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. 1986 Dec;82(4):1051–1056. doi: 10.1104/pp.82.4.1051

The Uptake of NO3−, NO2−, and NH4+ by Intact Wheat (Triticum aestivum) Seedlings 1

I. Induction and Kinetics of Transport Systems

Sham S Goyal 1, Ray C Huffaker 1
PMCID: PMC1056257  PMID: 11539085

Abstract

The inducibility and kinetics of the NO3−, NO2−, and NH4+ transporters in roots of wheat seedlings (Triticum aestivum cv Yercora Rojo) were characterized using precise methods approaching constant analysis of the substrate solutions. A microcomputer-controlled automated high performance liquid chromatography system was used to determine the depletion of each N species (initially at 1 millimolar) from complete nutrient solutions. Uptake rate analyses were performed using computerized curve-fitting techniques. More precise estimates were obtained for the time required for and the extent of the induction of each transporter. Up to 10 and 6 hours, respectively, were required to achieve apparent full induction of the NO3− and NO2− transporters. Evidence for substrate inducibility of the NH4+ transporters requiring 5 hours is presented. The transport of NO3− was mediated by a dual system (or dual phasic), whereas only single systems were found for transport of NO2− and NH4+. The Km values for NO3−, NO2−, and NH4+ were, respectively, 0.027, 0.054, and 0.05 millimolar. The Km for mechanism II of NO3− transport could not be defined in this study as it exhibited only apparent first order kinetics up to 1 millimolar.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Aslam M., Huffaker R. C., Rains D. W., Rao K. P. Influence of light and ambient carbon dioxide concentration on nitrate assimilation by intact barley seedlings. Plant Physiol. 1979 Jun;63(6):1205–1209. doi: 10.1104/pp.63.6.1205. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Breteler H., Nissen P. Effect of exogenous and endogenous nitrate concentration on nitrate utilization by dwarf bean. Plant Physiol. 1982 Sep;70(3):754–759. doi: 10.1104/pp.70.3.754. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Chantarotwong W., Huffaker R. C., Miller B. L., Granstedt R. C. In vivo nitrate reduction in relation to nitrate uptake, nitrate content, and in vitro nitrate reductase activity in intact barley seedlings. Plant Physiol. 1976 Apr;57(4):519–522. doi: 10.1104/pp.57.4.519. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Claassen N., Barber S. A. A Method for Characterizing the Relation between Nutrient Concentration and Flux into Roots of Intact Plants. Plant Physiol. 1974 Oct;54(4):564–568. doi: 10.1104/pp.54.4.564. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Deane-Drummond C. E., Glass A. D. Short Term Studies of Nitrate Uptake into Barley Plants Using Ion-Specific Electrodes and ClO(3): I. Control of Net Uptake by NO(3) Efflux. Plant Physiol. 1983 Sep;73(1):100–104. doi: 10.1104/pp.73.1.100. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Neyra C. A., Hageman R. H. Nitrate uptake and induction of nitrate reductase in excised corn roots. Plant Physiol. 1975 Nov;56(5):692–695. doi: 10.1104/pp.56.5.692. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Rao K. P., Rains D. W. Nitrate Absorption by Barley: II. Influence of Nitrate Reductase Activity. Plant Physiol. 1976 Jan;57(1):59–62. doi: 10.1104/pp.57.1.59. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Rao K. P., Rains D. W. Nitrate absorption by barley: I. Kinetics and energetics. Plant Physiol. 1976 Jan;57(1):55–58. doi: 10.1104/pp.57.1.55. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Thayer J. R., Huffaker R. C. Determination of nitrate and nitrite by high-pressure liquid chromatography: comparison with other methods for nitrate determination. Anal Biochem. 1980 Feb;102(1):110–119. doi: 10.1016/0003-2697(80)90325-5. [DOI] [PubMed] [Google Scholar]

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