Sheffield, United Kingdom
November 21, 2007
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 paper, Identification of a mechanism of photoprotective
energy dissipation in higher plants, will be published in Nature
on 22 November 2007.
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. |
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