Roots, Stems, and Leaves

1. Roots, Stems, and Leaves Biology 11

2. Organs Systems Plants have 4 organ system • 3 are vegetative organs • Leaf, stem root • 1 is reproductive • Flower

3. Roots • Absorb water and dissolved nutrients from soil • Anchor plants to ground • Hold plant upright

4. Stems • Can be thin and herbaceous or massive and woody • Provide structural support • Water and nutrient transport • Some stems for storage (ex. Potato is a tuber)

5. Leaves Function: • Large surface area for receiving sunlight • photosynthesis takes place in mesophyll • Covered in waxy cuticle

7. Stomata • Small openings in leaf that open or close • Opening and closing is regulated by guard cells • Mainly found on the underside of leaves (for land plants)

8. Functions: • Open to take in carbon dioxide and release oxygen and water • Close to decrease water loss

9. Vascular Tissue Xylem • Carries water and dissolved nutrients from roots to stems and leaves • Provides strength • Made of tracheid Cells • Functioning cells are dead

10. Phloem • Carry products of photosynthesis from one part to another • Main cells are sieve tube elements and companion cells • Functioning cells are alive

11. How Water Moves Up to the Leaves • Root Pressure • Roots absorb water that must move up • Capillary Action • Water movement opposes gravity in small tubes • adhesion (stick to side of tube) and cohesion (stick to each other) of water molecules • Transpiration from Leaves • evaporation of water causes the pulling of the next water molecule up to take place