摘要
在40℃高温胁迫条件下,研究了外源草酸对黄瓜叶片光合作用、叶绿素荧光参数和叶黄素循环的影响。结果表明,在高温胁迫前3d用5mmol·L-1草酸处理叶片减小了高温胁迫下净光合速率(Pn)、蒸腾速率(Tr)、原初光能转换效率(Fv/Fm)、光合电子传递量子效率(φPSⅡ)、光化学猝灭系数(qP)和非光化学猝灭系数(NPQ)的下降幅度,而对气孔导度(Gs)没有影响。草酸处理可提高叶黄素循环库的大小和(A+Z)/(V+A+Z),并使高温胁迫下叶黄素循环库、叶绿素、类胡萝卜素含量的下降幅度和(A+Z)/(V+A+Z)在胁迫后期的下降幅度减小。这些结果说明,草酸对高温胁迫下黄瓜叶片光合机构的破坏具有保护作用。
Effects of exogenous oxalate on photosynthesis, chlorophyll fluorescence and xanthophyll cycle in cucumber leaves under high temperature stress at 40℃ were studied. The cucumber leaves were sprayed by 5 mmol·L^-1 oxalate solution for 3 days before high temperature stress. The results showed that oxalate pretreatment alleviated the decreases of photosynthetic rate （Pn）, transpiration rate （Tr）, intrinsic photochemical efficiency （Fv/Fm）, quantum yield of PSⅡ （ φ PSⅡ ）, photochemical quenching （qP） and non-photochemical quenching （NPQ） by higher temperature, but has no effect on stomatal conductance （Gs） was observed. The xanthophyll cycle pool and （A＋Z）/（V＋A＋Z） （the de-epoxidation extent of xanthophyll cycle） pretreated by oxalate was evidently higher than the control. The decrease of xanthophyll cycle pool, chlorophyll and carotenoid content, and the later period decrease of （A＋Z）/（V＋A＋Z） during high temperature stress was inhibited by oxalate pretreatment. These results suggested that oxalate has a protective role against the damage of photosynthetic apparatus during high temperature stress.
出处
《中国农业科学》
CAS
CSCD
北大核心
2005年第9期1774-1779,共6页
Scientia Agricultura Sinica
基金
陕西省自然科学基金项目(2003C128)
