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Influence of microgravity on root-cap regeneration and the structure of columella cells in Zea maysWe launched imbibed seeds and seedlings of Zea mays into outer space aboard the space shuttle Columbia to determine the influence of microgravity on 1) root-cap regeneration, and 2) the distribution of amyloplasts and endoplasmic reticulum (ER) in the putative statocytes (i.e., columella cells) of roots. Decapped roots grown on Earth completely regenerated their caps within 4.8 days after decapping, while those grown in microgravity did not regenerate caps. In Earth-grown seedlings, the ER was localized primarily along the periphery of columella cells, and amyloplasts sedimented in response to gravity to the lower sides of the cells. Seeds germinated on Earth and subsequently launched into outer space had a distribution of ER in columella cells similar to that of Earth-grown controls, but amyloplasts were distributed throughout the cells. Seeds germinated in outer space were characterized by the presence of spherical and ellipsoidal masses of ER and randomly distributed amyloplasts in their columella cells. These results indicate that 1) gravity is necessary for regeneration of the root cap, 2) columella cells can maintain their characteristic distribution of ER in microgravity only if they are exposed previously to gravity, and 3) gravity is necessary to distribute the ER in columella cells of this cultivar of Z. mays.
Document ID
20040089821
Document Type
Reprint (Version printed in journal)
Authors
Moore, R. (Baylor University Waco, Texas 76798, United States)
McClelen, C. E.
Fondren, W. M.
Wang, C. L.
Date Acquired
August 21, 2013
Publication Date
January 1, 1987
Publication Information
Publication: American journal of botany
Volume: 74
Issue: 2
ISSN: 0002-9122
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 00-00
short duration
NASA Discipline Number 40-10
manned
NASA Discipline Plant Biology
STS-61C Shuttle Project
NASA Program Space Biology
Flight Experiment
Non-NASA Center
NASA Program Flight