For enzyme assays, pear fruit were wounded, and 15 lL of1.5 g/L chitosan or oligochitosan was added to each wound as described above, and fruits inoculated with sterile water in the wound served as control. After treatment, the fruits were stored at 25 C. Flesh samples surrounding the wounds of 10 fruits were taken at 0, 1, 2 and 3 days. Each treatment contained three replicates and the experiment was repeated twice.