Quirks and Quarks

Plants avoid sunburn by shivering away extra heat

MIT chemists now understand how plants mosses and algae can avoid getting burnt by the sun.
All the greenery around Dickson Falls in Fundy National Park of Canada in New Brunswick can switch between photosynthesis and photoprotection, depending on how how intense the sun shines. (Danielle Langlois)

Plants, algae and mosses have their own way of preventing sunburn and it involves a molecule that likes to wiggle when it gets too hot. A new study in Nature Chemistry, by MIT chemist Gabriela Schlau-Cohen, has found a protein that can switch between different states depending on how much sunlight the moss they studied is getting. If it's a beautiful sunny day, the protein has evolved a way to dissipate that excess heat by wagging a part of the molecule around in the cell. As soon as there's a bit of shade, that same protein becomes less stiff and now can absorb all the available sunlight to drive photosynthesis. 

This evolutionary light switch is controlled by the pH of the cell. When photosynthesis is chugging away on a sunny day, the pH of the cell decreases and that is the trigger that tells the cell to try to shake away that excess energy from the sun before it damages the cell. If only dancing sunburn away was that easy.