盐碱胁迫下丛枝菌根真菌对紫花苜蓿渗透调节物质及抗氧化能力的影响

Influence of arbuscular mycorrhizal fungus on the osmotic adjustment substance and antioxidant system of Medicago sativa under salt-alkaline stress

本研究旨在探讨盐碱胁迫下接种丛枝菌根真菌(AMF)对苜蓿幼苗耐盐碱性的影响。以紫花苜蓿(Medicago sativa L.)为试验材料,研究接种摩西球囊霉(Glomus mosseae)对苜蓿幼苗渗透调节物质及抗氧化系统的影响。结果表明,盐碱胁迫下,与未接菌处理相比,接种AMF处理的苜蓿叶片超氧阴离子(O_2^(·-))含量、过氧化氢(H_2O_2)含量和丙二醛(MDA)含量以及电解质透出率较低,分别降低了27.05%、40.29%、24.55%和45.06%,其超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性和过氧化氢酶(CAT)活性较高,分别提高了10.18%、6.77%和19.16%,渗透调节物质可溶性糖含量、可溶性蛋白含量和脯氨酸含量较高,分别提高了23.33%、10.64%和32.38%。说明,在盐碱胁迫下接种AMF可有效提高渗透调节物质可溶性糖含量、可溶性蛋白含量和游离脯氨酸含量,增强SOD活性、POD活性和CAT活性,减少O_2^(·-)含量、H_2O_2含量和MDA的含量及电解质渗出率,降低活性氧(ROS)水平,减轻膜脂过氧化伤害,提高苜蓿耐盐碱胁迫的能力。

To determine the influence of Glomus mosseae,a kind of arbuscular mycorrhizal fungus (AMF),on the salt tolerance of Medicago sativa cv.Gannong No.3 seedlings under salt-alkaline stress,the content of osmotic adjustment substance and the activity of antioxidant system of M.sativa were studied.AMF decreased the contents of superoxide anion (O_2^(·-)),hydrogen peroxide (H_2O_2) and malondialdehyde (MDA) and electrolyte leakage rate by 27.05%,40.29%,24.55% and 45.06%,respectively,but increased the activities of catalase (CAT),peroxidase (POD) and superoxide dismutase (SOD) by 10.18%,19.16% and 6.77%,respectively,compared to control (no AMF inoculation).The AMF also improved the accumulations of soluble sugar,soluble protein and free proline of M.sativa seedlings by 23.33%,10.64% and 32.38%,respectively.Taken together,the AMF reduced the accumulation of reactive oxygen species (ROS),lowered the contents of O_2^(·-),H_2O_2,and MDA,and boosted the accumulation of ostmotic adjustment substances,thereby improving the tolerance of M.sativa seedlings to salt-alkaline stress.