Nitrogenase activity and nitrogen-fixing bacteria associated with root base and root tip of rice plants

• Published in: Microbiological research Vol. 150; no. 2; pp. 173 - 177
• Main Authors: Kanungo, P.K., Patnaik, G.K., Adhya, T.K., Rajaramamohan Rao, V.
• Format: Journal Article
• Language: English
• Published: Basingstoke Elsevier GmbH 01-05-1995; Nature Publishing Group
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; associative nitrogenase activity; AZOSPIRILLUM; AZOTOBACTER; BACTERIA FIJADORA DEL NITROGENO; BACTERIE FIXATRICE DE L'AZOTE; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; CRECIMIENTO; CROISSANCE; ENZYMIC ACTIVITY; Fundamental and applied biological sciences. Psychology; GROWTH; Microbial ecology; Microbiology; Microflora of plants; NITROGEN FIXING BACTERIA; NITROGENASA; NITROGENASE; Nitrogenaseaktivitaet; ORYZA; Pflanzenwachstum; Physics, chemistry, biochemistry and biology of agricultural and forest soils; RACINE; RAICES; Reis; rice cultivar; root base; root tip; ROOTS; Soil science; Wurzelbasis; Wurzelspitze; root tip; associative nitrogenase activity; rice cultivar; root base; Monocotyledones; Spirillales; Enzyme; Azospirillum; Spirillaceae; Cereal crop; Oryza sativa; Rhizosphere; Enzymatic activity; Azotobacter; Azotobacteraceae; Gramineae; Nitrogenase; Angiospermae; Nitrogen fixation; Bacteria; Spermatophyta; Oxidoreductases; Plant growth promoting rhizobacterium; Diazotrophy
• ISSN: 0944-5013; 1618-0623
• DOI: 10.1016/S0944-5013(11)80053-4

An assessment of nitrogenase activity associated with the basal and terminal portions of rice roots from seven rice cultivars was made. Results indicate a definite partitioning of the nitrogenase activity within the root and a plant growth dependent shift in the activity associated with basal and terminal portion of the roots. Nitrogenase activity associated with the root base steadily declined with plant growth, while root tip associated nitrogenase activity increased sharply. Further, the basal portion had higher nitrogenase activity in the prereproductive phase while the root tip had higher activity during reproductive and maturity stages of the plant. Microbiological analysis of plant roots indicated the association of higher populations of
Azospirillum sp. and
Azotobacter sp. with the root base, while the root tips had higher populations of facultative anaerobic nitrogen-fixing bacteria.