1. Roots

2. IB Assessment Statement
9.2.1 – Outline how the root system provides a large surface area for mineral ions and water intake by means of branching and root hairs.

3. 9.2.1 Roots Structure and function
Function of Root
Absorb Water from soil
Uptake of mineral ions form soil

4. Structure of Roots
Roots have root hairs which increase the surface area of the root
Root Cap protects apical meristem tissue

5. Structure of Roots Vascular Cylinder –composed of xylem and phloem
Epidermis: Protective outer layer of root and root hairs
Cortex: involved in conducting water from soil to vascular cylinder

6. Root Hair are extensions of cell walls of cortex cells
The extension of the cell wall increases the surface area for the absorption of water and minerals at the cellular level.
The root hair cell provides both an increase in the cell wall (apoplastic pathway (outside the cell)) and the cytoplasmic route (symplastic pathway (inside the cell)) for the movement of water

8. Monocots vs. Dicot Roots
(a) The monocotyledon root has a fibrous highly branching structure which increases the surface area for the absorption of water.
(b) Dicotyledon root structure has a main tap root and often a surface branching root system for the absorption of surface run off.
Deeper in the soil the tap root branches to access deeper water and mineral.

9. Your turn…

10. Your turn… You will observe and draw detailed structure of:
Orchid Aerial Root
Corn prop root
Ranunculus root
Carrot root
Wheat Root Hairs