黄土高原地区春小麦对有限灌溉的反应及其生理生态基础

The responses and their physio-ecological bases of spring wheat to limited irrigation in Loess Plateau

从对黄土高原地区有限灌溉条件下作物生理生态反应的众多研究中得出 :( 1 )水分轻度亏缺时 ,作物可通过根信号物质 ABA调节叶片的气孔导度。非水力根信号作用太强 ,可因降低光合作用而减少干物质生产和影响干物质分配模式而影响产量和水分利用效率 ,故削弱非水力根信号的作用将有利于提高产量。 ( 2 )浅层根系占根系总量比例越高 ,对干旱越敏感 ,表现为根信号能力增强 ;深层根系所占比例越高 ,越有利于土壤深层水分利用 ,并可削弱根信号。同理 ,给土壤中下层补水或采用播种前灌溉 ,可因为减少了无效蒸发 ,且削弱根信号而提高水分利用率。( 3)本地区有限灌溉的最佳时期由于降水变率较高而变得较为复杂 ,不同降水年型 ,最佳灌溉时期差异很大 ,对有限灌溉进行科学管理还需要做更多的研究工作。

This paper discussed the responses and their physio ecological bases of spring wheat to limited irrigation based on many studies in Loess Plateau.Crop plants controls stomatal conductance through non hydraulic root signals in dry condition.The stronger the ABA regulation is,the lower the crop yield is,because enhancing ABA regulation can decrease photosynthetic production,and influence dry matter partitioning between roots and shoots,and as a result it would influence grain yield and water use efficiency.Higher ratio of deep root biomass to total root biomass will be favorable for utilizing deep soil water,and decreasing the role of non hydraulic root signals.So it will increase grain yield and water use efficiency through decreasing soil evaporation and weakening roles of non hydraulic signals.The optimizing management of limited irrigation strategy is very complex because of the great variance of precipitation each year.So there are many things to do for optimizing the strategy of limited irrigation in the area.