Peach (Prunus persica (L.) Batsch) is susceptible to chilling injury under improper low-temperature storage (2°C–5°C). Previous research has shown that abscisic acid (ABA) alleviates chilling injury in fruits and vegetables, but the potential mechanism is still unclear. To explore its effectiveness and potential mechanism in alleviating chilling injury during cold storage, exogenous ABA was applied to peach fruit by immersion in 100 μmol L⁻¹ solutions for 10 min. In our experiment, ABA alleviated chilling injury by reducing hydrogen peroxide (H₂O₂) content and ethylene production. In addition, ABA inhibited the expression of the ethylene synthesis-related genes PpACO1 and PpEIN2. At the same time, ABA activated the antioxidant enzymatic pathway and the ascorbate-glutathione (AsA-GSH) cycle, the transcript abundance encoding genes related to antioxidant enzyme activities also changed correspondingly. The results suggested that ABA alleviated chilling injury by scavenging excessive H₂O₂ by promoting antioxidant enzymes and the AsA-GSH pathway.

Browning and lignification often occur in fresh-cut apple processing, leading to quality deterioration and limiting the shelf life of products. In this study, 0.8% (v/v) phytic acid was used to improve the quality and shelf life of fresh-cut apples. From the results, the browning was inhibited by the phytic acid treatment and the browning index (BI) of the control fruit was 1.62 times that of phytic acid treatment at 2 d of storage. The lignin content in phytic acid-treated fruit significantly decreased at 2, 4, and 6 d of storage compared to the control. Phytic acid treatment also reduced H₂O₂ and malonaldehyde (MDA) contents, which may indicate lighter membrane damage to apples. Compared with the control, the polyphenol oxidase (PPO) and peroxidase (POD) activities decreased while superoxide dismutase (SOD) and catalase (CAT) activities increased in phytic acid-treated fruit. Consistent with the lignin content, the activities of phenylpropane metabolism-related enzymes phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), and 4-coumarate: CoA ligase (4CL) were inhibited by phytic acid treatment. In conclusion, phytic acid alleviated the browning and lignification of fresh-cut apples by reducing PPO and POD activities, maintaining cell membrane integrity, and inhibiting phenylpropane metabolism.

Currently, several studies have demonstrated that cold stress can cause the accumulation of reactive oxygen species (ROS) in fruit. However, little is known about the roles of gibberellic acid (GA₃) on the antioxidant system in the mitochondria of fruit. To explore the molecular basis of GA₃ interference with the chilling tolerance of fruit, ‘Jinqiuhongmi’ peach fruit was treated with 0.1 mmol L⁻¹ GA₃ after harvest. Exogenous GA₃ treatment relieved the chilling injury of postharvest peach fruit with a lower cold injury index and higher antioxidant level. In addition, GA₃ delayed the senescence of peaches by reducing the firmness, respiratory action, and ethylene production. The antioxidant enzyme activities were elevated, including superoxide dismutase (SOD) and catalase (CAT). Moreover, GA₃-treated peaches exhibited lower hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) in comparison with the control. These results showed that the application of 0.1 mmol L⁻¹ of GA₃ enhanced the chilling resistance of peach fruit by regulating the antioxidant system.

Peach (Prunus persica (L.) Batsch) fruit are susceptible to chilling injury that is often manifested as browning of the internal flesh. As the ethylene antagonist, 1-methylcyclopropene (1-MCP) is an important contributor to resist chilling stress during peach (Prunus persica (L.) Batsch) storage at low temperatures, but the molecular mechanism of it is still elusive. The study examined in detail the effects of two concentrations (1 and 2μL·L⁻¹) of 1-MCP on alleviating chilling injury (CI) of postharvest peach fruit stored at 4±0.5°C. The results showed that although all treatments relieved CI, treatment with 1μL·L⁻¹ more effectively alleviated CI symptoms of postharvest peach fruit than 2μL·L⁻¹. The internal browning (IB) and weight loss were significantly inhibited by 1μL·L⁻¹ 1-MCP. Lower concentration of 1-MCP maintained normal softening by decreasing the gene expression of expansin (Exp) 1,3, polygalacturonase (PG) 3, and pectate lyase (PLY) 1, 2, 3 and increased the content of soluble sugar during the whole storage period. Meanwhile, the activities of polygalacturonase, pectinmethylesterase (PME), and endo-1,4-β-glucanase (EGase) were reduced by lower concentration of 1-MCP. Our results demonstrate that 1-MCP inhibited CI by suppressing the degradation of cell wall. This study provides a theoretical basis for revealing that 1-MCP alleviates chilling injury in peach fruit.