2株草螺菌的鉴定及其对煤矸石胁迫下香根草的促生作用

Identification of two Herbaspirillum strains and its growth-promoting effect on Vetiveria zizanioides L.under coal gangue stress

【背景】植物-微生物联合修复技术在减轻环境胁迫作用、增强植物抗性、改善矿区景观等方面发挥重要作用,其中根际促生菌可与植物相互作用,促进植物生长,增强植物对非生物胁迫的耐受性。【目的】鉴定铜尾矿中分离得到的2株根际细菌,研究其对植物生长的促生特性,测定2株菌的接种对于煤矸石胁迫下香根草的影响。【方法】对铜尾矿中分离得到的2株菌进行16S rRNA基因序列鉴定和扫描电子显微镜观察,对菌株的促生特性进行测定,并将其分别接种于覆土5 cm的煤矸石和掺土10%的煤矸石中生长的香根草根际,测定2个月后香根草的理化指标和生理学指标。【结果】菌株P5-11和P5-19经鉴定均为草螺菌(Herbaspirillum),2株菌均具有固氮、溶磷、产吲哚乙酸(Indole-3-Acetic Acid,IAA)和产铁载体的特性,其中P5-19的产吲哚乙酸能力约为P5-11的2倍,具有较好的促生能力;2株菌均能提高香根草的株高、生物量、氮积累量和抗氧化酶活性,并降低丙二醛积累量。【结论】2株草螺菌均具有良好的促生特性,能够促进煤矸石胁迫下香根草的生长发育,这不仅为促生菌肥的研制提供了优良菌种,也为香根草在矿区生态恢复中的应用提供了参考价值。

[Background]Combined plant-microbial remediation technology plays an important role in reducing environmental stress,enhancing plant resistance and improving mining landscape.Rhizosphere microorganisms can interact with plants which can promote plant growth and enhance the tolerance of plant on abiotic stress.[Objective]To identify two strains of rhizosphere bacteria isolated from copper tailings,in order to study the growth-promoting properties of the two strains and determine the influence of the two strains on V.zizanioides grown on coal gangue.[Methods]16 S rRNA gene sequence identification and scanning electron microscope observation were performed on P5-11 and P5-19,the growth-promoting properties of the strains were measured.The strains were inoculated into V.zizanioides grown in coal gangue covered with 5 cm soil and coal gangue mixed with 10%soil.After two months,the physical and chemical indexes and physiological indexes of V.zizanioides were measured.[Results]P5-11 and P5-19 were Herbaspirillum,which had the functions of nitrogen fixation,phosphate-dissolving,produced indole-3-acetic acid(IAA)and siderophore.Among them,the IAA production capacity of P5-19 was about twice that of P5-11,and it had better growth-promoting properties.Herbaspirillum inoculation could improve plant height,biomass,total nitrogen accumulation and the antioxidant enzyme activity,and reduce the malondialdehyde accumulation.[Conclusion]The two strains of Herbaspirillum had good growth-promoting properties,which could promote the growth of V.zizanioides under coal gangue stress,which not only provided excellent strains for the preparation of microbial fertilizer,but also provided reference value for the application of V.zizanioides in the ecological restoration of mining areas.