This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (112) Citing Articles via Google Scholar Google Scholar Articles by Pate, J. S. Articles by Woo, K. C. Search for Related Content PubMed PubMed Citation Articles by Pate, J. S. Articles by Woo, K. C. Agricola Articles by Pate, J. S. Articles by Woo, K. C.

Articles

Nitrogen Nutrition and Xylem Transport of Nitrogen in Ureide-producing Grain Legumes ¹

Department of Botany, University of Western Australia, Nedlands, Western Australia 6009

Xylem sap composition was examined in nodulated and nonnodulated cowpea (Vigna unguiculata [L.] Walp.) plants receiving a range of levels of NO₃ and in eight other ureide-forming legumes utilizing NO₃ or N₂ as sole source of nitrogen. A ¹⁵N dilution technique determined the proportions of plant nitrogen derived from N₂ in the nodulated cowpeas fed NO₃. Xylem sap composition of NO₃-fed, nodulated cowpea varied predictably with the relative extents to which N₂ and NO₃ were being utilized. The ratios of asparagine to glutamine (N/N) and of NO₃ to ureide (N/N) in xylem sap increased with increasing dependence on NO₃ whereas per cent of xylem nitrogen as ureide and the ratio of ureide plus glutamine to asparagine plus NO₃ (N/N) in xylem sap increased with increasing dependence on N₂ fixation. The amounts of NO₃ and ureides stored in leaflets, stems plus petioles, and roots of cowpea varied in a complex manner with level of NO₃ and the presence or absence of N₂ fixation. All species showed higher proportions of organic nitrogen as ureide and several-fold lower ratios of asparagine to glutamine in their xylem sap when relying on N₂ than when utilizing NO₃. In nodulated (minus nitrate) cowpea and mung bean (Vigna radiata [L.] Wilczek) the percentage of xylem nitrogen as ureide remained constant during growth but the ratio of asparagine to glutamine varied considerably. The biochemical significance of the above differences in xylem sap composition was discussed.

This article has been cited by other articles:

				J. Yang and K.-H. Han Functional Characterization of Allantoinase Genes from Arabidopsis and a Nonureide-Type Legume Black Locust Plant Physiology, March 1, 2004; 134(3): 1039 - 1049. [Abstract] [Full Text] [PDF]

				H. C. Pelissier, A. Frerich, M. Desimone, K. Schumacher, and M. Tegeder PvUPS1, an Allantoin Transporter in Nodulated Roots of French Bean Plant Physiology, February 1, 2004; 134(2): 664 - 675. [Abstract] [Full Text] [PDF]

				E. H. NEWCOMB and S. R. TANDON Uninfected Cells of Soybean Root Nodules: Ultrastructure Suggests Key Role in Ureide Production Science, June 19, 1981; 212(4501): 1394 - 1396. [Abstract] [PDF]