The pericycle is a cylinder of

parenchyma Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms. Etymology The term ''parenchyma'' is New Latin from the word � ...

or sclerenchyma cells that lies just inside the

endodermis The endodermis is the central, innermost layer of cortex in land plants. It is a cylinder of compact living cells, the radial walls of which are impregnated with hydrophobic substances (Casparian strip) to restrict apoplastic flow of water to th ...

and is the outer most part of the

stele A stele ( ),Anglicized plural steles ( ); Greek plural stelai ( ), from Greek language, Greek , ''stēlē''. The Greek plural is written , ''stēlai'', but this is only rarely encountered in English. or occasionally stela (plural ''stelas'' or ...

of plants. Although it is composed of non-vascular parenchyma cells, it's still considered part of the vascular cylinder because it arises from the procambium as do the vascular tissues it surrounds. In

eudicots The eudicots, Eudicotidae, or eudicotyledons are a clade of flowering plants mainly characterized by having two seed leaves upon germination. The term derives from Dicotyledons. Traditionally they were called tricolpates or non-magnoliid dicot ...

, it also has the capacity to produce lateral roots. Branch roots arise from this primary

meristem The meristem is a type of tissue found in plants. It consists of undifferentiated cells (meristematic cells) capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants. These cells conti ...

tissue. In plants undergoing secondary growth, the pericycle contributes to the

vascular cambium The vascular cambium is the main growth tissue in the stems and roots of many plants, specifically in dicots such as buttercups and oak trees, gymnosperms such as pine trees, as well as in certain other vascular plants. It produces secondary xy ...

often diverging into a

cork cambium Cork cambium (pl. cambia or cambiums) is a tissue found in many vascular plants as a part of the epidermis. It is one of the many layers of bark, between the cork and primary phloem. The cork cambium is a lateral meristem and is responsible for ...

. In

angiosperms Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants ...

certain molecules within the

and the surrounding vasculature are sent to the pericycle which promotes the growth of the root

Location

The pericycle is located between the endodermis and phloem in plant roots. In dicot stems, it is situated around the ring of vascular bundles in the stele.

Function

In dicot roots, the pericycle strengthens the roots and provides protection for the

vascular bundle A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in the stem, which exists in two forms: xylem and phloem. Both these tissues are present in a vascular bundle, which in addition will inc ...

s. In dicot root, the vascular cambium is completely secondary in origin, and it originates from a portion of pericycle tissue. The pericycle regulates the formation of lateral roots by rapidly dividing near the xylem elements of the root. It has been known to often be confused with other parts of the plant. However, its unique ring structure allows it to be more easily identified. Past efforts to isolate such tissue have been successful. Monocot roots rarely branch, but can, and this branch will originate from the pericycle.

References

Plant morphology {{botany-stub