Researchers Discover Plants Respond Better to Overdoses of Light

Too much sunlight can damage plants, but researchers from Wageningen University & Research and Lithuania have discovered how the internal protection system works to help plants prevent damage from these overdoses.

Green plants are effective in capturing and processing sunlight. They divert the absorbed photons (light particles) to the reaction center - where a series of chemical reactions convert the energy into electrons and protons needed to produce molecules such as sugar. In bright sunlight, however, the reaction center is unable to do this. To prevent the next absorbed light particle from being sent to the reaction center before the previous one has been completely processed, plants deploy various protection mechanisms that convert some of the absorbed light into harmless heat.

To activate the protection system, the plant triggers various enzymes. This effect lasts some tens of seconds to several minutes. In fluctuating light, for example when leaves are blown by the wind, it can result in costly energy losses. The research team discovered that an important part of the activation process is much faster than expected. Although the activation process initially lasts tens of seconds, once the protection has been activated the system can respond to the state of the reaction center almost instantaneously. If the reaction center is still processing the previous bundle of energy, a new incoming bundle is converted into heat; but if the reaction center is available, then a much smaller fraction is converted into heat and so the energy losses are limited.

For more details, read the press release from Wageningen.