灌水量和灌水期对超高产小麦灌浆期光合特性及产量的影响

在连续多年创小麦超高产纪录试验田,通过Li-6400便携式光合测定仪,采用开放式气路测定旗叶净光合速率、胞间CO2摩尔分数、气孔导度等相关指标,研究灌水量和灌水期对超高产小麦灌浆期光合特性、水分利用率和产量的影响.结果表明,在灌水0～300 mm,灌水对超高产小麦生育后期的光合特性有显著调节作用；与CK处理相比,灌水可显著提高超高产小麦灌浆期旗叶SPAD值和叶面积指数,使小麦能够保持较好的叶片结构和功能状况,这是小麦获得超高产的基础；随着灌水量增加,超高产小麦旗叶气孔导度和蒸腾速率增加,胞间CO2摩尔分数降低,净光合速率提高；至T5处理(灌冬水、拔节水和灌浆水各60 mm)灌浆期旗叶各项光合指标协调,净光合速率最高,成熟期其产量最高,并达到超高产水平；进一步增加灌水量,小麦旗叶衰老加快,净光合速率降低,产量下降,水分利用率显著降低.在本试验条件下,灌冬水、拔节水和灌浆水各60 mm是超高产麦田适宜的用水方案.

Effects of Irrigation Amount and Stage on Photosynthetic Characteristics and Yield of Super high yield Wheat at Filling Stage

Under super-high-yield field conditions,the net photosynthesis rate,intercellular CO2 concentration and stomatal conductance were measured using Li-6400 portable photosynthesis system with an open flow gas exchange system to study the effects of irrigation stage and amount on the photosynthetic characteristics,water use efficiency and yield of super-high-yield wheat at filling stage.The results indicated that in the range of 0-300 mm irrigation amount,irrigation obviously improved the photosynthetic characteristics of super-high-yield wheat at filling stage.Compared to the control,irrigation significantly increased the SPAD value in flag leaf and LAI,and made the super-high-yield wheat maintain relatively superior leaf structure and functional status which was the precondition to super-high-yield.Besides,as the irrigation amount was increased,the stomatal conductance and transpiration rate arose,the intercellular CO2 dropped,and the net photosynthesis rate increased.Up to the treatment T5 which was irrigated 60 mm at wintering,jointing and filling stage respectively,all the photosynthetic indexes in flag leaf coordinated,the net photosynthesis rate was the highest at filling stage,and the yield was supreme up to super-high-yield level.Continuing to increase irrigation amount the flag leaf senescence accelerated,the net photosynthesis rate dropped,yield reduced,and water use efficiency decreased significantly.So under these experimental conditions,irrigated 60 mm at wintering,jointing and filling stage respectively was the feasible irrigation scheme to super-high-yield land.