Abstract
The interaction between ammonium and potassium during influx was examined in roots of dark-grown decapitated corn seedlings (Zea mays L., cv. Pioneer 3369A). Influx was measured during a 10-min exposure to either (15NH4)2SO4 ranging from 10 to 200 μM NH +4 with and without 200 μM K(86Rb)Cl or to K(86Rb)Cl ranging from 10 to 200 μM K+ with and without 200 μM NH +4 as (15NH4)2SO4. The simple Michaelis-Menten model described the data well only for potassium influx in the presence of ambient ammonium. For the other three instances, the data were improved by assuming that a second influx mechanism became operative as the low-concentration phase approached saturation. Two distinct mechanisms are thus indicated for both ammonium and potassium influx within the range of 10 to 200 μM.
The influx mechanism operating at low concentrations showed greater affinity for potassium than for ammonium, even though the capacity for ammonium transport was twice as large as that for potassium. It is suggested that this phase involved a common transport system for the two ions and that localized low acidity next to the internal surface, following H+ extrusion, favored ammonium deprotonation and dissociation from the transport system-ammonium complex. Parallel decreases in V max and increases in Km of the low-concentration saturable phase occurred for ammonium influx when ambient potassium was present and for potassium influx when ambient ammonium was present. The data support a mixed-type inhibition in each case. Simultaneous measurement of potassium and ammonium influx showed that they were highly negatively correlated at the lower concentrations, indicating that the extent to which influx of the inhibited ion was restricted was associated with influx of the inhibitor ion. Presence of ambient ammonium eliminated the second phase of potassium influx. In contrast, the presence of ambient potassium decreased the concentration at which the second phase of ammonium influx was initiated but did not restrict the rate.
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References
Atkins, G.L. (1976) Tests for goodness of fit of models. Biochem. Soc. Trans. 4, 357–361
Atkins, G.L., Gardner, M.L.G. (1977) The computation of saturable and linear components of intestinal and other transport kinetics. Biochim. Biophys. Acta 468, 127–145
Bange, G.G.J. (1962) The carrier theory of ion transport: A reconsideration. Acta Bot. Neerl. 11, 139–146
Borstlap, A.C. (1981) Invalidity of the multiphasic concept of ion absorption in plants. Plant Cell Environ. 4, 189–195
Breteler, H. (1977) Ammonium-rubidium uptake interaction in excised-maize roots. In: Transmembrane ionic exchanges in plants, pp. 185–191, Thellier, M., ed. Centre Nationale de la Reserche Scientifique, Paris
Cataldo, D.A., Schrader L.E., Youngs, V.L. (1974) Analysis by digestion and colorimetric assay of total nitrogen in plant tissues high in nitrate. Crop Sci. 14, 854–856
Cheeseman, J.M., Hanson, J.B. (1979). Energy-linked potassium influx as related to cell potential in corn roots. Plant Physiol. 64, 842–845
Deane-Drummond, C.E., Glass, A.D.M. (1983) Short-term studies of nitrate uptake into barley plants using ion-specific electrodes and 36C10 -3 . II. Regulation of NO -3 efflux by NH +4 . Plant Physiol. 73, 105–110
Epstein, E., Hagen, C.E. (1952) A kinetic study of the absorption of alkali cations by barley roots. Plant Physiol. 27, 457–474
Epstein, E., Rains, D.W., Elzam, O.E. (1963) Resolution of dual mechanisms of potassium absorption by barley roots. Proc. Natl. Acad. Sci. USA 49, 684–692
Hoagland, D.R., Arnon, D.I. (1950) The water culture method for growing plants without soil. Calif. Agric. Exp. Stat., Circ. No. 347
Hofstee, B.H.J. (1952) On the evaluation of the constants V max and K m in enzyme reactions. Science 116, 329–331
MacKown, C.T., Volk, R.J., Jackson, W.A. (1982) Nitrate assimilation by decapitated corn root systems: Effects of ammonium during induction. Plant Sci. Lett. 24, 295–302
McKenzie, H.A., Wallace, H.S. (1954) The Kjeldahl determination of nitrogen: A critical study of digestion conditions — Temperature, catalyst and oxidizing agent. Aust. J. Chem. 7, 55–70
Mengel, K. (1985) Potassium movement within plants and its importance in assimilate transport. In: Potassium in agriculture, pp. 397–411, Munson, R.D., ed. American Society of Agronomy, Madison, Wis
Mengel, K., Viro, M., Hehl, G. (1976) Effect of potassium on uptake and incorporation of ammonium nitrogen by rice plants. Plant Soil 44, 547–558
Munn, D.A., Jackson, W.A. (1978) Nitrate and ammonium uptake by rooted cuttings of sweet potato. Agron. J. 70, 312–316
Nissen, P. (1971) Uptake of sulfate by roots and leaf slices of barley: Mediated by single, multiphasic mechanisms. Physiol. Plant. 24, 315–324
Nissen, P., Fageria, N.K., Rayar, A.J., Hassan, N.M., Van Hai, T. (1980) Multiphasic accumulation of nutrients by plants. Physiol. Plant. 49, 222–240
Nye, P.H., Tinker, P.B. (1977) Solute movement in the soil-root system. University of California Press, Berkeley, Los Angeles
Pan, W.L., Jackson, W.A., Moll, R.H. (1985) Nitrate uptake and partitioning by corn root systems: Differential effects of ammonium among genotypes and stages of root development. Plant Physiol. 77, 560–566
Rosen, C.J., Carlson, R.M. (1984) Characterization of K+ and NH +4 absorption by Myrobalan plum and tomato: influence of plant potassium status and solution concentrations of K+ and NH +4 . J. Amer. Soc. Hort. Sci. 109, 552–559
Rufty, T.W., Jr., Jackson, W.A., Raper, C.D., Jr. (1982) Inhibition of nitrate assimilation in roots in the presence of ammonium: The moderating influence of potassium. J. Exp. Bot. 33, 1122–1137
SAS Institute, Inc. (1982) SAS User's Guide: Statistics. 1982 edn. SAS Institute, Inc., Cary, N.C., USA
Scherer, H.W., MacKown, C.T., Legget, J.E. (1984) Potassium-ammonium uptake interactions in tobacco seedlings. J. Exp. Bot. 35, 1060–1070
Smith, R.C., Epstein, E. (1964) Ion absorption by shoot tissue: Kinetics of potassium and rubidium absorption by corn leaf tissue. Plant Physiol. 39, 992–996
Torimitsu, K., Yozoki, Y., Nagasuka, K., Ohta, E., Sokata, M. (1984) Effect of external pH on the cytoplasmic and vacuolar pH's in mung bean root-tip cells: a 31P nuclear magnetic resonance study. Plant Cell Physiol. 25, 1403–1409
Tromp, J. (1962) Interactions in the absorption of ammonium, potassium and sodium ions by wheat roots. Acta Bot. Neerl. 11, 147–192
Vale, F.R. (1986) Ammonium-potassium interactions during influx into corn (Zea mays L.) root systems as affected by nitrogen and potassium status of the roots. Ph.D. dissertation. North Carolina State University, Raleigh, USA
Vale, F.R., Jackson, W.A., Volk, R.J. (1987) Potassium influx into maize root systems: influence of root potassium concentration and ambient ammonium. Plant Physiol. 84, 1416–1420
Volk, R.J., Jackson, W.A. (1979) Preparing nitrogen gas for nitrogen-15 analysis. Anal. Chem. 51, 463
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Paper no. 11131 of the Journal Series of the North Carolina Agricultural Research Service
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Vale, F.R., Volk, R.J. & Jackson, W.A. Simultaneous influx of ammonium and potassium into maize roots: kinetics and interactions. Planta 173, 424–431 (1988). https://doi.org/10.1007/BF00401031
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DOI: https://doi.org/10.1007/BF00401031