The vigorous metabolism of reactive oxygen species (ROS) in postharvest ‘Kyoho’ grapes shortens the storage period, and reduce the commercial value. In this study, different concentrations (0, 10, 30, 50 and 70 mg/L) of diethyl aminoethyl hexanoate (DA-6) were sprayed on table grapes at veraison to investigate the effects of DA-6 treatment on postharvest fruit quality and ROS metabolism in ‘Kyoho’ grapes. By measuring the physiological indexes related to fruit quality, it was found that DA-6 treatment significantly reduced fruit mass loss, and delayed the decrease in fruit firmness and total soluble solid content, and this effect was most significant at a concentration of 50 mg/L. More importantly, 50 mg/L DA-6 treatment significantly increased the activity of superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity and total reducing capacity, and suppressed the decrease in reduced ascorbic acid and glutathione contents and the accumulation of superoxide anion radical and malondialdehyde. In conclusion, pre-harvest spray of DA-6 maintained the stability of the ROS scavenging system in postharvest table grapes, kept ROS metabolism in a relatively balanced state, reduced oxidative damage, delayed fruit senescence, and prolonged the shelf life of ‘Kyoho’ grapes.

In order to investigate the effect of preharvest spraying of diethyl aminoethyl hexanoate (DA-6) on membrane lipid metabolism in ‘Kyoho’ grapes during postharvest storage, distilled water (control) and 50 mg/L DA-6 were used to spray grapes at the veraison stage. The grapes were harvested when they were ripe, stored at (0 ± 1) ℃ and relative humidity of 65%-70%, and evaluated for cell membrane related indicators of grape skin after 0, 20, 30, 40, 50, and 60 days. The results showed that compared with the control group, DA-6 treatment effectively inhibited the increase in the relative permeability of cell membrane during postharvest storage, maintained the activities of lipoxygense (LOX), lipase and phospolipase D (PLD), inhibited the decrease of phosphatidylcholine and phosphatidylinositol content and the increase of phosphatidyl acid content, and maintained a high relative content of unsaturated acids such as linoleic acid and linolenic acid as well as saturated fatty acids such as stearic acid, behenic acid, arachidic acid and palmitoleic acid, consequently maintaining the degree of unsaturation of fatty acids at a high level. Additionally, DA-6 treatment suppressed the expression of the LOX, Lipase, and PLD genes. In summary, preharvest spraying of 50 mg/L DA-6 can delay the senescence and prolong the storage period of ‘Kyoho’ grapes by effectively relieving the membrane lipid metabolism during storage.