Hydrogen Sulfide Prolongs Postharvest Shelf Life of Strawberry and Plays an Antioxidative Role in Fruits

Accumulating evidence shows that hydrogen sulfide (H2S) plays various physiological roles in plants, such as seed germination, root organogenesis, abiotic stress tolerance, and senescence of cut flowers. However, whether H2S participates in the regulation of ripening and senescence in postharvest fruits remains unknown. In the present study, the effect of H2S on postharvest shelf life and antioxidant metabolism in strawberry fruits was investigated. Fumigation with H2S gas released from the H2S donor NaHS prolonged postharvest shelf life of strawberry fruits in a dose-dependent manner. Strawberry fruits fumigated with various concentrations of H2S sustained significantly lower rot index, higher fruit firmness, and kept lower respiration intensity and polygalacturonase activities than controls. Further investigation showed that H2S treatment maintained higher activities of catalase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase and lower activities of lipoxygenase relative to untreated controls. H2S also reduced malondialdehyde, hydrogen peroxide, and superoxide anion to levels below control fruits during storage. Moreover, H2S treatment maintained higher contents of reducing sugars, soluble proteins, free amino acid, and endogenous H2S in fruits. We interpret these data as indicating that H2S plays an antioxidative role in prolonging postharvest shelf life of strawberry fruits.