Abstract:

The diameter of garlic bulbet is seemed as the aging index of postharvest garlic scape and the redistribution of cell contents affects seriously the edible value of garlic scape. In this study, the basal garlic scape was treated with various concentrations（0.1,0.2,0.3,0.4 mmol/L）of sodium nitroprusside (SNP), 0.1 mmol/L sodium nitrite and 0.1 mmol/L potassium ferricyanide for three hours, respectively, dried and then stored at 4 ℃. During the storage of garlic scape, the diameter of garlic bulbet and activities of related antioxidant enzymes were subjected to regular determination. The results showed that compared to control, the diameter enlargement of garlic bulbet and increases of content of hydrogen peroxide, activity of peroxidase (POD) and cell membrane permeability in the basal garlic scape were inhibited by treatment of different concentrations of SNP, but the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in garlic scape, and POD in apical garlic scape were increased by treatment of different concentrations of SNP in the storage process. Compared to the control (the garlic scape sample whose basal was soaked in distilled water for 3 h), different concentrations of SNP could effectively restrain the diameter enlargement of garlic bulbet and the content increase of hydrogen peroxide. 0.1 mmol/L SNP treatment presented the most remarkable effect (p < 0.05). No significant difference was found in diameter of garlic bulbet and activities of related antioxidant enzymes between 0.1 mmol/ L sodium nitrite or 0.1 mmol/L potassium ferricyanide-treated garlic scape and the control. Based on these, we concluded that exogenous nitric oxide can inhibit the diameter enlargement of garlic bulbet, and this effect may be related to inhibiting the content increase of hydrogen peroxide in the basal of garlic scape.

Key words: nitric oxide, garlic scape, aging, hydrogen peroxide