Effect Of Pruning Time On The Endogenous Contents And The Antioxidant Enzyme Activity And The Growing And Fruiting Of Longan

Longan was pruned in the 1st February,1st March,1st April,1st May,1st June,1st July to study the effects of pruning time on the growth and development,leaf enzyme activity,endogenous hormone content,tree nutrition and flowering results of longan tree.The differences between treatments were compared and selected the suitable pruning time of longan.The results of the study indicated that:1.The length,thickness,leaves and of tips of the longan branches gradually decreased with the pruning time.The length of the branches and leaves from February to April was more than others.The chlorophyll content and soluble total sugar content in leaves increased gradually from the middle of November,and were significantly higher from February to May than others.The pruning time from February to May was significantly higher than others about flowering rate,number of male and female flowers,yield and weight of longan2.The same mineral elements in the leaves showed the same trend with time,the content of mineral elements treated from February to May was significantly higher than other treatments.Higher levels of N,P,Ca,and Mg and low levels of K can promoted flower bud differentiation in longan.3.The activity of SOD,POD,CAT and PPO in leaves increased with the decrease of temperature.Under the same temperature condition(4?6?),the activities of pruning antioxidant enzymes from February to May was significantly higher than control,and there was no significant difference between the pruning from June to July and the control4.The content of the same endogenous hormone in leaves was consistent with time.The content of ABA,IAA,CTK and BR in leaves treated from February to May was higher than other treatments in flower bud differentiation stage,while GA3 content was lower than other treatments.High levels of ABA,IAA,CTK and BR and low level of GA3 in leaves can promote flower bud differentiation.In summary,From February to May is the suitable for pruning for Shixia longan.It can promote branch growth,inhibit winter shoot germination,promote flower bud differentiation and increase fruit yield.