Phytosulfokine-α treatment maintains fruit quality and alleviates chilling injury of peach fruit by regulating relative oxygen species and cell wall metabolisms

The effects of phytosulfokine-α (PSK-α) treatment on postharvest peach fruit CI were studied. Results showed that PSK-α treatment inhibited the increase of browning index, electrolyte leakage and malondialdehyde content of peach fruit and delayed the decline of hardness. In addition, PSK-α treatment did not change the types of volatile substances and reduced the acidity of the fruit, so as to maintain the good flavor of peach fruit. PSK-α can improve the antioxidant capacity of peach fruit by promoting the activity of some antioxidant enzymes, increasing the content of ascorbic acid, glutathione and inhibiting the production of reactive oxygen species. At the same time, PSK-α treatment delayed the degradation of cell wall materials by inhibiting the activity of polygalacturonase, pectin methylesterase, cellulase and some glycosidases. Generally, PSK-α treatment can maintain fruit quality and reduce the CI of peach fruit by improving antioxidant capacity and maintaining the stability of cell wall structure.