Electrogenic cells ofChara braunii andNitella flexilis were placed in a pulse-modulated radio-frequency electric field of up to 6000 V/m. Their vacuolar resting potentials were found to experience submillivoltdepolarizing offsets (typically 140 μV at 250 kHz) which were relatively indepencent of temperature, increased linearly with resting potential from a zero near −210mV, and had a cutoff (putatively due to ion transit times) near 5 MHz. By contrast, nonelectrogenic cells experiencedhyperpolarizing offsets (typically 1100 μV at 250 kHz) which increased in magnitude with increasing temperature, were independent of resting potential, and had a transit time cutoff near 10 MHz.
The ionic mobilities inferred from these cutoff frequencies are somewhat higher than would be expected for active transport and presumably reflect passive conductance mechanisms which therefore must be presumed different for the electrogenic and nonelectrogenic states.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
Bisson, M.A., Walker, N.A. 1980. TheChara plasmalemma at high pH. Electrical measurements show rapid specific passive uniport of H+ or OH−.J. Membrane Biol. 56:1–7
Ferrier, J.M., Morvan, C., Lucas, W.J., Dainty, J. 1979. Plasmalemma voltage noise inChara corallina.Plant Physiol. 63:709–714
Marrè, E. 1979. Fusicoccin: A tool in plant physiology.Annu. Rev. Plant. Physiol. 30:273–288
Pickard, W.F. 1973. Does the resting potential ofChara braunii have an electrogenic component?Can. J. Bot. 51:715–724
Pickard, W.F. 1974. Hydrodynamic aspects of protoplasmic streaming inChara braunii.Protoplasma 82:321–339
Pickard, W.F., Barsoum, Y.H. 1981. Radio-frequency bioeffects at the membrane level: Separation of thermal and athermal contributions in the Characeae.J. Membrane Biol. 61:39–54
Pickard, W.F., Galanis, J.C. 1981. What can be inferred about the ion transporting properties of a membrane from measurements of resting potential, tangential resistance, and tracer flux?Math. Biosci. 55:137–154
Pickard, W.F., Rosenbaum, F.J. 1978. Biological effects of microwaves at the membrane level: Two possible athermal electrophysiological mechanisms and a proposed experimental test.Math. Biosci. 39:235–253
Poole, R.J. 1978. Energy coupling for membrane transport.Annu. Rev. Plant Physiol. 29:437–460
Roa, R.L., Pickard, W.F. 1976b. Theuuse of membrane electrical noise in the study of characean electrophysiology.J. Exp. Bot. 27:460–472
Roa, R.L., Pickard, W.F. 1976b. The vacuolar pH ofChara braunii.J. Exp. Bot. 27:853–858
Saito, K., Senda, M. 1974. The effect of the external pH on the membrane potential ofNitella and its linkage to metabolism.Plant Cell Physiol. 15:1045–1052
Saito, K., Senda, M. 1974. The electrogenic ion pump revealed by the external pH effect on the membrane potential ofNitella. Influences of external ions and electric current on the pH effect.Plant Cell Physiol. 15:1007–1016
Spanswick, R.M. 1972. Evidence for an electrogenic ion pump inNitella translucens.Biochim. Biophys. Acta 288:73–89
Walker, N.A. 1980. The transport systems of charophyte and chlorophyte giant algae and their integration into modes of behaviour.In: Plant Membrane Transport: Current Conceptual Issues. R.M. Spanswick, W.J. Lucas, and J. Dainty, editors. pp. 287–300. Elsevier, Amsterdam
Walker, N.A., Smith, F.A., Beilby, M.J. 1979. Amino uniport at the plasmalemma of charophyte cells. II. Ratio of matter to charge transported and permeability of free base.J. Membrane Biol. 49:283–296
Wallen, D.G. 1973. Kinetics of amino acid influx intoNitella flexilis.J. Phycol. 9:148–152
Wallen, D.G. 1974. Glucose, fructose, and sucrose influx intoNitella flexilis.Can. J. Bot. 52:1–4
About this article
Cite this article
Barsoum, Y.H., Pickard, W.F. Radio-frequency rectification in electrogenic and nonelectrogenic cells ofChara andNitella . J. Membrain Biol. 65, 81–87 (1982). https://doi.org/10.1007/BF01870471
- ion flux
- radio-frequency bioeffects
- transit time