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 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 Google Scholar Google Scholar Articles by Roberts, J. K. M. Articles by Pang, M. K. L. Search for Related Content PubMed PubMed Citation Articles by Roberts, J. K. M. Articles by Pang, M. K. L. Agricola Articles by Roberts, J. K. M. Articles by Pang, M. K. L.

Metabolism and Enzymology

Estimation of Ammonium Ion Distribution between Cytoplasm and Vacuole Using Nuclear Magnetic Resonance Spectroscopy ¹

Department of Biochemistry, University of California, Riverside, California 92521

Evidence is presented that intracellular ammonium is trapped in vacuoles of maize (Zea mays L.) root tips because of rapid movement of ammonia between cytoplasm and vacuoles. The concentration of cytoplasmic ammonium is estimated to be <15 µM at extracellular ammonium concentrations up to 1 mM. The implications for pathways of ammonium assimilation are discussed.

This article has been cited by other articles:

				H Aarnes, A. Eriksen, D Petersen, and F Rise Accumulation of ammonium in Norway spruce (Picea abies) seedlings measured by in vivo 14N-NMR J. Exp. Bot., March 1, 2007; 58(5): 929 - 934. [Abstract] [Full Text] [PDF]

				J.K. Schjoerring, S. Husted, G. Mack, and M. Mattsson The regulation of ammonium translocation in plants J. Exp. Bot., April 15, 2002; 53(370): 883 - 890. [Abstract] [Full Text] [PDF]

				C. Stohr and G. Mack Diurnal changes in nitrogen assimilation of tobacco roots J. Exp. Bot., June 1, 2001; 52(359): 1283 - 1289. [Abstract] [Full Text] [PDF]

				A. J. Miller, S. J. Cookson, S. J. Smith, and D. M. Wells The use of microelectrodes to investigate compartmentation and the transport of metabolized inorganic ions in plants J. Exp. Bot., April 1, 2001; 52(356): 541 - 549. [Abstract] [Full Text] [PDF]

				D. T. Britto, A. D.M. Glass, H. J. Kronzucker, and M. Y. Siddiqi Cytosolic Concentrations and Transmembrane Fluxes of NH4+/NH3. An Evaluation of Recent Proposals Plant Physiology, February 1, 2001; 125(2): 523 - 526. [Full Text]

				J. Gerendas and R.G. Ratcliffe Intracellular pH regulation in maize root tips exposed to ammonium at high external pH J. Exp. Bot., February 2, 2000; 51(343): 207 - 219. [Abstract] [Full Text] [PDF]

				R. Brouquisse, J.-P. Gaudillère, and P. Raymond Induction of a Carbon-Starvation-Related Proteolysis in Whole Maize Plants Submitted to Light/Dark Cycles and to Extended Darkness Plant Physiology, August 1, 1998; 117(4): 1281 - 1291. [Abstract] [Full Text]