Characterization of rhizo-cyanobacteria and their associations with wheat seedlings

Abstract

Four heterocystous cyanobacteria, belonging to the genera Anabaena and Nostoc isolated from the rhizosphere of wheat, were tested for their ability to form associations with the roots of wheat seedlings under light and dark conditions using hydroponics. The cyanobacterial strains formed close associations with wheat plants, and were able to enter through root hairs and penetrate the epidermal layer of wheat roots. Significantly higher indole acetic acid production and chlorophyll accumulation was observed in such associations, and strain N1 recorded a several-fold enhancement in acetylene reduction activity. Supplementation of the medium with glucose, yeast extract or glutamic acid also enhanced the acetylene reduction activity of the N1 strain, indicative of its photoheterotrophic ability.

Keywords: ARA; Artificial associations; IAA; Rhizosphere

Egyptian Journal of Biology Vol. 10 2008: pp. 20-27