Predominance of Hydrogen-Utilizing Bacteria Among N2-Fixing Bacteria in Wetland Rice Roots

Watanabe, I.; Barraquio, W. L. and Daroy, Maria Luisa. 1982. Predominance of Hydrogen-Utilizing Bacteria Among N2-Fixing Bacteria in Wetland Rice Roots. Can. J. Microbiol., Volume 28 no. 9 p. 1051-1054

Heterotrophic bacteria were isolated from wetland soil, rhizosphere soil, root and basal shoot of wetland rice, dryland soil, and root of dryland rice. The isolates were tested for N2-fixing activity and the ability to grow autotrophically under H2 + CO2 + O2. N2-fixing bacteria capable of autotrophic growth were found almost exclusively from the rhizosphere and the root of wetland rice. In another experiment, all N2-fixing bacteria isolated from wetland rice root had uptake hydrogenase activity. These findings indicate the predominance of hydrogen-utilizing bacteria among N2-fixing bacteria from wetland rice roots.