Nitrogen Fixing Organisms

Part 1 Organisms that fix nitrogen: the range of nitrogen-fixing organisms; cyanobacterial symbioses. Part 2 Legume and non-legume nodules: legume-rhizobial symbioses; the "classical" picture of nodule development; stages of nodulation; stems and nodules; non-legumes (actinorhizal plants);comparisons between legume and non-legume nodules. Part 3 Metabolism of nitrogen fixation: the basic problem; the nitrogenase enzyme; the oxygen problem; ammonia assimilation. Part 4 Nitrogen fixation in agriculture: scope and problems; legumes; forage and pasture legumes; grain legumes; factors affecting legume nitrogen fixation in the field; free-living bacteria; associative symbiosis (bacteria angiosperm); cyanobacteria; non-legume symbioses. Part 5 Nitrogen fixation and forestry: nitrogen requirements in forests; direct use of nitrogen-fixing legume species; direct use of actinorhizal plants; indirect use of symbiotic nitrogen-fixing plants; nitrogen fixation by free-living micro-organisms in forests; cyanobacteria. Part 6 Nitrogen fixation in aquatic ecosystems: fixation and nitrogen budgets; freshwater aquatic systems; saline aquatic environments. Part 7 Nitrogen fixation in terrestrial ecosystems: possible classifications; soils; some systems involving symbiotic higher plants; the phyllosphere; three membered symbioses; colonization and pioneer associations; climax situations. Part 8 Evolution - and the future: the origins of biological fixation; the evolution of symbiotic systems; current developments and the future.