Plants spend their whole day sunbathing, and while they need sunlight for photosynthesis, overexposure to the Sun’s rays can cause serious damage to their DNA that can disrupt their development. So how do they protect their luscious leaves and shoots from burning to a crisp? A new study has discovered that plants produce a natural “sunscreen”.
This plant sunscreen isn’t like the white lotion that we use to protect ourselves from the Sun - it's a concoction of special molecules, called sinapate esters, that plants produce and then send to the outer layers of their leaves to form an invisible barrier.
Researchers from Purdue University in the US have now discovered that these molecules block ultraviolet-B (UVB) radiation whilst absorbing the light needed for photosynthesis. The team identified the various wavelengths of light that a type of sinapate ester called sinapoyl malate blocks, by converting the sinapoyl malate from a liquid to a gas, and then zapping it with UVB radiation from a laser. Interestingly, they found that the sinapoyl malate was able to soak up radiation at every wavelength across the UVB spectrum.
"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,” Gareth Jenkins, plant biologist at the University of Glasgow in the UK, who was not involved in the study, told Andy Coghlan from New Scientist.
The team says that the discovery could be useful for making plants that are even more resistant to UVB in the case of heatwaves which are becoming increasingly common with climate change.
With such an efficient mechanism for absorbing harmful radiation, it's not surprising that unlike us, plants only need a thin coating of sunscreen to protect themselves from sunburn.
The findings are published in the Journal of the American Chemical Society
Source: New Scientist