土壤水分胁迫对小麦产量的影响及节水灌溉的可行性

Effects of soil water stress on wheat yield and the feasibility of water-saving irrigation

综述了土壤水分胁迫对小麦产量形成的影响及小麦节水灌溉的可行性。近年我国北方时常出现的土壤水分胁迫 ,既影响小麦的物质生产 ,也影响籽粒形成的物质来源。由于土壤胁迫影响器官生长 ,使叶面积减小 ,叶绿素含量降低 ,群体和单叶光合性能都有所变劣。单叶光合性能的研究多集中在旗叶 ,干旱使旗叶光合速率降低 ,光合功能期缩短 ,而这些表现又与气孔导度的变化有关。土壤水分胁迫也使开花后的光合产物减少 ,灌浆物质不足 ,因此原贮存在营养器官中的物质向籽粒的运转速度加快 ,贮存物质在粒重中的比例提高 ,这可以在一定程度上弥补粒重和产量的降低。在小麦生产中的很多例证表明 :只要采用适宜的栽培技术 ,适当减少灌溉次数和灌水量并不严重影响产量 ,且能提高水分利用效率。通过试验研究 ,这些现象近年在理论上也得到证明。

In this paper, the effects of soil water stress on wheat yield and the feasibility of water-saving irrigation were summarized. In recent years, the frequently happened soil water stress in the north of China influenced both the dry matter production and the dry matter source of grain formation of wheat. The influences of water stress on the growth of organ led to smaller leaf area, lower chlorophyll content, and poorer photosynthetic performances in both community and single leaf levels. The study of photosynthetic performances on single leaf is mostly about flag leaf. Drought led to decreased photosynthetic rate and shortened photosynthetic duration in flag leaves, and these changes were relative to the change of stomatal behaviors. Soil water stress also reduced photosynthetic production after flowering, leading to insufficient grain filling matters, so that the assimilates reserved in vegetative organs before flowering translocated to grains quickly, and the proportion of mobilized assimilates from vegetative organs in grains increased. This may offset the decrease of grain weight and grain yield to a certain extent. So many results in wheat production showed that with rational cultivation techniques, reducing irrigation frequency and irrigation quantity did not significantly reduce wheat yields, and might enhance water use efficiency. These phenomena have also been explained theoretically by experiment. From these researches, the feasibility of water-saving irrigation of wheat was theoretically and practically explained.