Investigation on the Assimilation of Nitrogen by Maize Roots and the Transport of Some Major Nitrogen Compounds by Xylem Sap. II: Incorporation of Taken-up Nitrogen into Free Amino Acids and Proteins of Maize Roots

The amino acid and protein metabolism of roots of maize has been studied. The important role of the free amino acids and proteins of the roots as active agents in nitrogen assimilation is pointed out. Nitrogen supplied as nitrate is preferably incorporated into α-ketoglutaric acid, and then by trans-aminases transferred to other ketoacids. In the case of ammonia supply the function of a nitrogen-accumulating assimilation system leading to the formation of Arg, Glu-NH2 and Asp-NH2 is shown.