Inhibitors of cell division and protoplasmic streaming fail to cause a detectable effect on intracellular calcium levels in stamen-hair cells of Tradescantia virginiana L

The herbicides amiprophos-methyl (APM) and oryzalin disrupt mitosis and cytokinesis in plant cells by causing the depolymerization of microtubules. These drugs have also been shown to affect calcium sequestration by mitochondria. Controversy thus exists as to whether microtubule depolymerization occ...

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Bibliographic Details
Published inPlanta Vol. 186; no. 3; p. 361
Main Authors Keifer, A.O. (Massachusetts Univ., Amherst (USA). Dept. of Botany), Callaham, D.A, Hepler, P.K
Format Journal Article
LanguageEnglish
Published Germany 01.02.1992
Subjects
ANDROCEE
ANDROCEO
ANDROECIUM
CALCIO
CALCIUM
Calciumgehalt
CELL DIVISION
Chemikalie
COMMELINACEAE
Cytoplasma-Organellen
CYTOPLASMIC ORGANELLES
DIVISION CELLULAIRE
DIVISION CELULAR
HERBICIDAS
HERBICIDE
HERBICIDES
Herbizid
ORGANITE CELLULAIRE
ORGANULOS CITOPLASMATICOS
PLANTAS DE MACETAS
PLANTE EN POT
POT PLANTS
Stamen
Tradescantia
Zelle
Zellteilung
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Summary:The herbicides amiprophos-methyl (APM) and oryzalin disrupt mitosis and cytokinesis in plant cells by causing the depolymerization of microtubules. These drugs have also been shown to affect calcium sequestration by mitochondria. Controversy thus exists as to whether microtubule depolymerization occurs as a result of direct interaction between the drug and tubulin, or because of elevated intracellular calcium levels resulting from drug interference with calcium regulation. In order to clarify this issue we have directly measured the effect of these herbicides and other cell-motility-altering drugs on intracellular calcium levels in stamen-hair cells of Tradescantia. The results indicate that low levels (1-3 μM) of APM and oryzalin can act within 3-7 min causing disorganization of mitosis. Studies using the calcium indicator indo-1 injected into stamen-hair cells to monitor internal levels of calcium, show that at drug concentrations where inhibitory effects on mitosis and-or cytokinesis are clearly seen, APM, oryzalin, isopropyl-N-phenyl carbamate, caffeine and cytochalasin D produce no change in intracellular calcium levels. Furthermore, except for cytochalasin D, these drugs do not inhibit cytoplasmic streaming, a calcium-sensitive process. We conclude that the mode of action of these drugs on the cytoskeleton is independent of an effect on intracellular calcium.
Bibliography:F62
92G0177
ISSN:0032-0935
1432-2048
DOI:10.1007/BF00195316