Abstract: Based on maize sensitive to chlorimuron-ethyl, the degradability of Bacillus megaterium strain E-1 to chlorimuron-ethyl was investigated. The results showed that this bacterium could degrade all levels of chlorimuron-ethyl (2－50 μg/kg) when used with the concentration of 300 mL bacterial culture per kg soil. The recovery of maize roots was gradually declined along with the concentration increase of chlorimuron-ethyl. The highest recovery percentage of maize roots was 62.48% and the lowest was 18.31% when the dose of degrading bacteria was 30 mL/kg soil. Significant effects were observed in the degradation of chlorimuron-ethyl by bacteria, and the recovery percentage of maize roots was below to 50%. However, no significant differences were found between the treatments with and without bacteria when the dose of degrading barteria was 3 mL/kg soil.

Key words: Bacillus megaterium, chlorimuron-ethyl, bio-degradation, sensitive crop, bioassay