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Changes in the distribution of plastids and endoplasmic reticulum during cellular differentiation in root caps of Zea maysIn calyptrogen cells of Zea mays, proplastids are distributed randomly throughout the cell, and the endoplasmic reticulum (ER) is distributed parallel to the cell walls. The differentiation of calyptrogen cells into columella statocytes is characterized by the following sequential events: (1) formation of ER complexes at the distal and proximal ends of the cell, (2) differentiation of proplastids into amyloplasts, (3) sedimentation of amyloplasts onto the distal ER complex, (4) breakdown of the distal ER complex and sedimentation of amyloplasts to the bottom of the cell, and (5) formation of sheets of ER parallel to the longitudinal cell walls. Columella statocytes located in the centre of the cap each possess 4530 +/- 780 micrometers2 of ER surface area, an increase of 670 per cent over that of calyptrogen cells. The differentiation of peripheral cells correlates positively with (1) the ER becoming arranged in concentric sheets, (2) amyloplasts and ER becoming randomly distributed, and (3) a 280 per cent increase in ER surface area over that of columella statocytes. These results are discussed relative to graviperception and mucilage secretion, which are functions of columella and peripheral cells, respectively.
Document ID
Document Type
Reprint (Version printed in journal)
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
NASA Discipline Number 40-10
NASA Discipline Plant Biology
NASA Program Space Biology
Non-NASA Center