Production of Reactive Oxygen Species and Antioxidant Metabolism about Strawberry Leaves to Low Temperatures

This study examined the influence of low temperature on the production of reactive oxygen species and antioxidant metabolism in two strawberry (Fragaria ananassa Duch.) cultivars (cv. Zoji and Toyonaka). Low temperature treatment was imposed by maintaining the plants at 0? for 2, 4, 6, 8, 12, 24, 48 and 72 h in an artificial intelligent growth chamber. During the period of low temperature treatments, the activities of peroxidative (POD), superoxide disumutase (SOD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate (DHAR), glutathione reductase (GR), the production of O2- and H2O2, as well as the contents of antioxidant such as dehydroascorbate and reduced glutathione were up-regulated exception of the contents of ascorabte and chlorophyll in compared with the control. Meanwhile, cv. Toyonaka showed more tolerant to low temperatures than cv. Zoji since it showed higher activities of antioxidative enzymes, more contents of osmolytes (proline and soluble sugar) and less lipid peroxidation during the low temperature treatments. The present study suggested that plant had signal molecules sensing the environmental stress, following erecting its defensive system protective them against the damage caused by stress environment. However, if the stress were too powerful, plants could not response to acclimate that stress, the plants would be injured or even be dead finally. In the two cultivars examined, cv. Toyonaka has a more efficient antioxidant system against low temperature than cv. Zoji.