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A pharmacological analysis of high-affinity sodium transport in barley (Hordeum vulgare L.): a (24)Na(+)/(42)K(+) study
Soil sodium, while toxic to most plants at high concentrations, can be beneficial at low concentrations, particularly when potassium is limiting. However, little is known about Na(+) uptake in this ‘high-affinity’ range. New information is provided here with an insight into the transport characteris...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2012
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3346217/ https://www.ncbi.nlm.nih.gov/pubmed/22268152 http://dx.doi.org/10.1093/jxb/err419 |
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author | Schulze, Lasse M. Britto, Dev T. Li, Mingyuan Kronzucker, Herbert J. |
author_facet | Schulze, Lasse M. Britto, Dev T. Li, Mingyuan Kronzucker, Herbert J. |
author_sort | Schulze, Lasse M. |
collection | PubMed |
description | Soil sodium, while toxic to most plants at high concentrations, can be beneficial at low concentrations, particularly when potassium is limiting. However, little is known about Na(+) uptake in this ‘high-affinity’ range. New information is provided here with an insight into the transport characteristics, mechanism, and ecological significance of this phenomenon. High-affinity Na(+) and K(+) fluxes were investigated using the short-lived radiotracers (24)Na and (42)K, under an extensive range of measuring conditions (variations in external sodium, and in nutritional and pharmacological agents). This work was supported by electrophysiological, compartmental, and growth analyses. Na(+) uptake was extremely sensitive to all treatments, displaying properties of high-affinity K(+) transporters, K(+) channels, animal Na(+) channels, and non-selective cation channels. K(+), [Formula: see text] NH(4)(+), and Ca(2+) suppressed Na(+) transport biphasically, yielding IC(50) values of 30, 10, and <5 μM, respectively. Reciprocal experiments showed that K(+) influx is neither inhibited nor stimulated by Na(+). Sodium efflux constituted 65% of influx, indicating a futile cycle. The thermodynamic feasibility of passive channel mediation is supported by compartmentation and electrophysiological data. Our study complements recent advances in the molecular biology of high-affinity Na(+) transport by uncovering new physiological foundations for this transport phenomenon, while questioning its ecological relevance. |
format | Online Article Text |
id | pubmed-3346217 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2012 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-33462172012-05-07 A pharmacological analysis of high-affinity sodium transport in barley (Hordeum vulgare L.): a (24)Na(+)/(42)K(+) study Schulze, Lasse M. Britto, Dev T. Li, Mingyuan Kronzucker, Herbert J. J Exp Bot Research Papers Soil sodium, while toxic to most plants at high concentrations, can be beneficial at low concentrations, particularly when potassium is limiting. However, little is known about Na(+) uptake in this ‘high-affinity’ range. New information is provided here with an insight into the transport characteristics, mechanism, and ecological significance of this phenomenon. High-affinity Na(+) and K(+) fluxes were investigated using the short-lived radiotracers (24)Na and (42)K, under an extensive range of measuring conditions (variations in external sodium, and in nutritional and pharmacological agents). This work was supported by electrophysiological, compartmental, and growth analyses. Na(+) uptake was extremely sensitive to all treatments, displaying properties of high-affinity K(+) transporters, K(+) channels, animal Na(+) channels, and non-selective cation channels. K(+), [Formula: see text] NH(4)(+), and Ca(2+) suppressed Na(+) transport biphasically, yielding IC(50) values of 30, 10, and <5 μM, respectively. Reciprocal experiments showed that K(+) influx is neither inhibited nor stimulated by Na(+). Sodium efflux constituted 65% of influx, indicating a futile cycle. The thermodynamic feasibility of passive channel mediation is supported by compartmentation and electrophysiological data. Our study complements recent advances in the molecular biology of high-affinity Na(+) transport by uncovering new physiological foundations for this transport phenomenon, while questioning its ecological relevance. Oxford University Press 2012-04 2012-01-20 /pmc/articles/PMC3346217/ /pubmed/22268152 http://dx.doi.org/10.1093/jxb/err419 Text en © 2012 The Author(s). http://creativecommons.org/licenses/by-nc/3.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details) |
spellingShingle | Research Papers Schulze, Lasse M. Britto, Dev T. Li, Mingyuan Kronzucker, Herbert J. A pharmacological analysis of high-affinity sodium transport in barley (Hordeum vulgare L.): a (24)Na(+)/(42)K(+) study |
title | A pharmacological analysis of high-affinity sodium transport in barley (Hordeum vulgare L.): a (24)Na(+)/(42)K(+) study |
title_full | A pharmacological analysis of high-affinity sodium transport in barley (Hordeum vulgare L.): a (24)Na(+)/(42)K(+) study |
title_fullStr | A pharmacological analysis of high-affinity sodium transport in barley (Hordeum vulgare L.): a (24)Na(+)/(42)K(+) study |
title_full_unstemmed | A pharmacological analysis of high-affinity sodium transport in barley (Hordeum vulgare L.): a (24)Na(+)/(42)K(+) study |
title_short | A pharmacological analysis of high-affinity sodium transport in barley (Hordeum vulgare L.): a (24)Na(+)/(42)K(+) study |
title_sort | pharmacological analysis of high-affinity sodium transport in barley (hordeum vulgare l.): a (24)na(+)/(42)k(+) study |
topic | Research Papers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3346217/ https://www.ncbi.nlm.nih.gov/pubmed/22268152 http://dx.doi.org/10.1093/jxb/err419 |
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