BACKGROUND Despite the large stocks of organic nitrogen in soil, nitrogen availability limits plant growth in many terrestrial ecosystems because most plants take up only inorganic nitrogen, not organic nitrogen. Although some vascular plants can assimilate organic nitrogen directly, only recently has organic nitrogen been found to contribute significantly to the nutrient budget of any plant. C...

dissolved organic nitrogen (don) is an important constituent of dissolved organic matter (dom). it has a considerable effect on total dissolved soil nitrogen and it is very important as a nitrogen source of many aquatic and terrestrial ecosystems. dissolved inorganic nitrogen, which is another form of total soil dissolved nitrogen, includes no3, no2 and nh4, which is very important for plant nu...

Introduction Nitrogen, like many other chemical elements, has catenation ability. The variety and multiplicity of molecular structures with nitrogen-nitrogen bond is significantly smaller than for carbon. Such compounds are of particular interest as potential high-energy density materials (HEDM) [1], because they can undergo exothermic reaction Nx → (x/2)N2 releasing 50 kcal/mol or more per one...

Nitrogen absorption from the large intestine, largely as ammonia and possibly as amino acids (AAs), is generally thought to be of little nutritional value to nonruminant animals and humans. Ammonia-nitrogen absorbed from the large intestine, however, may be recycled into the small intestine as urea and incorporated into microbial AAs, whichmay then be used by the host. A cecal infusion study wa...

Nitrogen absorption from the large intestine, largely as ammonia and possibly as amino acids (AAs), is generally thought to be of little nutritional value to nonruminant animals and humans. Ammonia-nitrogen absorbed from the large intestine, however, may be recycled into the small intestine as urea and incorporated into microbial AAs, which may then be used by the host. A cecal infusion study w...

Cell growth rate is regulated in response to the abundance and molecular form of essential nutrients. InSaccharomyces cerevisiae(budding yeast), the molecular form of environmental nitrogen is a major determinant of cell growth rate, supporting growth rates that vary at least threefold. Transcriptional control of nitrogen use is mediated in large part by nitrogen catabolite repression (NCR), wh...

in order to evaluate the effect of different sources and rates of nitrogen the growth and biomass production of purslane, a randomized complete block design was conducted with three replications at the agricultural research farm of shahrekord university in 2012. fertilization treatments were consisted of control (no n amendment), 30 and 90 kg n ha-1in the form of urea fertilizer, 30 and 90 kg n...