Exogenous GA3 treatment could inhibit the PPO activity in the tubers when they started to bud.But after budding, it increased PPO activity, with the order being 10mg/L>CK>20mg/L. 6.

• 5、外源GA3处理可以促进萌芽阶段块茎内部多酚氧化酶活性的下降，而在块茎萌芽之后，芽条生长阶段，又促进了多酚氧化酶活性的上升，处理效果是10mg/L>CK>20mg/L。