Question

Where do dermatogen, periblem and plerome occur?
A) Secondary meristem
B) Apical meristem
C) Lateral meristem
D) Permanent tissues.

Answer 1

The meristem is a type of plant tissue. It consists of meristematic cells, capable of cell division. These cells can develop into all the other plant tissues and organs.

Complete Answer:
Major Criteria for the plant tissues’ classification are :-
->On the basis of part of the plant, they are present in.
->On the basis of the kind of cells they contain.
Classification on the basis of their location in the Plant

1. Vascular tissues – transport the dissolved substances and water, inside the plant.
2. Epidermal tissues – cover the outside of a plant in a single layer of cells.
3. Ground tissues – cover the interiors of a plant.
   Classification on the basis of the kind of cells contained
4. Meristematic; and 2. Permanent.
   Option a) : Secondary meristem - is responsible for the secondary growth in plants; as opposed to the primary meristem, involved in the primary growth. It consists of undifferentiated or partially differentiated cells.This option is incorrect.
   Option b) : Apical meristem - Meristematic cells are found just a few millimetres over the root cap. The meristem at the apex consists of:The outermost layer, called the Dermatogen.
   ->Inner to dermatogen, lies the Periblem.
   ->The central region is called the Plerome.
   Thus, this is the Correct option.
   Option c) : Lateral meristem exists in the radial portion of the stem or root. It upsurges the thickness of the plant. It consists of the vascular cambium and the cork cambium. This option is incorrect.
   Option d) : Permanent tissues - These are the tissues that are completely grown and have lost the ability of division, but are specialised to offer elasticity, flexibility and strength to the plant. The meristematic tissues divide and differentiate to form the permanent tissues. This also is an incorrect option.

Thus, the correct option is (B) Apical meristem.

Note: The apical meristem at the shoot tip divides to form 3 layers - Dermatogen, Periblem & Plerome. The cells of dermatogen mature into the epiblema and root cap, the cells of Periblem mature into the cortex, and the cells of Plerome mature into the stele.