Combined Salicyclic Acid and Ultrasound Treatments for Reducing the Chilling Injury on Peach Fruit

The effects of salicylic acid (SA; 1 mmol L-1) and ultrasound treatment (40 kHz, 10 min) either separately or combined on the chilling injury (CI) in cold-stored peach fruit (Prunus persica Batsch cv. Baifeng) were investigated. The results showed that SA treatment alone alleviated CI during storage. Ultrasound alone had no influence, but when it was combined with SA, it resulted in greater inhibition of CI than SA alone. The activities of antioxidant enzymes, such as catalase, ascorbate perwddase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase, were induced by a combination of SA with ultrasound. In addition, the combined treatment also increased the endogenous SA concentrations in peaches. These results suggested that the induced tolerance against CI by the combination of ultrasound and SA treatment in cold-stored peach fruit was related to the induction of antioxidant enzymes and the increase in the SA concentration.