Preface. 1. Evolution and diversity in the legume-rhizobium symbiosis: Chaos theory? J.I. Sprent. 2. Recent developments in Rhizobium taxonomy; E. Martnez-Romero. 3. Host range, RFLP, and antigenic relationships between Rhizobium fredii strains and Rhizobium sp. NGR234; H.B. Krishnan, S.G. Pueppke. 4. Rapid identification of Rhizobium species based on cellular fatty acid analysis; B.D.W. Jarvis, S.W. Tighe. 5. Ammonium sensing in nitrogen fixing bacteria: Functions of the glnB and glnD gene products; C. Kennedy, N. Doetsch, D. Meletzus, E. Patriarca, M. Amar, M. Iaccarino. 6. Regulation of nodulin gene expression; F.J. de Bruijn, R. Chen, S.Y. Fujimoto, A. Pinaev, D. Silver, K. Szczyglowski. 7. Synthesis, release, and transmission of alfalfa signals to rhizobial symbionts; D.A. Phillips. F.D. Dakora, E. Sande, C.M. Joesph, J. Zn. 8. Role of rhizobial lipo-oligosaccharides in root nodule formation on leguminous plants; O. Geiger, T. Ritsema, A.A.N. van Brussel, T. Tak, A.H.M. Wijfjes, G.V. Bloemberg, H.P. Spaink, B.J.J. Lugtenberg. 9. Sucrose transport and hydrolysis in Rhizobium tropici; V.I. Romanov, E. Martnez-Romero. 10. Shoot/root assimilate allocation and nodulation of Vigna unguiculata seedlings as influenced by shoot light environment; M.J. Kasperbauer, P.G. Hunt. 11. Mechanism of osmotically regulated N-acetylglutaminylglutamine amide production in Rhizobium meliloti; L. Tombras Smith, A. Ameer Allath, G.M. Smith. 12. What triggers the regulation of nitrogenase activity in forage legumenodules after defoliation? U.A. Hartwig, J. Nsberger. 13. Nodulation and nitrogen fixation in extreme environments; L.M. Bordeleau, D. Prvost. 14. Analysis and regulation of legume inoculants in Canada: The need for an increase in standards; P.E. Olsen, W.A. Rice, L.M. Bordeleau, V.O. Biederbeck. 15. Recent developments in the actinorhizal symbioses; A.M. Berry. 16. Characterization of Bradyrhizobium japonicum chromosomal genes involved in the regulation of hup gene expression in free-living conditions and in controlling hydrogenase activity; C. van Soom, J. Vanderleyden, A.P. van Gool. 17. Characterization of Rhizobium galegae by REP-PCR, PFGE and 165 rRNA sequencing; I. Huber, S. Selenska-Pobell. 18. A hypothesis for the role of malic enzyme in symbiotic nitrogen fixation in soybean nodules; D.A. Day, R.G. Quinnell, F.J. Bergersen. 19. Eastern Canadian soybean field trials of rhizobial strain NS 1 in two commercial carriers; R.E. Sanders. 20. Nitrogen fixation efficiency of cold-adapted rhizobia on sainfoin (Onobrychis viciifolia): Laboratory and field evaluation; D. Prvost, L.M. Bordeleau, R. Michaud, C. Lafrenire, J. Waddington, V.O. Biederbeck. 21. Survival of Bradyrhizobium japonicum in pig slurry used as carrier for soil inoculation; G. Ciafardini, G.C. Turtura. 22. Plasmid DNA content of several agronomically important Rhizobium species that nodulate alfalfa, berseem clover, or Leucaena; F.M. Hashem, D. Kuykendall. 23. International FAO/IAEA programm