Occurrence of Dinitrogen-fixing Bacteria and Acetylene Reduction Activity in a Rhizosphere of Five Selected Plants from Tropics
The aim of the papers is to characterize the occurence and distribution of dinitrogen-fixing bacteria including species of Azospirillum, Azotobacter and Clostridum in rhizosphere of the following plant species: Delonicsregia, Jecopina corsinea, Lagestroemia indica, Lawsonia inermis and Zae mays.
The samples of roots and rhizosphere soil were taken from Botanical Garden and University farm, University of Nigeria Nsukka Campus. The plant roots were studied for nitrogenase activity by acetylene reduction method. The effect of selected plants on bacteria was also determined.
Plate counts and tube dilution methods revealed the stimulation of development of bacteria in the rhizosphere of the investigated plants. The strongest stimulative effect of root systems on Azotobacter sp. was observed in the rhizosphere of Zea mays. Development of Clostridium sp. in the rhizosphere of selected plants was very irregular and dufficult to proper estimation.
All investigated root samples showed nitrogenase activity.
KeywordsRhizosphere Soil Acetylene Reduction Acetylene Reduction Activity Rhizosphere Effect Nonrhizosphere Soil
Unable to display preview. Download preview PDF.
- Becking J.J. (1981) The family Azotobacteriacea. In: The procayotes. Handbook on habitats, isolation and identification of bacteria. Vol. 1. Springer Verlag.Google Scholar
- Berkum P., Van Bohlool B.B. (1980) Evaluation of nitrogen fixation by bacteria in association with roots of tropical grasses, Microbiol. Rev. 44: 491–517Google Scholar
- Döbereiner J. (1966) Azotobacter paspali sp. uma bacteria fixadora de nitrogenio na rhizosfera de Paspalum notatum. Pesqu. Agropecu. Bas. 1:357–365Google Scholar
- Knowles R. (1977) The significance of a symbiotic nitrogen fixation by bacteria. In: A treatise on dinitrogen fixation. J.Wiley and Sons, New YorkGoogle Scholar
- Rennie R.J. (1981) Potential use of induced mutations in improve symbioses of crop plants with N2-fixing bacteria. In: Induced mutations a tool in plant breeding. International Atomic Energy Agency, Vienna. 293–321Google Scholar
- Rodriquez E.A. (1982) Improved medium for isolation of Azospirillum species. Applied Environ. Microbiol. 44: 990–991Google Scholar
- Rovira A.D., Davey C.B. (1975) Biology of the rhizosphere. In: Plant root and its environment. Univ. Press Virginia.Google Scholar
- Umali-Garcia M., Hubbell D.H., Gaskins M.H., Dazzo B (1980) Association of Azospirillum with grass roots. Applied Environ. Microbiol. 39: 219–226Google Scholar
- Umali-Garcia M., Hubbell D.H., Gaskins M.H., Dazzo B. (1981) Absorption and mode of entry of Azospirillum brasilense to grass roots. In: Associative N2 fixation. Vol. 1, CRC Press, Boca RatonGoogle Scholar