Variation in heat stress-induced antioxidant enzyme activities among three mulberry cultivars

The effects of high temperature on antioxidant enzymes were investigated in three mulberry (Morus alba L.) cultivars (cv. K-2, MR-2 and BC2-59). High temperature was imposed by maintaining the plants at 40degreesC for 120, 240 and 360 min in an environmental plant growth chamber. The activities of superoxide disumutase (SOD), catalase (CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) were assayed in the leaf extracts of control and high temperature-treated plants. Antioxidant enzyme activities were high in all the mulberry cultivars in response to high temperature treatment. However, cv. BC2-59 showed significantly higher activities of all the five antioxidant enzymes in response to high temperature compared to those from the leaves of K-2, and MR-2 mulberry cultivars. The present study suggested that the cv. BC2-59 has an efficient antioxidant system among the three cultivars, which could prevent the oxidative damage in the leaves caused by high temperature stress.