Abstract: The changes of phenolics and relate enzymes activity in sweet cherry buds and the effects of temperature on the content of phenolics were investigated during dormancy on 7-year-old sweet cherries ( Prunus avium L.‘Hongdeng’and P. avium L.‘Zaohongbaoshi’) trees. The result showed that the content of phenolics rose steadily in primary stage and dropp ing quickly in later stage. The time which the content of phenolics dropped was different in different cultivars. The content of phenlics in flower buds was higher than that of vegetative buds. PPO activity and PAL activity of flower buds were similar to that of vegetative buds in the same cultivar, but differentiate notably in different cultivars. The trend of PAL activity was positively related with the trend of the content of total phenolics. PPO activity rose steadily during endo-dormancy period. Low temperature (5℃) promoted the accumulation of the phenolics in primary stage , and made the phenolics content dropped earlier than that of controlled in middle stage, and p romoted the drop of phenolics
content. The effect of high temperature (20℃) was contrary to that of low temperature (5℃) . The effect of variable temperature (5℃/20℃) was less remarkable.

Key words: Sweet cherry, Bud, Endo-dormancy, Phenolics, Enzymes activity