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探讨清耕栽培苹果叶片衰老过程中PSⅡ荧光诱导动力学的变化,为延迟叶片衰老技术的应用提供理论依据。以清耕栽培‘寒富’苹果为试材,采用气体交换和叶绿素荧光诱导动力学分析技术,研究了叶片衰老过程中叶绿素含量、净光合速率(Pn)和PSⅡ荧光诱导动力学的变化。结果表明,9月30日~10月20日,光合机构通过调控单位面积PSⅡ反应中心数(RC/CSo)、活性反应中心数量(RC/ABS)、捕获的激子中用来推动电子传递链中超过QA的激子所占比率(ψo)和用于电子传递的量子产额(φEo)维持较高的PSⅡ的最大光化学效率(Fv/Fm);10月30日叶片I相和P相荧光强度明显降低,J相相对可变荧光(Vj)显著升高,说明PSⅡ的基本结构和功能受到严重破坏;11月9日叶片K相、J相、I相和P相荧光强度显著降低,可变荧光Fk占Fj-Fo振幅的比例(Wk)和Vj急剧上升,说明PSⅡ基本结构被瓦解、功能已丧失。因此,延缓叶片衰老的技术措施应于10月20日之前使用。
To investigate the changes of PS Ⅱ fluorescence-induced kinetics during the leaf senescence of cultivated apple cultivars, and to provide a theoretical basis for the application of delayed leaf senescence techniques. Using the techniques of gas exchange and chlorophyll fluorescence-induced kinetic analysis, the changes of chlorophyll content, net photosynthetic rate (Pn) and PSⅡ fluorescence induced kinetics of leaves during the senescence of leaves were studied. The results showed that from September 30 to October 20, photosynthetic apparatus controlled the number of PSⅡ reaction centers (RC / CSo) and the number of active reaction centers (RC / ABS) per unit area, and the trapped exciton was used to promote electron transfer chain (Ψo) over the QA exciton and the quantum yield (φEo) for electron transfer maintained a high maximum photochemical efficiency (Fv / Fm) of PSⅡ. On October 30, the fluorescence of I and P phases in leaves The intensity of J phase was significantly decreased, the J phase relative variable fluorescence (Vj) was significantly increased, indicating that the basic structure and function of PS Ⅱ were severely damaged. On November 9, the fluorescence intensity of K phase, J phase, I phase and P phase decreased significantly Fluorescence Fk Fj-Fo amplitude ratio (Wk) and Vj sharp rise, indicating that the basic structure of PS Ⅱ is disintegrated, the function has been lost. Therefore, the technical measures to delay leaf senescence should be used before October 20.