| 摘要: |
| 【目的】探究外源褪黑素对山楂果实贮藏品质和软化相关基因表达模式的影响，筛选出适宜的褪黑素 质量浓度，为山楂贮藏保鲜提供参考。【方法】以‘豫北红’山楂成熟果实为试验材料，分别用 0（CK），10，25，75和150 mg/L褪黑素溶液处理，研究不同处理山楂在常温（25±1）℃、相对湿度（85±5）%贮藏过程中的失重率、色泽、硬度、果 胶组分及其降解酶活性、丙二醛（MDA）和过氧化氢（H2O2）含量、多酚氧化酶（PPO）和抗氧化酶活性等贮藏品质，通过 转录组分析软化相关基因的变化规律，结合相关性分析解析生理指标与关键基因表达量之间的关联性。【结果】与CK相比，外源褪黑素处理不仅可以有效抑制贮藏期间山楂果实水分流失，延缓硬度下降，维持果实外观色泽；同时有 效抑制多聚半乳糖醛酸酶（PG）和 β-半乳糖苷酶（β-Gal）活性，减缓共价结合型果胶（CSP）降解和水溶性果胶（WSP） 含量的升高，降低果实软化速率，起到维持果实硬度的作用。贮藏30 d时，与CK相比，10和25 mg/L褪黑素处理山楂的 β-Gal活性分别降低20.37%和24.07%，WSP含量分别降低16.98%和17.57%，CSP含量分别升高101.08%和76.01%。与CK相比，褪黑素处理能显著降低MDA和H2O2含量，贮藏至30 d时，10和25 mg/L褪黑素处理MDA含量分别下降了47.01%和41.84%，H2O2含量分别降低了39.69%和30.11%；超氧化物歧化酶（SOD）、过氧化物酶 （POD）以及抗坏血酸过氧化物酶（APX）活性在贮藏期间较CK显著提高，其中以10和25 mg/L褪黑素处理的增幅较大，有效维持山楂采后贮藏过程中活性氧（ROS）的代谢平衡。转录组分析表明，外源褪黑素处理促使PME40、 PMEU1、PGLR、PLY3、XTH6、EXPA3等多个细胞壁降解相关基因下调表达，延缓了细胞壁的降解和果实软化，维持 贮藏期间山楂果实品质。【结论】外源褪黑素可通过下调细胞壁降解相关基因（PME40、PMEU1、PGLR、PLY3、 XTH6、EXPA3）的表达，抑制多聚半乳糖醛酸酶和 β-半乳糖苷酶的活性，延缓共价结合型果胶的降解和水溶性果胶含 量的积累，起到维持果实硬度的作用；外源褪黑素还可通过提升超氧化物歧化酶、过氧化物酶以及抗坏血酸过氧化物酶 等抗氧化酶的活性，维持活性氧的代谢平衡，延缓衰老过程，维持果实品质，且以10-25 mg/L褪黑素处理效果较佳。 |
| 关键词: 山楂保鲜 外源褪黑素 果实品质 抗氧化酶 基因表达分析 |
| DOI：10. 13207/j. jnwafu. 2026. 12. 009 |
| 分类号: |
| 基金项目:国家重点研发计划项目（2023YFD1600803） |
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| Effects of exogenous melatonin on fruit quality and expression of softening⁃related genes in hawthorn |
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WANG Yijun1, GUO Ronglin2, QIAN Shijiang3, YANG Jiangtao1, ZHENG Yanhao1, HAN Weijuan1, ZHU Jingle1, LI Hui4
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1.Key Laboratory of Non-timber Forestry Germplasm Enhancement & Utilization of State Forestry Administration，Research Institute of Non-timber Forestry of Chinese Academy of Forestry，Zhengzhou，Henan 450003，China;2.College of Forestry，Central South University of Forestry and Technology， Changsha，Hunan 410004，China;3.Henan Provincial Academy of Forestry Sciences，Zhengzhou，Henan 450008，China;4.Research Institute of Forestry Policy and Information，Chinese Academy of Forestry，Beijing 100091，China
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| Abstract: |
| 【Objective】This study aims to investigate the effects of exogenous melatonin on the storage quality and the expression patterns of softening-related genes in hawthorn fruit，and to screen for an optimal melatonin concentration，thereby providing a reference for hawthorn storage and preservation.【Method】Using mature‘ Yubeihong’ hawthorn fruits as experimental material，the fuits were treated with melatonin solutions at concentrations of 0（ CK），10，25，75，and 150 mg/L. The fruits were stored at（ 25±1） ℃ room temperature，and（ 85±5）% relative humidity.Parameters measured during storage included weight loss rate，color，firmness，pectin composition and the activities of its degrading enzymes，malondialdehyde（MDA） and hydrogen peroxide （H2O2） contents，as well as the activities of polyphenol oxidase（PPO） and antioxidant enzymes.Transcriptome analysis was conducted to investigate the changes in softening-related genes，and correlation analysis was combined to analyze the correlation between physiological indicators and the expression levels of key genes.【Result】Compared with CK，exogenous melatonin treatments not only effectively inhibited water loss of hawthorn fruit during storage，delayed firmness decline，and maintained the external color of hawthorn fruit，but also significantly suppressed the activities of polygalacturonase（PG） and β-galactosidase（ β-Gal），slowed down the degra-dation of covalently-bonded pectin（CSP） and increased water-soluble pectin（WSP） content，thereby reducing the fruit softening rate and playing a role in maintaining fruit firmness. After 30 days of storage，compared with the control，the β-Gal activity of hawthorn treated with 10 and 25 mg/L melatonin decreased by 20.37% and 24.07%，the WSP content decreased by 16.98% and 17.57%，and the CSP content increased by 101.08% and 76.01%，respectively. Compared with CK，melatonin treatments significantly lowered MDA and H2O2 contents， after 30 days of storage，the 10 and 25 mg/L melatonin treatments showed the largest reductions in MDA （47.01% and 41.84%） and H2O2 （39.69% and 30.11%）.The activities of superoxide dismutase（SOD），per-oxidase（POD），and ascorbate peroxidase（APX） were significantly higher than those of the control during stor-age，among which the 10 and 25 mg/L melatonin treatments showed the largest increases，effectively maintaining the metabolic balance of reactive oxygen species（ROS） in postharvest hawthorn. Transcriptome analysis revealed that exogenous melatonin treatment downregulated the expression of several cell wall degradation-related genes，including PME40，PMEU1，PGLR，PLY3，XTH6，and EXPA3，thereby delaying cell wall degradation and fruit softening，and maintaining fruit quality during storage.【Conclusion】Exogenous melatonin can maintain fruit firmness by downregulating the expression of cell wall degradation-related genes （PME40，PMEU1， PGLR，PLY3，XTH6，EXPA3），inhibiting the activities of PG and β-Gal，and slowing down the degradation of CSP and the accumulation of WSP. Furthermore，it enhances the activities of antioxidant enzymes such as SOD，POD，and APX，maintains ROS metabolic balance，delays senescence，and preserves fruit quality. The treat-ments with 10-25 mg/L melatonin show the most favorable effects. |
| Key words: hawthorn fresh preservation exogenous melatonin fruit quality antioxidant enzyme gene expression analysis |
