不同pH磷酸缓冲液对冬小麦花后干旱胁迫的减缓效应研究

Study on different pH buffers reducing the effect of drought stress after anthesis on winter wheat

为进一步明确pH缓冲液对冬小麦抗逆性的影响效应与机制,在温室盆栽环境下,于花后设置正常水分和干旱胁迫两种条件,考察了pH 5.5和pH 7.5磷酸缓冲液处理对干旱胁迫下旗叶的相对电导率、光合性状、抗氧化酶活性等指标及产量的影响。结果表明:干旱胁迫显著增加了旗叶相对电导率,但pH 5.5和pH 7.5缓冲液处理下旗叶相对电导率增加幅度较小,其质膜相对较稳定;2种缓冲液处理均减轻了干旱对旗叶光合性能的影响,表现在处理后叶片光合速率、叶绿素荧光参数(Fv/Fm)、SPAD值均显著高于喷水对照,特别是pH 5.5缓冲液处理效应更为明显;干旱胁迫诱导增强了旗叶CAT、POD和SOD等抗氧化酶活性,两种缓冲液处理进一步提高了CAT和POD的活性,其中pH 5.5缓冲液处理对CAT、pH 7.5缓冲液处理对POD相对影响效应更明显;干旱胁迫显著降低了穗粒重,但两种缓冲液处理的穗粒重降低幅度较小,其产量均显著高于喷水对照。综合研究认为,pH缓冲液处理能稳定细胞膜,增强旗叶抗氧化能力,能在一定程度上维持干旱胁迫下叶片的光合能力,减轻干旱胁迫对产量的不利影响。

In order to further clarify the effect of pH buffer on the stress resistance of winter wheat,pot experiments were carried out with normal water and drought stress conditions after anthesis in the greenhouse.Two pH phosphate buffer solutions（pH 5.5and pH 7.5）were sprayed after drought stress,changes of relative conductivity,photosynthetic characteristics,and the activities of antioxidant enzymes in flag leaf as well as grain yield were investigated.The results showed that drought stress significantly increased the leaf relative conductivity.However,plasma membrane was more relatively stable in the two pH buffer solution treatments.The effects of drought stress on flag leaf photosynthetic rate,chlorophyll fluorescence parameters（Fv/Fm）and SPAD value were significantly alleviated in buffer solutionstreatments,especially for pH 5.5.Drought stress increased the activities of leaf antioxidant enzymes including CAT,POD and SOD.Two buffer solutions further improved the activities of CAT and POD,in which pH 5.5buffer solution had greater effect on CAT,while pH 7.5 buffer solution had greater effect on POD.The grain weight per spike was significantly reduced under drought stress.However,the reduction was significantly smaller under two pH buffer solutions than control.This study clarified that pH buffer solution could stabilize cell membrane,increase leaf antioxidant capacity,maintain leaf photosynthetic ability to a certain extent and thus mitigate the adverse effects of drought stress on yield.