柑橘叶片中叶黄素循环对PSII反应中心D1蛋白的保护效应

用叶黄素循环抑制剂二硫苏糖醇（DTT）处理7h的柑橘离体叶片，其非光化学猝灭系数NPQ大幅度下降；在中等强度光（500μmol·m^-2·s^-1）和高强度光（1500μmol·m^-2·s^-1）下，DTT处理的叶片光化学效率（Fv/Fm）分别下降3．8％和39．7％，光合电子传递速率（ETR）分别下降12％和49．5％，D1蛋白含量也分别下降87％和92.3％；黑暗对DTT处理叶片的各种荧光参数和D1蛋白的影响不大。显示叶黄素循环在保护光系统（PS）II反应中心、抵御光抑制中有一定的积极效应，可能影响了D1蛋白周转。

Protective Effect of Xanthophyll Cycle on the D1 Protein of PSII in Leaves of Citrus reticulate Blanco.

In this study, NPQ （non-photochemical quenching coefficient） in leaves of Citrus reticulate Blanco. declined significantly after seven hours with DTT （dithiothreitol） treatment. After DTT treatment, under moderate light of 500 μmol·m^-2·s^-1, Fv/Fm （photochemical efficiency）, ETR （electron transport rate）, and the content of D1 protein in leaves of C. reticulate decreased by 3.8%, 12%, and 87%, respectively. Under high light of 1 500 μmol·m^-2·s^-1, the corresponding parameters decreased by 39.7%, 49.5%, and 92.3%, respectively. In the dark, DTT treatment did not have significant effect on the chlorophyll fluorescence parameters and the level of the D1 protein. This result indicated that xanthophyll cycle played role in protecting PSII against photoinhibition and might have effect on the D 1 protein turnover.