College of Biosystem Engineering and Food Science, Zhejiang University, Hangzhou 310058, China.
J Sci Food Agric. 2013 Feb;93(3):626-33. doi: 10.1002/jsfa.5858. Epub 2012 Aug 30.
The aim of the present study was to reveal the effect of fruit maturity on the chilling tolerance of cucumber (Cucumis sativus L.) fruit and the oxidative and antioxidative mechanisms involved. Chinese mini-cucumber (cv. Hangcui-1) fruits were harvested at four developmental stages: Immature (3-8 days after anthesis (DAA)), Mature (9-16 DAA), Breaker (17-22 DAA) and Yellow (35-40 DAA). All fruits were stored at 2 °C for 9 days and rewarmed at 20 °C for 2 days.
The chilling injury index declined with advancing fruit maturity. High superoxide anion radical production rate and hydrogen peroxide content were observed in Immature fruits after cold storage and rewarming. Under chilling stress, superoxide dismutase showed an early response. Fruits at earlier maturity stages exhibited higher catalase, ascorbate peroxidase and monodehydroascorbate reductase activities and glutathione content as well as its redox state, and lower peroxidase, dehydroascorbate reductase and glutathione reductase activities and ascorbate content as well as its redox state.
Fruits at the earlier developmental stage are more susceptible to chilling injury, which is related to increased oxidative stress. High peroxidase activity and ascorbate content and maintenance of the latter's redox state appear critical to the chilling tolerance of cucumber fruits at later developmental stages.
本研究旨在揭示果实成熟度对黄瓜果实耐冷性的影响及其涉及的氧化和抗氧化机制。选用中国迷你黄瓜（品系 Hangcui-1），在四个发育阶段（未成熟期[开花后 3-8 天]、成熟期[开花后 9-16 天]、破色期[开花后 17-22 天]和转色期[开花后 35-40 天]）采收果实。所有果实均在 2°C 下贮藏 9 天，然后在 20°C 下复温 2 天。
随着果实成熟度的提高，冷害指数下降。在冷藏和复温后，未成熟果实中超氧阴离子自由基产生速率和过氧化氢含量较高。超氧化物歧化酶在冷胁迫下表现出早期响应。在更早的成熟阶段，果实中的过氧化氢酶、抗坏血酸过氧化物酶、单脱氢抗坏血酸还原酶活性和谷胱甘肽含量及其氧化还原状态较高，而过氧化物酶、脱氢抗坏血酸还原酶和谷胱甘肽还原酶活性以及抗坏血酸含量及其氧化还原状态较低。
发育早期的果实对冷害更为敏感，这与氧化应激增加有关。高过氧化物酶活性和抗坏血酸含量以及维持后者的氧化还原状态对黄瓜果实后期发育阶段的耐冷性至关重要。
