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Measurement of intracellular potassium activity in protoplasts of Acer pseudoplatanus: origin of their electropositivity
Author(s) -
Cornel D.,
Grig C.,
Rona J. P.,
Heller R.
Publication year - 1983
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1983.tb00900.x
Subject(s) - protoplast , acer pseudoplatanus , potassium , intracellular , extracellular , microelectrode , biophysics , efflux , dilution , chemistry , membrane potential , ouabain , biochemistry , sodium , biology , physics , organic chemistry , electrode , thermodynamics
Membrane resistances, electrical potentials and intracellular K + activity have been studied in protoplasts of Acer pseudoplatanus L. using microelectrodes. The plasmalemma appears to be damaged during protoplast processing, so that it is almost completely depolarized. The positive polarization of the protoplasts is a property of their tonoplast. The osmotic shock of general dilution of the medium brings about a slight positive polarization of the protoplasts, which probably is the consequence of a dilution of the ionic contents of the cell. A rapid dilution of extracellular potassium produces the same effect by a considerable efflux of K + , which changes the concentration gradient so that electropositivity is accentuated. In general, certain states of shock can cause such polarization. These results, particularly the development of internal potassium activity, help in understanding the initial cause of the positive polarization that is sometimes observed in protoplasts.