钒钛磁铁废矿土壤中根瘤菌的捕获及其共生固氮效应  

The trapping of rhizobia in waste V-Ti magnetite mine soils and their symbiotic nitrogen-fixing effects

作　　者：康夏[1] 郑雯文[1] 瞿奎 崔永亮[2] 李艳梅[1] 陈强[1] 余秀梅[1] 

机构地区：[1]四川农业大学资源学院,成都611130 [2]四川省自然资源科学研究院,成都610041

出　　处：《应用与环境生物学报》2016年第2期230-235,共6页Chinese Journal of Applied and Environmental Biology

基　　金：教育部博士点基金项目(20135103120003);国家自然科学基金项目(31300461);四川农业大学"人才引进项目"资助~~

摘　　要：根瘤菌与豆科植物共生能提供植物氮营养、增强植株抗逆性、增加土壤氮积累因而被应用于重金属污染土壤的生物修复中,为筛选出重金属耐受性强的土著根瘤菌应用于钒钛磁铁废矿土壤的生物修复,以钒钛磁铁废矿土壤作为基质进行大豆和豇豆盆栽实验捕获根瘤内生细菌,并通过分子鉴定筛选出根瘤菌,再测试根瘤菌的共生固氮效应.大豆和豇豆的盆栽捕获实验分离获得43株根瘤内生菌,BOX-A1R PCR电泳图谱聚类分析在84%相似水平上聚类为13个群,从13个类群中选取大豆和豇豆根瘤内生代表菌株进行16SrDNA测序和系统发育树的构建,结果表明只有类群8上的两株代表菌株(ms12-11,syj1)是根瘤菌,属于慢生根瘤菌属(Bradyrhizobium).在盆栽回接实验中,ms12-11和syj1均能在贫瘠且重金属含量高的废矿土壤中与大豆和豇豆共生结瘤固氮,但ms12-11的固氮效率明显高于syj1;由于重金属的胁迫压力,播种于废矿土中的大豆和豇豆固氮效率明显低于蛭石中的大豆和豇豆固氮效率.综上表明钒钛磁铁废矿土壤中含有丰富的根瘤菌资源,能在逆境环境下与豆科植物共生固氮,增强植物抗逆性.The symbiosis of rhizobia and leguminous plants can provide nitrogen, enhance tolerance capacity for plants and increase nitrogen accumulation in soil. It has been utilized in the bio-remediation of metalliferous sites. For the purpose of bio-remediate the waste V-Ti magnetite mine soil, this research aimed to select native rhizobia with strong tolerance capacity against heavy metals. Using pot-wllture experiment method, soybean and cowpea were planted in the soil of a waste V-Ti magnetite mine at Panzhihua, Sichuan Province, to capture and isolate the endophytic bacteria from root nodules. Rhizobia were selected by molecule identification of BOX-A1 R PCR fingerprinting and phylogenetic analysis of 16srDNA. Plant experiments using soybean and cowpea were performed in both waste mine soil and vermiculite with inoculation to assess the symbiosis effect of rhizobia with legumes. As a result, a total of 43 endophytic bacteria were obtained from the root nodules of soybean and cowpea. These 43 strains were clustered into 13 groups with a similarity level of 84%. Fifteen representative strains were selected from the 13 groups to sequence for their 16 S r DNA and construct phylogenetic tree, which showed that only ms12-11 and syj1 from group 8 were rhizobia. Both were identified as belonging to the genus of Bradyrhizobium. In the pot culture experiment with inoculations, both Bradyrhizobium sp. ms12-11 and syj1 could form effective nitrogen-fixing associations with soybean and cowpea respectively in barren waste mine soil with high content of heavy metals. Nevertheless, the nitrogen-fixing efficiency of ms12-11 was significant higher than that of syj1. Due to the stress of heavy metals, the nitrogen-fixing efficiency of soybean and cowpea planted in the waste mine soil was significant lower than that in vermiculite. This study indicated that there are abundant rhizobia in the waste V-Ti magnetite mine soil. They can establish nitrogen-fixing symbiosis with leguminous plants in adverse environment to strengthen plants＇

关 键 词：根瘤菌 分子鉴定 钒钛磁铁废矿土壤 共生固氮 生物修复 

分 类 号：S154.3[农业科学—土壤学]