New Mexico Consortium (NMC) scientists Guangxi Wu, Lin Ma, Richard Sayre, and Choon-Hwan Lee recently published an article, Identification of the Optimal Light Harvesting Antenna Size for High-Light Stress Mitigation in Plants, in the journal Frontiers of Plant Science
It is well known that the low efficiency of photosynthesis is one of the main constraints in limiting growth in plants. Most of this inefficiency comes from light absorption and the conversion of light into chemical energy. This is because photosynthesis light saturates at one quarter full sunlight intensity in plants, and results in excess energy being dissipated as heat, fluorescence and through the production of damaging reactive oxygen species. Why is this? Why have plants evolved large fixed size light harvesting antenna sizes that light saturate at one quarter full sunlight intensity? This is another interesting question for future research.
Research has shown that it is it possible to adjust the size of a plant’s light harvesting antenna over a broad range of optical cross sections through targeted reductions in chlorophyll b content. This results in creating smaller and smaller peripheral light harvesting antenna in these plants.
In this study, the researchers have examined the impact of altering the light harvesting antenna size and how it affects the range of photoprotective activity and the evolutionary fitness or seed production in Camelina plants grown at different light intensities. This was done to help understand how plants select light harvesting antenna size that is a best fit for a range of light intensities.
This study shows that plants having light harvesting antenna sizes engineered for the greatest photosynthetic efficiency also have the greatest capacity to ease high light stress through nonphotochemical quenching and the reduction of reactive oxygen associated damage. When the plants are grown with less light, this study shows that the optimal light harvesting antenna size for photosynthesis is larger than that for plants grown at greater (or super-saturating) light intensities and is more similar to the antenna size of wild-type plants.
The results of this research suggest that the light harvesting antenna size of plants is designed to maximize fitness under low light conditions such as occurs in shaded environments and in light competition with other plants.
To read the entire article see:
Identification of the Optimal Light Harvesting Antenna Size for High-Light Stress Mitigation in Plants. Guangxi Wu, Lin Ma, Richard T. Sayre, Choon-Hwan Lee. Front. Plant Sci., 15 May 2020. 11:505. doi: 10.3389/fpls.2020.00505