Salt stress-induced chloride flux: a study using transgenic Arabidopsis expressing a fluorescent anion probe

Authors

  • Inken Lorenzen,

    1. Zentrum für Biochemie und Molekularbiologie, Universität Kiel, Am Botanischen Garten 9, 24118 Kiel, Germany, and
    2. Biochemisches Institut, Universität Kiel, Rudolf-Höber-Str. 1, 24098 Kiel, Germany
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  • Thomas Aberle,

    1. Zentrum für Biochemie und Molekularbiologie, Universität Kiel, Am Botanischen Garten 9, 24118 Kiel, Germany, and
    2. Biochemisches Institut, Universität Kiel, Rudolf-Höber-Str. 1, 24098 Kiel, Germany
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  • Christoph Plieth

    Corresponding author
    1. Zentrum für Biochemie und Molekularbiologie, Universität Kiel, Am Botanischen Garten 9, 24118 Kiel, Germany, and
      For correspondence (fax +49 431 880 4368; e-mail cplieth@zbm.uni-kiel.de).
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For correspondence (fax +49 431 880 4368; e-mail cplieth@zbm.uni-kiel.de).

Summary

Salt stress leads to massive accumulation of toxic levels of Na+ and Cl ions in plants. By using the recombinant fluorescent probe CLOMELEON, we demonstrate passive anion flux under salt stress. Chloride influx is restricted in the presence of divalent cations like Mg2+ and Ca2+, and completely blocked by La3+. The amount but not the rate of the reported chloride uptake is independent from the kind of corresponding permeable cation (K+ versus Na+), external pH and magnitude of osmotic stress. Cl efflux however seems to involve stretch-activated transport. From the influence of Ca2+ on reported changes of cytosolic anion concentrations, we speculate that transport mechanisms of Cl and Na+ might be thermodynamically coupled under saline conditions.

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