Abstract
The membrane potential (pd) of duck weed (Lemna gibba G1) proved to be energy dependent. At high internal ATP levels of 74 to 105 nmol ATP g-1 FW, pd was between -175 and -265 mV. At low ATP levels of 23 to 46 nmol ATP g-1 FW, pd was low, about -90 to -120 mV at pH 5.7, but -180 mV at pH 8. Upon addition of glucose in the dark or by light energy the low pd recovered to the high values. The active component of the pd was depolarized by the addition of hexoses in the dark and in the light. Hexose-dependent depolarization of the pd (=Δ pd) followed a saturation curve similar to active hexose influx kinetics. Depolarization of the pd recovered in the dark even in the presence of the hexoses and with a 10fold enhancement in the light. Depolarization and recovery could be repeated several times with the same cell. Glucose uptake caused a maximum depolarization of 133 mV, fructose uptake half that amount, sucrose had the same effect as glucose. During 3-O-methylglucose and 2-deoxyglucose uptake the depolarizing effect was only slightly lower. The pd remained unchanged in the presence of mannitol. The glucose dependent Δ pd and especially the rate of pd recovery proved to be pH-dependent between pH 4 and pH 8. It was independent of the presence of 1 mM KCl. Although no Δ pH could be measured in the incubation medium, these results can be best explained by a H+-hexose cotransport mechanism powered by active H+ extrusion at the plasmalemma.
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Abbreviations
- LD:
-
longday
- SD:
-
shortday
- pd:
-
membrane electropotential difference
- Δ pd:
-
maximum membrane potential depolarization
- L:
-
light
- D:
-
dark
- FW:
-
fresh weight
- d:
-
days of culture of Lemna gibba
- 1X:
-
perfusing solution without sugar, see methods
References
Brinckmann, E., Lüttge, U.: Lichtabhängige Membranpotential-schwankungen und deren interzelluläre Weiterleitung bei panaschierten Photosynthese-Mutanten von Oenothera. Planta 119, 47–57 (1974)
Cleland, R.E.: Kinetics of hormone-induced H+ excretion. Plant Physiol. 58, 210–213 (1976)
Findlay, G.P., Hope, A.B.: Electrical properties of plant cells: methods and findings. In: Encyclopedia of Plant Physiology, New Ser. 2A, pp. 53–92, Lüttge, U., Pitman, M.G., eds. Berlin-Heidelberg-New York: Springer 1976
Gradmann, D.: “Metabolic” action potentials in Acetabularia. J. Membrane Biol. 29, 23–45 (1976)
Haschke, H.-P., Lüttge, U.: β-Indolylessigsäure-(IES)-abhängiger K+−H+-Austauschmechanismus und Streckungswachstum bei Avena-Koleoptilen. Z. Naturforschg. 28c, 555–558 (1973)
Higinbotham, N.: Electropotentials of plant cells. Ann. Rev. Plant Physiol. 24, 25–46 (1973)
Higinbotham, N., Etherton, B., Foster, R.J.: Effect of external K, NH4, Na, Ca, Mg and H ions on the cell transmembrane electropotential of Avena coleoptiles. Plant Physiol. 39, 196–203 (1964)
Higinbotham, N., Graves, J.S., Davis, R.F.: Evidence for an electrogenic ion transport pump in cells of higher plants. J. Membrane Biol. 3, 210–222 (1970)
Hutchings, V.M.: Sucrose and proton cotransport in Ricinus cotyledons. PhD thesis, Cambridge U.K. (1976)
Jones, M.G.K., Novacky, A., Dropkin, V.H.: Transmembrane potentials of parenchyma cells and nematode-induced transfer cells. Protoplasma 85, 15–37 (1975)
Komor, E.: Proton-coupled hexose transport in Chlorella vulgaris. FEBS Letters 38, 16–18 (1973)
Komor, E., Rotter, M., Tanner, W.: A proton-cotransport system in a higher plant: sucrose transport in Ricinus communis. Plant Science Letters 9, 153–162 (1977)
Lüttge, U.: Nectar composition and membrane transport of sugars and amino acids: A review on the present state of nectar research. Apidologie 8 (1977) (In press)
Malek, F., Baker, D.A.: Proton co-transport of sugars in phloem loading. Planta 135, 297–299 (1977)
Mitchell, P.: Translocation through natural membranes. Advances in Enzymology 29, 33–87 (1967)
Racusen, R.H., Galston, A.W.: Electrical evidence for rhythmic changes in the cotransport of sucrose and hydrogen ions in Samanea pulvini. Planta 135, 57–62 (1977)
Raven, J.A., Smith, F.A.: Characteristics, functions and regulation of active proton extrusion. In: Regulation of Cell Membrane Activities in Plants. pp. 25–40, Marrè, E., Ciferri, O. eds. Elsevier/North-Holland Biomedical Press Amsterdam, 1977
Rottenberg, H.: The driving force for proton(s) metabolites cotransport in bacterial cells. FEBS Letters 66, 159–163 (1976)
Slayman, C.L., Long, W.S., Lu, C.Y.-H.: The relationship between ATP and an electrogenic pump in the plasma membrane of Neurospora crassa. J. Membrane Biol. 14, 305–338 (1973)
Slayman, C.L., Slayman, C.W.: Depolarization of the plasma membrane of Neurospora during active transport of glucose: evidence for a proton-dependent cotransport system. Proc. Natl. Acad. Sci. USA 71, 1935–1939 (1974)
Spanswick, R.M.: Evidence for an electrogenic ion pump in Nitella translucens. I. The effects of pH, K+, Na+, light and temperature on the membrane potential and resistance. Biochim. Biophys. Acta 288, 73–89 (1972)
Strehler, B.L.: Adenosine-5′-triphosphate and creatine phosphate Determination with luciferase. In: Methods of Enzymatic Analysis, pp. 559, Bergmeyer, H.U., ed. New York: Academic Press 1965
Tanner, W., Komor, E., Fenzl, F., Decker, M.: Sugar-proton cotransport systems. In: Regulation of Cell Membrane Activities in plants, pp. 79–90, Marrè, E., Ciferri, O., eds. Amsterdam: Elsevier/North-Holland Biomed. Press. 1977
Ullrich-Eberius, C.I., Novacky, A., Lüttge, U.: Active hexose uptake in Lemna gibba G1 Planta 1978 (in Press)
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Novacky, A., Ullrich-Eberius, C.I. & Lüttge, U. Membrane potential changes during transport of hexoses in Lemna gibba G1. Planta 138, 263–270 (1978). https://doi.org/10.1007/BF00386821
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DOI: https://doi.org/10.1007/BF00386821