Plants make their own sunscreen to block damaging rays
Here’s an interesting article from New Scientist referencing recent research published in the Journal of the American Chemical Society about how plant’s protect themselves from UV rays while sitting out in the sun all day…
- 31 October 2014 by Andy Coghlan
They bask in the sun for hours, but just like us, plants need to protect themselves from damaging ultraviolet rays. Now we know how they do it.
Many plants use a group of chemicals called sinapate esters to defend against the sun, while they absorb light for photosynthesis. These aromatic compounds sit in the upper cell layers of these plants’ leaves and one type – sinapoyl malate – provides the bulk of this UV protection.
A team led by Timothy Zwier of Purdue University in West Lafayette, Indiana, has probed how sinapoyl malate works, finding that it filters out the entire spectrum of ultraviolet-B radiation, which is known to damage plant and human DNA.
“It can absorb all wavelengths of UV-B radiation, with no ‘gaps’ in coverage,” says Zwier.
Close to zero
Zwier and his colleagues identified the wavelengths that sinapoyl malate intercepts by cooling the substance to near absolute zero and trapping it in argon gas to stop it from evaporating before its ability to block UV-B could be measured.
Gareth Jenkins, who studies UV-B absorption by plants at the University of Glasgow, UK, says that the work shows how effective the sinapate esters are at cutting out radiation. “Plants do not usually show signs of UV damage in sunlight, so the mechanisms they’ve evolved for UV protection, which include sunscreen production, evidently work pretty well,” he says.
The range of UV wavelengths blocked by sinapoyl malate is the same as those that damage human tissues, but Zwier has no plans to develop it as a sun cream ingredient. Closely related natural substances called cinnamates are equally as effective, and are already used widely in sunblocks.
Instead, Zwier says his finding could be useful for developing plants that are even more resistant to UV radiation – something that could come in handy as heatwaves, which have more UV, become more common with climate change.
Journal reference: Journal of the American Chemical Society, DOI: 10.1021/ja5059026