Abstract:

Changes of endogenous ABA, GA₃ content, ABA/GA_³ value in sweet cherry flower buds and effects of correlative environmental factors were investigated during dormancy on 8-year-old ‘Jueze’ (]h4IeMMa)and ‘Zao Hongbaoshi’(Py6Hnoaaa) sweet cherry trees with HPLC (High Performance Liquid Chromatography)．It was found that ABA content rose steadily in primary stage and dropped in later stage during dormancy, and its maximum appeared at the begin of November.Contrary to ABA, GA₃ content dropped sharply in primary stage of dormancy and rose steadily during release of dormancy, its minimum appeared at the end of November. Moreover, ABA/GA₃ value rose with the deepening of dormancy and dropped with the release of dormancy. Temperature affected ABA and GA₃ content in dormant flower buds: low temperature(5℃)raised GA₃ content and reduced ABA content obviously, moreover, the time when ABA began to fall and GA₃ content began to rise advanced after low temperature treatment, which made flower buds release dormancy earlier than contro1. The efect of high temperature(20℃)was contrary to that of low temperature(5℃)．Variable temperature(5/20℃)affected dormancy release slightly, but its effect was less remarkable than 5℃ treatment because of the counteract of 20℃. Overshadow treatment before defoliation could reduce GA₃ content slightly, but its effect on ABA content was little. The synthesis of GA₃ was promoted and synthesis of ABA was inhibited after long photoperiod treatment，contrary to that，short photoperiod treatment raised ABA content and reduced GA₃ content sharply．

Key words: GA₃, HPLC