Abstract: In order to explore the attenuating effect and mechanism of cold shock combined with glycine betaine treatment on chilling injury of zucchini, the effects of cold shock (ice-water mixture at 0 ℃), glycine betaine (10 mmol/L) and their combination on chilling injury index, relative electric conductivity, malondialdehyde (MDA) content, chlorophyll content, energy metabolism-related enzyme activities in zucchini stored at low temperature ((4 ± 1) ℃) were investigated. The results showed that all three treatments could inhibit the increase in chilling injury index, relative conductivity and MDA content, and delay the decrease in chlorophyll content and the increase in a* and b* values. Moreover, the treatments could maintain high activities of Ca2+-ATPase, H+-ATPase, succinate dehydrogenase (SDH) and cytochrome c oxidase (CCO), retard the decrease in ATP and ADP content, inhibit the increase in AMP content, and maintain high levels of energy charge in zucchini during storage. In conclusion, these treatments could effectively inhibit chilling injury of zucchini fruit, among which the combined treatment was the most effective, which may be related to maintaining high levels of energy charge in zucchini by regulating energy metabolism and consequently maintaining cell membrane integrity. This study provides a scientific basis for the application of cold shock combined with glycine betaine treatment in quality preservation of zucchini during low temperature storage and transportation.

Key words: cold shock, glycine betaine, zucchini, chilling injury, energy metabolism