Synergism between Phyllobacterium sp (N-2-fixer) and Bacillus licheniformis (P-solubilizer), both from a semiarid mangrove rhizosphere

Mangrove seedlings were treated with a mixture of two bacterial species, th e slow-growing, N-2-fixing bacterium Phyllobacterium sp. and the fast-growi ng, phosphate-solubilizing bacterium Bacillus licheniformis, both isolated from the rhizosphere from black, white, and red mangroves of a semiarid zon e. Nitrogen fixation and phosphate solubilization increased when the mixtur e was used compared to the effects observed when adding individual cultures , notwithstanding that there was no increase in bacterial multiplication un der these conditions. Inoculation of black mangrove seedlings in artificial seawater showed the mixture performed somewhat better than inoculation of the individual bacterium; more leaves were developed and higher It levels o f N-15 were incorporated into the leaves, although the total nitrogen level decreased. This study demonstrates that interactions between individual co mponents of the rhizosphere of mangroves should be considered when evaluati ng these bacteria as Plant growth promoters. (C) 2001 Federation of Europea n Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.