Nitrogen Metabolism and Nitrogenous Constituents in Plants

Nitrogen has a wide range of valence states in compounds, which may be used in plant metabolism. Although some compounds have oxidation-reduction states of +7, as in pernitric acid, plant metabolites have oxidation- reduction states ranging from +5 (nitric acid, nitrate) to -3 (ammonia, ammonium) (4). Organic, nitrogen-containing compounds are at the oxidation-reduction state of nitrogen in ammonium (-3). Biologically important organic molecules in plants include proteins, nucleic acids, purines, pyrimidines, and coenzymes (vitamins), among many other compounds.