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草业学报 ›› 2024, Vol. 33 ›› Issue (6): 64-75.DOI: 10.11686/cyxb2023366

• 研究论文 • 上一篇    下一篇

盐胁迫下根施AMF和褪黑素对紫花苜蓿生长、光合特征以及抗氧化系统的影响

谭英1(), 尹豪2,3   

  1. 1.北京市朝阳区四得公园管理处,北京 100016
    2.北京林业大学园林学院,北京 100083
    3.城乡生态环境北京实验室,北京 100083
  • 收稿日期:2023-09-27 修回日期:2023-10-30 出版日期:2024-06-20 发布日期:2024-03-20
  • 通讯作者: 谭英
  • 作者简介:E-mail: tanying197004@126.com
    谭英(1971-),女,北京人,本科。E-mail: tanying197004@126.com
  • 基金资助:
    国家重点研发计划项目(2019YFD1100400);北京林业大学热点追踪项目(2022BLRD05);北京市共建项目专项资助

Effects of root application of an arbuscular mycorrhizal fungus and melatonin on the growth, photosynthetic characteristics, and antioxidant system of Medicago sativa under salt stresss

Ying TAN1(), Hao YIN2,3   

  1. 1.Side Park,Chaoyang District,Beijing City,Beijing 100016,China
    2.Landscape Architecture School,Beijing Forestry University,Beijing 100083,China
    3.Laboratory of Urban and Rural Ecological Environment,Beijing 100083,China
  • Received:2023-09-27 Revised:2023-10-30 Online:2024-06-20 Published:2024-03-20
  • Contact: Ying TAN

摘要:

本试验旨在探究盐胁迫下根施丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)和褪黑素处理对紫花苜蓿生长、光合特征和抗氧化系统的影响。设置盐胁迫下(100 mmol·L-1 NaCl)对紫花苜蓿根施褪黑素(0、50、100、150、200 μmol·L-1)并接种AMF变形球囊霉以及不接种对照共10个处理。结果表明,AMF与紫花苜蓿能形成稳定共生关系,根施褪黑素能够增加AMF菌根侵染率以及泡囊数,菌根侵染率最高达65.2%。在根施褪黑素100 μmol·L-1水平下,与对照相比,接种AMF处理的紫花苜蓿总生物量、叶绿素a、叶绿素b含量分别提高5.4%、7.3%和45.3%,根冠比下降39.5%;净光合速率(Pn)、蒸腾速率(Tr)、胞间CO2浓度(Ci)和气孔导度(Gs)分别增加23.3%、28.3%、17.6%和14.1%;最大光化学效率(Fv/Fm)和PSⅡ潜在活性(Fv/Fo)分别提高19.6%和22.9%;叶片中氮、磷、钾含量分别是对照的1.4、1.1和1.2倍,钠含量比对照下降11.1%;紫花苜蓿铜锌超氧化物歧化酶(Cu/Zn-SOD)基因表达量提高33.9%,POD基因表达量提高16.8%,CAT基因表达量提高6.4%,抗氧化酶系统中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性也表现为一定幅度的增加。结论认为,AMF和褪黑素均能够增加紫花苜蓿对氮、磷、钾等养分的吸收量而降低对钠的吸收量,进而提高光合作用能力以及叶绿素a、b含量和叶绿素荧光参数,上调Cu/Zn-SODPODCAT基因表达量并显著增加SOD、POD、CAT等活性,其中以接种AMF配合根施100 μmol·L-1褪黑素改善紫花苜蓿生长状况、光合特征,提高抗盐性的作用最为显著。

关键词: 丛枝菌根真菌, 褪黑素, 紫花苜蓿, 光合, 叶绿素, 养分

Abstract:

The aim of this study was to investigate the effects of an arbuscular mycorrhizal fungus (AMF) and melatonin treatments on the photosynthetic parameters and antioxidant system of Medicago sativa (alfalfa) plants under salt stress. Melatonin was applied at a range of concentrations (0, 50, 100, 150, and 200 μmol·L-1) to roots of M. sativa under salt stress (100 mmol·L-1 NaCl). A total of 10 treatments were inoculated with an AMF (Glomus versiforme), whereas the control plants were left uninoculated. It was found that this AMF formed a stable symbiotic relationship with alfalfa, with a maximum mycorrhizal infection rate of 65.2%. Compared with the control group, the group inoculated with AMF and treated with melatonin at 100 μmol·L-1 showed increased total biomass (by 5.4%) and chlorophyll a and chlorophyll b contents (by 7.3% and 45.3%, respectively), a decreased root to shoot ratio (by 39.5%), and increased net photosynthetic rate, transpiration rate, intercellular CO2 concentration, and stomatal conductance (by 23.3%, 28.3%, 17.6%, and 14.1%, respectively). Compared with the control group, the group inoculated with AMF and treated with melatonin at 100 μmol·L-1 showed increased maximum photochemical efficiency and PS Ⅱ potential activity (by 19.6% and 22.9%, respectively); increased nitrogen, phosphorus, and potassium contents in the leaves (to 1.4-times, 1.1-times, and 1.2-times that in the control, respectively), and decreased sodium content (by 11.1%). Comparisons of gene transcript levels between the control group and the group inoculated with AMF and treated with melatonin at 100 μmol·L-1 revealed increased transcript levels of Cu/Zn-SOD (by 33.9%), POD (by 16.8%), and CAT (by 6.4%) in the latter group. The activities of superoxide dismutase, peroxidase, and catalase were increased to different degrees in the group inoculated with AMF and treated with melatonin at 100 μmol·L-1. We concluded that AMF and melatonin can synergistically increase the chlorophyll a and b contents and chlorophyll fluorescence parameters of alfalfa, improve photosynthesis, increase the absorption of nutrients such as nitrogen, phosphorus, and potassium, reduce the absorption of sodium, and upregulate the expression of Cu/Zn-SOD, POD, and CAT, leading to increased activities of superoxide dismutase, peroxidase, and catalase. Among the treatments tested here, AMF inoculation combined with root application of 100 μmol·L-1 melatonin had the strongest effect to promote plant growth under salt stress and improve salt resistance.

Key words: arbuscular mycorrhizal fungi, melatonin, Medicago sativa, photosynthesis, chlorophyll, nutrient