Salicylic Acid Maintains the Cell Membrane Integrity of Potato Tissue by Regulating Reactive Oxygen Species Homeostasis during Early Wound Healing Period

In this study, artificially wounded potato tubers were treated with 2 mmol/L salicylic acid (SA) for 10 min. Reactive oxygen species (ROS) production and ROS scavenging enzyme activities were determined, and in vitro antioxidant capacity and cell membrane integrity in the wounds were analyzed during the early wound healing (within 12 h after wounding) period. The results showed that SA increased the activities of NADPH oxidase and superoxide dismutase, and promoted the accumulation of superoxide anion radical and H₂O₂ in tuber wounds during the early wound healing period. SA increased the activity of peroxidase, but decreased the activity of catalase. SA also increased the activities of ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase and glutathione reductase, and increased the levels of ascorbic acid and reduced glutathione. In addition, SA treatment improved the capacity to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical and ferric reducing antioxidant power (FRAP) and reduced cell membrane permeability and malondialdehyde (MDA) content. In conclusion, SA could maintain cell membrane integrity and consequently ensure the smooth progress of normal metabolism during early wound healing by regulating ROS homeostasis and improving in vitro antioxidant activity in potato tuber wounds.