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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)
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.