花后脱叶对冬小麦产量形成和水分利用效率的影响

Effects of after-anthesis defoliation on grain yield formation and water use efficiency of winter wheat

受水资源日益短缺的影响,提高作物水分生产效率显得越来重要,通过调控冠层大小减少蒸腾水分消耗是其中的一个手段。该文通过水分胁迫条件下不同程度脱叶和不同水分条件下脱叶-不脱叶的田间试验(附以相应盆栽试验),研究了减少蒸腾器官对冬小麦光合特性、干物质转移、产量和水分利用效率的影响。结果表明:脱叶增强了保留叶片的光合能力;水分胁迫下的脱叶促进了干物质由保留叶片和茎向籽粒产量的转移,其中30%和60%脱叶最为显著;30%和60%脱叶水平没有对产量产生明显影响,而90%脱叶造成产量大幅降低;水分胁迫条件下脱叶减少了对土壤储水的消耗,但高强度的脱叶(90%)产量降低明显,反而降低了水分利用效率。研究结果显示,干旱缺水条件下,适度减少蒸腾器官的数量,可以实现在不影响产量条件下减少蒸腾耗水,增加土壤储水量,有利于作物度过水分胁迫期。

With the increasing water shortage, improving water use efficiency is becoming more and more important. Reducing the transpiration of a plant is a way to reduce crop water use. Experiments were carried out. The effects of defoliation on photosynthesis, dry matter translocation, grain yield and water use efficiency （WUE） were investigated with different defoliation degrees and different soil water levels. The field experimental results show that defoliation enhanced the photosynthetic capacity of the remaining leaves. The defoliation under water deficit conditions advances dry mater translocation from the remaining leaves and the straw to the wheat grain, and the treatments of 30% and 60% defoliation increased more translocation of dry matter to the wheat grain than that of the others. The 30% and 60% defoliation treatments did not affect grain yield of the winter wheat, while the 90% defoliation under deficit conditions significantly reduced crop water use, but resulted in significant decrease of grain yield and reduced WUE. Moderate defoliation under water stress might be beneficial to crop production.