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Regulation of electrical coupling between Arabidopsis root hairs

Regulation of electrical coupling between Arabidopsis root hairs Voltage clamp was used to measure the voltage dependence of cell-to-cell coupling via plasmodesmata between higher-plant cells (root hairs of Arabidopsis thaliana (L.) Heynh.). In addition, ionophoresis was used to introduce a variety of ions [Ca2+, inositol-trisphosphate, Li+, K+, Mg2+, ethylene glycol-bis(β-aminoethyl ether)-N,N,N′, N′-tetraacetic acid (EGTA), 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA), H+, and OH−] to examine whether they regulate cell-to-cell coupling. Electrical coupling showed high variability in this single cell type at the same developmental stage; the coupling ratio ranged from near 0% to about 90% with a mean value of 32%. It was voltage independent for intracellular voltage gradients (transplasmodesmatal) of -163 to 212 mV. While Ca2+ closes the plasmodesmatal connections (at concentrations higher than those causing cessation of cytoplasmic streaming), inositol-trisphosphate and lithium are without effect. Apparently, inositol-trisphosphate may not cause increased cytosolic Ca2+ in root hairs. Alkalinization by OH ionophoresis caused a modest decline in cell-to-cell coupling, as did acidification by H+ ionophoresis (to an extent causing the cell to become flacid). Increases in cytosolic K+, Mg2+, and the calcium chelator BAPTA by ionophoresis had no effect on cell-to-cell coupling. The regulation (and lack thereof) reported here for plant plasmodesmata is quite similar to that of gap junctions. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Planta Springer Journals

Regulation of electrical coupling between Arabidopsis root hairs

Lew, Roger
Planta , Volume 193 (1) – Jul 12, 2004
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References (30)

Publisher
Springer Journals
Copyright
Copyright © 1994 by Springer-Verlag
Subject
Life Sciences; Plant Sciences; Agriculture; Ecology; Forestry
ISSN
0032-0935
eISSN
1432-2048
DOI
10.1007/BF00191608
Publisher site
See Article on Publisher Site

Abstract

Voltage clamp was used to measure the voltage dependence of cell-to-cell coupling via plasmodesmata between higher-plant cells (root hairs of Arabidopsis thaliana (L.) Heynh.). In addition, ionophoresis was used to introduce a variety of ions [Ca2+, inositol-trisphosphate, Li+, K+, Mg2+, ethylene glycol-bis(β-aminoethyl ether)-N,N,N′, N′-tetraacetic acid (EGTA), 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA), H+, and OH−] to examine whether they regulate cell-to-cell coupling. Electrical coupling showed high variability in this single cell type at the same developmental stage; the coupling ratio ranged from near 0% to about 90% with a mean value of 32%. It was voltage independent for intracellular voltage gradients (transplasmodesmatal) of -163 to 212 mV. While Ca2+ closes the plasmodesmatal connections (at concentrations higher than those causing cessation of cytoplasmic streaming), inositol-trisphosphate and lithium are without effect. Apparently, inositol-trisphosphate may not cause increased cytosolic Ca2+ in root hairs. Alkalinization by OH ionophoresis caused a modest decline in cell-to-cell coupling, as did acidification by H+ ionophoresis (to an extent causing the cell to become flacid). Increases in cytosolic K+, Mg2+, and the calcium chelator BAPTA by ionophoresis had no effect on cell-to-cell coupling. The regulation (and lack thereof) reported here for plant plasmodesmata is quite similar to that of gap junctions.

Journal

Planta – Springer Journals

Published: Jul 12, 2004

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