灌浆期高温胁迫对强筋小麦旗叶叶绿素a荧光参数的影响

Effects of Post-Anthesis Heat Stress on Chlorophyll a Fluorescence Parameters in Flag Leaves of Strong-Gluten Winter Wheat

采用人工气候模拟的方法,系统地研究了小麦灌浆期高温对强筋小麦品种豫麦34旗叶叶绿素a荧光动力学参数的影响。结果表明,高温胁迫降低旗叶F o、F v、Fm、F v/Fm及F v/F o,从而导致PSⅡ潜在活性及光化学效率降低。在籽粒灌浆的不同阶段,高温胁迫效应表现有差异:高温处理开始时各荧光参数下降明显,之后植株有适应性恢复,但灌浆后期下降幅度最大,处理间的差异达显著或极显著水平,表明随着植株的衰老PSⅡ损伤加剧。灌浆期间植株光合性能的削弱导致籽粒灌浆速率降低,粒重显著下降。

Heat stress after anthesis of winter wheat is one of the main natural calamities for wheat production in northern China, which results in plant senescence and decrease of grain yield. This study was carried out on the effect of heat stress on the chlorophyll a fluorescence parameters in flag leaves of stronggluten wheat cultivar. The results indicated that heat stress deceased the chlorophyll a fluorescence parameters of flag leaf, such as Fv （variable fluorescence）, Fm （maximal fluorescence）, Fv/Fm, Fv/Fo（Fo is the minimal fluorescence）,which indicated that primary light energy conversion and potential photosynthetic activity and electron transport of PS Ⅱ had been inhibited. But differences were found at different stages of grain-filling： great decrease of Fv/Fo and Fv/Fm in flag leaves occured when （or just after） treated, then adapted recovery happened, and significant decrease occured in late stage of winter wheat, which indicated serious damage of PS Ⅱ in flag leaves and early senescence of plant. And decrease of net photosynthetic rate （Pn） in flag leaves resulted in decrease of 1000-grain weight and grain yield.