Unformatted text preview: Endodermis . The innermost layer of the cortex is the endodermis , which is readily identifiable by the presence of Casparian strips , bands of suberin present on transverse and radial walls of its cells—the walls perpendicular to the surface of the root. The endodermis regulates the passage of water and dissolved substances by forcing them to move through living plasma membranes and plasmodesmata and not simply diffuse through the porous cell walls. The absorption and translocation of materials is thus selective; not everything in the surrounding soil gets through and into the plant body. An endodermis almost always is present in roots and generally never in stems. Storage parenchyma . The bulk of the cortex consists of thin-walled, living parenchyma cells, which store starch and other substances. The cells expand or shrink as materials move in and out of their and other substances....
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This note was uploaded on 11/14/2011 for the course BIO 1421 taught by Professor Farr during the Fall '08 term at Texas State.
- Fall '08