Effect of inoculant strain and organic matter content on kinetics of 2,4-dichlorophenoxyacetic acid degradation in soil.
AUTOR(ES)
Greer, L E
RESUMO
We monitored rates of degradation of soluble and sorbed 2,4-dichlorophenoxyacetic acid (2,4-D) in low-organic-matter soil at field capacity amended with 1, 10, or 100 micrograms of 2,4-D per g of wet soil and inoculated with one of two bacterial strains (MI and 155) with similar maximum growth rates (mu max) but significantly different half-saturation growth constants (Ks). Concentrations of soluble 2,4-D were determined by analyzing samples of pore water pressed from soil, and concentrations of sorbed 2,4-D were determined by solvent extraction. Between 65 and 75% of the total 2,4-D was present in the soluble phase at equilibrium, resulting in soil solution concentrations of ca. 8, 60, and 600 micrograms of 2,4-D per ml, respectively. Soluble 2,4-D was metabolized preferentially; this was followed by degradation of both sorbed (after desorption) and soluble 2,4-D. Rates of degradation were comparable for the two strains at soil concentrations of 10 and 100 micrograms of 2,4-D per g; however, at 1 microgram/g of soil, 2,4-D was metabolized more rapidly by the strain with the lower Ks value (strain MI). We also monitored rates of biodegradation of soluble and sorbed 2,4-D in high-organic-matter soil at field capacity amended with 100 micrograms of 2,4-D per g of wet soil and inoculated with the low-Ks strain (strain MI). Ten percent of total 2,4-D was present in the soluble phase, resulting in a soil solution concentration of ca. 30 micrograms of 2,4-D per ml.(ABSTRACT TRUNCATED AT 250 WORDS)
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=195626Documentos Relacionados
- Effect of Dissemination of 2,4-Dichlorophenoxyacetic Acid (2,4-D) Degradation Plasmids on 2,4-D Degradation and on Bacterial Community Structure in Two Different Soil Horizons
- Monitoring of the harmful concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) in soils with and without organic matter
- Effect of 2,4-Dichlorophenoxyacetic Acid on Photosynthesis and Respiration12
- Kinetics of Malic Dehydrogenase Inhibition by 2,4-Dichlorophenoxyacetic Acid 123
- Use of gene probes to aid in recovery and identification of functionally dominant 2,4-dichlorophenoxyacetic acid-degrading populations in soil.