6-Benzylaminopurine alleviates chilling injury of postharvest cucumber fruit through modulating antioxidant system and energy status.

Background: 6-Benzylaminopurine (6-BA) has a close relationship with the stress resistance of plants. Little research has been carried out on the effects of 6-BA on the cold resistance of postharvest fruits and vegetables. Therefore the aim of the present study was to evaluate the effects of 6-BA on chilling injury (CI), antioxidant system and energy status in cucumber during storage.

Results: The results showed that 6-BA at 50 mmol L(-1) was most effective to restrain CI in cucumber fruit. Fruits treated with 50 mmol L(-1) 6-BA maintained higher levels of chlorophyll, ascorbic acid, total phenolics and total antioxidant capacity. Furthermore, this treatment reduced the increases in membrane permeability and lipid peroxidation, delayed the increases in both rate of O2•- production and H2O2 content and increased the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) under chilling stress. The treatment also increased the content of adenosine triphosphate (ATP) and resulted in a higher level of energy charge.

Conclusion: These results indicated that 6-BA alleviated CI in cucumber fruit through improving antioxidant enzyme activities and total antioxidant capacity and maintaining higher levels of ATP content and energy charge.