Question

Epiblema of roots is equivalent to
A. Pericycle
B. Endodermis
C. Epidermis
D. Stele

Answer 1

Hint: Epidermis is usually a single layered structure; found all over the surface of the plant body. In case of roots, it is called epiblema instead of epidermis.

Complete answer:
Epiblema or piliferous layer (rhizodermis) is the outermost layer of the root. It is made up of compactly arranged thin-walled flattened and slightly elongated parenchymatous cells. Epiblema is derived from protoderm. Some of the cells of epiblema give rise to root hairs which take part in the absorption of water and mineral salts.
In plants, epidermis is also an outermost, protoderm-derived layer of cells covering almost all parts of the plant like the stem, root, leaf, flower, fruit, and seed. The epidermis and its waxy cuticle layer provide a protective shield against mechanical injury, water loss, and infection. Thus, epiblema of root is equivalent to epidermis.

Among the given options:
The pericycle is a layer of parenchymatous or sclerenchymatous cells that is found just below the endodermis and is also known as the outermost layer of the stele of plants.

The root endodermis is composed of a single layered boundary that divides the inner vascular tissue from the outer cortex and functions as an apoplasmic barrier for selective nutrient uptake.

Stele is a term collectively used for vascular tissues in case of vascular plants like gymnosperms and angiosperms. In a vascular plant, the stele is the central part of the root or stem with the tissues derived from the procambium.

So, the correct answer is option C.

Note:
Epiblema is the single celled outermost layer of the root. It is mostly colorless, shadeless and polygonal without any intercellular spaces and related issues, with the presence and occurrences of unicellular root hairs of plants, hence also called a piliferous layer or rhizodermis.