The change of peroxidases (POD) , catalase (CAT) , IAAoxidase and sucrase activity in leaves during flower bud differentiation of “Pingguoli”was studied. The results showed that POD , IAAoxidase and sucrase activity
were high , but CAT activity was low in the critical period of flower bud differentiation (23 , July) . CAT activity increased , sucrase activity decreased and IAAoxidase , POD activity decreased little during alabastrum , calyx differentiation. POD , IAAoxidase activity gradually increased , sucrase activity didn’t change significantly , CAT activity declined to the lowest during petal , stamen , pistil differentiation.