高温下干旱和渍水对冬小麦花后旗叶光合特性和物质转运的影响

以蛋白质含量不同的两个冬小麦品种扬麦9号和豫麦34为材料，研究了不同温度和水分条件下小麦花后旗叶光合特性的变化、营养器官花前贮藏干物质和氮素转运特征及其与籽粒产量和品质形成的关系.结果表明，高温及干旱和渍水均明显降低了旗叶光合速率和叶绿素含量（SPAD值），但高温下干旱和渍水对光合作用的影响加重.小麦营养器官花前贮藏干物质、氮素转运量和转运率在适温下表现为干旱>对照>渍水，高温下则表现为对照>干旱>渍水.适温下花后同化物积累量表现为对照>渍水>干旱，高温下则表现为对照>干旱>渍水.花后氮素积累量在适温和高温下均表现为对照>渍水>干旱.籽粒淀粉含量以适温适宜水分处理最高，高温渍水下最低；蛋白质含量以高温干旱下最高，适温渍水下最低.温度和水分逆境下小麦粒质量和淀粉含量的降低与花后较低的光合能力及干物质积累有关，而蛋白质含量则与花前贮藏氮素的转运量和转运率有关.

Effects of drought and waterlogging on flag leaf post-anthesis photosynthetic characteristics and assimilates translocation in winter wheat under high temperature

With winter wheat varieties Yangmai 9 and Yumai 34 as test materials, this paper studied post-anthesis photosynthetic characteristics in flag leaves, the translocation of assimilates and nitrogen stored in vegetative organs before and after anthesis and their relationships with grain yield and quality under different temperature and water conditions. The results showed that high temperature, drought, and waterlogging all had significant negative effects on photosynthetic rate and chlorophyll content (SPAD value) of flag leaves, and the effects of drought and waterlogging were greater under high temperature than under optimum temperature. The translocation amount and rate of assimilates and nitrogen stored in vegetative organs before anthesis declined in the order of drought > normal soil moisture content > waterlogging under optimum temperature, but normal soil moisture content > drought > waterlogging under high temperature. The amount of post-anthesis assimilates translocated into grain declined in the order of normal soil moisture content > waterlogging > drought under optimum temperature, but normal soil moisture content > drought > waterlogging under high temperature, while that of post-anthesis accumulated nitrogen declined in the order of normal soil moisture content > waterlogging > drought under both high and optimum temperature. The starch and protein contents in grains were the lowest under high temperature x waterlogging, but the highest under optimum temperature x normal soil moisture content. Overall, the decrease of grain mass and starch content under high temperature and water stresses was associated with the lower photosynthetic rate and less post-anthesis assimilates accumulation, while grain protein content was related to the translocation amount and rate of nitrogen stored before anthesis.