Endodermis


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Endodermis

The single layer of plant cells that is located between the cortex and the vascular (xylem and phloem) tissues. It has its most obvious development in roots and subaerial stems. The endodermis has many apparent functions: absorption of water, selection of solutes and ions, and production of oils, antibiotic phenols, and acetylenic acids.

The endodermis has been found to have extra sets of chromosomes as compared with cortical and other cells in the plant. In some plants the chromosome numbers may be so high in the endodermis that four sets of chromosomes may occur in each endodermal cell. The larger amount of nuclear material and nucleic acid in the cells of the endodermis may in part account for the great capacity of endodermal cells to produce large amounts of chemical substances, such as acetylenic oils, high in caloric energy. See Cortex (plant)

Endodermis

 

the innermost single-row layer of compact parenchymatous cells of the primary cortex adjacent to the central cylinder of the axial organs of higher plants. The endodermis is not highly differentiated in stems and usually contains secondary starch. In the roots, the radial and transverse walls of the endodermal cells have bandlike thickenings containing suberin and lignin. The cells involved in the exchange of molecules remain thin-walled. Thus, the endodermis is a physiological barrier that regulates the entry of water and ions from the primary cortex to the central cylinder of the root.

endodermis

[¦en·dō¦dər·məs]
(botany)
The innermost tissue of the cortex of most plant roots and certain stems consisting of a single layer of at least partly suberized or cutinized cells; functions to control the movement of water and other substances into and out of the stele.
References in periodicals archive ?
1997) resaltaron el caracter secretor de la endodermis.
Small and medium-sized veins are immersed in the mesophyll and present endodermis (bundle sheath).
the endodermis, the inner two-thirds of the cortex is crushed, and the
Leaf anatomy of Bonnetiaceae, including observations on a foliar endodermis.
At the costa, there is a central, parenchymatose area, surrounded by an endodermis with Casparian strips, with conducting tissues; xylem assumes the shape of an open V, and scarce phloem develops at the ends of the xylem arms.
Thus, the endodermis of a nonaccumulator limits the movement of aluminum to the stele, whereas the endodermis of an hyperaccumulator does not.
Alrededor de las meristelas se presenta la endodermis, distintiva por las celulas rectangulares y la banda de Caspari en sus paredes radiales.
Endodermis in adult stem or axis: 0 = absent; 1 = present.
In contrast, the strongly reinforced, tertiary endodermis and the central cylinder are durable and have a considerable tensile strength.
Contact with adjoining strips seals the endodermis as a whole, and thus water and dissolved substances must enter the protoplast, which to some extent controls what passes in and out of the stele.
The cell layer in which roots are initiated apparently varies among species, from the immediate meristematic precursors of endodermis and outer stelar tissues (see von Guttenberg, 1966) or of the outer cortex (Stevenson, 1976a).