用10 mmol·L-1 CaCl2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 ℃,1600 μmol·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.
Aimed to understand the effects of exogenous Ca2+ on the D1 protein phosphorylation and PSⅡ performances of wheat leaf chloroplasts under high temperature and illumination stress, wheat leaves at grain-filling stage were sprayed with 10 mmol·L-1 of CaCl2 or water (as control), and then subjected to high temperature and illumination stress (35 ℃ and 1600 μmol·m-2·s-1) for various hours, with the changes in photosynthetic electron transport rate (ETR), net photosynthetic rate, chlorophyll fluorescence parameters, and relative amount of phosphorylated and nonphosphorylated D1 protein in thylakoid membranes determined. After spraying with Ca2+, the PSⅡ reaction center under the stress was reversibly inactivated, the net degradation of D-protein was effectively restrained, the D1 protein phosphorylation was maintained at a higher level, and the ETR of whole chain and PSⅡ, the maximal photochemical efficiency of PSⅡ (Fv/Fm), the actual photochemical efficiency of PSⅡ (ФPSⅡ), the photochemical quenching coefficient (qP ), and net photosynthetic rate (Pn) were all higher, suggesting that exogenous Ca2+ could improve the PSⅡ performances and mitigate its damage under high temperature and illumination stress via regulating the turnover of D1 protein in wheat leaf chloroplasts.