Gibberellic acid enhances postharvest toon sprout tolerance to chilling stress by increasing the antioxidant capacity during the short-term cold storage

Gibberellic acid (GA(3)) has been known as an important phytohormone signal in plants. Here, we investigated the physiology responses underlying GA(3)-induced postharvest toon sprout tolerance to chilling stress for 5 d. Results showed that exogenous application of GA(3) remarkably decreased the browning and decay index of toon sprout. GA(3) treatment prevented anthocyanin breakdown and inhibited the decreases of the total flavonoid, Vitamin C and titratable acidity in toon sprout during postharvest cold storage. In comparison to distilled water treatment, exogenous GA(3) application maintained significantly higher levels of reducing sugar, soluble sugar and proline in toon sprout. Meanwhile, GA(3) significantly reduced the accumulation of malondialdehyde (MDA) and hydrogen peroxide (H(2)0(2)) in toon sprout. Furthemore, GA(3) enhanced the activities of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) and reduced those of peroxidase (POD) and polyphenol oxidase (PPO). Taken together, our results suggested that exogenous application of GA(3) effectively enhanced postharvest toon sprout tolerance to chilling stress by regulating antioxidant enzymes and weakening lipid peroxidation.