1. Leaves: Structure and Function

2. Main Functions 1. Principle sites of photosynthesis 6CO 2 + 6H 2 O 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O 6O 2 + C 6 H 12 O 6 2. Gas Exchange 3. Water Movement

4. Structures 1. Blade: flattened area, has a network of veins 2. Petiole: connects leaf to stem

5. Leaf Scars and Bundle Scars…

7. Structure 3. VEINS: Vascular bundles Made up of: Made up of: XYLEM: transports water and minerals XYLEM: transports water and minerals PHLOEM: transports food PHLOEM: transports food

8. STRUCTURE 4. Epidermis: Covers entire surface (upper and lower) Covers entire surface (upper and lower) Waxy transparent layer: Cuticle Waxy transparent layer: Cuticle Protection: Protection: Temp Temp Wind Wind Disease Disease

9. 5. Mesophyll: between 2 layers of epidermis, chloroplasts in this layer

10. STRUCTURE 6. Stomates: Opening in underside of leaf Gas Exchange: Which Gases? Gas Exchange: Which Gases? CO 2 O 2 Transpiration: water movement Transpiration: water movement Open in daylight, closed in darkness Open in daylight, closed in darkness 7. Guard Cells: Controls stomate opening Filled with water, stoma is open Filled with water, stoma is open Water is removed, stoma closes Water is removed, stoma closes

12. Stomate Open