AMF对盐胁迫下玉米生理及生长影响研究

Effects of Arbuscular mycorrhizal fungi on maize physiology and growth under salt stress

关键词:  AMF, 盐胁迫, 玉米, 离子稳态, 抗氧化系统, 基因表达

Key words:  arbuscular mycorrhizal fungi, salt stress, maize, ion homeostasis, antioxidant system, gene expression

摘要:

土壤盐渍化严重制约玉米生产。为探究丛枝菌根真菌(AMF)对玉米耐盐性的调控作用及其生理与分子机制,该研究以玉米‘郑单958'为材料,采用盆栽实验,设置盐胁迫与AMF接种处理,系统分析玉米的生长指标、抗氧化系统[丙二醛(MDA)含量、抗氧化酶活性]、光合特性、离子稳态(Na⁺、K⁺含量)及相关基因(ZmNHX1、ZmHAK1)的表达变化。结果表明:(1)盐胁迫显著抑制玉米生长,导致MDA积累、光合效率降低和地上部Na⁺过量积累。(2)接种AMF使株高、地径和干重分别提高22.7%、18.9%和31.4%,叶片MDA含量降低26.5%,并增强抗氧化酶活性与光合性能。(3)AMF促进根系Na⁺外排和K⁺吸收,使叶片Na⁺/K⁺比值下降34.2%,同时上调ZmNHX1和ZmHAK1的表达。综上,AMF通过激活抗氧化防御系统、维持离子稳态、改善光合功能及调控关键转运基因表达,有效增强玉米耐盐性。该研究为利用AMF修复盐渍化土壤及玉米抗逆育种提供了理论依据。

Abstract:

Soil salinization is a major abiotic stress limiting maize production. This study aimed to investigate the effects of arbuscular mycorrhizal fungi(AMF)on enhancing salt tolerance in maize and to elucidate the underlying physiological and molecular mechanisms. A pot experiment was conducted using the maize cultivar‘Zhengdan 958'. Plants were subjected to salt stress with or without AMF inoculation. Growth parameters, antioxidant system(MDA content, antioxidant enzyme activities), photosynthetic characteristics, ion homeostasis(Na⁺ and K⁺ contents), and the expression changes of key transporter genes(ZmNHX1 and ZmHAK1)were systematically analyzed. The results were as follows:(1)Salt stress significantly inhibited maize growth, leading to MDA accumulation, reduced photosynthetic efficiency, and excessive Na⁺ accumulation in shoots.(2)AMF inoculation increased plant height, stem diameter, and dry weight by 22.7%, 18.9%, and 31.4%, respectively. AMF decreased leaf MDA content by 26.5%, enhanced antioxidant enzyme activities, and improves photosynthetic performance.(3)AMF promoted root Na⁺ exclusion and K⁺ uptake, resulting in a 34.2% decrease in the leaf Na⁺/K⁺ ratio. These changes were accompanied by upregulated expression of ZmNHX1 and ZmHAK1 genes. In conclusion, AMF enhances maize salt tolerance by activating the antioxidant defense system, maintaining ion homeostasis, improving photosynthetic function, and regulating key transporter gene expression. This study provides a theoretical foundation for the application of AMF in saline soil remediation and stress-resistant maize breeding.