冬小麦中轻度水分胁迫的增产节水效应研究

利用大型水分试验场的防雨棚遮挡自然降水,采用人工定量补水进行冬小麦土壤含水量占田间持水量40%～50%、45%～50%、50%～55%、50%～60%、55%～60%、60%～70%持续时间分别为5、10、15天水分胁迫处理的控制试验。试验结果表明:50%～70%的中轻度水分胁迫处理,冬小麦具有显著的增产节水效果;2年平均,增产6.3%～7.4%,节水28.2%～34.1%。中轻度水分胁迫下,冬小麦增产节水作用机制的实现,主要是通过水分胁迫效应诱发增强:①冬小麦根系的找水功能;②产量构成因子的优化;③复水后光合速率的提高。冬小麦水分胁迫效应的最佳利用时间为返青-拔节期,此时进行水分胁迫效应利用最有利于冬小麦稳产增产。

The experimental research on slight and moderate water stress effcts on increasing yield and saving water mechanism of winter wheat

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.