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草业学报 ›› 2025, Vol. 34 ›› Issue (9): 206-214.DOI: 10.11686/cyxb2024400

• 研究简报 • 上一篇    

外源褪黑素对盐胁迫下紫花苜蓿的缓解作用

刘沂欣(), 隋晓青(), 王鑫尧, 郎梦卿, 孙凌子寅, 吉尔尔格   

  1. 新疆农业大学草业学院,西部干旱荒漠区草地资源与生态教育部重点实验室,新疆草地资源与生态重点实验室,新疆 乌鲁木齐 830052
  • 收稿日期:2024-10-16 修回日期:2024-12-02 出版日期:2025-09-20 发布日期:2025-07-02
  • 通讯作者: 隋晓青
  • 作者简介:E-mail: sxq303@163.com
    刘沂欣(1999-),女,河南鹤壁人,在读硕士。E-mail: liuyixin202203@163.com
  • 基金资助:
    农业生物育种重大项目(2022ZD0401104);第三次新疆综合科学考察项目(2022xjkk0401)

Mitigating effects of exogenous melatonin on alfalfa under salt stress

Yi-xin LIU(), Xiao-qing SUI(), Xin-yao WANG, Meng-qing LANG, Ling-zi-yin SUN, Er-ge JIER   

  1. College of Grassland,Xinjiang Agricultural University,Key Laboratory of Grassland Resources and Ecology,Ministry of Education,Western Arid Desert Region,Xinjiang Key Laboratory of Grassland Resources and Ecology,Urumqi 830052,China
  • Received:2024-10-16 Revised:2024-12-02 Online:2025-09-20 Published:2025-07-02
  • Contact: Xiao-qing SUI

摘要:

盐胁迫严重制约植物的生长,对农业可持续发展造成威胁。褪黑素是一种强大的抗氧化剂,在不同植物抵抗各种胁迫环境中发挥着重要作用。以‘公农1号’紫花苜蓿(‘Gongnong No.1’)为材料,通过水培试验探究不同浓度外源褪黑素对150 mmol·L-1 NaCl胁迫下紫花苜蓿生理特性的影响和调节。结果显示,外施50、100、150 μmol·L-1褪黑素均可缓解盐胁迫给苜蓿幼苗带来的一系列生理损伤,例如:增加盐胁迫下游离脯氨酸、可溶性蛋白和可溶性糖等渗透调节物质含量。增加盐胁迫下羟自由基清除率,降低丙二醛、过氧化氢含量和相对电导率等损伤,增加超氧化物歧化酶、过氧化氢酶、过氧化物酶、谷胱甘肽S-转移酶、谷胱甘肽还原酶等抗氧化酶活性和抗坏血酸、还原型谷胱甘肽等抗氧化物含量,增加K含量,降低Na含量以平衡离子稳态;但200 μmol·L-1褪黑素会给苜蓿造成渗透应激、氧化胁迫和离子失衡等不利影响。主成分分析表明过氧化氢酶活性、过氧化氢含量和K/Na可作为评价紫花苜蓿耐盐性的关键指标。运用隶属函数对17个生理指标进行综合评价,结果显示,150 μmol·L-1褪黑素处理对盐胁迫缓解效果最佳。本研究结果进一步表明,褪黑素通过两种方式增强苜蓿对盐胁迫的抵抗力:一种是通过直接途径,如直接清除活性氧;另一种是通过间接途径,如通过增强抗氧化酶系统、渗透调节物质等代谢物含量,调节离子稳态。

关键词: 紫花苜蓿, 褪黑素, 盐胁迫, 缓解作用, 综合评价

Abstract:

Salt stress severely restricts plant growth and poses a threat to sustainable agricultural development. Melatonin is a powerful antioxidant that plays an important role in the resistance of different plants to various stressful environments. This research was conducted using ‘Gongnong No.1’ alfalfa (Medicago sativa), and the effect and regulation of physiological characteristics of alfalfa under 150 mmol·L-1 NaCl stress when different concentrations of exogenous melatonin were applied, were investigated in hydroponically grown plants. It was found that external application of 50, 100 and 150 μmol·L-1 melatonin alleviated various symptoms of physiological damage to alfalfa seedlings caused by salt stress. For example, under salt stress exogenous melatonin increased the content of osmotic adjustment substances such as free proline, soluble protein and soluble sugar, the hydroxyl radical scavenging rate was increased under salt stress, and the damage of malondialdehyde, hydrogen peroxide content and relative conductivity was reduced. Exogenous melatonin also increased the activity of antioxidant enzymes such as superoxide dismutase, catalase, peroxidase, glutathione S-transferase, glutathione reductase and the content of antioxidant such as ascorbic acid and reduced glutathione. Finally, exogenous melatonin increased the content of K+ and reduced the content of Na+ which acted to balance ionic homeostasis. However, 200 μmol·L-1 melatonin caused osmotic stress, oxidative stress and ionic imbalance in alfalfa. Principal component analysis indicated that catalase activity, hydrogen peroxide content and K+∶Na+ could be used as key indicators for evaluating alfalfa for salt tolerance. The results of a multi-trait evaluation of 17 physiological indexes using an affiliation function methodology showed that 150 μmol·L-1 melatonin treatment provided the most effective salt stress alleviation. A further insight from the results of this experiment was that melatonin enhances the resistance of alfalfa to salt stress in two ways: one is through direct pathways, such as direct scavenging of reactive oxygen species; the other is through indirect pathways, such as regulation of ionic homeostasis through the enhancement of metabolite content of the antioxidant enzyme system and osmoregulatory substances.

Key words: alfalfa, melatonin, salt stress, mitigating effects, comprehensive evaluation