钙对高温下巨峰葡萄叶片光合作用和叶绿素荧光的影响

 【目的】分析钙对高温胁迫下葡萄叶片光合、荧光参数的影响,以探明钙在高温胁迫下对叶片光合机构的保护作用。【方法】选取高温时期,以田间生长的巨峰葡萄为试材,研究CaCl2、CaCl2+Ca2+螯合剂EGTA、CaCl2+钙调素抑制剂氯丙嗪（CPZ）预处理对高温胁迫下葡萄叶片的光合、荧光参数及丙二醛（MDA）含量的影响。【结果】喷施CaCl2显著提高了高温胁迫下葡萄叶片的净光合速率（Pn）,使光系统Ⅱ（PSⅡ）维持较高的活性,光化学猝灭系数（qP）、PSⅡ的天线转换效率（Fv’/Fm’）、光系统Ⅱ最大光化学效率（Fv/Fm）均极显著高于对照,初始荧光（Fo）极显著小于对照,膜脂过氧化产物MDA含量稍低于对照;添加抑制剂EGTA、CPZ明显抑制了光合作用,2个处理的Pn分别比钙处理的低29.4%、26.5%;其PSⅡ功能和活性也受到了显著抑制,导致叶片中MDA含量分别比钙处理高33.7%和40.2%。【结论】喷施CaCl2有效缓解了高温对葡萄叶片光合作用的抑制以及对PSⅡ系统的损害。

Effects of Calcium on Photosynthesis and Chlorophyll Fluorescence of 'Kyoho'Grape Under High Temperature Stress

【Objective】 In order to reveal the protection function of calcium on photosynthetic organ in leaves of ‘Kyoho’ grape under high temperature stress, the effects of CaCl2 on photosynthesis and chlorophyll fluorescence under heat stress were studied. 【Method】 During the period of high temperature, the grapes grown in the field were pretreated with CaCl2, CaCl2+Ca2+ chelator EGTA and CaCl2+CaM antagonist CPZ. Photosynthetic rate, chlorophyll fluorescence and MDA content were determined. 【Result】The net photosynthesis rate (Pn), qP, Fv’/Fm’ and Fv/Fm in the grape leaves pretreated with CaCl2 were much higher than that of the control, while Fo was much less than that of the control, and the accumulation of final product of membrane lipid peroxidation (MDA) was slightly lower than the control. EGTA and CPZ pretreatments significantly inhibited the photosythesis, Pn were 29.4% and 26.5% lower than that of CaCl2 pretreatment; the activity of PSⅡ was inhibited significantly, the accumulation of MDA were 33.7% and 40.2% higher than that of CaCl2 pretreatment. 【Conclusion】 CaCl2 pretreatment effectively alleviated the inhibition of photosynthesis in grape leaves under high temperature stress and the damage to the function of PSⅡ to some extent.