Elevated growing temperatures during the day improve the postharvest chilling tolerance of greenhouse-grown cucumber (Cucumis sativus) fruit

Growing cucumber fruit in a greenhouse at elevated temperatures during the day increased their tolerance to postharvest chilling. Fruit grown with an average day temperature of 32 +/- 1 degreesC (high temperature) had a storage life (i.e. time to loose 7% fresh weight) of 16 days at 10 degreesC and did not exhibit chilling injury, while fruit grown at 27 +/- 1 degreesC (control) developed symptoms of chilling injury (i.e. appearance of translucent, water-soaked areas in the mesocarp) after 12 days at 10 degreesC. The rate of fresh weight loss and the storage life (i.e. 7%, water loss) of fruit from both treatments was 12 days when stored at 20 degreesC. Chilling-induced ion leakage from mesocarp disks was lower from high temperature grown fruit than from control fruit. During storage at 10 degreesC, firmness, vitamin C content, and activity of superoxide dismutase (SOD; EC 1.15.1.1), and catalase (CAT; EC 1.11.1.6) were higher in high temperature grown fruit than in control fruit. Enhanced antioxidant enzyme activity in high temperature grown fruit may have contributed to increased chilling tolerance. (C) 2002 Elsevier Science B.V. All rights reserved.