New Mexico Consortium, Los Alamos, NM, 87544, USA.
Pebble Labs, 100 Entrada Drive, Los Alamos, NM, 87544, USA.
Sci Rep. 2019 Sep 10;9(1):13028. doi: 10.1038/s41598-019-49545-8.
Photosynthetic electron transport rates in higher plants and green algae are light-saturated at approximately one quarter of full sunlight intensity. This is due to the large optical cross section of plant light harvesting antenna complexes which capture photons at a rate nearly 10-fold faster than the rate-limiting step in electron transport. As a result, 75% of the light captured at full sunlight intensities is reradiated as heat or fluorescence. Previously, it has been demonstrated that reductions in the optical cross-section of the light-harvesting antenna can lead to substantial improvements in algal photosynthetic rates and biomass yield. By surveying a range of light harvesting antenna sizes achieved by reduction in chlorophyll b levels, we have determined that there is an optimal light-harvesting antenna size that results in the greatest whole plant photosynthetic performance. We also uncover a sharp transition point where further reductions or increases in antenna size reduce photosynthetic efficiency, tolerance to light stress, and impact thylakoid membrane architecture. Plants with optimized antenna sizes are shown to perform well not only in controlled greenhouse conditions, but also in the field achieving a 40% increase in biomass yield.
高等植物和绿藻的光合电子传递速率在大约四分之一的全日照强度下达到饱和。这是由于植物光捕获天线复合物的大光学横截面，其以比电子传递限速步骤快近 10 倍的速度捕获光子。因此，在全日照强度下捕获的 75%的光被重新辐射为热或荧光。以前已经证明，减少光捕获天线的光学横截面可以导致藻类光合作用速率和生物量产量的大幅提高。通过调查通过降低叶绿素 b 水平实现的一系列光捕获天线大小，我们已经确定存在一个最佳的光捕获天线大小，从而产生最大的整个植物光合作用性能。我们还发现了一个明显的转折点，其中进一步减少或增加天线大小会降低光合作用效率、对光胁迫的耐受性以及对类囊体膜结构的影响。具有优化天线大小的植物不仅在受控温室条件下表现良好，而且在田间也表现良好，生物量产量增加了 40%。
