Abstract Nitric oxide (NO), a major signalling molecule with various physiological functions in plants, participates in many responses to abiotic disorders such as cold stress. Chilling injury (CI) is the most costly postharvest problem in zucchini fruit (Cucurbita pepo L.), since it diminishes market acceptability and shelf life. This study investigates the effect of NO treatment on zucchini fruit during postharvest cold storage. Fruit were dipped in an aqueous solution of sodium nitroprusside (SNP; 25, 100, and 500 μM) as a NO donor and in potassium ferricyanide (a structural analogue of SNP) and distilled water, both used as controls and responding the same during postharvest cold storage. The results showed that the application of 25 μM SNP treatment reduced weight loss and CI in zucchini fruit during cold storage. S-nitrosylated proteins detected in the exocarp of NO-treated fruit were more abundant than in non-treated fruit. The application of SNP improved the quality of zucchini fruit stored at 4 °C, with a reduction of weight loss, electrolyte leakage, content of malondialdehyde and H2O2, and delayed loss of firmness during cold storage. NO-treated fruit showed a higher activity of superoxide dismutase, ascorbate peroxidase, glutathione reductase, and phenylalanine ammonia lyase during the first days of cold storage. Total antioxidant capacity was higher in the NO-treated fruit during the first days of cold storage, supported also by higher concentrations of phenols. NO appeared to play a regulatory role in the antioxidant balance in zucchini fruit, maintaining the cellular redox homeostasis and thus modulating ROS toxicity, thereby improving fruit quality during cold conservation.

中文翻译：

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储存前一氧化氮处理通过蛋白质的 S-亚硝基化和抗氧化反应的调节增强了西葫芦果实 (Cucurbita pepo L.) 的耐寒性

摘要 一氧化氮（NO）是植物体内具有多种生理功能的主要信号分子，参与应对冷胁迫等非生物疾病的多种反应。冷害 (CI) 是西葫芦果实 (Cucurbita pepo L.) 收获后代价最高的问题，因为它会降低市场接受度和保质期。本研究调查了 NO 处理对采后冷藏期间西葫芦果实的影响。将水果浸入硝普钠水溶液（SNP；25、100 和 500 μM）作为 NO 供体以及铁氰化钾（SNP 的结构类似物）和蒸馏水中，两者都用作对照，并在收获后做出相同反应冷库。结果表明，应用 25 μM SNP 处理降低了西葫芦果实在冷藏期间的失重和 CI。在 NO 处理的果实的外果皮中检测到的 S-亚硝基化蛋白比未处理的果实中更丰富。SNP的应用改善了4°C贮藏西葫芦果实的品质，减少了失重、电解质泄漏、丙二醛和H2O2含量，并延缓了冷藏过程中的硬度损失。在冷藏的最初几天，NO 处理的水果显示出更高的超氧化物歧化酶、抗坏血酸过氧化物酶、谷胱甘肽还原酶和苯丙氨酸解氨酶的活性。在冷藏的第一天，NO 处理过的水果的总抗氧化能力更高，这也得到了更高浓度的酚类物质的支持。NO 似乎在西葫芦果实的抗氧化平衡中发挥调节作用，维持细胞氧化还原稳态，从而调节 ROS 毒性，