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用10mmol·L-1CaCl2溶液预处理灌浆期小麦叶片,以水预处理为对照,然后将预处理植株进行高温强光(35℃,1600μmol·m-2·s-1)胁迫,测定胁迫处理过程中小麦旗叶光合电子传递速率、净光合速率、叶绿素荧光参数及D1蛋白的变化,以研究外源Ca2+对高温强光胁迫下小麦叶片类囊体膜D1蛋白磷酸化和PSⅡ功能的影响.结果表明:CaCl2溶液预处理使小麦叶片在高温强光逆境下PSⅡ反应中心发生可逆失活,有效抑制了高温强光下D1蛋白的净降解,保持了较高的D1蛋白磷酸化水平,暗恢复后PSⅡ反应中心活性迅速恢复,全链电子传递速率和PSⅡ电子传递速率恢复至对照水平,维持了较高的PSⅡ原初光化学效率(Fv/Fm)、实际光化学效率(ФPSⅡ)、光化学猝灭系数(qP)和净光合速率(Pn).表明外源Ca2+通过调节小麦叶绿体D1蛋白的周转,促进了PSⅡ的正常运转,减轻了高温强光胁迫对叶片光合机构的损伤.
The leaf of wheat at grain filling stage was pretreated with 10 mmol·L-1 CaCl2 solution, and the water pretreatment was used as the control. The pretreated plants were exposed to high temperature and high light (35 ℃, 1600 μmol · m-2 · s-1) The changes of photosynthetic electron transport rate, net photosynthetic rate, chlorophyll fluorescence parameters and D1 protein in flag leaf of wheat were studied in order to study the effects of exogenous Ca2 + on the phosphorylation of D1 protein and the function of PSⅡ in wheat leaf thylakoid membrane under high temperature and high light stress.Results The results showed that: CaCl2 pretreatment reverses the inactivation of PSⅡ reaction in wheat leaves under high temperature and high light stress, effectively inhibits the net degradation of D1 protein under high temperature and high light, and maintains a high level of D1 protein phosphorylation. After dark recovery The activity of PSⅡ reaction center recovered rapidly, and the electron transfer rate of whole chain and the rate of PSⅡ electron transfer returned to the control level, which maintained high initial photochemical efficiency (Fv / Fm), actual photochemical efficiency (ФPSⅡ) and photochemical quenching coefficient (qP ) And net photosynthetic rate (Pn), indicating that exogenous Ca2 + can promote the normal operation of PSⅡ and reduce the damage of photosynthetic apparatus under high temperature and high light stress by regulating the turnover of D1 protein in wheat chloroplasts.