An international team of researchers, led by physicist Nathaniel M. Gabor at the University of California, Riverside, has finally uncovered why plants are green. To achieve this, they built a model that reproduces a general feature of photosynthetic light-harvesting.
"Our model shows that by absorbing only very specific colors of light, photosynthetic organisms may automatically protect themselves against sudden changes - or 'noise' - in solar energy, resulting in remarkably efficient power conversion," said in a statement Gabor, an associate professor of physics and astronomy, who led the study.
"Green plants appear green and purple bacteria appear purple because only specific regions of the spectrum from which they absorb are suited for protection against rapidly changing solar energy," Gabor added.
Once completed, Gabor's model was extended to include a wider range of photosynthetic organisms. The researchers were then able to show that the model could be applied in other organisms besides green plants.
This indicated that the model identified a general and fundamental property of photosynthetic light-harvesting.
"Our study shows how, by choosing where you absorb solar energy in relation to the incident solar spectrum, you can minimize the noise on the output - information that can be used to enhance the performance of solar cells," said Richard Cogdell, a renowned botanist at the University of Glasgow in the United Kingdom and a co-author on the research paper.
The researchers illustrated how plants and other photosynthetic organisms use a variety of tactics to prevent damage due to overexposure to the sun. These include everything from the molecular mechanisms of energy release to the physical movement of leaves.
The scientists further explained how photosynthetic organisms avoid undergoing oxidative stress which damages cells. If the flow of solar power into the organism's light-harvesting network is larger than the flow out, the photosynthetic network must adapt or risk having its organism damaged.
As such, the system automatically adapts. Now, the researchers plan to design a microscopy technique to test their ideas.