POD activity in ‘Golden Delicious’ apple peels increased grad-ually and reached a plateau at 51 DABF in the control. However,the exogenous CA treatment showed an overall inhibitory effecton POD activity that was 73% of the control in average (Fig. 6A).Meanwhile, PPO activity in the control of ‘Golden Delicious’ apple in 7 days after application. Although it also increased later, the max-imum activity was only 55% of the control. Thus, the application of exogenous CA inhibited the POD and PPO activity in young fruit peels.