Synergistic effect of glutathione and nitric oxide treatment on storage quality and antioxidant activity in tomato

【Objective】Synergistic effects of reduced glutathione（GSH）and donor sodium nitroprusside（SNP）of nitric oxide（NO）treatment on storage quality and antioxidant capacity of tomato，which can provide a theoretical basis for improving the storage quality and prolonging the shelf life of tomato fruit.【Method】Qianxitomato was used as the experimental material，and the tomato fruits at post-harvest maturity stage were soaked for 5 min with exogenous 2 mmol/L GSH and 0.25 mmol/L SNP，respectively，and soaked in distilled water for 5 min as control. The fruit quality，antioxidant enzyme activity and antioxidant substance content of tomato during storage period were analyzed.【Result】Compared to control，the weight loss rate of tomato fruits were significantly decreased by 52.86%-56.07%（P<0.05，the same below），and the content of propectin were significantly increased by 29.67%- 39.34% under the synergistic treatment of exogenous GSH and SNP，which delayed the decrease of fruit hardness. Compared to control，the content of total soluble solid（TSS） in the early/middle stage of storage（5-10 d）were significantly increased by 23.36%-46.25%，titratable acid（TA）and soluble sugar contents during the whole storage period were significantly increased by 93.95%-96.78% and 8.32%-11.21%，respectively，under the synergistic treatment of exogenous GSH and SNP in tomato fruits. Compared to control，the total antioxidant capacity of tomato fruits was significantly increased by 17.25%-53.82%，and the content of malondialdehyde （MDA），hydrogen peroxide（H₂O₂）and the production rate of superoxide anion（O₂^-·）in tomato fruits were significantly decreased by 49.28%-52.27%，34.71%-42.75% and 23.82%-53.60%，respectively，under the synergistic treatment of exogenous GSH and SNP. The synergistic treatment of exogenous GSH and SNP also increased the activities of superoxide dismutase（SOD），catalase（CAT）and peroxidase（POD）in tomato fruits by 12.73% - 143.80%，37.11% - 95.24% and 20.73%-91.45%，and the contents of GSH，ascorbic acid（AsA）and NO in tomato fruits were significantly increased by 16.01%-44.63%，38.49%-39.73% and 48.56%-73.96%，respectively，compared with control.【Conclusion】The synergistic treatment of exogenous GSH and SNP synergistic treatment can maintain fruit firmness，increase TSS，TA and soluble sugar content，improve SOD，CAT and POD activities，and GSH and AsA contents，maintain the balance of reactive oxygen species in fruit，reduce oxidative damage during storage，and thus enhance the storage tolerance of the tomato fruit.