Why do plants never seem to get burnt by the UV-B rays within sunlight – this most powerful section of sun radiation which can damage plants as well as humanity?
Most people never give it a second thought, but for fifteen years a team of Glasgow researchers have spent their time working out why plants never seem to get burnt by the UV-B rays within sunlight – this most powerful section of sun radiation whichcan damage plants as well as humanity.
Yet that flora rarely shows any sign of suffering damage caused by sunlight, in spite of being exposed to it all day without access to things people rely on such as protective clothing and sunscreen, because, as researchers found, plants have evolved to produce their own chemical protection within their leaves.
They create a protein – UVR8 – within their leaves which detects the presence of the unwanted UV-B rays, immediately starting off a leaf-protecting chemical reaction, because UVR8 is a photoreceptor – a protein with the facility to detect light, sensing particular regions of the daylight spectrum.
Whilst all vertebrate animal has photo-receptors in the eyes for vision, the photo-receptors that plants employ direct their growth towards any light sources, triggering especially when the plants come into bloom.
UVR8 is, however, a completely new type of photoreceptor by all accounts, this protein employing tryptophan amino acids within its own structure to effectively detect UV-B light. Glasgow University Professor of Plant Cell and Molecular Biology – Gareth Jenkins described this finding as truly groundbreaking, because
searching for this elusive UV-B photoreceptor had been a biological Holy Grail to plant photo-biologists, and the discovery that UVR8 detects UV-B by an entirely novel mechanism was an added and very welcome bonus.