Document Detail

Differential ion accumulation and ion fluxes in the mesophyll and epidermis of barley.
MedLine Citation:
PMID:  10712547     Owner:  NLM     Status:  MEDLINE    
In barley (Hordeum vulgare L.) leaves, differential ion accumulation commonly results in inorganic phosphate (Pi) being confined to the mesophyll and Ca(2+) to the epidermis, with preferential epidermal accumulation of Cl(-), Na(+), and some other ions. The pattern was confirmed in this study for major inorganic anions and cations by analysis of barley leaf protoplasts. The work focused on the extent to which differences in plasma membrane ion transport processes underlie these observations. Ion transport across the plasma membrane of barley epidermal and mesophyll protoplasts was investigated electrophysiologically (by microelectrode impalement and patch clamping) and radiometrically. Data from both approaches suggested that similar types of ion-selective channels and membrane transporters, which catalyze the transport of Ca(2+), K(+), Na(+), and Pi, exist in the plasma membrane of the two cell types. In general, the simple presence or absence of ion transporters could not explain cell-type-specific differences in ion accumulation. However, patch-clamp data suggested that differential regulation of instantaneously activating ion channels in the plasma membrane could explain the preferential accumulation of Na(+) in the epidermis.
A J Karley; R A Leigh; D Sanders
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Plant physiology     Volume:  122     ISSN:  0032-0889     ISO Abbreviation:  Plant Physiol.     Publication Date:  2000 Mar 
Date Detail:
Created Date:  2000-05-25     Completed Date:  2000-05-25     Revised Date:  2013-04-16    
Medline Journal Info:
Nlm Unique ID:  0401224     Medline TA:  Plant Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  835-44     Citation Subset:  IM    
Department of Biology, University of York, P.O. Box 373, York YO10 5YW, United Kingdom.
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MeSH Terms
Calcium / metabolism
Cell Membrane / metabolism
Hordeum / metabolism*
Ion Channels / metabolism
Ion Transport
Membrane Potentials
Patch-Clamp Techniques
Phosphates / metabolism
Plant Leaves / metabolism
Potassium / metabolism
Protoplasts / metabolism
Sodium / metabolism
Reg. No./Substance:
0/Ion Channels; 0/Phosphates; 7440-09-7/Potassium; 7440-23-5/Sodium; 7440-70-2/Calcium

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