Effects of exogenous spermidine on endogenous polyamines in leaves of Red Fuji apple and starkrimson in flower bud physiological differentiation period

The changes of endogenous polyamine contents and the effects of exogenous spermidine on endogenous polyamines in leaves during flower bud physiological differentiation were studied with Red Fuji apple and Starkrimson.The results showed that on 29th of May the Putrescine content level peaked in the Red Fuji apple leaves.In addition,the spermidine and spermine content level slowly changes throughout the testing period.For the Starkrimson apple,the content levels for putrescine,spermidine and spermine peaked on 2nd of June in leaves.In the Red Fuji apple leaves,the exogenous spermidine treatment significantly increased the levels of spermidine,and also the putrescine contents increased.In the Starkrimson leaves,the spermidine and spermine contents increased.Exogenous spermidine treatment increased(Spd+Spm)/Put ratio and it had a better effect on Red Fuji apple.