Root segments of Convolvulus arvensis, the field bindweed, were examined with the electron microscope to make possible a description of the fine structural correlates of lateral root protrusion through cortical parenchyma. Particular attention was directed to the outermost primordium cells, derived by meristematic activity from the endodermis, and to the contiguous cortical parenchyma cells. By following the fate of the Casparian strip through numerous divisions of the endodermal cell, information has been obtained relating to the minimum contribution of the endodermis to the root primordium structure. Cortical parenchyma cells during lateral root growth are specifically degraded so that only the cell wall remains. A layer of cell wall material, representing numerous cortical parenchyma cells, accrues at the tip of the advancing root primordium. It is suggested that the intensive coated-vesicle activity along the plasmalemma of the outermost primordium cell and the appearance of the vesicle contents in the outer wall of this cell are indicative of the secretion of hydrolases which move through the wall and attack the adjacent cortical parenchyma cells.
Article| January 01 1969
CORTICAL CELL DEATH DURING LATERAL ROOT FORMATION
Howard T. Bonnett, Jr.
From the Department of Biology, University of Oregon, Eugene, Oregon 97403
Received: May 22 1968
Revision Received: September 04 1968
Online ISSN: 1540-8140
Print ISSN: 0021-9525
Copyright © 1969 by The Rockefeller University Press.
Howard T. Bonnett; CORTICAL CELL DEATH DURING LATERAL ROOT FORMATION . J Cell Biol 1 January 1969; 40 (1): 144–159. doi: https://doi.org/10.1083/jcb.40.1.144
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