1. ROOTS

2. Types of Roots
1. Taproot, when there is mainly a primary root and the secondary roots remain much smaller. Mainly found in dicots. (Ex. trees, carrots, dandelions, beets, & radishes) 2. Fibrous root, when all roots branch out so that no single root is larger or longer than all the rest. Mainly found in monocots. (grasses)

3. Root Structure
3. Root hairs, tiny cellular projections that increase surface area for absorption. 4. Vascular cylinder, includes the vascular tissue (xylem & phloem) 5. Root cap, the tough tip of the root that forces through soil. Specialized cells secrete a lubricant for this process. 6. Apical meristem, area of fast cell division as new cells are quickly added to the growing root.

4. Root Function
7. Anchor a plant in the ground. 8. Absorb water. 9. Absorb dissolved nutrients from the soil.

5. STEMS

6. Stem Structure & Function
1. Three main functions are: a) Produce leaves, branches, & flowers b) Hold leaves up to sunlight c) Transport substances between roots and leaves 2. Nodes, where leaves attach & Internodes, regions between leaves 3. Buds, can produce new stems & leaves 4. Lenticles, very small openings in stems that gases (CO2 and O2) enter and exit through.

7. Growth in Stems
5. Primary growth, in most stems is produced by cell divisions of the apical meristem. 6. Secondary growth, is mainly lateral growth (thickening of the stem). The Vascular cambium produces vascular tissue and increases the thickness over time. The Cork cambium produces the outer coverings of stems.

8. LEAVES

9. Leaf Structure
1. Leaves are specialized for optimizing absorption of light energy and for carrying out Photosynthesis. 2. Blade, thin flattened section that captures sunlight. 3. Petiole, attaches the blade to the stem at the node. 4. Leaves are generally either Simple or Compound.

10. Leaf Structure

11. Leaf Functions - PHOTOSYNTHESIS
5. 6. Photosynthesis occurs primarily in the Palisade layer of mesophyll tissue. 7. Water enters the leaf through the Xylem. 8. Carbohydrates that are produced leave through the Phloem. 9. The Spongy layer is filled with air spaces that store CO2 and O2 gas.
6CO2 + 6H2O C6H12O6 + 6O2

12. Leaf Functions - PHOTOSYNTHESIS
10. Transpiration is the loss of water through leaves. 11. The Cuticle is a waxy layer (composed of lipids) on top of leaves that helps prevent water loss.

13. Leaf Functions – GAS EXCHANGE
12. Exchange of CO2 and O2 gas is essential in order to carry out Photosynthesis. 13. Gases enter and exit leaves through small openings called Stomata (stoma=singular). 14. Guard Cells open and close in order to regulate how much gas enters and exits a leaf. 15. Plants cannot keep their Stomata open all of the time because too much Transpiration would occur.