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Topic Name: Scientists has discovered unravel plants' natural defenses

Category: Environmental engineering

Research persons: Professor Horton, Dr Alexander Ruban

Location: University of Sheffield, United Kingdom

Details

A team of researchers, led by the University of Sheffield and Queen Mary, University of London, has discovered how plants protect their leaves from damage by sunlight when they are faced with extreme climates. The new findings, which have been published in Nature, could have implications both for adapting plants to the threat of global warming and for helping man better harness solar energy.

Photosynthesis in plants relies upon the efficient collection of sunlight. This process can work even at low levels of sunlight, when plants are in the shade or under cloud cover for example. However, when the sun is very bright or when it is cold or very dry, the level of light energy absorbed by leaves can be greatly in excess of that which can be used in photosynthesis and can destroy the plant. However, plants employ a remarkable process called photoprotection, in which a change takes place in the leaves so that the excess light energy is converted into heat, which is harmlessly dispersed.

Until now, researchers hadn’t known exactly how photoprotection works. By joining forces with their physicist colleagues in France and the Netherlands, the UK team have determined how this process works. They were able to show how a small number of certain key molecules, hidden among the millions of others in the plant leaf, change their shape when the amount of light absorbed is excessive; and they have been able to track the conversion of light energy to heat that occurs in less than a billionth of a second.

Many plant species can successfully inhabit extreme environments where there is little water, strong sunlight, low fertility and extremes of temperature by having highly tuned defence mechanisms, including photoprotection. However, these mechanisms are frequently poorly developed in crop plants since they are adapted for high growth and productivity in an environment manipulated by irrigation, fertilisation, enclosure in greenhouses and artificial shading. These manipulations are not sustainable, they have high energy costs and may not be adaptable to an increasingly unstable climate. Researchers believe that in the future, the production of both food and biofuel from plants needs to rely more on their natural defence mechanisms, including photoprotection.

Professor Horton, of the University of Sheffield’s Department of Molecular Biology and Biotechnology, who lead the UK team, said: “These results are important in developing plants with improved photoprotective mechanisms to enable them to better cope with climate change. This may be hugely significant in our fight against global warming. It is a fantastic example of what can be achieved in science when the skills of biologists and physicists are brought together.”

Moreover, there are other global implications of this research. Dr Alexander Ruban of Queen Mary's School of Biological and Chemical Sciences, comments: “As we seek to develop new solar energy technology it will be important to not only understand, but to mimic the way biology has learnt to optimise light collection in the face of the continually changing intensity of sunlight.”

The research project is a collaboration between the University of Sheffield, UK; Queen Mary, University of London, UK; the University of Amsterdam, Netherlands; the University of Wageningen, Netherlands; CEA Saclay and CNRS Gif-sur-Yvette, France.

The work was supported by grants from UK Biotechnology and Biological Sciences Research Council, the Netherlands Organization for Scientific Research via the Foundation of Earth and Life Sciences, Laserlab Europe; ANR, and the Marie Curie Research Training Network.

Note for Photosynthesis

Photosynthesis is the conversion of light energy into chemical energy by living organisms. The raw materials are carbon dioxide and water, the energy source is sunlight, and the end-products include glucose and oxygen. It is arguably the most important biochemical pathway, since nearly all life depends on it. It is a complex process occurring in higher plants, phytoplankton, algae, as well as bacteria such as cyanobacteria. Photosynthetic organisms are also referred to as photoautotrophs.
Photosynthesis uses light energy and carbon dioxide to make triose phospates (G3P). G3P is generally considered the prime end-product of photosynthesis. It can be used as an immediate food nutrient, or combined and rearranged to form monosaccharide sugars, such as glucose, which can be transported to other cells, or packaged for storage as insoluble polysaccharides such as starch.

Note for Climate change

Climate change refers to the variation in the Earth's global climate or in regional climates over time. It describes changes in the variability or average state of the atmosphere over time scales ranging from decades to millions of years. These changes can be caused by processes internal to the Earth, external forces (e.g. variations in sunlight intensity) and, more recently, human activities.
In recent usage, especially in the context of environmental policy, the term "climate change" often refers to changes in modern climate which according to the IPCC are 90-95% likely to have been in part caused by human action. Consequently the term anthropogenic climate change is frequently adopted; this phenomenon is also referred to in the mainstream media as global warming. In some cases, the term is also used with a presumption of human causation, as in the United Nations Framework Convention on Climate Change (UNFCCC). The UNFCCC uses "climate variability" for non-human caused variations. In the 1970s timeframe, this term was more often associated with the phenomena of global cooling.
For information on temperature measurements over various periods, and the data sources available, see temperature record. For attribution of climate change over the past century, see attribution of recent climate change.

Note for Global warming

Global warming refers to the increase in the average temperature of the Earth's near-surface air and oceans in recent decades and its projected continuation.
The global average air temperature near the Earth's surface rose 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the last 100 years. The Intergovernmental Panel on Climate Change (IPCC) concludes, "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations" via the greenhouse effect. Natural phenomena such as solar variation combined with volcanoes probably had a small warming effect from pre-industrial times to 1950 and a small cooling effect from 1950 onward. These basic conclusions have been endorsed by at least 30 scientific societies and academies of science, including all of the national academies of science of the major industrialized countries. While individual scientists have voiced disagreement with some of the main conclusions of the IPCC, the overwhelming majority of scientists working on climate change are in agreement with them.

Note for Solar energy

Solar energy is energy from the Sun. This energy drives climate and the weather supports virtually all life on Earth. Heat and light from the sun, along with solar-based resources such as wind and wave power, hydroelectricity and biomass, account for over 99.9 percent of the available flow of renewable energy.
Solar energy technologies harness the sun's energy for practical ends. These technologies date from the time of the early Greeks, Indian, Native Americans and Chinese, who warmed their buildings by orienting them toward the sun. Modern solar technologies provide heating, lighting, electricity and even flight.

Solar power is used synonymously with solar energy or more specifically to refer to the conversion of sunlight into electricity. This can be done either through the photovoltaic effect or by heating a transfer fluid to produce steam to run a generator.