Diazotrophic bacteria convert atmospheric nitrogen to plant-useable form and this input of nitrogen through biological fixation is of great agronomic importance. The contributions presented in this volume relate to free-living nitrogen fixers and the diazotrophs associated with plants. Symbiotic association of Frankia with non-legumes and cyanobacterial associations are also discussed. Research topics covered in this volume include the biochemistry and genetics of diazotrophs, recent developments in improvement of plant-microbe interactions and their molecular basis, the use of molecular probes in taxonomy and ecology of diazotrophs and reports on field applications, agronomic importance and improvement in methodologies for assessing their contribution to plants. This book provides valuable information not only for researchers working in the field of biological nitrogen fixation but also for biochemistry, molecular biologists, microbiologists and agronomists.

Zusammenfassung
Proceedings of the 7th International Symposium on Nitrogen Fixation with Non-Legumes, held 16-21 October 1996 in Faisalabad, Pakistan

Inhalt
Opening lecture.- 1. Biological nitrogen fixation by endophytic diazotrophs in non-leguminous crops in the tropics.- Section I Biochemistry and genetics of diazotrophs.- 2. Analysis of nitrogen fixation and regulatory genes in the sugar cane endophyte Acetobacter diazotrophicus.- 3. Functional analysis of a cloned nifA homologous gene of Azospirillum brasilense Yu62.- 4. Identification of plant growth hormones produced by bacterial isolates from rice, wheat and kallar grass.- Section II Ecophysiological studies for the improvement of plantmicrobe interaction.- 5. The rice endophytic diazotroph and PGPR.- 6. Effect of Azospirillum inoculation on growth and N2 fixation of maize subjected to different levels of FYM using 15N-dilution method.- 7. Contribution of non-leguminous biofertilizers to rice biomass, nitrogen fixation and fertilizer-N use efficiency under flooded soil conditions.- 8. Detection of inoculated plant growth-promoting rhizobacteria in the rhizosphere of rice.- Posters.- 9. Salt tolerance of diazotroph Alaligenes faecalis and its salt-tolerant association with host rice.- 10. Interaction of Azorhizobium caulinodans with different rice cultivars for increased N2-fixation.- 11. Response of wheat to an associative diazotroph inoculums under different rates of nitrogen fertilizer.- 12. Effects of high temperature on nitrogen fixation in soybean cultivars.- 13. Effect of plant growth regulators and Rhizobium inoculums on N2-fixation and yield of chickpea.- Section III Paranodulation and forced association of diazotrophs with non-legumes.- 14. Prospects for facilitated evolution of effective N2-fixing associations with cereals: comparative performance of Azospirillum brasilense Sp7-S with various free-living diazotrophs in para-nodulated wheat.- 15.Transgenic rice plants with Parasponia haemoglobin gene and its expression.- 16. Cell structure of pseudonodules formed on the roots of barley and rice.- Posters.- 17. Induction of paranodulation by 2,4-D, IAA and tryptophan in wheat inoculated with various diazotrophs.- 18. Optimizing zinc and phosphate statuses for enhancing field colonization and contribution of the symbiotic association Azolla-Anabaena to rice performance.- 19. Enhancement of rice performance and incidence of natural fungal and insect damage with cyanobacterization, microelements, combined nitrogen and certain pesticides.- Section IV Molecular biology of plant-diazotroph interaction.- 20. Colonization and nifH expression on rice roots by Alcaligenes faecalis A15.- 21. Responses of Azospirillum brasilense to salinity stress.- 22. Studies on the diploid indeterminate nodule-forming plant Melilotus alba Desr., white sweetclover.- Section V Molecular probes in taxonomy and ecology of diazotrophs.- 23. Isolation and identification of diazotrophic bacteria from rice, wheat and kallar grass.- Section VI Applicability and agronomic importance of associative diazotrophs.- 24. Diazotrophs associated with non-legumes grown in sandy soils.- 25. Effect of inoculation with nitrogen-fixing Klebsiella on potato yield.- 26. Responses of rice plants to inoculation with Azospirillum sp. under field conditions.- Posters.- 27. BGA technology for rice cultivation in northern India.- 28. Modified combined carbon N-deficient medium for isolation, enumeration and biomass production of diazotrophs.- 29. Contribution of integrated symbiotic and associative systems of biological nitrogen fixation to N-status of intercropped legumes and non-legumes in sandy soils of Egypt.- 30. Some physiological studies of diazotrophic bacteria associated with maize in a temperate and a tropical soil.- 31. In-vitro propagation using phytohormones produced by associative diazotrophs.- 32. Effect of inoculation of Azotobacter and PSM on fertilizer economy, plant growth and yield of winter maize.- 33. Accumulation of radionuclides by associative bacteria and the uptake of 134Cs by the inoculated barley plants.- 34. The influence of chosen fungicides on Azospirillum dinitrogen fixation in the soil.- Section VII Methodologies for assessing nitrogen fixation.- 35. Evaluation of biological nitrogen fixation associated with non-legumes.- 36. Use of 15N isotope dilution method to quantify nitrogen fixation in legumes and its potential use for non-legumes.- Section VIII Actinorhizal and cyanobacterial association.- 37. Competitivity and persistence of Frankia in a managed environment.- 38. Symbiotic association between Frankia and actinorhizal plants.- 39. Ecophysiological studies of cyanobacteria in paddy soils of Bangladesh.- 40. Cyanobacterial root nodules in Tribulus terrestris L. (Zygophyllaceae).- Posters.- 41. Use of Azolla as biofertilizer to enhance crop yield in a rice-wheat cropping system under mild climate.