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Hydrostatic pressure mimics gravitational pressure in characean cellsHydrostatic pressure applied to one end of a horizontal Chara cell induces a polarity of cytoplasmic streaming, thus mimicking the effect of gravity. A positive hydrostatic pressure induces a more rapid streaming away from the applied pressure and a slower streaming toward the applied pressure. In contrast, a negative pressure induces a more rapid streaming toward and a slower streaming away from the applied pressure. Both the hydrostatic pressure-induced and gravity-induced polarity of cytoplasmic streaming respond identically to cell ligation, UV microbeam irradiation, external Ca2+ concentrations, osmotic pressure, neutral red, TEA Cl-, and the Ca2+ channel blockers nifedipine and LaCl3. In addition, hydrostatic pressure applied to the bottom of a vertically-oriented cell can abolish and even reverse the gravity-induced polarity of cytoplasmic streaming. These data indicate that both gravity and hydrostatic pressure act at the same point of the signal transduction chain leading to the induction of a polarity of cytoplasmic streaming and support the hypothesis that characean cells respond to gravity by sensing a gravity-induced pressure differential between the cell ends.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Staves, M. P. (Cornell University Ithaca, New York, United States)
Wayne, R.
Leopold, A. C.
Date Acquired
August 21, 2013
Publication Date
January 1, 1992
Publication Information
Publication: Protoplasma
Volume: 168
Issue: 3-4
ISSN: 0033-183X
Subject Category
Life Sciences (General)
Distribution Limits
NASA Discipline Number 40-50
NASA Discipline Plant Biology
Non-NASA Center
NASA Program Space Biology