Question

Root cap regenerated/dead torn cells of root cap are replaced by the activity of
A. Plerome
B. Dermatogen
C. Calyptrogen
D. Periblem

Answer 1

Hint: The root cap is a category of tissue at the tip of a plant root. It is also known as calyptra. Root caps contain osteocytes that are implicated in gravity perception in plants as well as in humans. If the cap is carefully discarded the root will grow randomly. Calyptrogen is the formative tissue present in the growing stage of a root, giving rise to the root cap. Calyptrogen is considered to be characteristic of monocotyledonous plants.

Complete answer:
Option – A – Plerome
The middle column of parenchyma in a developing stem or root is known as Plerome. According to the histone theory, Plerome provides help to raise the stele as well as endodermis of a plant.
Option – B – Dermatogen
Dermatogen is said to be the outer main meristem of a plant or plant part. It is also called the outer apical meristem of a root tip.
Option – C - Calyptrogen
The root apical meristem grant rise to three key meristems that are as following –
-procambium,
-ground meristem, and
-the root cap called as Calyptrogen
Calyptrogen is a specialized internal meristematic cell that originated from the root apical meristem. They divide internally to generate a protective cap-like structure at the root tip called the root cap The root cap is also referred to as calyptra. In general terms we can define the term as a layer of rapidly dividing cells present at the very top of a plant root, from where the root cap is formed. The common example of it is Grass.
Option – D – Periblem
According to the histogen theory Periblem is a key meristem that allows the growth of the cortex along with it is situated between Plerome as well as dermatogen.

Hence, the correct answer is option (C).

Note: In many dicotyledonous plants, there are tissues instead of calyptrogen. The tissue present gives rise to the root’s absorbent external piliferous layer. These tissues are known as dermato calyptrogen.