D1蛋白周转和叶黄素循环在青花菜叶片强光破坏防御中的作用  

The Role of D1 Protein Turnover and Xanthophylls Cycle in Protecting Photosynthetic Apparatus of Broccoli Leaves Against Photodamage

作　　者：颉敏华[1,2] 张继澍[1] 郁继华[3] 颉建明[3] 

机构地区：[1]西北农林科技大学生命学院,陕西杨凌712100 [2]甘肃省农业科学院农产品贮藏加工研究所,兰州730070 [3]甘肃农业大学农学院,兰州730070

出　　处：《中国农业科学》2009年第5期1582-1589,共8页Scientia Agricultura Sinica

基　　金：国家科技支撑计划(2007BAD52B01);甘肃省自然科学基金(3ZS051-A25-062);甘肃农业大学创新基金(GAU-CX0517)

摘　　要：【目的】明确青花菜叶片的光抑制特性和主要光破坏防御机制,为青花菜高产高效栽培和选育光破坏防御能力强的品种提供理论依据。【方法】应用抑制剂法和叶绿素荧光测定技术,研究D1蛋白周转和叶黄素循环在青花菜叶片强光破坏防御中的作用。【结果】1800μmol·m-2·s-1强光下胁迫1～4h,或夏季晴天中午强光高温下,青花菜叶片的最大光能转化效率Fv/Fm降低,初始荧光Fo升高;暗中恢复5h或下午光强减弱后,Fv/Fm和Fo均可恢复。硫酸链霉素(SM)或二硫苏糖醇(DTT)处理使强光下青花菜叶片的Fv/Fm、光化学猝灭系数(qP)、开放的PSⅡ有效光能转化效率(F’v/F’m)和实际光化学效率(ΦPSⅡ)的下降幅度增大,SM处理的下降幅度大于DTT处理。强光处理4h后再暗恢复12h的青花菜叶片在1000μmol·m-2·s-1光强下进行荧光诱导,诱导结束时SM处理的ΦPSⅡ和F’v/F’m分别较CK降低85.71%和80.31%,DTT处理的分别较CK降低22.45%和11.48%。【结论】青花菜叶片具有完善的光破坏防御机制,抑制D1蛋白周转和叶黄素循环,均可使强光下青花菜叶片的PSⅡ反应中心遭受破坏,抑制D1蛋白周转的破坏程度大于抑制叶黄素循环;D1蛋白周转在青花菜叶片光破坏防御中的作用大于叶黄素循环。[Objective] The objective of this study is to understand the characteristics ofphotoinhibition and mechanisms of photoprotection in broccoli leaves. [Method] The roles olD1 protein turnover and xanthophylls cycle in protecting photosynthetic apparatus of broccoli leaves against photodamage were studied by using their inhibitors and chlorophyll fluorescence parameters. [Result] Significant decreases in Fv/Fm and increases in Fo were observed in broccoli leaves exposed to strong light stress （light intensity 1 800 μmol·m^-2·s^-1） for 1-4 h or a natural high temperature and strong light condition at noon in summer, the changes of Fv/Fm or Fo showed recovery in darkness for 5h or when sunlight intensity decreased after 14：00. SM and DTT resulted in stronger degree of reducement in Fv/Fm, qP, F＇v/F＇m and ФPS Ⅱ when broccoli leaves were treated with strong light. Compared to the control, ФPS Ⅱ and F＇v/F＇m after chlorophyll fluorescence induction with light intensity 1 000 μmol·m^-2·s^-1 for 660 seconds in SM-treated leaves decreased by about 85.71%, 80.31% in broccoli leaves treated under 1 800 μmol·m^-2·s^-1 for 4h and then recovered in the dark for 12h, and in DTT-treated leaves reduced by about 22.45% and 11.48%, respectively. [ Conclusion ] These results suggested that there were perfect mechanisms of photoprotection in broccoli leaves, and that photosynthetic apparatus in SM- or DTT-treated leaves were photodamaged under strong light. More severe photodamage occurred in SM-treated leaves than that in DTT-treated ones, indicating that D 1 protein turnover might play more important role in protecting photosynthetic apparatus of broccoli leaves against photodamage than xanthophylls cycle.

关 键 词：青花菜 强光 D1蛋白周转 叶黄素循环 SM DTT 

分 类 号：S635.3[农业科学—蔬菜学]