Nitrogen is fundamental to all life forms and is also one of the most limiting of nutrients for plant growth. Several clades of angiosperms have developed symbiotic relationships with actinorhizal bacteria that fix atmospheric nitrogen and increase access to this nutrient. However, the evolutionary patterns of actinorhizal nitrogen-fixing symbioses remain unclear to date. Furthermore the underl...

Rhododendron aureum Georgi is a perennial evergreen dwarf shrub that grows at all elevations within the alpine tundra of northern China. Previous research has investigated the plant communities of R. aureum; however, little information is available regarding interspecific competition and underground soil microbial community composition. The objective of our study was to determine whether the pr...

Seven diazotrophs that grow well under Mo-deficient, N(2)-fixing conditions were isolated from a variety of environments. These isolates fall in the gamma subdivision of the class Proteobacteria and have genes that encode the Mo nitrogenase (nitrogenase 1) and the V nitrogenase (nitrogenase 2). Four of the isolates also harbor genes that encode the iron-only nitrogenase (nitrogenase 3).

Nitrogen-fixing activity associated with different wetland rice varieties was measured at various growth stages by an in situ acetylene reduction method after the activities of blue-green algae (cyanobacteria) in the flood water and on the lower portion of the rice stem were eliminated. Nitrogen-fixing activities associated with rice varieties differed with plant growth stages. The activities i...

the main objective of this study was to determine the effects of nitrogen fixing bacteria and manure application on the seed yield and yield components in black cumin (nigella sativa l.). the experiment was carried out at the ran research station in firouzkouh in 2012. a 4×4 factorial experiment, arranged in a randomized complete blocks designed with three replications. the treatments consisted...

Two new diazotrophic bacteria, Listonella anguillarum and Vibrio campbellii, and one nonnitrogen-fixing bacterium, Staphylococcus sp., were isolated from the rhizosphere of mangrove trees. Strains of these newly-defined diazotrophs are known as pathogenic bacteria in fish and shellfish. During the purification of diazotrophic species from the entire rhizosphere population, N2 -fixation of the b...

This study set out to investigate the effect of bio-fertilizers containing nitrogen-fixing bacteria and phosphorus on grain yield and yield components of Faba bean. To this end a factorial experiment on the basis of randomized complete block design with four replications was conducted in Behbahan region at South eastern part of Khuzestan Province of Iran. The experimental treatments included Ni...

The dynamics of a model of a free-living nitrogen-fixing population, grown in a chemostat alone or in competition with a non-nitrogen-fixing population, was studied through bifurcation analysis. It is demonstrated that the ability of the nitrogen-fixing population to survive depends on the ammonia and carbon source concentrations and the kinetics parameters of the system. Under competitive cond...

Fourteen strains of nitrogen-fixing bacteria were isolated from different agricultural plant species, including cassava, maize and sugarcane, using nitrogen-deprived selective isolation conditions. Ability to fix nitrogen was verified by the acetylene reduction assay. All potentially nitrogen-fixing strains tested showed positive hybridization signals with a nifH probe derived from Azospirillum...