【摘要】 强光辐照下高等植物光系统Ⅱ(PSⅡ)会产生超氧阴离子自由基(O2·),该过程中产生的O2·在高等植物光合作用活性氧自由基代谢中具有重要作用.莱茵衣藻光系统结构与高等植物非常相近.应用新型高特异性自旋捕获-ESR方法及四唑氮蓝还原法,首次在莱茵衣藻的类囊体膜和PSⅡ中检测到O·2的生成,通过与有关菠菜的ESR实验结果对比发现两者的O2·产生分子机制可能极为相似.相比高等植物,单细胞莱茵衣藻具有结构简单、遗传背景清晰与基因组测序工作完备等诸多特点.因而,针对莱茵衣藻的O·2分析可能为深入研究高等植物光合系统中的活性氧代谢机制提供新的契机.更多还原

【Abstract】 Higher plant photosystem Ⅱ (PS Ⅱ) generates superoxide anion radicals (O2·) under strong illumination, in which the O2· plays a pivotal role in reactive oxygen species (ROS) metabolism during higher plant photosynthesis. The photosystem of Chlamydomonas reinhardtii is highly similar to that of higher plants. The generation of O2· in C. reinhardtii thylakoid membranes and PS Ⅱ particles has been firstly proved by means of spin trapping-ESR technique and NBT-mediated spectral assay. Referring to the spin trapping-ESR evidences in spinach, the mechanisms of O2· generation both in C. reinhardtii and spinach look identical. Compared to higher plant, C. reinhardtii has several irreplaceable advantages: simpler structure; clearer genetic background and genomic sequencing has been finished; easy to introduce mutations in photosystem. As a result, the study concerning the O2· generation in C. reinhardtii introduces a new promising model for further investigation of ROS metabolism in higher plant photosynthesis.更多还原