NO3-胁迫及恢复对黄瓜幼苗叶片叶绿素荧光参数及ATPase活性的影响

通过水培试验,探讨了不同NO₃^-浓度胁迫及恢复对黄瓜幼苗叶片叶绿素含量、叶绿素荧光参数及ATPase活性的影响.结果表明，胁迫7 d后，高浓度NO₃^-(168 mmol·L^-1)可极显著提高叶绿素a、叶绿素b、总叶绿素和类胡萝卜素含量,极显著提高初始荧光(F_o)、Mg ATPase和Ca-ATPase活性，而PSⅡ原初光能转化效率(F_v/F_m)、PSⅡ潜在活性(F_v/F_o)和PSⅡ光合电子传递量子效率(ΦPSⅡ)，却随NO₃^-浓度的增加而降低.恢复7 d后，所有处理叶绿素和类胡萝卜素含量均低于对照；初始荧光基本都恢复至对照水平;PSⅡ原初光能转化效率和PSⅡ光合电子传递量子效率在NO₃^-浓度低于126 mmol·L^-1时，基本恢复至对照水平，而高于这一水平时，仍显著低于对照;PSⅡ潜在活性在NO₃^-浓度为42和126 mmol·L^-1的处理基本达对照水平，其它处理仍极显著低于对照；Mg-ATPase和Ca-ATPase活性均出现先降低后升高的变化趋势.

Effects of NO3-stress and recovery on chlorophyll fluorescence parameters and ATPase activities of cucumber seedling leaves

With water culture, this paper studied the effects of NO3- stress and recovery on the chlorophyll contents, chlorophyll fluorescence parameters, and ATPase activities of cucumber seedling leaves. The results showed that under stress for 7 days, the chlorophyll a, chlorophyll b, total chlorophyll and carotenoid contents, intrinsic fluorescence (Fo), and Mg-ATPase and Ca-ATPase activities were increased significantly when the NO3- concentration was high (168 mmol x L(-1)), while the intrinsic photochemical efficiency (Fv/Fm), potential activities (Fv/Fo) and quantum yield (phiPS II) of PSII were decreased with increasing NO3- concentration. After recovery for 7 days, the chlorophyll and carotenoid contents of all treatments with NO3- were lower than CK, while the intrinsic fluorescence, intrinsic photochemical efficiency and quantum yield of PS II were similar to CK when the NO3- concentration was < or = 84 mmol x L((-1), and the Fv/Fm and phiPS II were significantly lower than CK when the NO3-concentration was > 84 mmol x L(-1). The potential activity of PS II was similar to CK when the NO3- concentration was 42 and 126 mmol x L(-1), but significantly lower than CK in other treatments. The activities of Mg-ATPase and Ca-ATPase were decreased firstly but increased then when the NO3- concentration was > 84 mmol x L(-1).