关键词: 冬小麦, 水分胁迫效应, 增产节水机理

Abstract: Using large movable rainshelters to keep off precipitation,the field experiments on the water stress treatments of different soil moistures and duration of winter wheat are conducted under controlled irrigation conditions.The soil relative moistures for different treatments were controlled at40%～50%,45%～50%,50%～55%,50%～60%,55%～60%,60%～70%and CK(80%),and the duration of water stress was5,10and15days respectively.The result indicated that:for the slight and moderate water stress treatment with soil moisture being50%～70%,the efficiency of increasing yield and saving water of winter wheat was significant;in which the yield increased by3%～17%for treatment with55%～60%and50%～60%,the average yield of two years increased by7.4%;the yield increased by1%～23%for treatment with55%～60%and60%～70%,the average yield of two years increased by6.3%.For different treatments,water consumption of winter wheat decreased significantly,than that of CK,the average water consump-tion of two years for treatments with40%～50%,50%～60%and55%～70%decreased by48.5%,34.1%and28.2%respectively,more than those of CK.Under the slight and moderate water stress treatments,the realization of winter wheat increasing yield and saving water mechanism was mainly using water stress effects to accelerate:(1)the water seeking function of roots,and water use efficiency of roots at depth of100to200cm improved markedly;(2)the optimiza-tion of yield factors,weight of thousand grains and grains per spike increased,unfertilized spike and retrogressive spike decreased;(3)the stomal resistance of leaves enlarged,tran spiration rate decreased and photosynthetic rate increased after rewatering.The best time to use the water stress effects of winter wheat was from regreening to enlongation,when it is favorable for stable yields or increasing yields of winter wheat.

Key words: increasing yield and saving water mechanism, winter wheat, water stress