Na+/H+ antiport activity in tonoplast vesicles from roots of the salt-tolerant Plantago maritima and the salt-sensitive Plantago media |
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Authors: | Marten Staal Frans J. M. Maathuis J. Theo M. Elzenga J. Hans M. Overbeek Hidde B. A. Prins |
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Affiliation: | Dept of Plant Biology, Ecotrans, Univ. of Groningen, PO Box 14, 9750 AA Haren, The Netherlands;Dept of Botany, KB 15, Univ. of Washington, Seattle, WA 98195, USA;Centre for Agrobiological Research, PO Box 14, 6700 AA Wageningen, The Netherlands;. |
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Abstract: | Plantago species differ in their strategy towards salt stress, a major difference being the uptake and distribution of Na+ ions. A salt-sensitive ( Plantago media L.) and a salt-tolerant ( P. maritima L.) species were compared with respect to Na+/H+ antiport activities at the tonoplast. After exposure of the plants to 50 m M NaCl for 6 days isolated tonoplast vesicles of P. maritima showed Na+/H+ antiport activity with saturation kinetics and a Km of 2.4 m M Na+, NaCl-grown P. media and the control plants of both species showed no antiport activity. Selectivity of the antiport system for Na+ was high and was determined by adding different chloride salts after formation of a Δ pH in the vesicles. Specific tonoplast ATPase activities were similar in the two species and did not alter after exposure to NaCl stress. |
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Keywords: | Plantago maritima Plantago media proton-sodium antiport salt tolerance tonoplast |
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