In this study, ‘French’ prune fruits were treated with O₂ at concentrations of 50%, 70%, and 90% and stored at 1–2 ℃ and a relative humidity (RH) of 90%–95% for up to 120 days. For comparison, air treatment was used as the control. Sampling was done every 20 days for measurement of relevant parameters to analyze the effect of highoxygen treatment on postharvest browning of prune fruits. The results showed that the high-oxygen treatments effectively inhibited browning. Among them, the 70% O₂ treatment for 6 h was the most effective, reducing the browning index by 22.06% compared with the control at the end of storage (P < 0.05). The 70% O₂ treatment significantly suppressed the activities of polyphenol oxidase (PPO) and peroxidase (POD) during storage, while maintaining the contents of total phenolics, flavonoids, and individual phenolic compounds such as caffeic acid, protocatechuic acid, and quercetin. Moreover, it enhanced the activities of superoxide dismutase (SOD) and catalase (CAT), and significantly decreased the rate of superoxide anion (O₂^-·) generation and hydrogen peroxide (H₂O₂) content. It also suppressed the increase in cell membrane permeability and malondialdehyde (MDA) content, preserving membrane stability. Consequently, the 70% O₂ treatment effectively alleviated browning in prune fruits.

This study aimed to investigate the effect of nitric oxide(NO) treatment on the resistance of prunes to postharvest black spot disease. After harvest, Xinjiang-grown ‘France' prunes were subjected to vacuum infiltration (0.02 MPa for 2 min followed by atmospheric pressure for 8 min) using solutions of the NO donor sodium nitroprusside (SNP) at concentrations of 0.0125, 0.025, and 0.05 mmol/L, respectively. Thereafter, the treated fruits were wounded, inoculated with Alternaria alternata, and stored at (1.0 ± 0.5) ℃ and relative humidity of 90%–95% for 120 d. Samples were collected every 20 days to measure infection incidence, lesion diameter, superoxide anion radical production rate, hydrogen peroxide (H₂O₂) content, ATP and ADP levels, energy charge, and the activities of enzymes related to reactive oxygen species (ROS) and energy metabolism. The results indicated that NO treatment suppressed infection incidence and lesion expansion in prunes, with the most effective treatment being 0.025 mmol/L NO. Compared with the control group, infection incidence and lesion diameter at the end of storage were reduced by 27.89% and 33.73%, respectively (P < 0.05). NO treatment enhanced the activity of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) in prunes, and significantly suppressed the decline in the activities of succinate dehydrogenase (SDH), cytochrome c oxidase (CCO), H⁺-ATPase, and Ca²⁺-ATPase during storage, while inhibiting the production of superoxide anion radical and H₂O₂. It maintained higher ATP and ADP levels and energy charge in prunes, suppressed the increase in malondialdehyde (MDA) content, and maintained the balance between intracellular ROS production and scavenging, thereby effectively enhancing prune resistance to black spot disease.

This study investigated the effect of preharvest application of chitosan oligosaccharides (COS) on the control of postharvest black spot disease in ‘French’ prune fruits. Prune fruits were sprayed with different concentrations of COS (0.05%, 0.10% and 0.20%) or water as a control at four developmental stages (fruit set, enlargement, color change and maturity). After preharvest COS treatment, the fruits were inoculated with Alternaria alternata and stored for 90 days at (1.0 ± 1.0) ℃ and a relative humidity of 90%-95%. Samples were taken every 15 days to measure relevant indicators. The in vitro inhibitory effect of COS on A. alternat was also tested. The results showed that COS significantly hindered the colony growth and spore germination of A. alternata. Scanning electron microscopic examination showed that the hyphae of A. alternata treated with COS exhibited a rough surface and were irregular in thickness with partial collapse, indicating notable disruption of the hyphal integrity. Notably, the preharvest application of 0.10% COS significantly inhibited the incidence of black spot disease and lesion progression in prune fruits inoculated with A. alternata during postharvest storage. Furthermore, preharvest COS treatment elevated the activities of superoxide dismutase (SOD), catalase (CAT), chitinase (CHT), β-1,3-glucanase (GLU), phenylalanine ammonia-lyase (PAL), 4-coumarate:coenzyme A ligase (4CL), and cinnamate-4-hydroxylase (C4H), and facilitated the accumulation of total phenols, flavonoids, and lignin along with a rapid surge in H₂O₂ levels during the early storage phase, which was maintained at lower levels in later stages. These findings suggest that the preharvest application of COS can enhance the black spot disease resistance of postharvest prune fruits by directly exerting an antifungal effect and inducing disease resistance. This study provides a new idea and theoretical basis for disease prevention and control in prune fruits.

In this study, the effects of melatonin on chilling injury and reactive oxygen metabolism were investigated during the storage of postharvest apricot fruit at (0 ± 1) ℃ and 90%–95% relative humidity. ‘Saimaiti’ apricots were impregnated with different concentrations of melatonin (50, 100 and 200 μmol/L) at 0.05 MPa for 2 min and then at atmospheric pressure for 8 min before storage. Distilled water was used as a control. Chilling injury incidence and chilling injury index were periodically recorded, and malondialdehyde (MDA) content, cell membrane permeability, superoxide anion radical production rate, H₂O₂ content and antioxidant enzyme activities were measured in apricot fruit. Compared to the control group, melatonin treatment obviously reduced chilling injury incidence and index in apricot fruit (P < 0.05), and 100 μmol/L melatonin was the most effective in reducing chilling injury. Furthermore, apricot fruit treated with melatonin increased the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), inhibited the accumulation of superoxide anion radical and H₂O₂, reduced membrane lipid peroxidation, and maintained membrane integrity. These results suggested that the inhibition of exogenous melatonin on chilling injury of apricot fruit was closely related to the regulation of reactive oxygen metabolism. These findings can provide a theoretical basis for the application of melatonin in controlling chilling injury of postharvest apricot fruit.

The present research was undertaken in order to study the effect of exogenous fructose treatment on postharvest softening of apricot fruits. ‘Saimaiti’ apricots were subjected to osmotic treatment in 300 mmol/L fructose solution at 0.05 MPa for 2 min followed by normal pressure for another 5 min before storage at (0 ± 1) ℃. Distilled water was used as control treatment. Fruit hardness, cell membrane permeability, water soluble pectin (WSP), chelate soluble pectin (CSP), Na₂CO₃ soluble pectin (NSP) and cellulose contents, and polygalacturonase (PG), pectin methyl esterase (PME), β-galactosidase (β-Gal) and cellulase (CEL) activities were determined every seven days during storage, and cell ultrastructure was observed by transmission electron microscopy (TEM). The results showed that exogenous fructose treatment could significantly inhibit the activity of cell wall degrading enzymes and maintain the contents of CSP, NSP, and cellulose, thereby inhibiting the degradation of the cell wall. On day 49 of storage, compared with the control group, the contents of CSP, NSP and cellulose in fructose-treated apricot fruits increased by 31.30%, 10.58%, and 14.30% (P < 0.05). The WSP content and cell membrane permeability of the control group were 1.09 and 1.25 times as high as those in the control group, respectively. Furthermore, this treatment maintained the integrity of organelles and the membrane system, and effectively delayed the decline in fruit hardness.

In order to explore the effect of exogenous glucose (Glc) treatment on the postharvest storage quality and antioxidant metabolism of apricot fruit, ‘Saimaiti’ apricot fruit from Xinjiang were stored for up to 49 days at (0 ± 1) ℃ and a relative humidity of 90%–95% after vacuum osmosis treatment (holding for 2 min at 0.05 MPa followed by soaking for 5 min at atmospheric pressure) with different concentrations (100, 200 and 400 mmol/L) of Glc or distilled water as a control. Fruit quality and antioxidant metabolism-related indexes were determined during the storage period. The results showed that exogenous Glc treatment could effectively maintain the firmness, soluble solids content (SSC) and titratable acid (TA) levels, and significantly reduce the respiration intensity of apricot fruit, with the most pronounced effect being observed at 200 mmol/L Glc. In addition, exogenous Glc treatment increased the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) in apricot fruit compared with the control group, and effectively maintained the contents of ascorbic acid (ASA) and glutathione (GSH), thus delaying the accumulation of superoxide anion radical, hydrogen peroxide, malondialdehyde (MDA) and the increase of cell membrane permeability. These findings indicate that exogenous Glc treatment could maintain the storage quality of apricot fruit by regulating its antioxidant metabolism during storage, which will provide a theoretical basis and technical reference for the application of Glc in postharvest storage and preservation of fruits and vegetables.

This study was conducted in order to explore the effect of exogenous glucose treatment on postharvest cold resistance and sugar metabolism in apricot fruit. Xinjiang-grown ‘Saimati’ apricots were subjected to vacuum osmosis treatment with different concentrations of glucose followed by cold storage at (0 ± 1) ℃ for 49 days. The incidence of chilling injury, chilling injury index, quality and sugar metabolism-related indicators of apricot fruit were measured at regular intervals during the storage period. The results showed that 200 mmol/L exogenous glucose treatment could effectively inhibit the increase in the incidence of chilling injury, chilling injury index, cell membrane permeability and the accumulation of malondialdehyde (MDA), and well maintain the hardness, color, soluble solids content (SSC), titratable acid (TA) and ascorbic acid (ASA) contents of apricot fruit. Meanwhile, compared with the control group, the exogenous glucose treatment increased the activities of acid invertase (AI), neutral invertase (NI), sucrose phosphate synthase (SPS) and sucrose synthase (SS) in apricot fruit, and significantly increased the accumulation of glucose and fructose during storage. However, the content of sucrose decreased during the mid-to-late stage of storage (21–49 days). In summary, exogenous glucose treatment could enhance the contents of glucose and fructose by regulating the activity of enzymes related to sugar metabolism, thereby enhancing cold resistance and maintaining the storage quality of the fruit. The results of this study can provide a reference for controlling chilling injury in postharvest apricot fruit.

In order to explore the effects of melatonin (MT) treatment on cold resistance in apricot fruits, Xinjianggrown ‘Saimaiti’ apricot fruits were treated with MT or distilled water as a control at 0.05 MPa for 2 min followed by atmospheric pressure for 8 min. During 49 days of storage at (0 ± 0.5) ℃ and relative humidity of 90%–95%, chilling injury index, incidence of chilling injury, cell membrane permeability, malondialdehyde (MDA) content, superoxide anion (O₂^-·) production rate, hydrogen peroxide (H₂O₂) content, antioxidant content, energy substance content and related enzyme activity were measured every 7 days, and mitochondrial structure was observed by transmission electron microscopy (TEM). The results showed that MT treatment effectively inhibited the increase of cell membrane permeability and the accumulation of MDA during storage, significantly reduced the incidence and index of chilling injury, and delayed the occurrence of chilling injury symptoms. In addition, compared with the control group, MT treatment enhanced the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), aseorbate peroxidase (APX) and glutathione reductase (GR), inhibited the increase of · production rate and the accumulation of H₂O₂, increased glutathione (GSH) content, delayed the decrease of ascorbic acid (ASA) content, and effectively maintained the balance of intracellular ROS. MT treatment could also effectively delay the decrease of succinic dehydrogenase (SDH), cytochrome c oxidase (CCO) and H⁺-ATPase and Ca²⁺-ATPase during storage, maintain high levels of adenosine triphosphate (ATP), adenosine diphosphate (ADP) and energy state, and preserve the integrity of mitochondrial structure and function. In conclusion, MT treatment could enhance the cold resistance of apricot fruits by regulating the energy metabolism and antioxidant capacity. This provides a new theoretical basis for chilling injury control of apricot fruits.