SCREENING OF NITROGEN FIXERS FROM RHIZOSPHERIC BACTERIAL ISOLATES ASSOCIATED WITH IMPORTANT DESERT PLANTS

Free living nitrogen fixers represent a range of microorganisms including bacteria living on plant residues (saprophytes), bacteria which live entirely within plants (endophytes) and bacteria living in close association with the plant roots (rhizobacteria). We have isolated a number of rhizosphere associated bacteria from two of the hot arid zone plants and explored these in terms of nitrogen fixing ability both in solid and liquid culture conditions. The maximum coloring zone was developed in T-1 (22 mm) whereas minimum was in T-3 (4 mm) in case of the C. polygonoides associated bacterial community. The coloring zone was found maximum in TS-2 (27 mm) and minimum in TS-1 (11 mm), in case of isolates associated with rhizosphere of L. sindicus. The highest and lowest acetylene reduction activity (ARA) was detected in TS-13 (8303 n moles/24 h) and T-10 (1658 n moles/24 h), respectively.