The Characteristics of β-Gal and LOX Activities in Apple (Malus domestica Borkh.) Fruit and Their Relation to Fruit Softening

For understanding the role of β-galactosidase(β-Gal)and lipoxygenase(LOX)during fruit development,ripening and softening,the fruits of apple(Malus domestica Borkh.)cultivars,'Fuji' and 'Golden Delicious',were used to investigate the activity changes of β-Gal and LOX over this period,and during postharvest regulation by ethylene.The results indicated that the β-Gal activity in 'Golden Delicious' was markedly higher than that in 'Fuji' during fruit development and ripening and the difference was in particular significant during ripening and softening.The LOX activity in 'Fuji' was dramatically increased and higher than that in 'Golden Delicious' after flowering,but its activity was markedly reduced and maintained lower than that of 'Golden Delicious' before fruit ripening.The β-Gal and LOX activities of apple fruit were markedly inhibited by 1-methycyclopene(1-MCP)and increased by ethephon.The changes of β-Gal and LOX activity showed a similar trend and the β-Gal be much easier to be regulated by ethylene than LOX.These results suggested that the change of β-Gal and LOX activities be correlated with the storage characteristic of apple fruit and β-Gal might have an important role in the early stage of fruit softening.