Question

Which meristem is responsible for increase in girth of stem/root? ____.

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

Hint:

To easily remember: "Apical" is at the apex/top (Length), "Intercalary" is at the intervals/nodes (Regrowth), and "Lateral" is at the sides (Girth/Width).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Plant growth occurs in two distinct axes: elongation (height) and expansion (girth). Specialized regions of actively dividing cells called meristems direct these growth patterns.

Step 2: Detailed Explanation:
The tissues responsible for the secondary growth (increase in thickness or girth) of a plant stem or root are the lateral meristems. These meristems lie parallel to the lateral sides of the stem and roots. When their cells divide, they produce secondary xylem, secondary phloem, and cork tissue, widening the plant structure. Examples include the vascular cambium and cork cambium.
• Apical meristems are located at the tips of stems and roots and increase the plant's length.
• Intercalary meristems are located at the nodes or leaf bases, primarily helping in internodal elongation.

Step 3: Final Answer:
The lateral meristem is responsible for the increase in the girth of a stem or root.