Abstract: ‘Redchief’and‘Red Fuji’apple tree ( Malus domestica Mill. ) were used as materials to test for the effect of treatments of paclobutrazol ( PP₃₃₃ ) and GA3 on the contents of endogenous hormones in buds. The results
showed that the contents of and ZR , and ZR/ IAA , ZR/ GAS , ABA/ IAA and ABA/ GAS ratios in spur bud were remarkably increased , PP₃₃₃ treatment by while GAS and IAA content in spur bud were decreased. The contents of GAS and IAA in spur bud were remarkably increased by GAS treatment , while ZR and ABA content , ZR/ IAA , ZR/ GAS , ABA/ IAA , and ABA/ GAS in spur bud were decreased. As to the effects of spraying PP₃₃₃ or GA₃ , it was noted that PP₃₃₃ could increase the leaf bud node number , but no effect was noted for flower bud ; GA₃ had no effect on the node number of leaf bud , but had a trend to decrease the node number for flower bud.