Question

The calyptrogen of the root apex forms
A)Rhizoids
B)Root nodules
C)Root hairs
D)Root cap

Answer 1

Hint: In general, It is present in all crop species (in the roots). Its structure also varies in different plant species. It is a mass of cells which covers and protects the growing tip of a root and looks like a thimble-shaped and this generally produced by the apical meristem.

Complete answer:
-The three primary meristems that are procambium ground meristem and protoderm in addition to the root cap produced by root apical meristem.
-Root cap has a separate primary meristem which is known as calyptrogen.
-It mostly occurs in the roots that have definite initials for the tissue of the root body.
Calyptogena- it is a layer of cells that are repeatedly dividing at the tip of the plant which results in the formation of the root cap. It is mainly seen in the grasses and many other plants.
-The outer edge of the root tip has a layer of meristematic cells that continuously cut its new cells. This usually replaced the worn-out cells of the root cap known as calyptra as a root pushes through the soil.

Additional information:
-The main purpose of the root cap is to allow the downward growth of the root. The root cap also protects the growing tip in the plants.
-The root cap also allows the plant to grow downwards that is towards the gravity or upwards that is against the gravity.
Rhizoids - these are the projections that extend from the lower epidermal cells of the bryophytes and algae. They are both similar in structure and function to the root hairs of the vascular land plants. They can be unicellular or multicellular.
Root hairs- they facilitate the absorption of water. They are so long that they can go deep between the soil particles and prevent the harmful bacteria from entering the plant roadie xylem vessels.
Root nodules- they have the symbiotic bacteria known as rhizobia in their nodules which produce nitrogen compounds and help the plant to compete with the other plants and also helps plants to grow.
So, the correct answer is, “root cap”.

Note: -The root cap has the living parenchyma cells, whenever the cells of the root caps are destroyed, the new parenchyma cells are joined by special meristematic cells present internally known as calyptrogen.
-In some parasitic plants and aquatic plants, the root cap is absent instead they have a sac-like structure called a root pocket.
-Root cap comprises the parenchyma cells that have a protective function.