Ethephon Accelerates Wound Healing in Ginger Rhizomes by Modulating Antioxidant Enzyme Activities and Secondary Metabolite Production

Ginger rhizomes are subject to mechanical damage during harvest, handling, and transportation, and ethephon has been reported to promote plant wound healing. In this study, the effect and mechanism of ethephon treatment after harvest on wound healing in ginger rhizomes were investigated. The results indicated that 50 mg/L ethephon treatment retarded mass loss, and enhanced the contents of hydrogen peroxide, total phenolic compounds and lignin in ginger rhizomes during the wound healing process. The activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) involved in reactive oxygen species (ROS) metabolism were increased in the ethephon-treated ginger rhizomes. The accumulation of phenolic compounds and lignin during wound healing were correlated with a significant increase in peroxidase (POD) and phenylalanine ammonia lyase (PAL) activities. These findings suggest that ethephon treatment can promote the wound healing process of ginger rhizomes by modulating key enzyme activities involved in ROS metabolism and the phenylpropanoid pathway to enhance antioxidant capacity and accumulate secondary metabolites.