Cold stress is an important environmental factor restricting the cultivation of melons in winter and spring. Exogenous trehalose (Tre) can improve the stress tolerance of crops. However, the mechanistic role of Tre in regulating crop cold tolerance is not completely clear and whether hydrogen peroxide (H₂O₂) and nitric oxide (NO) act as signalling molecules in Tre regulation melon cold tolerance remains unknown. Thus, this study was conducted to analyse the cold tolerance of cold-tolerant (IVF571) and cold-sensitive (IVF004) melon varieties and their H₂O₂ and NO levels. Then, the roles of exogenous Tre in regulating the cold tolerance of melons and the interaction of H₂O₂ and NO in Tre-regulated cold tolerance were investigated. Results showed that the damage to membrane lipid peroxidation in IVF571 plants was significantly slighter than that in IVF004 plants, and the levels of H₂O₂ and NO in IVF571 plants were significantly higher than those in IVF004 plants under cold stress. Exogenous Tre was more effective than sucrose and glucose in significantly increasing the maximal quantum yield of PSII photochemistry, reducing the relative electrical conductivity in melon leaves under cold stress by increasing the superoxide dismutase (SOD) activity under normal conditions and enhancing SOD, glutathione reductase and ascorbate peroxidase activities and GSH/GSSG ratio under cold stress. Exogenous Tre could induce the increase in H₂O₂ and NO levels. The removal of endogenous H₂O₂ with dimethylthiourea weakened the role of exogenous Tre, whereas eliminating NO with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide almost abolished the effects of exogenous Tre and H₂O₂. In summary, the higher cold tolerance of IVF571 seedlings than that of IVF004 seedlings might be related to the increase in H₂O₂ and NO levels triggered by cold stress. Tre might have a unique effect on the regulation of cold-induced oxidative stress in melon. Tre could elevate endogenous H₂O₂ and NO levels, which stimulated the stress response system of melon. Consequently, when melon plants were exposed to cold stress, antioxidant enzyme activities improved, and the damage to membrane lipid peroxidation was reduced. In this process, H₂O₂ and NO participated in the roles of Tre, and NO might be located downstream of H₂O₂.

冷胁迫是限制冬春季节瓜类栽培的重要环境因素。外源海藻糖（Tre）可以提高农作物的抗逆性。但是，Tre在调节作物耐寒性中的机制作用尚不完全清楚，过氧化氢（H ₂ O ₂）和一氧化氮（NO）是否在Tre调节瓜耐寒性中作为信号分子尚不清楚。因此，本研究旨在分析耐寒（IVF571）和耐寒（IVF004）甜瓜品种的耐寒性及其H ₂ O ₂和NO水平。然后，外源Tre在调节瓜的耐寒性和H ₂ O ₂相互作用中的作用和NO在Tre调节的耐寒性中进行了研究。结果表明，在低温胁迫下，IVF571植物对膜脂过氧化的损害明显小于IVF004植物，而IVF571植物的H ₂ O ₂和NO水平明显高于IVF004植物。外源Tre比蔗糖和葡萄糖更有效地提高PSII光化学的最大量子产率，通过增加正常条件下的超氧化物歧化酶（SOD）活性并增强SOD，谷胱甘肽还原酶和冷胁迫下抗坏血酸过氧化物酶活性和谷胱甘肽/谷胱甘肽比 外源Tre可能诱导H ₂ O增加₂，没有水平。用二甲基硫脲去除内源性H ₂ O ₂减弱了外源性Tre的作用，而用2-（4-羧基苯基）-4,4,5,5-四甲基咪唑啉-1-氧基-3-氧化物消除NO则几乎消除了这种作用。外源Tre和H ₂ O _2的组成。综上所述，IVF571幼苗的耐寒性高于IVF004幼苗，可能与冷胁迫引起的H ₂ O ₂和NO水平升高有关。Tre对调节冷诱导瓜的氧化应激可能具有独特的作用。Tre可以升高内源性H ₂ O ₂和NO水平，刺激了甜瓜的应激反应系统。因此，当甜瓜植物暴露于冷胁迫下时，抗氧化酶活性提高，并且对膜脂质过氧化的损害减少。在该过程中，H ₂ O ₂和NO参与了Tre的作用，NO可能位于H ₂ O _2的下游。