陕西商州铅锌尾矿区豆科植物根瘤菌耐铅锌胁迫能力及其生理生化特征

以从陕西商州铅锌尾矿区豆科植物中分离纯化的12株根瘤菌为对象，采用固体平板接种培养法研究了菌株耐铅、锌单盐与铅锌双盐胁迫的能力，同时用液体试管振荡培养法测定了菌株的生理生化特征。结果表明，该区域的豆科植物根瘤菌对铅、锌单盐胁迫具有良好的耐性，但对铅锌双盐胁迫的耐性明显低于单盐。耐性菌株在生理生化特性上存在广泛差异，对铅锌耐性越强的根瘤菌，其阳性生理生化特征也越多。实验初步筛选到了3株耐铅锌胁迫能力强的根瘤菌菌株CH3、MX7和HZ10，它们分别与豆科植物刺槐（Robinia pseucdoacacia）、天蓝苜蓿（Medicago lupulina）和多花胡枝子（Lespedeza floribunda Bunge）共生。研究可以得出耐性根瘤菌对铅锌胁迫的抵抗能力可能是建立在其具有多种生理代谢反应基础上的，即它们通过改变代谢途径以适应重金属的污染环境，对铅锌胁迫耐性强的根瘤菌菌株在重金属尾矿区的土壤和植被恢复中有潜在的开发应用价值。

Tolerance and physiological response of rhizobia isolated from leguminous plants to lead-zinc stress in tailing area of Shangzhou District

With twelve rhizobium strains that were isolated from nodules of leguminous plants growing naturally in the tailing area of lead-zinc mine in Shangzhou District, Shangluo City, Shaanxi Province as study object, their tolerance to lead salt stress, zinc salt stress and lead-zinc double salt stress was investigated by using solid tablet inoculation culture method, and their physiological and biochemical characteristics were determined by using liquid tube oscillation culture method. The results showed that the rhizobium strains exhibited strong capability to tolerate single lead or zinc salt, but their tolerance capability to lead-zinc double salt was significantly lower than that to single salt. There were considerable differences of physiological and biochemical characteristics among the strains. The stronger the tolerance to lead-zinc stress a rhizobium strain possessed, the more positive physiological and biochemical characteristics it showed. Three rhizobium strains with high tolerance to lead and zinc stress were preliminarily screened out, i.e., CH3 isolated from nodules of Robinia pseucdoacacia, MX7 isolated from Medicago lupulina and HZ10 isolated from Lespedeza floribunda Bunge. It can be concluded that the tolerance of rhizobia to lead-zinc stress is seemingly built on the basis of their various physiological metabolism reactions, that is to say, the rhizobia are likely to adjust their metabolic pathway to be adaptable to the environment contaminated by lead and zinc. The rhizobium strains with strong tolerance to lead-zinc stress exhibit a potential application value in soil remediation and revegetation in tailing area of lead-zinc mine.