1. RHS Level 2 Certificate Year 1 Week 5: Stems and Leaves

5. Young Dicot stem

9. Leaves –function and structure (2) Epidermis – cells that form ‘skin’ of leaf Cuticle –waxy layer on surface that slows water loss Chloroplasts – site of photosynthesis Palisade cells – arranged like picket fence, contain chloroplasts Stomata – active control of entry and exit of gasses and water vapour. Spongy mesophyll – packing cells, allow water vapour and other gasses through Xylem – water and mineral nutrients Phloem – dissolved sugars

10. Leaf – internal structure

12. Electron-micrograph of lettuce stomata