Question

Epidermal tissue system is derived from
a. Protoderm
b. Procambium
c. Periblem
d. Plerome

Answer 1

Hint: The epidermal tissue system forms the outermost covering of the plant body. It consists of Epidermal cells, epidermal structures (stomata), epidermal appendages (trichomes and hairs).

Complete answer:
The epidermal tissue system is derived from protoderm. Protoderm is a thin outer layer of the meristematic tissue in vascular plants which gives rise to the epidermal tissue system.

Epidermal tissue system is composed of three parts:
> Epidermis: It is the outermost and single layer of the plant body. It can be multilayered (composed of several layers of epidermal layers), e.g., Ficus. The epidermal cells are living cells having cytoplasm and nucleus. These cells are parenchymatous cells which possess a large central vacuole and peripheral cytoplasm lining the cell wall. Outside of the epidermis is covered with a thick waxy layer called cuticle which prevents water loss. Cuticles are absent in roots and hydrophytes.

> Stomata: They are the minute pores present in the epidermis of the leaves. They are absent in the epidermis of the root and composed of Kidney shaped cells known as guard cells and tiny stomatal pore. Stomata regulate the process of transpiration and gaseous exchange.

> Epidermal appendages: It is an outgrowth from the outer surface of the plant body. These are the outgrowth of layer epidermis. These are commonly present on the roots and shoots.

Function of Epidermal tissue system:
- The epidermis and waxy cuticle provides protection from external injuries, evaporation and mechanical shocks.
- Stomatal apparatus used for gaseous exchange.
- Absorption of water and minerals.

Hence, the correct answer is option (A).

Note: Procambium is the meristematic tissue located next to the protoderm and gives rise to primary tissues (xylem and phloem). Periblem is primary meristem which gives rise to cortex and plerome is also primary meristem which gives rise to stele.