Question

Which meristem helps in increasing the girth of the plant?

• A. Primary meristem
• B. Apical meristem
• C. Intercalary meristem
• D. Lateral meristem

Hint:

Distinguish between primary growth (length, by apical and intercalary meristems) and secondary growth (girth, by lateral meristems like cambium).

Answer 1

The Correct Option is D

Step 1: Understanding the Question:
The question asks to identify the type of meristematic tissue responsible for the increase in the diameter (girth) of a plant stem or root.

Step 3: Detailed Explanation:
Meristematic tissues are plant tissues where cells continuously divide to produce new cells. They are classified based on their position and function:
1. Apical meristem: Located at the tips of roots and shoots. Responsible for primary growth, which increases the length of the plant.
2. Intercalary meristem: Located at the base of internodes and leaves, particularly in monocots. Also responsible for primary growth (lengthening).
3. Lateral meristem: Consists of the vascular cambium and cork cambium. These meristems are responsible for secondary growth, which increases the girth or thickness (diameter) of the stem and root.
4. Primary meristem: A general term for meristems that contribute to primary growth (increase in length).
Therefore, lateral meristems are directly responsible for the increase in plant girth.

Step 4: Final Answer:
Lateral meristem helps in increasing the girth of the plant.