How Plants Cope With Excess Light

Photosynthesis relies on efficient absorption of sunlight . However in cases of extreme sunlight, plants are forced to absorb light energy in excess of what is needed in photosynthesis. The excess light energy can cause serious damages, such as bleaching in leaves. To protect themselves from damages, plants employ a mechanism wherein the excess light energy is converted to heat which is harmlessly released. The process is called photoprotection.

 A group of researchers from the Netherlands, France and United Kingdom has discovered the exact molecular mechanisms of photoprotection. They were able to demonstrate how the light-harvesting antenna pigments in the leaves change in conformation upon absorption of excess sunlight. The molecules then convert the excess light energy into heat in a process that occurs in less than a billionth of a second. The switch between the conformational changes of the light-harvesting molecule dictates the flow of energy in the leaves, controlling the balance between gathering light energy for photosynthesis and its dissipation as heat. Scientists are now conducting studies on how to use the discovery in developing plants with improved photoprotective mechanisms that can cope with climate change.

The abstract of the paper published by Nature is available at http://www.nature.com/nature/journal/v450/n7169/abs/nature06262.html