Session 1: Mechanisms of infection of plants by N2-fixing microorganisms.- Mechanisms of infection of plants by nitrogen fixing organisms.- Session 2: Frankia and Parasponia symbiosis.- Effective nodulation of Coriaria myrtifolia L. induced by Frankia strains from Alnus glutinosa L. (Gaertn.).- Biology of the Parasponia-Bradyrhizobium symbiosis.- Glasshouse evaluation of the growth of Alnus rubra and Alnus glutinosa on peat and acid brown earth soils when inoculated with four sources of Frankia.- Ultrastructure of Frankia isolated from three Chilean shrubs (Rhamnaceae).- Session 3: Azolla and cyanobacteria.- Physiology and agronomy of Azolla-Anabaena symbiosis.- Heterotrophic metabolism and diazotrophic growth of Nostoc sp. from Cycas circinalis.- Light dependent nitrogen chlorosis in a heterocy stous cyanobacterium.- Isolation and characterization of the N2-fixing symbiotic cyanobacterium Anabaena azollae.- Bacteria in the Azolla-Anabaena symbiosis.- New data on the Azolla-Anabaena symbiosis. I. Morphological and histochemical aspects.- New data on the Azolla-Anabaena symbiosis. II. Cytochemical and immunocytochemical aspects.- Session 4: Isolation and identification of plant-associated N2-fixing bacteria.- Isolation and identification of root associated diazotrophs.- Occurrence and survival of Azospirillum spp. in temperate regions.- Klebsiella sp. NIAB-1: A new diazotroph, associated with roots of kallar grass from saline sodic soils.- Session 5: Physiology of Azospirillum and other diazotrophs.- Ecophysiological aspects of growth and nitrogen fixation in Azospirillum spp..- The phytohormonal interactions between Azospirillum and wheat.- Investigations on growth, nitrogen fixation and ammonium assimilation by a bacterium isolated from rice soil.- Session 6: Genetics of Azospirillum and other diazotrophs.- Regulation of nif genes expression in Azospirillum brasilense and Herbaspirillum seropedicae.- Homology between plasmids of Azospirillum brasilense and Azospirillum lipoferum.- Self-transmissible nif-plasmids in Enterobacter.- Identification of Bacillus azotofixans nitrogen fixation genes using heterologous nif probes.- Isolation and properties of Azospirillum lipoferum and Azospirillum brasilense surface polysaccharide mutants.- Session 7: Mechanisms of association of N2-fixing bacteria with grasses and cereals.- Plant-bacteria interactions with special emphasis on the kallar grass association.- Location of diazotrophs in the root interior with special attention to the kallar grass association.- Field inoculation of sorghum and rice with Azospirillum spp. and Herbaspirillum seropedicae.- Session 8: Mechanisms of response of cereal crops to Azospirillum inoculation.- Involvement of IAA in the interaction between Azospirillum brasilense and Panicum miliaceum roots.- Influence of inoculation with Azospirillum brasilense and Glomus fasciculatum on sorghum nutrition.- Inoculation with associative N2-fixers in Egypt.- Session 9: Quantification of plant-associated biological nitrogen fixation.- Association between N2-fixing bacteria and pearl millet plants: Responses, mechanisms and persistence.- Effect of inorganic N and organic fertilizers on nitrogen-fixing (acetylene-reducing) activity associated with wetland rice plants.- Impact of soil environmental factors on rates of N2-fixation associated with roots on intact maize and sorghum plants.- Session 10: Effects of plant genotype and environmental factors on plant-associated N2-fixation.- Natural 15N abundance as a method of estimating the contribution of biologically fixed nitrogen to N2-fixing systems: Potential for non-legumes.- Survival and colonization of inoculated bacteria in kallar grass rhizosphere and quantification of N2-fixation.- Selection of sugar cane cultivars for associated biological nitrogen fixation using 15N-labelled soil.- Occurrence of effective nitrogen-scavenging bacteria in the rhizosphere of kallar grass.- General summary and conclusions.- Titles of posters presented at the meeting.