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以叶绿素快相荧光动力学曲线(OJIP)为探针,研究了外源钙对干旱胁迫下烤烟幼苗光系统Ⅱ(PSⅡ)功能的影响.结果表明:干旱胁迫降低了烤烟幼苗PSⅡ原初光能转换效率(Fv/Fm)和电子传递速率(ETR),抑制了光合作用的原初过程,烤烟幼苗叶片发生了明显的光抑制.叶面喷施10.0mmol·L-1CaCl2溶液后烤烟叶片的光合电子传递能量比例(φEo)在干旱胁迫下的降低幅度明显小于对照(喷施清水),电子转运效率(ETo/RC)在干旱胁迫下明显高于对照.叶面喷施CaCl2溶液增加了PSⅡ捕获光能用于光合电子传递的比例、剩余有活性反应中心的效率和电子传递链中的能量传递,使烤烟叶片的光系统Ⅱ在干旱胁迫下保持相对较高的活性,从而提高了烤烟幼苗的抗旱能力.
The effect of exogenous calcium on the photosystem Ⅱ (PSⅡ) function of flue-cured tobacco seedlings under drought stress was investigated by using the fast chlorophyll fluorescence kinetic curve (OJIP). The results showed that drought stress reduced the primary light energy conversion (Fv / Fm) and electron transfer rate (ETR), inhibited the photosynthesis of the initial process, flue-cured tobacco seedling leaf photosynthetic obvious inhibition.Flower spraying 10.0mmol·L-1CaCl2 solution photosynthetic electron transfer The decrease of energy ratio (φEo) under drought stress was significantly lower than that of control (sprayed with clear water), electron transport efficiency (ETo / RC) under drought stress was significantly higher than that of CK The ratio of photosynthetic electron transfer, the efficiency of the remaining reactive centers and the energy transfer in the electron transfer chains allowed photosystem II of flue-cured tobacco leaves to maintain relatively high activity under drought stress, thereby increasing the drought resistance of flue-cured tobacco seedlings .