植物叶片中RuBP羧化酶／加氧酶及光反应机构衰老机理的研究进展

ADVANCES ON MECHANISMS OF SENESCENCE OF RIBULOSE-1, 5-BISPHOSPHATE CARBOXYLASE/OXYGENASE AND PHOTOSYNTHETIC ELECTRON TRANSPORT CHAIN IN PLANT

在作者及其实验室多年研究的基础上，针对今后的研究方向，对国内外在植物光合机构与功能衰老研究的进展进行综述和讨论。叶向导度、ＲｕｂｉｓＣＯ含量、ＲｕＢＰＣａｓｅ活性及光系统活性是老化过程中光合速率的内部限制因素。在衰老过程中，１，５－二磷酸核酮糖羧化酶／加氧酶活性降低，ＲｕｂｉｓＣＯ蛋白合成在转录和翻译水平上均受到抑制，同时ＲｕｂｉｓＣＯ蛋白也受到蛋白水解酶的分解；类囊体膜结构紊乱，膜上结合色素、脂类和功能蛋白受到破坏，光合电子传递链活性及光合磷酸化水平发生衰退。植物光合机构及功能衰老在多条途径上渐次展开，叶绿体内光合电子传递生成还原物质的过程与碳素、氮素同化及Ｍｅｌｈｅｒ反应利用还原物质过程之间的失衡可能是光合机构不可逆衰老的重要机制。

The present paper reviews the advances on physiology and mechanisms of senescence of plant photosynthesis on the basis of our research. The limiting factors of photosynthetic rate during senescence include mesophyll conductance, RubisCO protein content, RuBPCase activity and photosystem activity. During senescence, RuBPCase/Oase activity decreases. RubisCO protein synthesis is inhibited in both transcription and translation, and RubisCO pramtein is hydrolyzed by proteinase. The thylakoid structure disorders, pigment and protein bound to thylakoid membraneare damaged, and photosynthetic electron transport rate decreases. The possible mechanism of irreversible senescenceof plant photosynthesis is imbalance of the production of reductive agent by electron transport and utilization of thatby carbon assimilation, nitrogen assimilation and Mehler reaction