Contribution of oxidative stress to the development of cold-induced damage to leaves of chilling-sensitive plants: 2. The activity of antioxidant enzymes during plant chilling

摘要

Changes in the activities of cytosolic superoxide dismutase, ascorbate peroxidase, and catalase were studied in 7-11-day-old seedlings of maize (Zea mays L.), cucumber (Cucumis sativus L.), millet (Panicum miliaceum L.), and etiolated potato (Solanum tuberosum L.) sprouts. The assays were performed immediately after chilling at 2degreesC for 1-24 h and one day after 24-h chilling. During the first 1-2 h of chilling, enzyme activities were substantially reduced in chilling-sensitive plants (cucumber and maize). Further chilling resulted in a gradual increase in the enzyme activities to a degree dependent on plant species. One day after the plants were returned to a high temperature, the enzyme activities were restored to an initial level or exceeded it (excluding maize superoxide dismutase). In the potato (cold-resistant species), we did not observe any regular changes in the activities of antioxidant enzymes. On the whole, the activities of these enzymes inversely depended on species cold-resistance. The conclusion is that one of the cold-resistance factors is the capacity of antioxidant enzymes to maintain their activities during chilling and restore them relatively rapidly after plant transfer to warm conditions.