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研究了NaHSO3对不同强度UV-B辐射下菠菜幼苗光合速率、Hill反应速率、叶片色素含量以及叶绿素荧光参数的影响。结果表明,UV-B辐射降低了叶片光合色素含量、净光合速率(Pn)、原初光能转化效率(Fv/Fm)、光化学猝灭系数(qP)、非光化学猝灭系数(qN)、实际光化学效率(ΦPSⅡ)及Hill反应速率;提高了叶绿素a与b(Chl.a/b)和类胡萝卜素与叶绿素(Car./Chl.)的比值;在UV-B辐射胁迫和NaHSO3复合作用下,NaHSO3降低了重度UV-B辐射胁迫下上述指标的变化幅度,而轻度UV-B辐射胁迫下变化无显著差异。分析认为,随着UV-B辐射胁迫剂量的累积,NaHSO3的正效应可以减轻UV-B辐射对菠菜的负效应。复合处理下叶片Chl.a含量、Hill反应速率、原初光能转化效率(Fv/Fm)及ΦPSⅡ的升高是NaHSO3提高UV-B胁迫下Pn的内在原因。
The effects of NaHSO3 on photosynthetic rate, Hill reaction rate, leaf pigment content and chlorophyll fluorescence parameters of spinach seedlings under UV-B radiation were studied. The results showed that UV-B radiation reduced photosynthetic pigment content, Pn, Fv / Fm, qP, qN, Photochemical efficiency (ΦPSⅡ) and Hill reaction rate. The ratios of chlorophyll a and b (Chl.a / b) and carotenoid to chlorophyll (Car./Chl.) Were increased. Under UV-B radiation stress and NaHSO3 , NaHSO3 reduced the change range of these indexes under severe UV-B radiation stress, but there was no significant difference under mild UV-B radiation stress. It is considered that the positive effect of NaHSO3 can reduce the negative effect of UV-B radiation on spinach with the accumulation of UV-B radiation stress dose. The contents of Chl.a, Hill reaction, Fv / Fm and ΦPSⅡin the composite treatment were the intrinsic reasons for the increase of Pn under UV-B stress by NaHSO3.