The root cap is a type of tissue at the tip of a plant root. [1] It is also called calyptra. Root caps contain statocytes which are involved in gravity perception in plants. [1] If the cap is carefully removed the root will grow randomly. The root cap protects the growing tip in plants. [1] It secretes mucilage to ease the movement of the root through soil, [1] and may also be involved in communication with the soil microbiota. [1]
The purpose of the root cap is to enable downward growth of the root, with the root cap covering the sensitive tissue in the root. [2] Thanks to the presence of statocytes, the root cap enables geoperception or gravitropism. This allows the plant to grow downwards (with gravity) or upwards (against gravity). [3]
The root cap is absent in some parasitic plants [4]: 138 and some aquatic plants, in which a sac-like structure called the root pocket may form instead. [5]: 2–76