ABSTRACT
Transport of nitrogen in soybeans occurs in both the phloem and xylem. Nitrate-N and much of the nitrogen arising from nitrogen fixation in the nodules are transported in the xylem. Israel (8) has discussed the translocation of nitrogen in the xylem. Nitrogen exported from leaves to other plant parts is transported in the phloem. Most of this nitrogen is in the form of amino acids derived either from the reduction of nitrate in the leaves, remobilization of protein stored in the leaves, or from the assimilation of ureides, amides, or amino acids produced in the root and nodules during nitrogen fixation and/or nitrate reduction before transport via the xylem to leaves.
