Effects Of Sparying GA₃ And 6-BA On Endogenous Hormones,Branching Composition And Flowering Ang Fruiting "Fuji" Apple Top Bud

"Fuji"is the main variety of apple in China,its planting area has reached more than 65%in China.It is difficult to the"Fuji"flowering in the production and easy to happend biennial bearing.It has been reported that the use of exogenous hormones will have a important effect on plant flower formation,thus finding the problem that can be used to alleviate the problem of"Fuji"flower formation,and then discuss the regulation mechanism of the exogenous hormone on the flowering or branching of plants.In order to explore the biennial bearing of"Fuji"by exogenous GA₃ and 6-BA,and the effect of flowering and branching.In this experiment,the 4 year old"Fuji"was used as the plant material to treat the tree body with the same concentration of GA₃,6-BA at different growth stages and the different times of GA₃,6-BA spraying at different concentrations.The change of endogenous hormone?GA₃,IAA,ABA,ZT?in the top bud of the branch was measured by super high performance liquid chromatography.Meanwhile,the flowering rate and branch rate of different branches were observed.The results are as follows:?1?GA₃ was sprayed at different growth stages to inhibit the flowering rate and promote the shoot formation rate.The endogenous GA₃ content in all shoot terminal buds was promoted,and the endogenous IAA content in the short branch was decreased,while the ABA and ZT content in the middle and long shoot terminal bud was decreased.At the same time,exogenous 6-BA increased the rate of flower formation and branch formation,and the effect was the most significant one month after flowering.The effects of exogenous 6-BA on endogenous hormones were as follows:the content of endogenous GA₃ decreased after two months of flowering,the content of IAA in the terminal bud of short branch and the content of ZT in the terminal bud of medium and long branch decreased,and the content of ABA in terminal bud of medium and long branch increased.After increasing the concentration of exogenous hormones,it was found that the effect of the two exogenous hormones on the flower forming rate and branch forming rate of“Fuji”branch had no change,and the effect on endogenous hormones in different types of shoot terminal bud was not obvious.?2?Single spraying of GA₃ inhibited flower formation and promoted shoot formation rate.After single application of exogenous GA₃,the changes of endogenous hormones were as follows:increase of endogenous GA₃,decrease of IAA concentration in short shoot,increase of endogenous ABA in high concentration of GA₃,decrease of low concentration of GA₃,and increase of content of ZT in short branch;Multiple spraying of exogenous GA₃reduced the flower forming rate and increased the branch forming rate,and the effect was more obvious with the increase of spraying times.Endogenous hormones:promoting the contents of endogenous IAA,ZT and GA₃,inhibiting the endogenous ABA in short branches.The rate of flower formation and shoot formation were increased by single spraying of 6-BA.The content of endogenous GA₃ increased,the content of IAA in shoot terminal bud decreased,and the content of ABA and ZT in shoot terminal bud increased.After spraying6-BA for several times,the flower forming rate and branch forming rate of branches were promoted.The endogenous changes were as follows:GA₃ and IAA were increased,the ZT and ABA contents of all branches were inhibited,and spraying times and concentrations had different effects on endogenous hormone synthesis and shoot forming rate.However,GA₃inhibited flower bud differentiation and decreased flower formation rate,while 6-BA promoted flower formation and increased branch formation rate.