Elevated O2 alleviated anaerobic metabolism in postharvest winter jujube fruit by regulating pyruvic acid and energy metabolism

Over-accumulation of anaerobic metabolites is a typical characteristic of postharvest senescence in winter jujube fruit. Here, elevated O2 was applied during cold storage to investigate its regulation on anaerobic respiration. The results found 60 % O2 was the optimal concentration to inhibit anaerobic respiration, which showed 83.82 % lower acetaldehyde and 57.13 % lower ethanol compared with control. Elevated O2 maintained energy status by activating succinate dehydrogenase and cytochrome C oxidase, with 1.11-fold higher energy charge observed as compared with the control. In addition, activated aerobic respiration also accelerated the consumption of pyruvic acid, and pyruvic acid content was reduced by 63 % in elevated O2-treated fruit. Sufficient energy supply and reduced pyruvic acid content in elevated O2-treated fruit induced the alleviation of anaerobic respiration, leading to attenuating the accumulation of ethanol and acetaldehyde as a result. The study proved elevated O2 repressed anaerobic metabolism by regulating pyruvic acid level and energy metabolism.

Automated summary

The over-accumulation of anaerobic metabolites in winter jujube fruit after harvest is a typical characteristic of postharvest senescence. In this study, elevated O2 concentration was applied during cold storage to investigate its regulation on anaerobic respiration. The results showed that 60% O2 concentration was the optimal concentration to inhibit anaerobic respiration, leading to significant reduction in acetaldehyde and ethanol content compared to the control group. Elevated O2 concentration maintained energy status by activating succinate dehydrogenase and cytochrome C oxidase, resulting in higher energy charge compared to the control. Moreover, activated aerobic respiration also accelerated the consumption of pyruvic acid, leading to reduced pyruvic acid content in the elevated O2-treated fruit. These findings suggest that elevated O2 concentration represses anaerobic metabolism by regulating pyruvic acid level and energy metabolism.