pericyclet

The pericycle is a layer of cells in vascular plants located just internal to the endodermis and external to the vascular tissues. It is a region of undifferentiated cells that can contribute to secondary growth and the formation of lateral roots. In dicotyledonous plants, the pericycle is typically a single layer of parenchyma cells, while in monocots, it may be several cell layers thick and can include sclerenchyma.

The primary function of the pericycle is to give rise to lateral roots. These roots originate endogenously, meaning they develop from within the parent root. The pericycle cells dedifferentiate, divide, and form a new meristematic tissue called the lateral root primordium. This primordium then grows outward through the cortex and epidermis to emerge as a new root.

In plants that undergo secondary growth, the pericycle also contributes to the vascular cambium and, in some cases, the cork cambium. It can divide to form new xylem and phloem, increasing the diameter of the stem or root. The extent and nature of pericyclic contribution to secondary growth vary among plant species. The presence and characteristics of the pericycle are important features used in plant anatomy and identification.