DIAZOTROPHIC BACTERIAL POPULATION AND OTHER ASSOCIATED ORGANISMS ON THE PHYLLOSPHERE OF SOME CROP PLANTS

A quantitative survey of diazotrophic bacterial population on the leaf surfaces of different crop plants like wheat, rice, potato, tomato, b anana, sugarcane, mustard and jute was conducted. Isolations were made principally during November to March excepting from jute and rice pla nts which were done during July and September respectively. Isolated d iazotrophic bacteria were mostly the nonconventional types, although t hese were present on the phylloplanes of all the crops. Their numbers, however, were meagre on the leaf surfaces excepting on jute and tomat o leaves. The organism were identified as species of Corynebacterium, Flavobacterium, Azotobacter, Bacillus, Beijerinckia and Azomonas. High est density of microbial population was found on jute leaves including the fungi and next to this was on potato, while much lower numbers we re obtained from mustard and banana leaf surfaces. Nitrogen fixing abi lity of these diazotrophic bacteria were measured by Acetylene reducti on techznique.