Changing laws of chlorophyll content and photosynthetic rate in winter wheat leaves

The changes of chlorophyll content and photosynthetic rate in wheat leaves from different water treatments were studied．The results show that the chlorophyll content of winter wheat leaves has a decreasing tendency under water stress and chlorophyll b content declines obviously．The changing trends of chlorophyll content and photosynthetic rate under different water stresses and seasons aye identical basically．They increase from jointing stage to booting stage and decrease at milking stage，moreover the correlation between chlorophyll content and photosyn thetic rate is positive．Yield and economical coefficient of winter wheat decline with a strong water stress．