钒钛磁铁废矿土壤中根瘤菌的捕获及其共生固氮效应

发布时间：2018-12-16 22:16

【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.
[Abstract]:The symbiosis of rhizobia and legumes can provide plant nitrogen nutrition, enhance plant resistance, increase soil nitrogen accumulation, and thus be used in bioremediation of heavy metal contaminated soils. In order to screen indigenous rhizobia with strong tolerance to heavy metals for bioremediation of vanadium and titanium magnet waste soil, soybean and cowpea were used as substrate to capture endophytic rhizobia. The symbiotic nitrogen fixation effect of rhizobia was tested by molecular identification. 43 strains of endophytic rhizobia were isolated from soybean and cowpea by pot experiment. The cluster analysis of BOX-A1R PCR electrophoresis showed that there were 13 groups at 84% similarity level. Soybean and cowpea endophytic representative strains were selected from 13 groups for 16SrDNA sequencing and phylogenetic tree construction. The results show that only two representative strains (ms12-11,syj1) in Group 8 are rhizobia and belong to (Bradyrhizobium). In pot experiment, both ms12-11 and syj1 could form nodule and nitrogen fixation with soybean and cowpea in barren waste soil with high heavy metal content, but the nitrogen fixation efficiency of ms12-11 was significantly higher than that of syj1;. The nitrogen fixation efficiency of soybean and cowpea seeded in waste soil was significantly lower than that of vermiculite and cowpea because of the stress pressure of heavy metals. The results showed that the waste soil of vanadium and titanium magnets contained abundant rhizobia resources and could be symbiotic with legume plants to fix nitrogen and enhance plant resistance to stress.
【作者单位】：四川农业大学资源学院;四川省自然资源科学研究院;
【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~~
【分类号】：S154.3

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