Abstract: Changes of H₂O₂ content in buds associated with the endodormancy of some stone fruit tree and grape cultivars were studied. The results indicated that the H₂O₂ contents of dormancy buds were different due to different tree species and cult ivars. The trend was that H₂O₂ content of late􀀁maturing cultivars was higher than that of early maturing cultivars, and H₂O₂ content in flower bud was higher than that of vegetative bud; but grape cultivars were reverse. Dynamic state of H₂O₂ content in dormancy bud took on a trend of rising steadily in earlier stage and dropping quickly in later stage. The time which the H₂O₂ content dropped sharply was consistent with the
t ime of endodormancy release. Temperature affected the dormant bud H₂O₂ content : low temperature (5 ℃) obviously raised the H2O2 content , middle temperature (10 ℃) only raised the H₂O₂ content slightly, but high
temperature (20 ℃) lead to the drop of the H₂O₂ content. Spraying regulators of ABA ( 50 mg.L^-1) obviously raised the H₂O₂ content of dormant bud, however, 100 mg.L^-1 GA₃ and 6-BA reduced the H₂O₂ content. Chemicals of dormancy release of thiourea and KNO₃ had obvious effects on H₂O₂ content of stone fruits, CaCN₂ had no effect on stone fruit trees but affected the H₂O₂ content of grape cultivars.

Key words: Deciduous tree, Endodormancy, Bud, H₂O₂