Mineral absorption by plant roots occurs in the root hair zone, which is part of the epidermis.
Explanation:
- Root hairs: These are microscopic, filament-like outgrowths of epidermal cells, found near the root's apex. They are the main structures for taking up water and minerals from the soil, significantly increasing the root's surface area for enhanced absorption.
- Epidermis: This is the root's outer cellular layer, in direct contact with the soil. Epidermal cells within the root hair zone facilitate mineral and water uptake via osmosis and active transport.
- Root cap: The root cap does not absorb minerals but protects the root's growing tip as it penetrates soil and aids in directional growth.
Mineral Absorption Mechanism:
- Minerals from the soil are absorbed by root hairs through active transport (requiring energy) and passive transport (e.g., diffusion). Minerals such as potassium, calcium, and phosphate are typically absorbed via active transport.
- Following absorption, minerals move from root hair cells to adjacent root cells and subsequently to the vascular tissue (xylem), which distributes them throughout the plant.
Therefore, root hairs, situated within the epidermal layer close to the root tip, are the principal sites for mineral absorption in plants.