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Chloride uptake by oat coleoptile parenchyma described by combined influx and efflux transport systems


Babourina, OK and Knowles, AE and Newman, IA, Chloride uptake by oat coleoptile parenchyma described by combined influx and efflux transport systems, Australian Journal of Plant Physiology, 25, (8) pp. 929-936. ISSN 0310-7841 (1998) [Refereed Article]

DOI: doi:10.1071/PP98100


Chloride fluxes for oat coleoptile parenchyma were measured using the MIFE system for non-invasive microelectrode ion flux measurement. The effects on chloride fluxes of membrane potential, external chloride concentration, pH, cation composition of the bathing solution, and the anion channel blocker anthracene-9-carboxylic acid were studied. From the experimental data we propose that the step-like appearance of the chloride uptake curve at concentrations higher than 1 mm is due to combined activity of influx and efflux systems. According to this hypothesis the uptake of chloride ions is made by a pH sensitive active transport system with V(max) = 4000 nmol m-2 s-, K(m) = 7 mM [Cl-]. Chloride ions are released from the cell through channels with Gaussian type kinetics, the characteristics of which are dependent upon the external bathing solution: V(max) = -2300 nmol m-2 s-1 at 25 mM [Cl-] for CaCl2, and V(max) = -2000 nmol m-2 s-1 at 15 mM [Cl-] for KCl; with both curves having the same width of 17 mM [Cl-].

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Medical and biological physics
Research Field:Biological physics
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Babourina, OK (Dr Olga Babourina)
UTAS Author:Knowles, AE (Mr Andrew Knowles)
UTAS Author:Newman, IA (Dr Ian Newman)
ID Code:14499
Year Published:1998
Web of Science® Times Cited:8
Deposited By:Physics
Deposited On:1998-08-01
Last Modified:2011-08-09

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