Relationship between accumulation of sugar and sucrose-metabolizing enzymes during apricot fruit development.

The content of sucrose,glucose,fructose and the activities of sucrose-metabolizing enzymes(acid invertase,neutral invertase,sucrose synthase and sucrose phosphate synthase)in the fruits of Xinshiji apricot cultivar was measured.The results showed that a significant positive correlation was observed between the content of sucrose and the activities of sucrose synthase(synthetic direction) and sucrose phosphate synthase during fruit development,the correlation coefficients were 0.934 9** and 0.841 8*,respectively;while there was a significant negative correlation between the content of sucrose and NI activity,with the correlation coefficient of-0.842 5*.The transition of sugar accumulation and net-activity of sucrose-metabolizing enzymes was the period of the fruit stoning finished.Before the fruit stone finished,the net activity of sucrose-metabolizing enzymes was below zero,sucrose accumulated slowly in fruit.After the fruit stoning finished,the fruit coloring started,the net activity of sucrose-metabolizing enzymes was positive,and sucrose accumulated rapidly in fruit.