高产铁载体菌对重金属胁迫下牧草种子萌发的影响

Effects of Efficient Siderophore-producing Bacteria on Germination of Forage Seeds under Heavy Metal Stress

为研究贵州野生白三叶(Trifolium repens L.)根际高产铁载体菌TSTJ-5在重金属胁迫下对牧草种子萌发的影响,本试验对菌株进行鉴定,检测其促生特性,分别利用菌株发酵上清液、菌体和菌液,研究菌株在不同浓度的Cu^(2+)、Zn^(2+)和Pb^(2+)胁迫下对多花黑麦草和白三叶种子萌发的影响。结果表明,高产铁载体菌TSTJ-5鉴定为假单胞菌(Pseudomonas sp.),具有溶解无机磷、分泌IAA和固氮能力,多花黑麦草和白三叶种子对Zn^(2+)和Pb^(2+)均具有较强的耐性,TSTJ-5菌株在高浓度Cu^(2+)、Zn^(2+)和Pb^(2+)胁迫下能缓解重金属对供试牧草种子的毒害作用,提高种子抗逆性,促进种子发芽。研究结果可为铁载体在植物-微生物联合修复土壤重金属污染应用中提供有效的试验依据和可靠的候选菌种资源。

To study the effecicient siderophore-producing bacteria TSTJ-5 in the rhizosphere of wild Trifolium repens in Guizhou on the germination of forage seeds under heavy metal stress.The experiment identified the strain and tested the growth-promoting properties.Fermentation supernatant,mycelium,and fermentation broth were used in the study to test the effects of different concentrations of Cu^(2+),Zn^(2+),and Pb^(2+)stress on the seeds germination of Lolium multiflorum and Trifolium repens.The results showed that the efficient siderophore-producing bacteria TSTJ-5 was identified as Pseudomonas sp.,and the strain had the ability to dissolve inorganic phosphorus,secrete IAA,and fix nitrogen.The seeds of Lolium multiflorum and Trifolium repens had strong tolerance to both Zn^(2+)and Pb^(2+).The strain TSTJ-5 could alleviate the toxic effects of heavy metals on the tested forage seeds under high concentrations of Cu^(2+),Zn^(2+),and Pb^(2+)stress,improve seed resistance,and promote seed germination.The results could provide effective test basis and reliable candidate strain resources for the application of iron carrier in the remediation of soil heavy metal pollution by plant-microorganism combination.