| 外源ABA对低温胁迫下火龙果苗活性氧代谢的影响 |
| 投稿时间：2022-09-15 修订日期：2023-04-27 点此下载全文 |
| 引用本文：王楚侨,黄一梅,罗弦,等.外源ABA对低温胁迫下火龙果苗活性氧代谢的影响[J].西北植物学报,2023,43(8):1344~1351 |
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| 基金项目:四川省衔接推进乡村振兴科技项目（2022ZHXC0097）和四川农业大学专业建设计划（202103123） |
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| 中文摘要:以‘台湾6号’红心火龙果扦插苗为材料，在150 mg/L的外源脱落酸（ABA）预处理后，进行10d的低温胁迫（8℃/0℃，12 h/12 h），测定火龙果苗活性氧（ROS）含量、抗氧化酶活性、相对电导率（REC）、丙二醛（MDA）含量及抗坏血酸-谷胱甘肽（AsA-GSH）循环相关指标，探讨外源ABA对火龙果苗ROS代谢的调控作用，从ROS代谢的角度阐明ABA提高火龙果耐寒性的机理。结果表明：（1）低温胁迫10 d后火龙果苗受到寒害，出现水渍状斑点及萎焉黄化，寒害指数达0.52；150 mg/L的ABA预处理可以减轻火龙果苗的寒害症状，寒害指数降低至0.20。（2）低温胁迫打破了火龙果苗ROS代谢平衡，O2-产生速率和H2O2显著增加，膜脂过氧化加剧，MDA含量及REC显著升高；外源ABA预处理可以显著降低H2O2含量，改善膜脂过氧化，MDA含量和REC显著下降。（3）火龙果苗SOD、POD、CAT活性在低温胁迫下显著增强，而外源ABA预处理使SOD、POD、CAT活性进一步增强。（4）低温诱导了火龙果苗体内APX、DHAR、GR及MDHAR活性显著增加，AsA、GSH、DHA、GSSG含量也显著提升，但AsA /DHA比值和GSH/GSSG比值下降，ROS清除系统受到破坏；外源ABA预处理可显著提高低温条件下APX、GR及MDHAR活性，增加抗氧化剂AsA、GSH含量，提高AsA/DHA、GSH/GSSG比值，从而增强火龙果苗清除ROS的能力。综上所述，外源ABA通过增加火龙果苗抗氧化酶活性和AsA-GSH循环的代谢活性，增强了ROS的清除能力，维持了ROS代谢平衡，从而减轻膜脂过氧化程度和电解质外渗，有效缓解了火龙果苗受到的寒害。 |
| 中文关键词:火龙果 低温胁迫 脱落酸 活性氧 抗氧化酶 AsA-GSH循环 |
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| Effects of Exogenous ABA on ROS Metabolism of Pitaya Seedling under Cold Stress |
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| Abstract:The cutting seedlings of red pulp pitaya ‘Taiwan No. 6’ was used as experiment material, pretreated with 150mg/L ABA, and treated under cold stress (8℃/0℃，12 h/12 h) for 10 days. The effects of Reactive oxygen species (ROS) content, antioxidant enzyme activity, relative conductivity (REC), Malondialdehyde (MDA) content and AsA-GSH cycle related indicators were determined in order to study the regulatory effect of ABA on ROS metabolism of Pitaya seedlings, and to clarify the mechanism of ABA improving cold tolerance of Pitaya seedlings from the perspective of ROS metabolism. The results showed that: (1) Pitaya seedlings showed watery stains and wilted yellowing due to 10 days cold injury stress, and the index of chilling injury (CI) reached 0.52. Pretreatment with 150mg/L ABA can reduce the cold damage, the CI was reduced to 0.20. (2) Cold stress broke the balance of ROS metabolism. It significantly increased the O2- production rate and hydrogen peroxide (H2O2) content, and made membrane lipid peroxidation intensified, MDA and REC increased significantly in pitaya seedlings. Pretreatment with exogenous ABA can significantly reduced H2O2 content, reduce membrane lipid peroxidation, and significantly reduced MDA and REC. (3) The activities of SOD, POD, and CAT significantly increased in pitaya seedlings under cold stress. However, pretreatment with exogenous ABA further enhanced the activities of SOD, POD and CAT. (4) Cold stress caused the activities of APX, DHAR, GR and MDHAR significantly increased, and the contents of AsA, GSH, DHA and GSSG also increased in pitaya seedlings. However, the ratio of AsA/DHA and GSH/GSSG decreased, ROS scavenging system was damaged. Pretreatment with exogenous ABA can enhance the ability of pitaya seedlings to scavenge ROS under cold stress though by enhancing the activities of APX, GR and MDHAR, the content of antioxidants AsA and GSH, and the ratios of AsA/DHA and GSH/GSSG. In conclusion, exogenous ABA can effectively improve the cold tolerance of pitaya seedlings. It can enhance the scavenging ability of ROS and maintain the balance of ROS metabolism by increasing the activity of antioxidant enzymes and the metabolic activity of AsA-GSH cycle in pitaya seedlings, thereby reducing the degree of membrane lipid peroxidation and electrolyte leakage, and effectively alleviating the cold damage of pitaya seedlings. |
| keywords:pitaya cold stress abscisic acid reactive oxygen species antioxidant enzymes AsA-GSH cycle |
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