DEGRADATION OF BUTACHLOR AND DYNAMICS OF BUTACHLOR -DEGRADING BACTERIAL POPULATION IN WHEAT RHIZOSPHERE SOIL

摘要

Rhizoremediation as a promising technology for clearing off contaminants in soil attracts many researchers' attention in environmental research field. But knowledge about the biological mechanism of the increasing degradation is poorly understood so as to limit application of phytoremediation. In this experiment biodegradation of butachlor and dynamics of degrading- bacteria population in wheat rhizosphere soil were investigated. Our results illustrated that rhizosphere soil with and without inoculants decreased 96.6%, 91.84% of the added butachlor respectively, whereas the bulk soil only reduced 81.8% of that applied. Butachlor degradation half-lives at concentration of 50 mg/kg for the inoculated and uninoculated wheat rhizosphere soil, bulk soil, were 10.79 days, 17.91 days, 23.26 days respectively. The dynamics of butachlor degrading-bacteria correspond with the degradation pattern comparatively well. After incubation for a week, the number of butachlor-degrading population in the inoculated rhizosphere reaches the most value 5.4×10~(10) cfu/g dry weight soil, whereas that in the rhizosphere jumped to the maximum, 3.5×10~(10) cfu/g dry weight soil after a prolonged week.