灌浆期持续干旱对小麦光合、抗氧化酶活性、籽粒产量和品质的影响

Effects of Persistent Drought at Grain Filling Stage on Flag Leaf Photosynthesis,Antioxidant Enzyme Activity,Grain Yield and Quality of Wheat

为解析灌浆期持续干旱对优质强筋小麦生长发育的影响,以大面积推广种植的优质强筋早熟多抗小麦品种西农979为材料,从旗叶光合作用、抗氧化酶活性、籽粒淀粉和蛋白质积累过程等方面分析其在灌浆期不同阶段对干旱胁迫的响应特征。结果表明,与正常水分供应(CK)相比,干旱胁迫下花后10 d后小麦旗叶相对含水量下降,变化不显著,而POD、CAT和SOD活性升高,旗叶气孔导度、蒸腾速率、净光合速率等显著下降。随着干旱胁迫时间的延长,旗叶光合能力显著下降,活性氧清除酶活性均呈下降趋势,其中POD和SOD活性下降速度低于CK。灌浆期干旱胁迫显著降低植株结实率、籽粒长宽、饱满度、千粒重等,导致产量显著下降,并减少籽粒直链淀粉、支链淀粉和总淀粉含量及淀粉直支比,增加籽粒蛋白质含量。由此可见,灌浆期持续干旱会降低小麦光合能力,增强抗氧化能力,抑制籽粒淀粉合成和积累,影响植株结实、籽粒发育和品质形成。

In order to analyze the effect of persistent drought at grain filling stage on the growth and development of high-quality strong gluten wheat,this study used a high-quality,strong gluten,early-maturing and multi-resistant wheat variety Xinong 979 as thematerial,and analysed the response characteristics of flag leaf photosynthesis,antioxidant enzyme activity,grain starch and protein accumulation process at different stages during grain filling.The results showed that,compared with CK,the relative water content of flag leaf decreased,but the activities of POD,CAT and SOD increased,and the stomatal conductance,transpiration rate and net photosynthetic rate decreased significantly.With the extension of drought stress time,the photosynthetic capacity of flag leaves decreased significantly,and the activity of active oxygen scavenging enzyme decreased,with the decline rate of POD and SOD activity lower than that of the control.During the grain filling stage,drought stress significantly reduced the seed setting rate,grain length and width,plumpness and 1000-grain weight,which led to significant decreases in yield,and contents of amylose,amylopectin and total starch,but increase in protein content of grains.It can be seen that the persistent drought during the grain filling stage reduced the photosynthetic capacity,enhanced the antioxidant capacity,inhibited the starch synthesis and accumulation in the grain,and affected on seed-setting,grain development and quality formation.