4株红砂根际固氮菌分离鉴定及对幼苗促生作用的研究  

Isolation and identification of four strains of Reaumuria soongorica root zone nitrogen fixing bacteria and their role in seedling growth promotion

作　　者：张峰 种培芳[1] 包新光 王雪莹 ZHANG Feng;CHONG Pei-fang;BAO Xin-guang;WANG Xue-ying(College of Forestry,Gansu Agricultural University,Lanzhou 730070,China)

机构地区：[1]甘肃农业大学林学院,甘肃兰州730070

出　　处：《草业学报》2025年第3期144-153,共10页Acta Prataculturae Sinica

基　　金：国家自然基金:荒漠植物红砂根际促生细菌筛选及其抗逆性研究(32160407);甘肃省重点研发项目:典型荒漠灌木根际微生物固碳及高效菌肥资源挖掘与利用(23YFFA0065);草业生态系统教育部重点实验室开放课题:荒漠草原植物红砂耐盐促生菌的分离筛选、鉴定及其促生效果研究(KLGE202215)项目资助。

摘　　要：为了获得荒漠植物根际土壤中的优良固氮菌,探究其对红砂幼苗氮代谢的影响,验证固氮菌的促生效果。本研究采用稀释涂布平板法,利用Ashby固体培养基从红砂根际土中分离得到4株固氮菌,通过形态学、生理生化特征以及16S rDNA序列分析鉴定菌株的分类地位及促生特性。结果表明,菌株Y3与Y2为芽孢杆菌,菌株P4为桑树肠杆菌,菌株N12为阴沟肠杆菌;4株固氮菌均能提高红砂幼苗叶和根中硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)活性;接种菌株后红砂幼苗根长、叶片相对含水量、地上部和地下部鲜重间均有差异(P<0.05);其中,固氮菌P4促生效果最为显著,接种P4菌株后叶和根中NR活性分别提高了31.99%、34.63%(P<0.05),GOGAT活性分别提高了25.63%、25.08%(P<0.05),GS活性分别提高了23.31%、24.30%(P<0.05),且根长、叶片相对含水量、地上部和地下部鲜重分别增加27.99%、20.75%、33.34%、33.25%(P<0.05)。综上,4株固氮菌可促进红砂幼苗的生长发育,提高其成活率,同时也为研发微生物菌剂提供了优质菌种资源。The aim of this research was to isolate nitrogen fixing bacteria in the root zone soil of desert plants,investigate their effects on nitrogen metabolism of Reaumuria soongorica seedlings,and verify the growth-promoting effect of the isolated nitrogen fixing bacteria.In this study,four strains of nitrogen fixing bacteria were isolated from the root zone soil of R.soongorica by the dilution-coated plate method,using Ashby’s solid medium.The taxonomic status and growth-promoting characteristics of the strains were identified by morphological,physiological and biochemical characteristics as well as by 16S rDNA sequence analysis.The results showed that strains designated Y3 and Y2 were Bacillus sp.,strain P4 was Enterobacter mori,and strain N12 was Enterobacter cloacae.Inoculation with the four strains of nitrogen fixing bacteria increased the activities of nitrate reductase(NR),glutamine synthetase(GS),and glutamate synthetase(GOGAT)in the leaves and roots of the R.soongorica seedlings.There were also differences in the root length and relative water content of leaves,and aboveground and below-ground fresh weight of R.soongorica seedlings after inoculation with the isolated bacterial strains(P<0.05);among them,the nitrogen fixing bacterium P4 had the most significant growth-promoting effect,with the NR activity in leaves and roots increased by 31.9% and 34.6%,respectively(P<0.05),the GOGAT activity by 25.6% and 25.1%,respectively(P<0.05),and the GS activity by 23.3%and 24.3%,respectively(P<0.05).Furthermore,root length,leaf relative water content,above-ground and below-ground fresh weight were increased(P<0.05),respectively,by 27.9%,20.7%,33.3%and 33.2%.In conclusion,the four strains of nitrogen fixing bacteria exhibited ability to promote the growth and development of R.soongorica seedlings and improve their survival rate.The isolated strains represent high-quality resources for the development of microbial plant growth promoting agents.

关 键 词：固氮菌 分离鉴定 促生作用 氮代谢 红砂 

分 类 号：S793.9[农业科学—林木遗传育种]