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草业学报 ›› 2025, Vol. 34 ›› Issue (1): 80-93.DOI: 10.11686/cyxb2024093

• 研究论文 • 上一篇    下一篇

外源褪黑素与乙烯交互对盐胁迫下紫花苜蓿幼苗生长和生理特性的影响

蔡文祺1(), 李淑霞1,2,3(), 王晓彤1, 宋文学1, 麻旭霞1, 马小梅1, 李小红1, 代昕瑶1   

  1. 1.宁夏大学林业与草业学院,宁夏 银川 750021
    2.宁夏草牧业工程技术研究中心,宁夏 银川 750021
    3.农业农村部饲草高效生产模式创新重点实验室,宁夏 银川 750021
  • 收稿日期:2024-03-25 修回日期:2024-04-26 出版日期:2025-01-20 发布日期:2024-11-04
  • 通讯作者: 李淑霞
  • 作者简介:E-mail: lishuxia620@163.com
    蔡文祺(2002-),女,山东威海人,在读本科。E-mail: 19861590011@139.com
  • 基金资助:
    宁夏大学大学生创新创业训练计划项目(S202210749074);宁夏自然科学基金(2022AAC03124)

Effects of interaction between exogenous melatonin and ethylene on the growth and physiological characteristics of Medicago sativa seedlings under salt stress

Wen-qi CAI1(), Shu-xia LI1,2,3(), Xiao-tong WANG1, Wen-xue SONG1, Xu-xia MA1, Xiao-mei MA1, Xiao-hong LI1, Xin-yao DAI1   

  1. 1.College of Forestry and Prataculture,Ningxia University,Yinchuan 750021,China
    2.Ningxia Grassland and Animal Husbandry Engineering Technology Research Center,Yinchuan 750021,China
    3.Key Laboratory of Forage Efficient Production Mode Innovation of Ministry of Agriculture and Rural Affairs,Yinchuan 750021,China
  • Received:2024-03-25 Revised:2024-04-26 Online:2025-01-20 Published:2024-11-04
  • Contact: Shu-xia LI

摘要:

为明确外源褪黑素和乙烯在调控植物耐盐性方面的交互作用,以‘中苜一号’紫花苜蓿为试验材料,通过叶面喷施褪黑素、乙烯利和褪黑素+乙烯利的方法,研究外源施加褪黑素和乙烯对盐胁迫下紫花苜蓿幼苗生长和生理特性的影响。结果表明:外源施加一系列浓度的褪黑素处理(0.01、0.02、0.05、0.10 mmol·L-1 MT)和乙烯利处理(0.05、0.15、0.25、0.50 mmol·L-1 ETH)均对盐胁迫下(250 mmol·L-1 NaCl)紫花苜蓿幼苗的生长损伤具有缓解作用,并以0.05 mmol·L-1 褪黑素处理和0.15 mmol·L-1乙烯利处理缓解效果最佳,其幼苗株高、叶面积、鲜重、叶绿素含量和类胡萝卜素含量显著增加,相对电导率显著降低。采用以上最佳处理浓度试验发现:与对照组相比,盐胁迫下紫花苜蓿幼苗的生长明显被抑制;与单独盐处理组相比,外源施加激素后紫花苜蓿幼苗长势明显较好,尤其是同时施加褪黑素和乙烯利时,紫花苜蓿幼苗的株高、叶面积和鲜重分别增加了54.1%、76.8%和32.1%,组织含水量和叶绿素含量分别增加了46.2%和47.8%,相对电导率和丙二醛含量分别降低了23.5%和39.7%,过氧化氢和超氧阴离子含量分别减少了42.7%和63.8%,超氧化物歧化酶SOD、过氧化物酶POD、过氧化氢酶CAT和抗坏血酸过氧化物酶APX活性分别增加了54.1%、54.1%、59.1%和62.0%,还原性谷胱甘肽GSH含量增加32.8%,脯氨酸和可溶性糖含量增加了42.2%和27.2%,钾钠离子比值增加了217.5%,植株内源褪黑素和乙烯含量分别增加了60.0%和10.6%。综合分析表明,外源施加褪黑素和乙烯能够显著降低紫花苜蓿膜脂过氧化水平和活性氧积累,增加抗氧化酶活性和渗透调节物质含量,调控植株体内离子平衡,增加幼苗内源激素含量,提高紫花苜蓿幼苗的耐盐性,从而促进盐胁迫下幼苗的生长。

关键词: 紫花苜蓿, 盐胁迫, 褪黑素, 乙烯, 生理响应

Abstract:

The aim of this study was to clarify the effects of exogenous melatonin and ethylene in combination on the salt tolerance of alfalfa (Medicago sativa). An experiment was conducted in which the alfalfa cultivar ‘Zhongmu No.1’ was treated with exogenous melatonin, ethephon, and melatonin+ethephon, and then the growth and physiological characteristics of alfalfa seedlings under salt stress were determined. Exogenous application of a range of concentrations of melatonin (0.01, 0.02, 0.05, 0.10 mmol·L-1) and ethephon (0.05, 0.15, 0.25, 0.50 mmol·L-1) as foliar sprays alleviated the reduction in the growth of alfalfa seedlings caused by salt stress (250 mmol·L-1 NaCl). The strongest alleviation effects were in the 0.05 mmol·L-1 melatonin treatment and the 0.15 mmol·L-1 ethephon treatment. The application of melatonin and ethephon alone to alfalfa seedlings under salt stress resulted in significantly increased plant height, leaf area, fresh weight, chlorophyll content, and carotenoid content of alfalfa seedlings, and significantly decreased relative electrical conductivity. We conducted further experiments using the above optimal treatment concentrations of melatonin and ethephon. Compared with the control group, salt-stressed alfalfa seedlings showed significantly inhibited growth. Compared with salt-stressed seedlings, those treated with exogenous hormones showed improved growth, especially those treated with melatonin and ethephon simultaneously. Compared with salt-stressed alfalfa seedlings, the seedlings treated with melatonin and ethephon simultaneously showed increased plant height, leaf area, and fresh weight (by 54.1%, 76.8%, and 32.1%, respectively); increased tissue water content and chlorophyll content (by 46.2% and 47.8%, respectively); decreased relative conductivity and malondialdehyde content (by 23.5% and 39.7%, respectively); decreased hydrogen peroxide and superoxide anion contents (by 42.7% and 63.8%, respectively); increased activities of superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase (by 54.1%, 54.1%, 59.1%, and 62.0%, respectively); higher reduced glutathione content (by 32.8%); increased proline and soluble sugar contents (by 42.2% and 27.2%), a higher potassium ion∶sodium ion (by 217.5%), and increased contents of endogenous melatonin and ethylene (by 60.0% and 10.6%, respectively). These comprehensive analyses showed that exogenous application of melatonin and ethylene significantly reduced the levels of membrane peroxidation and reactive oxygen species in alfalfa, increased the activity of antioxidant enzymes and the contents of osmoregulatory substances, regulated the ionic balance, and increased the contents of endogenous hormones. Together, these changes improved the salt tolerance of alfalfa seedlings. Thus, melatonin and ethylene treatments can improve the growth of alfalfa seedlings under salt stress.

Key words: Medicago sativa, salt stress, melatonin, ethylene, physiological response