Abstract: Sugar accumulation and sucrose metabolism enzyme activities of strawberry fruits harvested in different month were measured by using forcing culture‘Tochiotome’ strawberry cultivar at various developmental stages. The results showed that the sugar content was different among fruits harvested in different month. The contents of total sugar and sucrose in fruits harvested in February were highest, followed by January, whereas lowest in April. The difference of sugar content in fruits harvested in different month was mainly attributed to the difference in its sucrose concentration. The activities of sucrose phosphate synthase (SPS) and sucrose synthase (SS) synthetic direction in fruits harvested in February were significantly higher than those in January, whereas the acid invertase activity in fruits maturated in February was significantly lower than that in January. This profile of sucrosemetabolizing enzymes is favorable to sucrose accumulation for fruit harvested in February. Although the level of invertase activity and sucrose synthetic activities (SPS and SSsynthetic direction) in fruit harvested in April was still equal to that in February, sucrose accumulation in fruit harvested in April was still much lower than that in February. The results indicated lack of sucrose accumulation in fruit harvested in April may not relate to sucrose metabolism.

Key words: Strawberry, Forced cultivation, Fruit, Sugar accumulation, Sucrose metabolism