Effects of water stress and rewatering at shooting stage of rice on chlorophyll pigments in leaves

Pot experiments were performed for study of the variation mechanism of chlorophyll pigments in rice leaves at different grades and for different durations of water stress after rewatering.Some conclusions are drawn: the duration of water stress is of greater effect on chlorophyll pigment than the grade of water stress;the water stress of short duration((5?d))leads to the increase of content of chlorophyll,while rewatering reduces the content of chlorophyll,and the compensation effect on chlorophyll by rewatering at high-grade water stress is greater than that at low-grade water stress;long duration((10?d)) of water stress decreases the chlorophyll content,while it is increased after rewatering,and the compensation effect on chlorophyll content by rewatering at low-grade water stress is greater than that at the high-grade water stress;water stress increases the ratio of chlorophyll a and chlorophyll b,while rewatering decreases the ratio;the variation of carotenoid content accords with that of chlorophyll content.