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root graviresponsiveness and columella cell structure in carotenoid-deficient seedlings of zea maysRoot graviresponsiveness in normal and carotenoid-deficient mutant seedlings of Zea mays was not significantly different. Columella cells in roots of mutant seedlings were characterized by fewer, smaller, and a reduced relative volume of plastids as compared to columella cells of normal seedlings. Plastids in columella cells of mutant seedlings possessed reduced amounts of starch. Although approximately 10 per cent of the columella cells in mutant seedlings lacked starch, their plastids were located at the bottom of the cell. These results suggest that (i) carotenoids are not necessary for root gravitropism, (ii) graviresponsiveness is not necessarily proportional to the size, number, or relative volume of plastids in columella cells, and (iii) sedimentation of plastids in columella cells may not result directly from their increased density due to starch content. Plastids in columella cells of normal and mutant seedlings were associated with bands of microtubule-like structures, suggesting that these structures may be involved in 'positioning' plastids in the cell.
Document ID
20040089635
Document Type
Reprint (Version printed in journal)
Authors
Moore, R.
(Baylor University Waco, Texas 76798, United States)
McClelen, C. E.
Date Acquired
August 21, 2013
Publication Date
January 1, 1985
Publication Information
Publication: Annals of botany
Volume: 56
ISSN: 0305-7364
Subject Category
Life Sciences (General)
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Number 40-10
Non-NASA Center
NASA Program Space Biology
NASA Discipline Plant Biology