• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of plntphysLink to Publisher's site
Plant Physiol. Dec 1993; 103(4): 1259–1267.
PMCID: PMC159114

Ammonium Uptake by Rice Roots (II. Kinetics of 13NH4+ Influx across the Plasmalemma).


Short-term influxes of 13NH4+ were measured in intact roots of 3-week-old rice (Oryza sativa L. cv M202) seedlings that were hydroponically grown at 2, 100, or 1000 [mu]M NH4+. Below 1 mM external concentration ([NH4+]0), influx was saturable and due to a high-affinity transport system (HATS). For the HATS, Vmax values were negatively correlated and Km values were positively correlated with NH4+ provision during growth and root [NH4+]. Between 1 and 40 mM [NH4+]0, 13NH4+ influx showed a linear response due to a low-affinity transport system (LATS). The 13NH4+ influxes by the HATS, and to a lesser extent the LATS, are energy-dependent processes. Selected metabolic inhibitors reduced influx of the HATS by 50 to 80%, but of the LATS by only 31 to 51%. Estimated values for Q10 (the ratio of rates at temperatures differing by 10[deg]C) for HATS were greater than 2.4 at root temperatures from 5 to 10[deg]C and were constant at approximately 1.5 between 5 and 30[deg]C for the LATS. Influx of 13NH4+ by the HATS was insensitive to external pH in the range from 4.5 to 9.0, but influx by the LATS declined significantly beyond pH 6.0. The data presented are discussed in the context of the kinetics, energy dependence, and the regulation of ammonium influx.

Full Text

The Full Text of this article is available as a PDF (965K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • 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. [PMC free article] [PubMed]
  • Clarkson DT, Warner AJ. Relationships between Root Temperature and the Transport of Ammonium and Nitrate Ions by Italian and Perennial Ryegrass (Lolium multiflorum and Lolium perenne). Plant Physiol. 1979 Oct;64(4):557–561. [PMC free article] [PubMed]
  • Cram WJ. Compartmentation and exchange of chloride in carrot root tissue. Biochim Biophys Acta. 1968 Nov 5;163(3):339–353. [PubMed]
  • Glass AD. Regulation of potassium absorption in barley roots: an allosteric model. Plant Physiol. 1976 Jul;58(1):33–37. [PMC free article] [PubMed]
  • Ingemarsson B, Oscarson P, Af Ugglas M, Larsson CM. Nitrogen Utilization in Lemna: II. Studies of Nitrate Uptake Using NO(3). Plant Physiol. 1987 Nov;85(3):860–864. [PMC free article] [PubMed]
  • King BJ, Siddiqi MY, Ruth TJ, Warner RL, Glass ADM. Feedback Regulation of Nitrate Influx in Barley Roots by Nitrate, Nitrite, and Ammonium. Plant Physiol. 1993 Aug;102(4):1279–1286. [PMC free article] [PubMed]
  • Kleiner D. The transport of NH3 and NH4+ across biological membranes. Biochim Biophys Acta. 1981 Nov 9;639(1):41–52. [PubMed]
  • Kochian LV, Lucas WJ. Potassium transport in corn roots : I. Resolution of kinetics into a saturable and linear component. Plant Physiol. 1982 Dec;70(6):1723–1731. [PMC free article] [PubMed]
  • Rodriguez-Navarro A, Blatt MR, Slayman CL. A potassium-proton symport in Neurospora crassa. J Gen Physiol. 1986 May;87(5):649–674. [PMC free article] [PubMed]
  • Sasakawa H, Yamamoto Y. Comparison of the uptake of nitrate and ammonium by rice seedlings: influences of light, temperature, oxygen concentration, exogenous sucrose, and metabolic inhibitors. Plant Physiol. 1978 Oct;62(4):665–669. [PMC free article] [PubMed]
  • Siddiqi MY, Glass AD, Ruth TJ, Rufty TW. Studies of the Uptake of Nitrate in Barley: I. Kinetics of NO(3) Influx. Plant Physiol. 1990 Aug;93(4):1426–1432. [PMC free article] [PubMed]
  • Tolley-Henry L, Raper CD., Jr Utilization of ammonium as a nitrogen source: effects of ambient acidity on growth and nitrogen accumulation by soybean. Plant Physiol. 1986;82:54–60. [PMC free article] [PubMed]
  • Vessey JK, Henry LT, Chaillou S, Raper CD., Jr Root-zone acidity affects relative uptake of nitrate and ammonium from mixed nitrogen sources. J Plant Nutr. 1990;13(1):95–116. [PubMed]
  • Wang MY, Siddiqi MY, Ruth TJ, Glass ADM. Ammonium Uptake by Rice Roots (I. Fluxes and Subcellular Distribution of 13NH4+). Plant Physiol. 1993 Dec;103(4):1249–1258. [PMC free article] [PubMed]

Articles from Plant Physiology are provided here courtesy of American Society of Plant Biologists


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...