Effect of Fertilizer and Auxin Application on Endogenous AuxinChange and Fruit－Set in the Jujube Tree

Hu Fangming；Xie Bixia；Liu Jiajiaand He Yehua（South Central Forestry University，Zhuzhou，Hunan 412006）

ABSTRACT Test results showed that fertilizer application prior to bud bursting and thefirst physiological fruit drop could remarkably increase the number of flowers，percentage offruit-set，and post-July fruit survival rate，although the promotion effect varied greatly withthe dosage。It was obvious that fertilizer application improved the conditions for endogenousauxin synthesis；however，a different effect was found in different time of the year，It wasalso found that applying auxin to the tree during first flower or prior to the first physiologicalfruit drop cotild temporarily breakthe balance of endogenous auxin，so that fruit-set was af-fected．The optimum concentration for GA3 to promote fruit-set was one of 10 ppm, and theworst effect was revealed in the combination of GA3 and IAA。KEY WORDS Jujbe（Zizyphus jujuba）；Fertilizer application；Endogenous auxin；Fruit-set。