Abstract: Objective: To investigate the promotion effect of postharvest benzothiadiazole (BTH) treatment on wound healing in harvested pear fruits, and to explore the role of phenylpropane metabolism and antioxidant enzymes in wound healing. Methods: The pear cultivar ‘Yuluxiang’ was tested in this study. After being subjected to artificial wounding, the fruits were treated with BTH at 100 g/L and then kept under dark condition at ambient temperature (20–25 ℃) and relative humidity (RH) of 80%–85% for wound healing. The healing efficiency was evaluated by determining weight loss rate and incidence in inoculated fruits, and the BTH treatment and control groups were compared for differences in the activities of phenylalanine ammonialyase (PAL), superoxide dismutase (SOD), peroxidase (POD) and polyphenol oxidase (PPO) and the contents of total phenolics, flavonoids and lignin during wound healing. Results: BTH treatment had no significant effect on fruit weight loss. During wound healing, the incidence of both the treated and control fruits decreased without any significant difference between them (P < 0.05). These findings indicated BTH treatment decreased the incidence of postharvest disease. BTH treatment also significantly increased PAL, SOD, POD and PPO activities. In addition, BTH treatment effectively promoted the accumulation of total phenols, flavonoids and lignin. The correlation analysis showed that disease incidence was significantly negatively related to PAL activity as well as total phenolic and flavonoid contents and highly significantly negatively related to POD and PPO activity in treated fruits. Conclusion: BTH treatment promotes wound healing in harvested pear fruits. Phenylpropane metabolism, POD and PPO play an important role in wounding healing.

Key words: pear fruit, wound healing, phenylpropanoid metabolism, antioxidant enzyme activities