Chinese chive usually develops an off-flavor after a short storage time.  To explore effective ways to maintain the postharvest quality of Chinese chive, the effect of exogenous application of 6-benzylaminopurine (6-BA) on postharvest quality and antioxidant activity of chive was evaluated, and the mechanism of the physiological responses of chive to 6-BA treatment was explored.  Chives were sprayed for 10 min with 100, 300, or 500 mg L^–1 6-BA or with alkaline solution as the control, then stored at (2±1)°C with a relative humidity (RH) of 80–85%.  We found that 300 mg L^–1 6-BA significantly delayed yellowing and chlorophyll degradation, maintained the total phenolic and flavonoid content, and improved the activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD).  In conclusion, we identified exogenous application of 6-BA as an effective method for maintaining postharvest quality of Chinese chive.  In addition, our finding that the activities of antioxidant enzymes increase in response to exogenous 6-BA provides new insights into the mechanism of cytokinin-based postharvest fresh-keeping. 

Effect of salicylic acid (SA) on chilling injury (CI) of sponge gourd during storage (9 days, 9°C) plus shelf life (2 days, 20°C) was evaluated in this study.  SA treatment at the concentration of 1.5 mmol L^–1 significantly reduced postharvest CI of sponge gourds.  Besides, the application of SA could effectively decrease the electrolyte leakage, reduce the accumulation of malondialdehyde (MDA) and total phenolics, enhance the activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX), and inhibit the activities of phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO).  The beneficial effects of SA could be attributed to preserved membrane integrity, inhibited membrane peroxidation, enhanced antioxidant system and suppressed activities of browning related enzymes.  In a sense, SA as a postharvest tool may be commercially used in alleviating CI of sponge gourd.

The antifungal activity of chitosan on a common fungal phytopathogen, Sclerotinia sclerotiorum, and the control effect on sclerotinia rot of carrot were investigated. Mycelial growth and fungal biomass were strongly inhibited by chitosan. Using propidium iodide stain combined with fluorescent microscopy, the plasma membrane of chitosan-treated S. sclerotiorum mycelia was observed to be markedly damaged. Concomitantly, protein leakage and lipid peroxidation was also found to be significantly higher in chitosan-treated mycelia compared to the control. Chitosan provided an effective control of sclerotinia rot of carrot, with induction of activity of defense-related enzymes including polyphenoloxidase and peroxidase. These data suggest that the effects of chitosan on sclerotinia rot of carrot may be associated with the direct damage to the plasma membrane and lipid peroxidation of S. sclerotiorum, and the elicitation of defense response in carrot.