Electrocoupling of Ion Transporters in Plants: Interaction with Internal Ion Concentrations

  title={Electrocoupling of Ion Transporters in Plants: Interaction with Internal Ion Concentrations},
  author={Dietrich Gradmann and Johannes Hoffstadt},
  journal={The Journal of Membrane Biology},
Abstract There are five major electroenzymes in the plasmalemma of plant cells: a driving electrogenic pump, inward and outward rectifying K+ channels, a Cl−-2H+ symporter, and Cl−-channels. It has been demonstrated previously (Gradmann, Blatt & Thiel 1993, J. Membrane Biol.136:327–332) how voltage-gating of these electroenzymes causes oscillations of the transmembrane voltage (V) at constant substrate concentrations. The purpose of this study is to examine the interaction of the same… Expand
Models for oscillations in plants
Ionic relations of plant cells comprise enzymes such as channels, pumps and co-transporters that catalyse the transition of ions through lipid membranes and, therefore, affect the membrane voltage, and models presented here that simulate such oscillations based on physical properties of the ion transporters. Expand
Impact of Apoplast Volume on Ionic Relations in Plant Cells
  • D. Gradmann
  • Chemistry, Medicine
  • The Journal of Membrane Biology
  • 2001
Ionic relations of plant cells with free-running transmembrane voltage, V, can be modelled by electrocoupling of known, V-relevant and V-gated transporters and converges to thermodynamic equilibrium for K+ between apoplast and symplast, and to equal steady-state rates of uptake and release for Cl− and H+. Expand
A Thermodynamic Model of Monovalent Cation Homeostasis in the Yeast Saccharomyces cerevisiae
A generalized thermodynamic description is developed for the complex interplay of the plasma membrane ion transporters, membrane potential and the consumption of energy for maintaining and restoring specific intracellular cation concentrations in the yeast cells of S. cerevisiae. Expand
Cellular mechanisms of potassium transport in plants.
The physiological aspects of potassium transport systems in the plasma membrane are reviewed, re-examining fundamental problems in the field such as the distinctions between high- and low-affinity transport systems, the interactions between K(+) and other ions such as NH(4)(+) and Na(+), the regulation of cellular K(+ pools, the generation of electrical potentials and the problems involved in measurement of unidirectional K(-) fluxes are reviewed. Expand
Oscillations in proton transport revealed from simultaneous measurements of net current and net proton fluxes from isolated root protoplasts: MIFE meets patch-clamp
The inhibitory effect of DCCD and stimulatory effect of fusicoccin were used to correlate current and H + flux through the H + -ATPase for which there was reasonably good agreement within the limits of the flux measurements. Expand
A Mathematical Model of Action Potential in Cells of Vascular Plants
The model supports a hypothesis about participation of H+-ATPase in AP generation and simulates a stationary level of the membrane potential and ion concentrations. Expand
KAT1 inactivates at sub-millimolar concentrations of external potassium.
The data show that a depletion of Ko+ results in a decrease in channel conductance, irrespective of whether K+ is simply removed or replaced by either Na+ or Li+. Expand
An Energy-Barrier Model for the Permeation of Monovalent and Divalent Cations Through the Maxi Cation Channel in the Plasma Membrane of Rye Roots
The depolarization-activated, high-conduc- tance "maxi" cation channel in the plasma membrane of rye (Secale cereale L.) roots is permeable to a wide variety of monovalent and divalent cations. TheExpand
An Energy-Barrier Model for the Permeation of Monovalent and Divalent Cations Through the Maxi Cation Channel in the Plasma Membrane of Rye Roots
The model adequately described the diverse current vs. voltage (I/V) relationships obtained over a wide variety of experimental conditions and enabled the prediction of unitary currents and ion fluxes through the maxi cation channel under physiological conditions. Expand
The guard cell as a single-cell model towards understanding drought tolerance and abscisic acid action.
Results are providing the first glimpses of an emerging signalling complex critical for modulating the stomatal aperture in response to environmental stimuli. Expand


Minimal Model for Oscillations of Membrane Voltage in Plant Cells
Abstract Major plasmalemma ion transporters in plants are voltage-gated. Such gating behavior can lead to sustained oscillations of membrane voltage, which allows long-term osmotic adjustment byExpand
K+ channels of stomatal guard cells: bimodal control of the K+ inward-rectifier evoked by auxin.
  • M. Blatt, G. Thiel
  • Biology, Medicine
  • The Plant journal : for cell and molecular biology
  • 1994
Over the concentration range examined, the auxins evoked membrane hyperpolarizations and depolarizations of up to +/- 12-19 mV, depending on the free-running membrane potential prevailing before auxin additions, and voltage response was a predictable consequence of auxin action on the K+ channels and, at 100 microM auxin, on the anion current. Expand
Electrophysiology of Stomata
The discovery in 1968 that osmotically driven movement of guard cells is correlated with substantial transport of K+ through the plasmalemma (Fisher 1968) has challenged electrophysiologists everExpand
Modeling the interrelations between the calcium oscillations and ER membrane potential oscillations.
It turns out that calcium oscillations can arise without a permanent influx of calcium into the cell, when a calcium-buffering system such as calmodulin is included. Expand
Inverse problem theory : methods for data fitting and model parameter estimation
Part 1. Discrete Inverse Problems. 1. The General Discrete Inverse Problem. 2. The Trial and Error Method. 3. Monte Carlo Methods. 4. The Least-Squares (l 2 -norm) Criterion. 5. The Least-AbsoluteExpand
Modelling the interrelations between calcium oscillations and ER membrane potential oscillations.Biophysical Chemistry68:221–239
  • 1997
Action Potentials in Guard Cells
  • 1996
Electrocoupling of ion
  • 1993
Relationship between cell turgor pressure, electrical membrane potential, and chloride efflux in Acetabularia mediterranea
  • J. Membrane Biol. 72:75–84
  • 1983