<正>Water stress treatment at different developmental stages of a winter wheat varietywas made in outdoor pot experiments from 1987 to 1988.It was found that the most sensitivestage was the booting stage and the second most sensitive stage was the flowering stage.Waterstress at most development stages affects the number of grains.Wheat water stress can be diag-nosed effectively and quickly by means of leaf temperature difference between the drought fieldand the well watered control plot measured by an infra-red thermometer.