
News - How parasites modify plants to attract insects
9th Nov 2011
alter their hosts - for example malaria parasites can make humans more
attractive to mosquitoes - but how they do it has remained a mystery.
Now, scientists have identified for the first time a specific molecule from a parasite
that manipulates development to the advantage of the insect host. The work was done by UK plant scientists at Norwich, at the John Innes Centre.
This finding could help scientists to find new ways of managing the spread of insect-borne crop diseases. This will be vital in order to ensure future food security, especially, in this case, in the face of climate change.
"Our findings show how this pathogen molecule can reach beyond its host to alter a third organism," said Dr Saskia Hogenhout from JIC.
Leaf hoppers are tiny sap-sucking, highly mobile and opportunistic agricultural pests. Certain species can acquire and transmit plant pathogens including viruses and phytoplasmas, which are small bacteria. Dr Hogenhout and her team focused on a phytoplasma strain called Aster Yellows Witches' Broom, which causes deformity in a diverse range of plants.
"It is timely to better understand phytoplasmas as they are sensitive to cold and could spread to new areas as temperatures rise through climate change," said Dr Hogenhout.
Infected plants grow clusters of multiple stems which can look like a witches' broom or in trees like a bird's nest. The strain was originally isolated from infected lettuce fields in North America.
The phytoplasma depends on both the leafhopper and the plant host for survival, replication and dispersal. The new findings show how it manipulates the interaction of the plant host and insect vector to its advantage.
The scientists sequenced and examined the genome of the witches broom phytoplasma and identified 56 candidate molecules, called effector proteins, which could be key to this complex biological interaction.
They found that a protein effector SAP11 reduces the production of a defence hormone in the plant that is used against the leafhopper. As a consequence, leafhoppers reared on plants infected with witches broom laid more eggs and produced more offspring. The leafhoppers may also be attracted to lay eggs in the bunched branches and stems.
The higher fecundity rate is probably matched by a similar increased rate in transmission of the witches broom phytoplasma by leafhoppers to other plants.
"Phytoplasmas that can enhance egg-laying and offspring numbers in leafhoppers are likely to have a competitive advantage," said Dr Hogenhout.
Given their opportunistic nature, the leafhoppers are likely to migrate to uninfected plants and spread the pathogen.
"This is a vivid example of the extended phenotype, a concept put forward by Richard Dawkins, where an organism's phenotype is based not only on the biological processes within it but also on its impact on its environment," said Dr Hogenhout.
Find out more about phytoplasmas in this Catalyst article, written for students studying GCSE and A-level Biology.
News - 100 most important questions in plant science
"Plants are fundamental to all life on Earth. They provide us with food, fuel, fibre, industrial feedstocks, and medicines. They render our atmosphere breathable. They buffer us against extremes of weather and provide food and shelter for much of the life on our planet. However, we take plants and the benefits they confer for granted. Given their importance, we should pay plants greater attention and give higher priority to improving our understanding of them.
Everyone knows that we need doctors, and the idea that our
best and brightest should go into medicine is embedded in our culture.
However, even more important than medical care is the ability to survive
from day to day; this requires food, shelter, clothes, and energy, all
of which depend on plants.
Plant scientists are tackling many of the most important
challenges facing humanity in the twenty-first century, including
climate change, food security, and fossil fuel replacement. Making the
best possible progress will require exceptional people. We need to
radically change our culture so that 'plant scientist' can join 'doctor', 'vet' and 'lawyer'
in the list of top professions to which our most capable young people
aspire." New Phytologist, 8 September 2011
This was the statement from a group of the world's leading plant scientists, who for the last two years have been working to identify the 100 most important challenges facing the world - and facing plant science researchers as a result. They asked both scientists and members of the public from around the world, opening up a website to invite people to list the world's greatest challenges to tackle. Their list of key questions was published in the New Phytologist journal, and is available on the project website, 100PlantScienceQuestions.org
We've taken the 'top ten' questions and published them here - to what extent do you and your students agree?
The 10 questions most important to society
A1. How do we feed our children’s children?
By 2050 the world population will have reached c. 9 billion people. This will represent a tripling of the world population within the average lifetime of a single human being. The population is not only expanding, but also becoming more discerning, with greater demands for energy-intensive foods such as meat and dairy. Meeting these increasing food demands over the years to come requires a doubling of food production from existing levels. How are we going to achieve this? Through the cultivation of land currently covered in rainforests, through enhanced production from existing arable land or by changing people’s habits to change food consumption patterns and reduce food waste? The reality is probably a combination of all three. However, if we are to reduce the impact of food production on the remaining wilderness areas of the planet then we need significant investment in agricultural science and innovation to ensure maximum productivity on existing arable land.
A2. Which crops must be grown and which sacrificed, to feed the billions?
The majority of agricultural land is used to cultivate the staple food crops wheat (Triticum aestivum), maize (Zea mays) and rice (Oryza sativa), the oil-rich crops soy (Glycine max), canola (Brassica napus), sunflower (Helianthus spp.) and oil palm (Elaeis guineensis) and commodity crops such as cotton (Gossypium spp.), tea (Camellia sinensis) and coffee (Coffea spp.). As the world population expands and meat consumption increases, there is a growing demand for staples and oil-rich crops for both human needs and animal feed. Without significant improvements in yields of these basic crop plants, we will experience a squeeze on agricultural land. It is therefore essential that we address the yield gap; the difference between future yield requirements and yields available with current technologies, management and gene pools. Otherwise we may be forced to choose between production of staple food crops to feed the world population and the production of luxury crops, such as tea, coffee, cocoa (Theobroma cacao), cotton, fruits and vegetables.
A3. When and how can we simultaneously deliver increased yields and reduce the environmental impact of agriculture?
The first green revolution of the late 1950s and early 1960s generated unprecedented growth in food production. However, these achievements have come at some cost to the environment, and they will not keep pace with future growth in the world population. We need creative and energetic plant breeding programmes for the major crops world-wide, with a strong public sector component. We need to explore all options for better agronomic practice, including better soil management and smarter intercropping, especially in the tropics. Finally, we need to be able to deploy existing methods of genetic modification that reduce losses to pests, disease and weeds, improve the efficiency of fertilizer use and increase drought tolerance. We also need to devise methods to improve photosynthetic efficiency, and move the capacity for nitrogen fixation from legumes to other crops. These are all desirable and, with public support, feasible goals.
A4. What are the best ways to control invasive species including plants, pests and pathogens?
Invasive species are an increasingly significant threat to our environment, economy, health and well-being. Most are nonindigenous (evolved elsewhere and accidentally introduced) and have been removed from the constraints regulating growth in their native habitat. The best method of control is to prevent establishment in the first place or to quickly identify establishment and adopt an eradication programme. However, if an invasive species becomes established many of the options for removal can cause environmental damage, for example chemical control or mechanical excavation. Biological control (introduction of a natural predator ⁄ pathogen) can work well as long as the control organism targets only the invasive species. Otherwise there is a risk that the control organism might also become an invasive species. Alternatives, such as manipulating existing natural enemies and ⁄ or the environment to enhance biological control, are also being developed. Sustainable solutions are required if we are to deal with the continually growing problem of invasive species.
A5. Considering two plants obtained for the same trait, one by genetic modification and one by traditional plant breeding techniques, are there differences between those two plants that justify special regulation?
The products of traditional plant breeding are subject to no special regulations, even though the wild sources of germplasm often used by breeders may contain new components that have not been assessed before. A plant derived by genetic modification, however, is highly regulated, even though the target genotype and the modification itself may both be highly characterized and accepted as innocuous for their intended use. This is a major exception to the norm for safety regulation in food and other areas, which is normally based on the properties of the object being regulated. It is important for food safety and for the public’s perception of science and technology in general to establish whether there are any objective differences between these groups of products that justify the different approaches to their regulation.
A6. How can plants contribute to solving the energy crisis and ameliorating global warming?
Plants use solar energy to power the conversion of CO2 into plant materials such as starch and cell walls. Plant material can be burnt or fermented to release heat energy or make fuels such as ethanol or diesel. There is interest in using algae (unicellular aquatic plants) to capture CO2 emissions from power stations at source. Biomass cellulose crops such as Miscanthus giganteus (Poaceae) are already being burnt with coal at power stations. There is understandable distaste for using food crops such as wheat and maize for fuel, but currently 30% of the US maize crop is used for ethanol production, and sustainable solutions are being found. Sugarcane (Saccharum officinarum) significantly reduces Brazil’s imports of fossil fuels. Agave (Agavea fourcroydes) in hot arid regions can provide very high yields (> 30 T ha)1) of dry matter with low water inputs compared with other crops. To ameliorate global warming, CO2 must be taken out of the air and not put back. There is considerable interest in ‘biochar’ in which plant material is heated without air to convert the carbon into charcoal. In this form, carbon cannot readily re-enter the air, and, if added to the soil, can increase fertility. Carbon markets do not currently provide sufficient incentive for farmers to grow crops simply to take CO2 out of the air.
A7. How do plants contribute to the ecosystem services upon which humanity depends?
Ecosystem services are those benefits we human beings derive from nature. They can be loosely divided into supporting (e.g. primary production and soil formation), provisioning (e.g. food, fibre and fuel), regulating (e.g. climate regulation and disease regulation) and cultural (e.g. aesthetic and recreational) services. Plants are largely responsible for primary production and therefore are critical for maintaining human well-being, but they also contribute in many other ways. The Earth receives virtually no external inputs apart from sunlight, and the regenerative processes of biological and geochemical recycling of matter are essential for life to be sustained. Plants drive much of the recycling of carbon, nitrogen, water, oxygen, and much more. They are the source of virtually all the oxygen in the atmosphere, and they are also responsible for at least half of carbon cycling (hundreds of billions of metric tons per year). The efficiency with which plants take up major nutrients, such as nitrogen and phosphorus, has major impacts on agricultural production, but the application of excess fertilizers causes eutrophication, which devastates acquatic ecosystems. Plants are already recognized as important for sustainable development (e.g. plants for clean water) but there are many other ways that plants might contribute. A combined approach of understanding both the services provided by ecosystems and how plants contribute to the functioning of such ecosystems will require interdisciplinary collaboration between plant scientists, biogeochemists, and ecologists.
A8. What new scientific approaches will be central to plant biology in the 21st Century?
Biologists now have a good general understanding of the principles of cell and developmental biology and genetics, and how plants function, change, and adapt to their environment. Addressing the questions in this list, including those related to generating crops that can deal with future challenges, will require detailed knowledge of many more processes and species. New high-throughput technologies for analysing genomes, phenotypes, protein complements, and the biochemical composition of cells can provide us with more detailed information in a week than has ever been available before about a particular process, organism or individual. This is delivering a deluge of information that is both exhilarating and daunting. The challenge is to develop robust ways of analysing and interpreting this mountain of data to answer questions and deliver new insights. The skill sets required to make full use of the new information extend far beyond those previously expected from biologists. There is general agreement that we need a new era of collaboration between all types of plant scientists, geographers, geologists, statisticians, mathematicians, engineers, computer scientists, and other biologists to evaluate complex data, find new relationships, develop and test hypotheses, and make discoveries. Challenges include understanding complex traits and interactions with the environment, generating ‘designer crops’, and using modelling to predict how different genotypes will cope with alterations in the climate.
A9. (a) How do we ensure that society appreciates the full importance of plants?
Plants are fundamental to all life on Earth. They provide us with food, fuel, fibre, industrial feedstocks, and medicines. They render our atmosphere breathable. They buffer us against extremes of weather and provide food and shelter for much of the life on our planet. However, we take plants and the benefits they confer for granted. Given their importance, should we not pay plants greater attention and give higher priority to improving our understanding of them? Awareness could be increased through the media, school education, and public understanding of science activities, but a major step-change in activity will be required to make a substantial difference.
A9. (b) How can we attract the best young minds to plant science so that they can address Grand Challenges facing humanity such as climate change, food security, and fossil fuel replacement?
Everyone knows that we need doctors, and the idea that our best and brightest should go into medicine is embedded in our culture. However, even more important than medical care is the ability to survive from day to day; this requires food, shelter, clothes, and energy, all of which depend on plants. Beyond these essentials, plants are the source of many other important products. As is clear from the other questions on this list, plant scientists are tackling many of the most important challenges facing humanity in the 21st Century, including climate change, food security, and fossil fuel replacement. Making the best possible progress will require exceptional people. We need to radically change our culture so that ‘plant scientist’ (or, if we can rehabilitate the term, ‘botanist’) can join ‘doctor’, ‘vet’ and ‘lawyer’ in the list of top professions to which our most capable young people aspire.
A10. How do we ensure that sound science informs policy decisions?
It is important that policy decisions that can affect us all, for example environmental protection legislation, are based on robust and objective evidence underpinned by sound science. Without this, the risk of unintended consequences is severe. Ongoing dialogue between policy makers and scientists is therefore critical. How do we initiate and sustain this dialogue? How do we ensure that policy makers and scientists are able to communicate effectively? What new mechanisms are needed to enable scientists to respond to the needs of policy makers and vice versa?
News - CSI Hedgerow
“'I went to the crime scene and said, “Don’t show me where the body was, I’ll show you. And I did. I was totally gobsmacked, because I hadn’t believed I could do it. I actually picked out the spot where the body had been.’”
The words of a police detective? A forensic investigator? Or an ecologist and plant scientist?
In a fascinating (and at times disturbing) interview, one of the UK’s foremost forensic botanists talks about the role of plant science in solving some of the highest profile murder enquiries of recent years: http://bit.ly/eferBu
News - The Plant Clock Gene that Regulates Human Cells
“A gene that controls part of the 'tick tock' in a plant's circadian clock has been identified by UC Davis researchers. And not only is the plant gene very similar to one in humans, but the human gene can work in plant cells - and vice versa. … When Harmer and colleagues made Arabidopsis plants with a deficient gene, they found that the plants' in-built circadian clock ran fast. A similar gene is found in humans, and human cells with a deficiency in this gene also have a fast-running clock. When the researchers inserted the plant gene into the defective human cells, they could set the clock back to normal - and the human gene could do the same trick in plant seedlings.”
Read more about the research, published in the Proceedings of the National Academy of Sciences, on Science Daily:
News - Carnivorous plants inspire new materials
26 September 2011
An unwary insect that finds itself on the rim of a pitcher plant doesn't have long to live. Not only do the pitcher plants (Nepenthes) have deep cavities to trap their prey, but the rims of these cavities are exceptionally slippery - and their biology has just inspired a scientist at Harvard University to develop a new material so slippery that no liquid can stick to it. The result could be cleaner surgical instruments, walls that are impervious to graffiti, car windscreens that can't ice up, and much more.
The rims of Nepenthes, called the peristomes, have a series of complex adaptations that cause insects to aquaplane along the surface and fall into the pitcher. Researchers at Cambridge University looked at the peristomes under a microscope, in order to understand just how they were so slippery.
Science journalist Ed Yong describes their findings: "[The peristome] is lined with cells that overlap one another, creating a series of step-like ridges and troughs. The plant secretes nectar onto this uneven surface. The troughs collect the nectar, and the ridges hold it in place, preventing it from draining away. The result is an extremely smooth, stable and slippery surface that repels the oils on the feet of insects." By capturing these insects, the plants gain an additional source of nitrogen, allowing them to thrive in nutrient-poor soils.
Tak-Sing Wong has mimicked the Nepenthes peristomes to create a new synthetic material which is ten times as slippery as the next most slippery synthetic.
His surfaces "are made of either stacks of tiny posts, each a thousand times thinner than a human hair, or a random network of similarly thin fibres. These provide a rough structure, which Wong filled with a lubricant, just as the pitcher plant saturates its rough cells with nectar. The lubricant mixes with neither water nor oils, and it barely evaporates," explains Yong.
Find out more and see the vidoes of the slippery surface in action at Discover Magazine.
News - Increased rainforest growth could release carbon
16 August 2011
For the last six years an international team of plant scientists have been working in the rainforest in Panama, looking at the potential effects of climate change on the rainforest ecosystem. Among the research underway was a careful study of the role of litterfall – the dead plant material such as leaves and bark that builds up on the ground under the trees. The group hypothesised that, as climate change stimulates increased growth in tropical forests, that litterfall would increase in turn, and that this would have a significant impact on the soil.
Tropical forests play an essential role in regulating the carbon balance. It is thought that trees will respond to rising levels of carbon dioxide by with increasing growth, and taking up more carbon. However, increased tree growth will result in more leaves, and hence more litterfall.
Plant scientist Dr Emma Sayer, who has a fellowship that has seen her spending time in both Cambridge and Panama, chose to investigate three key questions: What interactions exist between fine roots in the soil and litter in the forest floor? Does increased litterfall cause loss of soil carbon through priming effects? What are the relative contributions of roots and litter to total soil respiration? Over the years, she has carefully worked on a number of test plots on the Gigante Peninsula in the Barro Colorado Nature Monument. "In brief, we remove all the litter from five 45-m x 45-m plots once a month and add it to five others, leaving five undisturbed as controls," Dr Sayer says.
Her study now concludes that that a large proportion of the carbon sequestered by greater tree growth in tropical forests could in turn be lost from the soil. She and her colleagues estimate that a 30% increase in litterfall could release about 0.6 tonnes of carbon per hectare from lowland tropical forest soils each year. This amount of carbon is greater than estimates of the climate-induced increase in forest biomass carbon in Amazonia over recent decades. Given the vast land surface area covered by tropical forests and the large amount of carbon stored in the soil, this could affect the global carbon balance.
Dr Sayer says “Most estimates of the carbon sequestration capacity of tropical forests are based on measurements of tree growth. Our study demonstrates that interactions between plants and soil can have a massive impact on carbon cycling. Models of climate change must take these feedbacks into account to predict future atmospheric carbon dioxide levels.”
Find out more at the University of Cambridge's Research News website.
News - How plants shaped our landscapes & rivers
24 August 2011
New research suggests that the familiar landscapes we see around the world today – the rivers, fertile plains, and rich forest ecosystems - were shaped around 330 million years ago by the steady evolution of plants. And in turn, these landscapes would eventually encourage the growth of settled farming societies, shaping human society.
We've often heard about how deforestation can lead to barren and vulnerable landscapes, with water washing away the soil, which is no longer held together by tree roots. So what would the ground have looked like in a world without any kind of roots at all?
“The continuing evolution and expansion of land plants irrevocably altered the alluvial landscape,” write Neil Davies and Martin Gibling, in an article published in Nature Geoscience, August 2011. The team of paeleobotanists and geologists from the Dalhouseie University, Nova Scotia, have been conducting numerous field trips and analysing over 330 published studies of river channels in rock strata, to link together the evolution of key features in plants with the changing landscape in the Carboniferous period.
Animals came onto land before the ancestors of our modern plants, so these early organisms were arriving in a world that was already inhabited by potential 'predators'. We might find it difficult to recognise these plant ancestors as such - these early plants had no conducting tissues (phloem and xylem), and so were severely limited in size, nor did they have any roots.
"Shallow rooting first becomes apparent in Lower Devonian (Lochkovian) strata as a mechanism for water supply and stabilising arborescent vegetation. Subsequently, as the size and diversity of arborescent vegetation increased through the later
Devonian and Carboniferous, the depth and diversity of rooting increased dramatically. ... With Carboniferous plants using an increasingly diverse array of morphologies and life strategies, plant groups would have interacted in various ways with their environment," the scientists write.
Davies and Gibling postulate that without these tight root networks holding the soil particles together, early rivers were not confined to channels as they usually are today, but instead tended to flood across the landscape in shallow. The result might perhaps have looked more like a perpetually moving flood than what we think of as a river.
When tree-like plants with deep roots developed some 330 million years ago, they could hold together soil, limiting the spread of river channels. "This would have greatly boosted the stability of the entire floodplain," write the authors. Rather than spreading broadly across the landscape, rivers became single, deeper channels, the landscape we know today.
The landscape these newly-evolving plants created supported new ecosystems in its turn. These stable lowlands with fixed rivers are well watered and could develop deep, organic soil, which allowed rich ecosystems to systems. Flood plains also provide fertile farmland for humans, which probably acted to encourage more settled societies.
Find out more about the research at Nature Geoscience online.
If you'd like to explore plant evolution and development for yourself, why not take a look at the Plant Evolution timeline, an interactive online presentation of plant evolution created by members of the University of Cambridge's Department of Plant Science for their students. It's particularly interesting to look at the evolution of new species by selecting 'Species and Speciation' (lower graph), the development of roots, stomata and conducting tissues, ('Physiological Developments' on the lower graph) and the changes in carbon dioxide (on the top graph).
News - ‘Artificial leaf’ is a potential source of clean energy
30 July 2011
Look around you. All over the world, plants are harnessing the sun’s energy to split water molecules, causing oxygen to be released. It’s a process that needs nothing more than light, carbon dioxide, water – and some immensely sophisticated biochemistry on the part of the plants.
For years, scientists have dreamt of creating ‘artificial leaves’ – power sources that would need as few and as simple inputs as real leaves do. These could produce energy for billions of people in parts of the world where electricity is currently unavailable or unreliable.
Now, researchers at MIT, one of the USA’s foremost universities, have taken an important step towards making the dream a reality. Their prototype ‘artificial leaf’ combines a standard silicon solar cell with a catalyst developed by Prof Dan Nocera and his team. When immersed in water and exposed to sunlight, the ‘leaf’ causes bubbles of oxygen to separate out of the water. Again, they’ve learnt from biochemistry to develop their new technology. “The catalyst has the same structure as the leaf’s water-splitting machine but with cobalt instead of manganese,” Prof Nocera explains.
The next step to producing a usable ‘artificial leaf’, the team reports, is to integrate an additional catalyst to bubble out hydrogen molecules. These could then be used to generate electricity or to make fuel for vehicles.
The MIT news office reports: “ultimately, Nocera wants to produce a low-cost device that could be used where electricity is unavailable or unreliable. It would consist of a glass container full of water, with a solar cell with the catalysts on its two sides attached to a divider separating the container into two sections. When exposed to the sun, the electrified catalysts would produce two streams of bubbles — hydrogen on one side, oxygen on the other — which could be collected in two tanks, and later recombined through a fuel cell or other device to generate electricity when needed.”
Read all about it on the MIT news website
Or see Professor Nocera talk about his dream of personalised energy through 'artificial leaves' (discussion of photosyntehsis begins at 12.28)
News - Cucumbers blast off to explore gravitropism
Japanese astronauts are taking cucumbers into space in a major new experiment to understand off-planet plant growth.
We all know that plants are fundamental to life on Earth, not only providing the oxygen we breathe, but the food we eat as well. For long term space missions to be carried out successfully, the astronauts will need to take plants with them. But how will plants respond to the environment of a space station, and in particular, the lack of gravity?
The first study on cucumbers by the Japan Aerospace Exploration Agency (JAXA) looked at directional root growth. They found that, rather than growing downwards, under microgravity the cucumber roots grew sideways.
In the latest study, the team will investigate whether hydrotropism can be used to control the direction of root growth in microgravity.
The NASA website reports that "To perform the HydroTropi experiment, astronauts transport the cucumber seeds from Earth to the space station and then coax them into growth. The seeds, which reside in Hydrotropism chambers, undergo 18 hours of incubation in a Cell Biology Experiment Facility or CBEF. Then the crewmembers activate the seeds with water or a saturated salt solution, followed by a second application of water 4 to 5 hours later. The crew harvests the cucumber seedlings and preserves them using fixation tubes called Kenney Space Center Fixation Tubes or KFTs, which then store in one of the station MELFI freezers to await return to Earth.
The results from HydroTropi, which returns to Earth on STS-133, will help investigators to better understand how plants grow and develop at a molecular level. The experiment will demonstrate a plant’s ability to change growth direction in response to gravity (gravitropism) vs. directional growth in response to water (hydrotropism). By looking at the reaction of the plants to the stimuli and the resulting response of differential auxin -- the compound regulating the growth of plants -- investigators will learn about plants inducible gene expression. In space, investigators hope HydroTropi will show them how to control directional root growth by using the hydrotropism stimulus; this knowledge may also lead to significant advancements in agriculture production on Earth."
News - Biofuels that also clean polluted waters?
When we talk about biofuels, it's often about the food - fuel conflict: the worry that growing plants for fuel comes at the expense of necessary food crops. Around the world, plant science researchers are trying to overcome this conflict, looking at the role of algae, of willows, and of perennial crops like Miscanthus.
A team of US researchers have a bigger hope - to find a source of biofuels which grows by feeding on polluted waters, cleaning up contamination as it grows. The potential plant biofuel is duckweed, a dull looking plant that spreads across ponds with incredible rapidity.
“You plant corn and get one crop a year,” says Dr. Jay Cheng, an associate professor in the Department of Biological and Agricultural Engineering at North Carolina State University. “We need to develop sources for fuel that are more renewable and won’t divert our nation’s food resources.”
Three-quarters of the mass of Cheng's duckweed is starchy content that can be broken down and fermented into ethanol. Because the duckweed can be harvested almost daily, it can produce four times the amount of ethanol per acre as corn, says his colleague Dr Anne-Marie Stomp, who previously modified the plant to produce proteins for pharmaceuticals.
They're now growing their duckweed on hog-waste lagoons - huge 'lakes' full of pig faeces and urine which are the result of factory pig farms. The hog-waste lagoons pollute the water and air around them, and may damage the health of people living nearby. It's a serious problem in the US, particularly in North Carolina and Iowa, which are the nation's biggest pig producers.
The duckweed consumes the excess nutrients from waste lagoons, cleaning the water as it grows. Farmers would need to be trained to grow and harvest duckweed, Stomp says, but the crop could produce jobs in rural North Carolina—as well as fuel and cleaner water.
News - Ethics report on biofuels published
The Nuffield Council on Bioethics has published its recommendations on ethical standards for biofuels, together with a collection of free teaching resources on the subject.
Concerns over energy security, economic development and climate change are driving the development of biofuels. However, biofuels production, which currently mainly uses food crops, has been controversial because in some cases it has led to deforestation, and to disputes over rising food prices and land use.
New types of biofuels, such as those using non-food crops and algae, are being developed with the aim of meeting our energy demands whilst avoiding the problems of the past.
This report on the ethical implications of biofuels lays out 6 clear principals for future development to follow, and would make an interesting base for discussion in the classroom.
They recommend that:
- Biofuels development should not be at the expense of human rights
- Biofuels should be environmentally sustainable
- Biofuels should contribute to a reduction of greenhouse gas emissions
- Biofuels should adhere to fair trade principles
- Costs and benefits of biofuels should be distributed in an equitable way
The Council has published a set of teaching resources for KS3 and above based on its 2011 report 'Biofuels: ethical issues'.
The resources are split into two lessons. In the first lesson, students will begin by learning about the different types of biofuels that are being produced as alternative renewable sources of energy. They will explore the advantages and disadvantages of these different types of biofuels, and begin to make comparisons. The second lesson includes a role-play exercise to aid further exploration of the impacts of biofuels production in countries such as Brazil, Malaysia and the USA.