PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “NITROGEN FIXATION”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources
PubMed2004

Magnesium-content of Rhizobium nodules in different plants: the importance of magnesium in nitrogen-fixation of nodules.

OBJECTIVE: Rhizobium bacteria induce nodules (tumors) in roots of leguminous crops that fix nitrogen (N2) from the atmosphere. METHODS: Trials were carried on in sterile perlite where two species of peas were grown hydroponically, and in two different soil types (brown forest soil and meadow silt soil), in a field where different leguminous plants were chosen for test plants: lupin, soybean, broad-bean, lentil and bean inoculated by Rhizobium bacteria. The Mg-content of the nutrient solution was higher than that of the control, but in the soil tests 1% Mg leaf fertilization was applied after bacterial inoculation. Number, weight and Mg-content of nodules were evaluated using an AAS method compared with the thick and thin hair/roots of the given plant. RESULTS AND CONCLUSIONS: Our results clearly show that the Mg nutrition treatment increased the number of Rhizobium nodules and their Mg-content, resulting in increased N2-fixation and yield.

Fabaceae↗
PubMed1982

Expression of an alternative nitrogen fixation system in Azotobacter vinelandii.

Nitrogenase activities were determined from maximum acetylene reduction rates for mutant strains of Azotobacter vinelandii which are unable to fix N2 in the presence of molybdenum (Nif-) but undergo phenotypic reversal to Nif+ under conditions of Mo deficiency. The system responsible for N2 fixation under these conditions is thought to be an alternative N2 fixation system (Bishop et al., Proc. Natl. Acad. Sci. U.S.A. 77:7342-7346, 1980). Phenotypic reversal of Nif- strains to Nif+ strains was also observed in N-free medium without Mo but with either V or Re. Two protein patterns were found on two-dimensional gels of proteins from the extracts of wild-type cells cultured in N-free medium without Mo and with or without V or Re. The expression of each protein pattern in the wild-type strain of A. vinelandii seemed to depend upon the physiological state of the N2-fixing culture. Electron paramagnetic resonance experiments were conducted on whole cells of A. vinelandii grown under conditions of Mo deprivation in the absence of fixed N. No g = 3.65 signal (an electron paramagnetic resonance signal characteristic of the Mo-containing component of nitrogenase) was detectable in these cells, regardless of whether V or Re was present during growth of these cells, These results are discussed from the perspective that the well-known effect of V on N2 fixation by A. vinelandii may involve an alternative N2 fixation system.

Acetylene↗