The root cap is a type of tissue at the tip of a plant

root In vascular plants, the roots are the plant organ, organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often bel ...

. It is also called calyptra. Root caps contain

statocyte Statocytes are gravity-sensing ( gravitropic) cells in higher plants. They contain amyloplasts-statoliths – starch-filled amyloplastic organelles – which sediment at the lowest part of the cells. In the roots, sedimentation of the statoliths ...

s which are involved in gravity perception in plants. If the cap is carefully removed the root will grow randomly. The root cap protects the growing tip in plants. It secretes

mucilage Mucilage is a thick gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion, with the direction of their movement always opposite to that of the secretion of ...

to ease the movement of the root through soil, and may also be involved in communication with the soil microbiota. 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. 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). The root cap is absent in some parasitic plants and some aquatic plants, in which a sac-like structure called the ''root pocket'' may form instead.

References

Plant anatomy {{Plant-morphology-stub