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.
KeywordsMaize Bacillus Acetylene Nigeria International Atomic Energy Agency
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