Study on physiological basis for high yield of Jimai 19 with high grain-leaf ratioII.Changes of chlorophyll and enzyme activity in system of scavenging active oxygen

The senescence of wheat varieties Jimai 19 and Lumai 14 with different grain-leaf ratio was studiedThe results are as follows:the changes of chlorophyll and enzyme activity differ greatly in comparison with Lumai 14;the degradation of chlorophyll in flag-leaf of Jimai 19 with high grain-leaf ratio is slower; the enzyme activity of SOD, CAT and POD etc in the system of scavenging active oxygen is relative higher; the damage of flag-leaf cell is slighter, and the content of MDA is lower So the senescence of flag-leaf in Jimai 19 becomes more slowly than that in Lumai 14, and it plays an important role in increasing yield