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Amyloplasts that sediment in protonemata of the moss Ceratodon purpureus are nonrandomly distributed in microgravityLittle is known about whether or how plant cells regulate the position of heavy organelles that sediment toward gravity. Dark-grown protonemata of the moss Ceratodon purpureus displays a complex plastid zonation in that only some amyloplasts sediment along the length of the tip cell. If gravity is the major force determining the position of amyloplasts that sediment, then these plastids should be randomly distributed in space. Instead, amyloplasts were clustered in the subapical region in microgravity. Cells rotated on a clinostat on earth had a roughly similar non-random plastid distribution. Subapical clusters were also found in ground controls that were inverted and kept stationary, but the distribution profile differed considerably due to amyloplast sedimentation. These findings indicate the existence of as yet unknown endogenous forces and mechanisms that influence amyloplast position and that are normally masked in stationary cells grown on earth. It is hypothesized that a microtubule-based mechanism normally compensates for g-induced drag while still allowing for regulated amyloplast sedimentation.
Document ID
20040112485
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Kern, V. D.
(Ohio State University Columbus, Ohio 43210, United States)
Smith, J. D.
Schwuchow, J. M.
Sack, F. D.
Date Acquired
August 21, 2013
Publication Date
April 1, 2001
Publication Information
Publication: Plant physiology
Volume: 125
Issue: 4
ISSN: 0032-0889
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
Non-NASA Center
Flight Experiment
STS-87 Shuttle Project
NASA Discipline Plant Biology
manned
short duration
NASA Experiment Number 9600005

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