Journal Article

Temporal Relationship between Cytosolic Free Ca<sup>2+</sup> and Membrane Potential during Hypotonic Turgor Regulation in a Brackish Water Charophyte <i>Lamprothamnium succinctum</i>

Yoshiji Okazaki, Mitsuo Ishigami and Naohiko Iwasaki

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 43, issue 9, pages 1027-1035
Published in print September 2002 | ISSN: 0032-0781
Published online September 2002 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pcf127
Temporal Relationship between Cytosolic Free Ca2+ and Membrane Potential during Hypotonic Turgor Regulation in a Brackish Water Charophyte Lamprothamnium succinctum

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Internodal cells of a brackish water charophyte, Lamprothamnium succinctum, regulate turgor pressure in response to changes in external osmotic pressure by modifying vacuolar concentrations of KCl. An increase in cytosolic concentration of free Ca2+ ([Ca2+]c) is necessary for the progress of turgor regulation induced by hypotonic treatment. Initial changes in membrane potential and [Ca2+]c upon hypotonic treatment were measured to examine the temporal relationship between the two parameters. Fura-dextran (potassium salt, Mr 10,000, anionic) that had been injected into the cytosol was used to measure [Ca2+]c. Membrane potential and membrane conductance under a current-clamp condition were also measured. Decrease in external osmotic pressure by 0.16 Osm induced a simultaneous increase in [Ca2+]c with both depolarization of the membrane and increase in the membrane conductance. Decrease in external osmotic pressure by 0.05 Osm induced a simultaneous increase in [Ca2+]c with membrane depolarization but the increase in membrane conductance started later than the other two processes. There was a close temporal relationship between the increase in [Ca2+]c and membrane depolarization on the initial response of turgor regulation induced by hypotonic treatment.

Keywords: Keywords: Cytoplasmic streaming — Cytosolic Ca2+ — Lamprothamnium — Membrane conductance — Membrane potential — Turgor regulation.; Abbreviations: ASW, artificial sea water; [Ca2+]c, cytosolic concentration of free Ca2+; [Ca2+]e, external concentration of Ca2+; FD, fura-dextran; EGTA, O,O′-bis(2-aminoethyl) ethyleneglycol-N,N,N′,N′-tetraacetic acid; PIPES, piperazine-N-N′-bis(2-methanesulfonic acid).

Journal Article.  5327 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.