Question

Which is not a primary meristem?
A. Promeristem
B. Protoderm
C. Periblem
D. Ground tissue

Answer 1

Hint: The meristem lies on the tips of the growing parts of the plant. In addition, it is not present at the tissues present at the base or ground level of the plant.

Complete step by step answer:
The Primary meristem is responsible for the primary growth of the plant rather than increasing the diameter of the plant. It is always present at the top of the growing stem and the tips of other plant parts.

Promeristem contains isodiametric thin-walled cells which makes up a major portion of the primary meristem. The cells actively divide and help in the longitudinal growth of plants. So, this is referred to as the primary meristem.
Protoderm forms the outer layer of the root and shoots called the epidermis. It is the primary meristem derived from the apex of root and shoot. Thus, It is acquired from the apical meristem.
Periblem is also derived from the apical meristem. It is the primary meristem which forms the endoderm and makes up the cortex. It is found between the plerome and dermatogens.
Ground tissue is a type of permanent tissue that performs the function of storing carbohydrates produced by the plant. It lies between the dermal tissue and vascular tissue and is also derived from the apical meristem. But it is not a primary meristem.

Thus, option D is the correct answer to this question.

Note: The ground tissue performs the function of storing while the other three tissues are involved in the active division. Except for the ground tissue, all the other three tissues stimulate plant growth. Although the source of Protoderm, Periblem, and Ground tissue is the same.