Abstract: A cadmium-resistant endophytic bacterium GR42,which may grow in the culture medium with 900 mg/L of Cd²⁺ concentration,was identified and studied for its biological characteristics in order to provide theoretical basis for its application. 16S rDNA sequence analysis,morphological,as well as physiological and biochemical experiments were used to identify the species,to explore the influences of culture conditions on the growth of the strain,and to test its cadmium-removed rate,its tolerance to lead and zinc,growth promoting characteristics,and the promotion effect on the cadmium-resistance of wheat seeding. As results,the strain GR42 was identified as Bacillus aryabhattai,and the optimal temperature,pH,loading volume,and salt concentration was 28℃,7.0,50 mL/250 mL,and 5-10 g/L,respectively. Cadmium-removed rate was 41.1% at 800 mg/L Cd²⁺concentration;toleration of Pb²⁺ and Zn²⁺ was 2000 mg/L and 1200 mg/L respectively;siderophore activity was 76.74%,and ACC deaminase activity was 0.627 U/mg;the capacity of the strain dissolving phosphorus and potassium was 13.801 mg/g and 8.868 mg/g,respectively;it also showed significant promoting effects on the cadmium-resistance of wheat seedlings. In conclusion,the cadmium-resistant endophytic bacterium GR42 is B. aryabhattai,its lead-zinc-cadmium resistance and cadmium-removed rate are high,and it has ability of promoting growth,therefore it owns application potential in promoting plant growth and remediating cadmium-contamination soil.

Key words: Bacillus aryabhattai, cadmium-resistant endophytic bacteria, ability of promoting growth, soil remediation