会泽铅锌尾矿区豆科植物根瘤菌耐铅锌性及其生理生化特征研究

Tolerance and Physiological Response to Lead-zinc Stress of Rhizobia Isolated from Nodules of Leguminous Plants in Lead-zinc Mining Tailing of Huize,China

研究铅锌尾矿区豆科植物根瘤菌对铅锌的响应,可为利用豆科植物改良尾矿区土壤及植被恢复提供理论依据。会泽铅锌尾矿土壤被铅锌严重污染,铅锌含量分别是全国土壤(A层)的110倍和54倍。通过现场采样、室内分离和耐性培养,对10株分离自会泽铅锌尾矿区豆科植物的根瘤菌的铅、锌单盐与铅锌双盐逆境进行了耐性研究。结果表明,该区域的豆科植物根瘤菌对铅、锌单盐逆境具有良好的耐性,但是对铅锌双盐的耐受明显减弱。对这10株根瘤菌的生理生化特征研究结果表明,会泽尾矿区根瘤菌的生理生化特性存在广泛差异,根瘤菌铅锌耐性越强,其阳性生理生化特征越多。一株与三叶草共生接瘤的HS3,一株与香豌豆共生接瘤的HX6和一株与猪屎豆共生接瘤的HZ8,它们不但表现出耐铅锌,而且生理代谢广泛,显示这3株根瘤菌在铅锌尾矿区的利用具有较好的潜能。

It is improtant and useful for soil remediation and revegetation in lead-zinc mining tailings to study lead-zinc tolerance of rhizobia.The soil of Huize lead-zinc mining tailings was seriously contaminated by Pb,Zn.The contents of Pb and Zn were about 110 and 54 times of the average content of heavy meltals of soil layer A in China respectively.In this paper,ten rhizobia strains were isolated from nodules of leguminous plants occurring naturally in Huize lead-zinc mining tailings,and their tolerance to single lead salt,single zinc salt and lead-zinc salt were studied.The results showed that most of strains exhibited significantly strong capability to tolerate single lead and single zinc salt,but the tolerance capability to lead and zinc salt was very weak.The results of study on physiological and biochemical characteristics of these strains showed that there existed metabolic differences among them,and the stronger rhizobia possesses lead-zinc tolerance,the more positive physiological and biochemical characteristics there appeared to be.This phenomenon suggested seemingly that the rhizobia adjusted their metabolic pathway to contaminated environment by lead-zinc.Among them,strain HS3,HX6 and HZ8 not only manifested strong lead-zinc tolerance,but also showed diversified metabolic pathways.Strain HS3 was isolated from nodules of Trifolium repens,strain HX6 from Lath-yrus odoratus and strain HZ8 from Crotalaria mucronats respectively,Which could be applied for soil remediation and revegetation in lead-zinc mining tailings.