高温强光下水杨酸对黄瓜叶片叶绿素荧光和叶黄素循环的影响

Effects of salicylic acid on chlorophyll fluorescence and xanthophyll cycle in cucumber leaves under high temperature and strong light.

在高温强光条件下，研究了外源水杨酸对黄瓜叶片叶绿索荧光参数和叶黄素循环的影响．结果表明，在高温强光胁迫前2d用50～400μmol·L^-1水扬酸处理叶片，抑制了高温强光下原初光能转换效率（Fv／Fm）、光合电子传递量子效率（ФPSⅡ）、最大荧光（Fm）和光化学猝灭系数（qP）的下降，分别比对照提商，16．1％～30．2％、11．9％～33．0％、7．2％～41．0％和27．2％～160．8％。促进了非光化学猝灭系数（NPQ）的升高，比对照提高了13．1％～62．9％，而对初始荧光（R）影响不大．水杨酸处理可减小高温强光下叶黄素循环库的下降幅度。使（A＋Z）／（V＋A＋Z）升高，分别比对照高29．5％和24．6％．这些结果说明。水杨酸可通过提高非辐射能量耗散，对高温强光引起的黄瓜叶片光合机构的破坏具有保护作用．

In this study, cucumber leaves were under high temperature and strong light stress after two days of spraying with 50- 400μmol· L^-1 salicylic acid （SA） solution. The measurements showed that SA pretreatment could inhibit the decrease of intrinsic photochemical efficiency （Fv/Fm）, quantum yield of PSⅡ（Ф9PSⅡ）, maximum fluorescence value（Fro ）, and photochemical quenching （ qP ） by 16.1% - 30.2 %, 11.9 % - 33.0 %, 7.2 % - 41.0 % and 27.2 % -160.8%, respectively, and promote the increase of non photochemical quenching （NPQ） by 13.1%- 62.9 %, but had little effect on initial fluorescence value （Fo）. SA pretreatment could also inhibit the decrease of xanthophyll cycle pool in cucumber leaves, and increase the de-epoxidation extent of xanthophyll cycle （A ＋ Z）/（ V ＋ A ＋ Z）, which was 29.5% and 24.6% higher than control, respectively. It was suggested that SA could protect the photosynthetic apparatus of cucumber leaves under high temperature and strong light through promoting non radiative energy dissipation,