par Lannoye, Robert ;Tarr, S.E. S.E.;Dainty, Jack
Référence Journal of Experimental Botany, 21, 3, page (543-551)
Publication Publié, 1970-08
Article révisé par les pairs
Résumé : The effects of pH on the resting and action potentials and on the fluxes of potassium, sodium, and chloride across the membranes of internodal cells of Chara australis have been investigated.Experiments were carried out in an artificial pond water (A.P.W.) of standard composition: CaCl 2, 01 mM; KCl, 0.1 mM; NaCl, 1.0 mM. The resting potential decreased as the pH was lowered from 6.5, being depolarized by about 75 mV at pH 4.5. Measurements of the ion fluxes as a function of pH suggested that this depolarization was caused by an increase in the permeability to sodium and a decrease in permeability to potassium at pH 4.5. Action potentials of constant peak value can be elicited for some time at pH 4.5, but after 20 min or so the cell becomes refractory. All these effects on resting and action potentials are fully reversible. We briefly speculate about the mechanism of these pH effects. © 1970 Oxford University Press.