(Division of Microbiology, Indian Agricultural Research Institute, New Delhi, 110012 and Department of Botany, Sri Venkateswara College, University of Delhi, New Delhi)
Online published on 25 January, 2012.
One of the novel methods that have been suggested in recent years in the field of nitrogen fixation has been the cultivation of root calli of legumes and non-legumes and subsequent inoculation of calli with nitrogen fixing bacteria. Root calli of Pisum sativum, Arachis hypogea, Cajanus cajan and Cicer arietinum were inoculated with homologous Rhizobium sp. Significant amounts of acetylene were reduced by inoculated calli of Pisum, Arachis and Cajanus. Light microscopic observations of sections of inoculated calli revealed bacterial penetration in the form of infection threadlike structures and host cells filled with bacteria like cells. In Cicer, characteristic nodular outgrowths were seen and callus cells were found to be full of bacteria. Uninoculated calli did not reduce acetylene nor were there any bacteria inside the cells.
