Abstract:
Changes in soluble sugarswere studied during fruit ripening and delayed harvest in grape ber
ries of J ingxiu, Alexander and 20 individuals of the cross p rogenies from two crosses: J ingxiu ×Alexander and
J ingxiu ×Xiangfei. Soluble sugars in the berry of Jingxiu and 8 individuals accumulated significantly during
three-week delayed harvest period while no significant changes in soluble sugars were observed in Alexander
and the other 12 individuals. Acid invertase (AI) , neutral invertase (NI) , sucrose synthase ( cleavage direc
tion) tended to increase during the delayed harvest period in J ingxiu and 97-2-23, which belonged to sugar
accumulation type, while those ofAlexander and 97-2-24, which were the sugar stable type, decreased signifi
cantly during the three weeks of delayed harvest. Moreover, there was difference in the resp iratory rate of ber
ries between the two types. It is suggested that the difference in resp iratory rate and sink strength reflected by
the activities of sucrose degradation enzymes in berries may be an important factor in soluble sugar changes
during delayed harvest between the two types.

Key words: Grape, Delayed harvest, Sugar, Sucrose metabolizing enzymes