中文摘要：

【目的】从Cd^2＋ 污染土壤中分离获取强耐Cd^2＋ 微生物，研究其生物学特性。【方法】采用选择性培养基TSA对广东省大宝山重金属污染土壤中耐镉（Cd^2＋ ）细菌进行分离筛选，结合细菌形态观察、生理生化检测、16SrRNA基因序列分析等方法确定了它们的分类地位，并开展了细胞形态、Cd^2＋ 耐受性、Cd^2＋ 吸附性、对不同pH和盐度适应性、以及对抗生素的抗性等生物学特性的研究。【结果】从土壤中分离到8株具有强耐Cd^2＋ 能力的细菌（YN-6、YN-7、YN-8、YN-9、YN-16、YN-17、YN-18、YN-19），初步鉴定其分别属于Rhizobium、Roseateles、Cupriavidus、Methylobacterium、Variovorax、Rhizobium、Achromobacter和Leifsonia属。细菌生物学特性研究表明，8株耐Cd^2＋细菌的形态存在一定的差异，其中YN-6、YN-8、YN-9、YN—16、YN-17和YN-18菌体为短杆状，而YN-7和YN-19菌体为长杆状。它们对Cd^2＋ 的最低抑制浓度均在3mmol／L以上，且每克细胞吸附1mg以上的Cd^2＋。其中，菌株YN-8对Cd^2＋的耐受性最强（9mmol／L），菌株YN-9对Cd^2＋的吸附能力最强（316．7mgCd^2＋／g cells）。不同pH、盐度和抗生素对8株细菌生长的影响存在较大差异。【结论】菌株YN-8和YN-9对环境的适应性较强，可以作为较好的试验材料应用于生物修复重金属Cd^2＋污染土壤的研究。

英文摘要：

[Objective] To isolate and obtain cadmium-tolerant bacteria from polluted soil by cadmium and to study their biological characteristics. [Methods] The cadmium-tolerant bacte-ria were isolated from the heavy metals contaminated soil around the Dabao Mine, Guangdong Province by the selective TSA medium, and identified based on morphological observation, physiological-biochemical test and 16S rRNA gene sequence analysis. Their biological char-acteristics including morphology, Cd^2＋ tolerance and absorption, the growth range of pH and salinity as well as antibiotic resistance were investigated. [Results] Eight cadmium-tolerant isolates （YN-6, YN-7, YN-8, YN-9, YN-16, YN-17, YN-18 and YN-19） belonged to the genus of Rhizobium, Roseateles, Cupriavidus, Methylobacterium, Variovorax, Rhizobium, Achro-mobacter and Leifsonia. They were different in the morphology, with YN-6, YN-8, YN-9, YN-16, YN-17 and YN-18 being short rod sharp, while YN-7 and YN-19 being long rod sharp. Their minimum inhibitory concentrations （MIC） of Cd^2＋ were 3 mmol/L or above, and 1 g cells could at least adsorb 1 mg Cd^2＋. Among these strains, YN-8 was the most tolerant to Cd2＋ （9 mmol/L） while YN-9 showed the highest adsorbing capacity of Cd^2＋ （316.7 mg Cd^2＋/cells）. The eight bacteria differed in the response to pH, salinity and antibiotic. [Conclusion] YN-8 and YN-9 were much more adaptive to the environment, which could be used for further stud-ies on soil bioremediation polluted by cadmium.