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

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

[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。

[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.