Paul Matthew J, Pellny Till K
Crop Performance and Improvement, Rothamsted Research, Harpenden, Herts. AL5 2JQ, UK.
J Exp Bot. 2003 Jan;54(382):539-47. doi: 10.1093/jxb/erg052.
Photosynthesis is regulated as a two-way process. Light regulates the expression of genes for photosynthesis and the activity of the gene products (feedforward control). Rate of end-product use down-stream of the Calvin cycle, determined largely by nutrition and temperature, also affects photosynthetic activity and photosynthetic gene expression (feedback control). Whereas feedforward control ensures efficient light use, feedback mechanisms ensure that carbon flow is balanced through the pathways that produce and consume carbon, so that inorganic phosphate is recycled and nitrogen is distributed optimally to different processes to ensure growth and survival. Actual mechanisms are sketchy and complex, but carbon to nitrogen balance rather than carbon status per se is central to understanding carbon metabolite feedback control of photosynthesis. In addition to determining the activity of the metabolic machinery, carbon metabolite feedback mechanisms also regulate photosynthesis at the leaf level through the regulation of leaf development. This review summarizes the current sketchy, but growing, knowledge of the mechanisms through which carbon metabolite feedback mechanisms regulate leaf photosynthesis.
光合作用作为一个双向过程受到调控。光调节光合作用相关基因的表达以及基因产物的活性（前馈控制）。卡尔文循环下游的终产物利用速率，很大程度上由营养和温度决定，也会影响光合活性和光合基因表达（反馈控制）。前馈控制确保光的有效利用，而反馈机制确保碳流在产生和消耗碳的途径中保持平衡，从而使无机磷酸盐得以循环利用，氮能最优地分配到不同过程以确保生长和存活。实际机制尚不明确且复杂，但碳氮平衡而非碳状态本身是理解光合作用碳代谢物反馈控制的核心。除了决定代谢机制的活性外，碳代谢物反馈机制还通过调节叶片发育在叶片水平上调控光合作用。本综述总结了目前关于碳代谢物反馈机制调控叶片光合作用的尚不完整但不断增长的知识。
