Abstract:

Sugar accumulation and changes of sucrose-metabolizing enzyme activities were studied during the fruit development of ‘Chunjie’peach ( Prunus persica ). Results showed that most soluble sugars had been reduced at early stage of fruit development, the reduced sugar maintained in a low level during mid and late stage of fruit development while non-reduced sugars accumulated. Sucrose content increased from the beginning to the end of fruit development and the content of glucose and fructose tended to decrease at early stage of fruit development and remained in a low level thereafter. The highest activities of acid invertase (A I) and neutral invertase (N I) at early stage of fruit development decreased with fruit development and maintained
in a low level during mid and late stage of fruit development. During the early fruit development, the activity of sucrose synthase ( SS-h) kept the highest level, while that of SS-s increased continuously with fruit development and maintained in a low level at late stage of fruit development. The activity of SPS increased continuously, but the change of activity of SPS was less than that of SS. A significantly positive correlation was found between glucose content and activities ofA I, N I and SS-h, and between fructose content and A I and SS-h activities. The content of sucrose was positively correlated with the activity of SS-s and no any correlation with the activity of SPS was found.

Key words: Peach, Protected culture, Sugar accumulation, Invertase, Sucrose synthase, Sucrose phosphate synthase