Community structure and in situ activity of nitrifying bacteria in Phragmites root-associated biofilms.

ABSTRACT: The amount of oxygen released by Phragmites roots and the community structure and in situ activity of nitrifying bacteria in the root biofilms were analyzed by the combined use of 16S rRNA gene-cloning analysis, quantitative PCR (qPCR) assay and microelectrodes. Axial and radial O₂ microprofiles were obtained for individual roots of Phragmites in a horizontal flow reactor fed with artificial medium continuously. Axial O₂ profiles revealed that O₂ was released at a rate of 0.21 μmol O₂ cm⁻² (root surface area) h⁻¹ only in the apical region (up to ca. 40 mm from the root apex), where there was a high abundance (10⁷ to 10⁸ copies g⁻¹ biomass) of Nitrosomonas-like AOB and Nitrospira-like NOB. This abundance, however, sharply declined to the detection limit at positions more basal than 80 mm. P

SUBMITTER: Okabe S 

PROVIDER: S-EPMC4036055 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature