endodermis

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.

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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)