Incorporation of(15)NO3-into amino acids was studied during the anaerobic germination of rice seeds. In treated coleoptiles, the label was incorporated into glutamine, glutamate, alanine,γ-aminobutyric acid (Gaba), arginine, aspartate and methionine. These findings are consistent with a primary incorporation of nitrate nitrogen into glutamine, glutamate and aspartate, and their further conversion to alanine, Gaba, arginine and methionine.