Shikanai Toshiharu
Graduate School of Agriculture, Kyushu University, Fukuoka, Japan 812-8581.
Annu Rev Plant Biol. 2007;58:199-217. doi: 10.1146/annurev.arplant.58.091406.110525.
The light reactions in photosynthesis convert light energy into chemical energy in the form of ATP and drive the production of NADPH from NADP+. The reactions involve two types of electron flow in the chloroplast. While linear electron transport generates both ATP and NADPH, photosystem I cyclic electron transport is exclusively involved in ATP synthesis. The physiological significance of photosystem I cyclic electron transport has been underestimated, and our knowledge of the machineries involved remains very limited. However, recent genetic approaches using Arabidopsis thaliana have clarified the essential functions of this electron flow in both photoprotection and photosynthesis. Based on several lines of evidence presented here, it is necessary to reconsider the fundamental mechanisms of chloroplast energetics.
光合作用中的光反应将光能转化为ATP形式的化学能，并驱动从NADP⁺生成NADPH。这些反应涉及叶绿体中的两种电子流。线性电子传递既产生ATP也产生NADPH，而光系统I循环电子传递仅参与ATP合成。光系统I循环电子传递的生理意义一直被低估，我们对其相关机制的了解仍然非常有限。然而，最近利用拟南芥的遗传学方法已经阐明了这种电子流在光保护和光合作用中的基本功能。基于此处提供的几条证据，有必要重新审视叶绿体能量学的基本机制。
