水杨酸对高温强光胁迫下小麦叶绿体D1蛋白磷酸化及光合机构运转的影响

目的]研究外源SA对高温强光胁迫下小麦叶片类囊体膜D1蛋白磷酸化和光合机构运转的影响。方法]用0.5 mmol/L水杨酸（SA）溶液预处理灌浆期小麦叶片,以水预处理为对照,将预处理植株进行高温强光35℃,1600μmol/（m2.s）]胁迫,测定胁迫处理过程中小麦旗叶活性氧代谢、叶绿素荧光参数及D1蛋白的变化。结果]SA预处理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,高效防护了高温强光所致的氧化损伤,维持较高的超氧化物岐化酶（SOD）和抗坏血酸过氧化物酶（APX）活性,维持了较高的通过PSⅡ电子传递速率（Fv/Fo）、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）。结论]SA预处理明显减轻了高温强光胁迫对光合机构的损伤,保证了PSⅡ的正常运转。

Effects of Salicylic Acid on D1 Protein Phosphorylation and Operation of Photosynthetic Apparatus in Wheat Leaves under Heat and High Irradiance Stress

Objective]The aim was to study the effects of exogenous SA on the D1 protein phosphorylation and operation of photosynthetic apparatus of wheat leaf chloroplasts under high temperature and illumination stress.Method] Wheat leaves at grain-filling stage were sprayed with 0.5 mmol/L of SA or water(as control) under high temperature and illumination stress 35 ℃,1 600 μmol/(m2·s)] for various hours,the changes in active oxygen metabolism,chlorophyll fluorescence parameters,relative amount of phosphorylated and nonphosphorylated D1 protein in thylakoid membranes were determined.Result] The results showed that after the folia application of SA,the degradation of D1 protein reduced and its level of the phosphorylation increased.Higher activity of superoxide dismutase(SOD) and ascorbate peroxidase(APX),Fv/Fm(the maximal photochemical efficiency of PSII),ФPSⅡ(the actual photochemical efficiency of PSII),qP(the photochemical quenching coefficient) and Fm/Fo(rate of electron transport through PSII) in SA-pretreated leaves were maintained under stress conditions.Conclusion] SA pretreatment improved PSⅡ performance under high temperature and irradiance stress and pre vented D1 protein from damage.