Contribution of Methanotrophic and Nitrifying Bacteria to CH4 and NH4+ Oxidation in the Rhizosphere of Rice Plants as Determined by New Methods of Discrimination
AUTOR(ES)
Bodelier, Paul L. E.
FONTE
American Society for Microbiology
RESUMO
Methanotrophic and nitrifying bacteria are both able to oxidize CH4 as well as NH4+. To date it is not possible to estimate the relative contribution of methanotrophs to nitrification and that of nitrifiers to CH4 oxidation and thus to assess their roles in N and C cycling in soils and sediments. This study presents new options for discrimination between the activities of methanotrophs and nitrifiers, based on the competitive inhibitor CH3F and on recovery after inhibition with C2H2. By using rice plant soil as a model system, it was possible to selectively inactivate methanotrophs in soil slurries at a CH4/CH3F/NH4+ molar ratio of 0.1:1:18. This ratio of CH3F to NH4+ did not affect ammonia oxidation, but methane oxidation was inhibited completely. By using the same model system, it could be shown that after 24 h of exposure to C2H2 (1,000 parts per million volume), methanotrophs recovered within 24 h while nitrifiers stayed inactive for at least 3 days. This gave an “assay window” of 48 h when only methanotrophs were active. Applying both assays to model microcosms planted with rice plants demonstrated a major contribution of methanotrophs to nitrification in the rhizosphere, while the contribution of nitrifiers to CH4 oxidation was insignificant.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=91262Documentos Relacionados
- Low-Concentration Kinetics of Atmospheric CH4 Oxidation in Soil and Mechanism of NH4+ Inhibition
- Short-Term Regulation of Nitrogenase Activity by NH4+ in Rhodobacter capsulatus: Multiple In Vivo Nitrogenase Responses to NH4+ Addition
- Identification of a high affinity NH4+ transporter from plants.
- Ecophysiological Interaction between Nitrifying Bacteria and Heterotrophic Bacteria in Autotrophic Nitrifying Biofilms as Determined by Microautoradiography-Fluorescence In Situ Hybridization
- Optimizing grain yields reduces CH4 emissions from rice paddy fields