Abstract: In this paper，the fruit of‘Jingbaili’pear was used to measure the changes in activity and gene expression of polygalacturonase（PG），glycosidase（β-Gal，α-L-Af）and lipoxygenase（LOX）after being respectively treated by 1-MCP and cold storage，in order to explore their roles and inter-relationship during fruit softening. The results showed that there was a softening trend with slow（within 3 d of harvest）–fast（3–9 d of harvest）–slow（after 9 d of harvest）in‘Jingbaili’pear fruit，and the activity and gene expression of PG，β-Gal，α-L-Af and LOX increased in varying degrees with fruit softening. β-Gal and LOX activity showed a rapid rising within 3 days after harvest，and accompanied by the rapidly increasing in both gene expression，which indicating that both β-Gal and LOX may play a very important role at early softening stage in‘Jingbaili’pear fruit. Both 1-MCP treatment and cold storage could significantly inhibit the activity and gene expression of β-Gal，α-L-Af，LOX and PG，and thus delayed the fruit softening. What，s more，1-MCP treatment may play stronger inhibition in the activity and gene expression of β-Gal and LOX，particularly at early time of 1-MCP treatment. Cold storage could maintain the initial activity in both PG and β-Gal during storage，while mainly inhibit their gene expressions at early stage. The activity and gene expression of LOX maintained very low level under cold storage，indicating LOX was more sensitive to low temperature than other three enzymes. Therefore，it was concluded that PG，β-Gal，α-L-Af and LOX were all involved in fruit softening to varying degrees，among which both β-Gal and LOX maybe take more contribution to early softening stage. We think that 1-MCP treatment play a more important role in fruit softening by inhibiting the activity and gene expression of both β-Gal and LOX，and cold storage delay fruit softening mainly due to inhibiting the LOX activity and gene expression in‘Jingbaili’pear fruit.

Key words: Pyrus, polygalacturonase, fruit, postharvest, glycosidase, lipoxygenase, gene expression