The Formation of Cork Cambium in Dicot Roots

Cork cambium, also known as phellogen, is a type of lateral meristem that is responsible for the formation of the outer bark in dicot roots. It is derived from the pericycle, a layer of cells located just inside the endodermis.

Role of Pericycle
The pericycle is a specialized tissue found in the roots of vascular plants. It surrounds the central vascular cylinder and is responsible for the initiation and development of lateral roots. In dicot roots, the pericycle is also the source of cork cambium.

Formation of Cork Cambium
The formation of cork cambium in dicot roots occurs due to the activity of the pericycle. Here is a detailed explanation of the process:

1. Initial Stages: In the early stages of root development, the pericycle consists of a single layer of cells located just inside the endodermis. These cells are meristematic, meaning they have the ability to divide and give rise to new cells.

2. Periclinal Division: Under certain conditions, the pericycle cells start to divide periclinally, which means they divide parallel to the surface of the root. This periclinal division leads to the formation of a secondary meristem called the cork cambium.

3. Activity of Cork Cambium: The cork cambium is responsible for producing new cells both inwardly and outwardly. The cells produced inwardly are known as phelloderm, while the cells produced outwardly are called phellogen or cork.

4. Phelloderm Formation: The cells produced inwardly by the cork cambium differentiate into phelloderm. Phelloderm cells are parenchymatous in nature and function to provide mechanical support to the growing root.

5. Cork Formation: The cells produced outwardly by the cork cambium differentiate into cork cells. Cork cells are dead at maturity and are characterized by the deposition of a substance called suberin in their cell walls. Suberin makes the cork cells impermeable to water and gases, providing protection to the underlying tissues.

Conclusion
In dicot roots, the cork cambium is formed by the pericycle, a layer of cells located just inside the endodermis. The pericycle undergoes periclinal division to give rise to the cork cambium, which is responsible for the formation of phelloderm and cork cells. This process plays a crucial role in the development of the outer bark and provides protection to the root.

B) pericycle