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The present study investigated the role of abscisic acid (ABA) application in photosynthesis, photosystems I and II (PSI and PSII), antioxidant system and ABA-related genes expression under sub-high temperature and high light (STHL) stress. STHL treatment led to an irreversible reduction in the photosynthetic rate (Pn),damaged PSII firstly at three hours , and then inhibited RuBPCase activity at seven hours, at last injured PSI after eleven hours. During 11 hours STHL stress, exogenous ABA can alleviate the degree of Pn decreasing, improve the activity of RuBPCase, protect PSII to photoinhibition, and promote the ability of reactive oxygen removal .When severe stress occured, exogenous ABA has certain effect, but can not ease photoinhibition and photodamage. In addition, exogenous ABA effected significantly on genes of upstream regulatory ABA biosynthesis key enzymes and downstream response MYB transcription factors. |
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Keywords:hlorophyll fluorescence; MYB transcription factors; photosynthesis parameters; sub-high temperature and high light; tomato; |
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