Molecular mechanism for the inhibition of photosynthesis by UV and excess photon energy and its proteshon

阳光对植物生长至关重要，但它的紫外线成分抑制光合作用。即使是光合作用必需的可见成分也会产生活性氧（ROS）并引起光抑制，当叶片暴露在超过固定co2所需的阳光强度时。本文主要从以下几个方面对光抑制的分子机制及其保护作用进行了研究。1)抗坏血酸过氧化物酶是ROS诱导光抑制的主要靶分子，2)植物ζ -结晶蛋白的酶学性质和生理功能，3)单脱氢抗坏血酸还原酶还能催化苯氧基自由基的还原，4)紫外线照射诱导蓝绿荧光组分的生物合成及其细胞定位，5)P700的氧化还原变化揭示了PSI周围循环电子传递的特征。6)叶片细胞单线态氧的检测；7)叶绿体和虫黄体水循环的生理功能。

The sunlight is essential for plant growth, but its UV components inhibit photosynthesis. Even the photosynthetically-essential visible components also produces reactive species of oxygen (ROS) and causes the photoinhibition, when leaves are exposed to sunlight intensities in excess of that required for CO_2-fixation. In the present research, the molecular mechanisms of photoinhibition and its protection have been studied on the following topics. 1) Ascorbate peroxidase is the primary target molecules of ROS to induce photoinhibition, 2) Enzymatic properties and physiological functions of zeta-crystallin protein of plants, 3) Monodehydroascorbate reductase is able to catalyze also the reduction of phenoxyl radicals, 4) Induced biosynthesis of blue-green fluorescence components by UV irradiation and its cellular localization, 5) Characteristic properties of the cyclic electron transport around PSI, as revealed by redox change of P700, 6) Detection of singlet oxygen photoproduced in leaf cells, 7) Physiological functions of the water-water cycle in chloroplasts and Zooxanthelle.