ISSN:
1432-2048
Keywords:
Arabidopsis (root hairs)
;
Calcium
;
Electrical coupling of cells (pH, voltage)
;
Inositol trisphosphate
;
Plasmodesma
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
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.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00191608
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