Question

What is a periderm? How does periderm formation take place in dicots?

Answer 1

Dicots or dicotyledons are seeds which have two cotyledons or embryonic leaves. They come under angiosperms.

Complete Answer:
The cork cambium is the outermost lateral meristem found in woody plants. Periderm is formed towards the surface of roots and stems which have phelloderm, phellogen and phellem and these three together are known as the bark of the tree. It is a type of secondary growth which is seen in plants.

The phellogen is also known as cork cambium is a meristematic tissue which develops into a subepidermal layer which is found in the stem and in the root and undergoes bipolar division. The cells which are present on the outer layer undergo the process of suberization followed by tannin deposition and the cellular contents present in the cell die.

The outer layer consisting of the dead cells is known as phellem or cork. In certain places, it consists of aerating pores or lenticels which have loosely arranged suberised complementary cells.

The cells which are formed by phellogen on the inner side are known as phelloderm or secondary cortex.

So, this is how the periderm formation takes place in dicots.

Additional information:
In plants growth can be of two types,

Primary growth - Apical meristem
Secondary growth - Lateral meristem

Note: Periderm comes under secondary growth. The secondary growth of plants basically increases the girth of the stem due to lateral stems. There are two types of tissues involved,

Vascular cambium
Cork cambium