Collenchyma is a supportive tissue of vascular plants that is mainly found in young organs and organs that grow upwards (stems, petiole, etc.).
The cells of this living tissue are characterised by very thick cellulose walls, a single, voluminous vacuole and a generally fusiform shape. This tissue gives a plant support and elasticity.
Different types of collenchyma
Depending on the thickness of this wall there are:
- annular collenchyma, with uniform cellulose deposits on the wall. This type of collenchyma rigidifies certain stems and petioles;
- angular collenchyma, where the thickening of the cellulose is concentrated in the corners of the wall;
- tangential collenchyma, where only the tangential walls, those parallel to the external surface, are thickened. This type of collenchyma is found in the bark of branches.
A cross section of a pumpkin stem. The cellular layer located under the epidermis is collenchyma. © BlueRidgeKitties CC by-nc-sa 2.0