What are the different types of meristems found in flowering plants w.r.t. position? Name them and describe any one.

Based on position in the plant body, meristems are classified as:

1. Apical meristems
2. Intercalary meristems
3. Lateral meristems

Detailed Description of Apical Meristems:

Definition: Meristems located at the tips (apices) of roots and shoots.

Characteristics:

• Shape: Dome-shaped or conical
• Cell Structure: Small, thin-walled, densely cytoplasmic cells with large nuclei
• Function: Responsible for primary growth (increase in length)
• Derivatives: Produce protoderm (→ epidermis), procambium (→ vascular tissues), and ground meristem (→ cortex, pith)

Example:Root apical meristem (RAM) is protected by root cap and exhibits quiescent center (zone of inactive cells) that serves as a reservoir for regeneration.

NEET Relevance: Questions often focus on histogen theory (Hanstein) and tunica-corpus theory (Schmidt) of shoot apex organization.