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THE MECHANISM OF CHLORIDE TRANSPORT IN CHARACEAN CELLS
Author(s) -
SMITH F. A.
Publication year - 1970
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1970.tb02470.x
Subject(s) - chemistry , ammonium , biophysics , efflux , chloride , ion transporter , electrochemical gradient , ammonium chloride , cell permeability , respiration , photosynthesis , biochemistry , membrane , botany , biology , organic chemistry
S ummary Active chloride uptake by cells of Chara corallina decreases as the pH of the bathing solution is increased, using a range of buffers. Superimposed on this effect, large stimulations of Cl − uptake can be obtained by the addition of imidazole and tris buffers or ammonium sulphate. ‘Stimulated’ or ‘normal’ Cl − influxes respond similarly to the presence of metabolic inhibitors. It is suggested that these effects are not due to changes in photosynthesis or respiration, but reflect the dependence of Cl − transport on the pH gradient across the plasmalemma. Possible ways in which Cl − transport might be linked to H + or OH − fluxes are discussed. It is proposed that the pH gradient across the plasmalemma is controlled by charge‐separating reactions which produce an active H + efflux, and that Cl − uptake is linked to OH − efflux by ion‐exchange reactions. The metabolic implications of this scheme are discussed in detail, with reference to previous work on Characean and other plant cells.