Exogenous Gibberellic Acid Ameliorates Chilling Injury in Peach (Prunus persica L.) by Improving the Antioxidant System

Currently, several studies have demonstrated that cold stress can cause the accumulation of reactive oxygen species (ROS) in fruit. However, little is known about the roles of gibberellic acid (GA(3)) on the antioxidant system in the mitochondria of fruit. To explore the molecular basis of GA(3) interference with the chilling tolerance of fruit, 'Jinqiuhongmi' peach fruit was treated with 0.1 mmol L-1 GA(3) after harvest. Exogenous GA(3) treatment relieved the chilling injury of postharvest peach fruit with a lower cold injury index and higher antioxidant level. In addition, GA(3) delayed the senescence of peaches by reducing the firmness, respiratory action, and ethylene production. The antioxidant enzyme activities were elevated, including superoxide dismutase (SOD) and catalase (CAT). Moreover, GA(3)-treated peaches exhibited lower hydrogen peroxide (H2O2) and malondialdehyde (MDA) in comparison with the control. These results showed that the application of 0.1 mmol L-1 of GA(3) enhanced the chilling resistance of peach fruit by regulating the antioxidant system.