Abstract:The effects of fumigation treatment with nitric oxide on disease control and potentiation of metabolism of reactive oxygen species in post-harvest muskmelons were investigated. Xinjiang “Xizhoumi No. 25” muskmelons were fumigated with 60 μL/L of nitric oxide (NO) for 3 h in sealed boxes; melons kept in boxes without NO gas and sealed for 3 h were used as controls. After a 12 h treatment, the samples were inoculated with Alternaria alternata and stored at room temperature. The lesion diameter, lesion depth, rate of production of superoxide anion free radicals (O2-?), hydrogen peroxide (H2O2) content, and the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) of the muskmelons were measured at regular intervals during storage. The results showed that the NO treatment significantly decreased the lesion diameter and lesion depth of muskmelons inoculated with A. alternata during the storage at room temperature. The NO treatment also induced the rapid accumulation of H2O2, and increased the rate of production of O2-? early in the storage. Furthermore, the NO treatment significantly enhanced SOD, CAT, and POD activities. This suggests that the disease resistance induced by NO treatment in post-harvest fruits is closely related to the regulation of the metabolism of reactive oxygen species.
