The Fifth International Symposium on Nitrogen Fixation with Non-legumes was held in Florence (Italy) on 10-14 September, 1990. Earlier Symposia of this series were held in Piracicaba (Brazil), Banf Alberta (Canada), Helsinki (Finland) and Rio De Janeiro (Brazil). The Symposium's main objectives were to bring together scientists working in many different fields of nitrogen fixation, to stimulate discussion on this important process and to have an appraisal of the most recent studies concerning nitrogen fixation with non-legumes. The Symposium was attended by 230 scientists from 32 different countries. This volume collects the contributions of 65 lectures and 87 posters, which are an up-to-date account of the state of knowledge on biological nitrogen fixation with non-legumes. The book provides a valuable reference source not only for specialists in nitrogen fixation, but also for researchers working on related aspects of agronomy, biochemistry, genetics, microbiology, molecular biology and plant physiology. It is with great pleasure that we aknowledge the contributions of the authors in assuring the prompt pubblication of this volume. We would also like to express our thanks to Kluwer Academic Publishers B.V. for the publication of these Proceedings. M. Polsinelli R. Materassi M. Vincenzini ORGANIZING COMMITTEE President M. Polsinelli M. Vincenzini Secretary F. Favilli Treasurer E. Galli E. Gallori L. Giovannetti R. Materassi M.P. Nuti M.R. Tredici SCIENTIFIC COMMITTEE M. Bazzicalupo Florence, Italy H. Bothe Cologne, West Germany R.H. Burris Madison, U.S.A.

Inhalt
A critical evaluation of the prospects for nitrogen fixation with non-legumes.- Regulation of expression of genes for three nitrogenases in Azotobacter vinelandii.- Genetic characterization of nitrogen fixation in Enterobacter strains from the rhizosphere of cereals.- Analysis of nitrogenase reaction using monoclonal antibodies against -subunit of component I of A. vinelandii.- Involvement of GroEL in Klebsiella pneumoniae nif gene expression and nitrogenase assembly.- The effect of some terrestrial oligochaeta on nitrogenase activity in the soil.- Cassette mutagenesis of a proposed DNA-binding motif in klebsiella pneumoniae rpon (sigma 54).- Characterization of a mutant of Azotobacter chroococcum resistant to some fungicides.- A chromosomal linkage map of Azotobacter vinelandii.- Energy coupling and electron transfer in nitrogenase.- Fluctuation of the ara under elaeagnus angustifolia canopy.- The influence of root exudates on dinitrogen fixation of chosen free-living bacteria.- Soil redox potential in presence of azospirillum.- Biofertilization of maize with free-living nitrogen fixing bacteria: results of field trials on grain production.- Kinetics of kelthane uptake and distribution in azospirillum lipoferum.- Bioaccumulation of the acaricide kelthane (dicofol) by azospirillum lipoferum.- Effect of biofertilizers on controlling fusarium solani f. Sp. phaseoli.- Phyllospheric nitrogen fixing bacteria in tillandsia leaves.- Nif and nod genes in Azospirillum.- Control of nitrogenase in Azospirillum sp..- Biology of nitrogen-fixing bacteria.- Biological nitrogen fixation associated with sugar cane.- Physiological properties of Azospirillum brasilense involved in root growth promotion.- Regulation of the nifHDK genes transcription in Azospirillum brasilense.- Cloning ofthe nifA and nifB genes of Azospirillum brasilense strain FP2.- Regulation of nitrogen fixation genes in Azospirillum: characterization of A nif regulatory region.- Azospirillum-plant interaction: a biochemical approach.- Osmotollerance of diazotrophic rhizosphere bacteria.- Azospirillum-gramineae interaction: effect of indole-3-acetic acid.- DNA restriction fingerprint for the identification of Azospirilla.- Alteration in membrane potential and in proton efflux in plant roots induced by Azospirillum brasilense.- Effect of soil organic matter on chickpea inoculated with Azospirillum brasilense and Rhizobium leguminosarum bv. ciceri.- Active attachment of Azospirillum brasilense to root surface of non-cereal plants and to sand particles.- Association of Alcaligenes faecalis with wetland rice.- Sunflower inoculation with Azospirillum and other P.G.P.R..- Characterization of a pectinolytic activity in Azospirillum irakense.- Associative N2-fixation in plants growing in saline sodic soils and its relative quantification based on 15N natural abundance.- Genetic analysis of the Azospirillum plant-root interaction.- Dinitrogen fixation and infection of grass leaves by Pseudomonas rubrisubal-bicans and Herbaspirillum seropedicae.- Growth parameters of microaerobic diazotrophic rhizobacteria determined in continuous culture.- Infection of intact roots of kallar grass and rice seedlings by Azoarcus.- Strain-specific salt tolerance and chemotaxis of Azospirillum brasilense and their associative N-fixation with finger millet in saline calcareous soil.- Nitrate reductase activity of Azospirillum brasilense sp7 and sp245 V - and C -forms in continuous culture.- Microcalorimetric study of the growth of Azospirillum brasilense: relation between heat production and other growth parameters.- Nitrogen fixation in P- nodules of wheat roots by introduced free-living diazotrophs.- Firefly luciferase expression on nitrogen fixation with non-legumes.- Nucleotide sequence of regulatory regions of Azospirillum brasilense.- Nucleotide sequence and expression of an Azospirillum nod homologous region.- Isolation and characterization of TN5 induced Azospirillum brasilense mutants alterated in calcofluor straining.- In vitro construction of Lacz gene fusions with the nifhdk operon of azospirillum brasilense.- Isolation and characterization of Azospirillum Brasilense mutants altered in the production of siderophores.- Taxonomic relationships between [Pseudomonas] Rubrisubalbicans, some clinical isolates (EF group 1), Herbaspirillum Seropedicae and [Aquaspirillum] Autotrophicum.- Study on the binding of azospirillum strains to plant tissues.- Effect of Azospirillum lipoferum and GA3 on root growth in corn.- Interactions of VA-mycorrhizae with Acetobacter diazotrophicus inoculated into sweet potatoes (Ipomoea batatas L. Lam.).- Genetic and biochemical studies on the production of indole-3-acetic acid (IAA) in azospirillum lipoferum.- Autoregulation of pH by Azospirillum spp..- Nitrogen fixing bacteria isolated from maize root and antagonistic activity against Fusarium sp.- Some characters of Azospirillum spp. isolated from the rice fields near Hanoi, Vietnam.- Melanin production by Azospirillum Lipoferum strains.- Effect of pO2, pCO2 and agitation on growth kinetics of Azospirillum lipoferum under fermentor conditions.- Selection of wetland rice genotypes for associated biological nitrogen fixation.- Enrichment of tomato sand cultures with composite inocula of associative dinitrogen fixers, p-dissolving bacilli and vam..- Partial purification and properties of two aromatic amino acid aminotransferases from the A. brasilense UAP 14 strain indole-3-acetic acid producer.- Characterization and regulation of two enzymatic activities involved in biosynthesis of indoleacetic acid in Azospirillum Brasilense UAP 14 strain.- Analysis of extracellular polysaccharides of Azospirillum Brasilense.- NO3- and Fe++ uptake in durum wheat is affected by Azospirillum brasilense inoculation.- Efficiency of Azotobacter strains depending of nitrogen level and sugar beet genotypes.- Specific responses of azotobacter strains and sugar beet genotypes.- Associative diazothrops of different systematic groups and their effect on the productivity of agricultural crops.- Construction of a growth chamber for long-termed axenic plant cultivation.- N2 fixing bacteria in the Rhizosphere of natural populations of Italian Ryegrass (Lolium multiforum L.).- Studies on few strains of azospirilla colonizing maize rhizosphere: their establishment on roots and effects on plant physiology.- …