Abstract: To investigate the effect of low temperature stress on ascorbate content , activities of its relative oxidative enzymes and superoxide dismutase (SOD) , the ascorbate and dehydroascorbate content and activities of SOD and four enzymes involved in the ascorbate-glutathione cycle (AsA-GSH cycle) in strawberry were studied. The results showed that under low temperature stress the activities of SOD, ascorbate peroxidase (APX) and monodehydroascorbate reductase (MDAR) increased, while the acitivities of dehydroascorbate reductase (DHAR) and glutathione reductase (GR) decreased. Meanwhile, low temperature stress induced decrease in ascorbate (AsA) content and increase in dehydroascorbate (DHA) content. When low temperature stress continued, more reactive oxygen species (ROS) were produced and could not be removed efficiently by defense system. The results also indicated that APX had a strong ability to oxidize AsA and MDAR was a main enzyme to regenerate AsA in AsA-GSH cycle.

Key words: Strawberry, Low temperature stress, Ascorbate, SOD, Ascorbate-glutathione cycle