Question

Periderm is made up of
A) Phellem
B) Phellogen
C) Phelloderm
D) All of the above

Answer 1

Hint: Periderm basically consists of cork cambium, suberized cells and parenchyma-like cells that are derived from the cork cambium. Periderm acts as a defensive line for the plants and protects woods from the abiotic and biotic stresses.

Complete Answer:
Periderm is the cylindrical tissue and acts as a protective or outer layer that absorb many of the nutrients from the amniotic fluid to supply epidermal demands. It is formed on the surface of stems and roots of the plant.

Periderm composed of phellem, phellogen and phelloderm.
(i) Phellem are also called suberized cells which develop outside of the plant. They protect plants from the penetration, ingestion by animals, temperature changes, excessive evaporation etc. There are two types of phellem i.e. soft and hard. Hard phellem has thick walls and soft phellem has thin walls.
(ii) Phellogen is also called cork cambium and it is the meristematic layer that is responsible for the development of periderm. They also provide mechanical strength to the phloem and xylem tissue.
(iii) The phelloderm are the parenchyma-like cells which are derived from the phellogen. They are very thin and form the secondary cortex. Phelloderm is present inside of cork cambium.

Thus, the correct answer is option D i.e., All of the above.

Note: The word periderm means “around or about the skin”. Therefore, it is an outer protective layer. It replaces the epidermis in the plant body and protects the plant from mechanical damage, climatic changes, heat injury, etc. So, periderm is composed of 3 parts: phellem, phelloderm, phellogen.