土壤中Cd^2＋胁迫对gfp基因标记的饭豆(Vigna umbellate L．)根瘤菌生物毒性的研究  

Bio-toxicity of Cd^(2+) Stress on a gfp Gene Marked Rice Bean (Vigna umbellate L.) Rhizobium Strain JMC1402G in Soil

作　　者：邵继海[1] 何绍江[1] 冯新梅[1] 

机构地区：[1]华中农业大学农业微生物国家重点实验室

出　　处：《农业环境科学学报》2008年第2期457-461,共5页Journal of Agro-Environment Science

基　　金：国家自然科学基金(30070027)

摘　　要：利用绿色荧光蛋白基因(gfp)标记研究了土壤中Cd2+胁迫对饭豆(Vigna umbellate L.)根瘤菌JMC1402G腐生存活的影响,同时也探讨了Cd2+胁迫对其共生固氮能力的影响。结果表明,YMA培养基平板培养时,Cd2+对JMC1402G的LC50为8.15μg·mL-1。不管土壤灭菌与否,当土壤中Cd2+添加量为3mg·kg-1时,向土壤接种的37d内对JMC1402G的腐生存活无影响,当Cd2+添加量为20mg·kg-1时,土壤中JMC1402G的数量明显低于对照,随着Cd2+添加量的进一步增大,土壤中JMC1402G的数量迅速落于104cfu·g-1以下。饭豆盆栽试验结果表明,Cd2+添加量在0￣20mg·kg-1范围内对JMC1402G共生固氮能力的影响不大,当土壤中Cd2+添加量达到50mg·kg-1时,对JMC1402G产生较明显的生理毒性,当Cd2+添加量达到100mg·kg-1,饭豆根瘤菌-饭豆体系失去结瘤能力。JMC1402G质粒快检结果表明,JMC1402G在Cd2+添加量为0、3、20、50、100mg·kg-1的土壤中营腐生生活37d,未出现质粒丢失情况。The effects of Cd^2＋ on the saprophytic survival and the symbiotic nitrogen fixation ability of a gfp gene-marked rice bean （Vigna umbellate L.） rhizobium strain JMC1402G in soils were studied. The results showed that the LC50 of Cd^2＋ to JMC1402G was 8.15 μg.mL^-1 in the YMA plates. No inhibition effect was observed on the numbers of JMC1402G in 37 d after it was inoculated into the sterile soil when the amendment amount of Cd^2＋ was 3 mg. kg^-1. The number of JMC 1402G was one hundred times less than the control from 23 d to 37 d when the amendment amount of Cd^2＋ reached 20 mg·kg^-1. The number of JMC 1402G decreased from 10^8 cfu·g^-1 to l0^5 cfu·g^-1 in 9 d after inoculated when the amendment concentration of Cd^2＋ was 100 mg·kg^-1. In the non-sterile soil, there was also no obvious inhibition effect on the saprophytic survival of GMC 1402G, but the inhibition effect appeared when Cd^2＋ amendment was 20 mg·kg^-1. And the numbers of JMC 1402G decreased from 10^8 cfu·g^-1 to 10^4～10^5 cfu·g^-1 respectively in 23 d after inoculation when the concentration of Cd^2＋ amendment were 0～20 mg·kg^-1. The numbers of JMC 1402G declined to less than 10^4 cfu·g^-1 with the increment of amended Cd^2＋. The results of pot experiment showed that there was no serious inhibition effect of external amendment of Cd^2＋ on symbiotic nitrogen fixation ability in soils when the external Cd^2＋ amendment was less than 20 mg·kg^-1, but obvious bio-toxicity was found when the concentration of amended Cd^2＋ was 50 mg·kg^-1, and no nodule was observed when the concentration reached to 100 mg·kg^-1. The plasmid profile of the strains JMC1402G recovered respectively from soils amended different levels of Cd^2＋ indicated that there were no plasmid elimination effect appeared in 37 d after inoculation at the concentration of Cd^2＋ amendment less than 100 mg·kg^-1.

关 键 词：饭豆 根瘤菌 CD 生物毒性 土壤 

分 类 号：X503.23[环境科学与工程—环境工程]