1. Plant organs and their functions
Leaves, Roots, Stems
Plant organs and their functions

2. Leaves

3. Leaf Parts
Two major parts to the leaf:
Blade
Petiole

4. Leaf microanatomy Epidermis and cuticle do what? Mesophyl does what?
Veins do what?
Guard cells in the lower epidermis do what?

5. Photosythesis
The purpose of photosynthesis is to produce organic (carbon-based) molecules (such as sugars).
The plants use these molecules for two purposes:
As an energy source
As building material

6. Roots

7. Types of root systems Taproot systems: main root, lateral branches.
Fibrous root systems: lose the primary root, replaced by many smaller roots.

8. Root Anatomy Parts of a root: Root cap Root meristem
Zone of elongation
Zone of maturation

9. Roots: Epidermis
Root epidermis lacks a cuticle, and is porous. Usually has many root hairs.
Water enters through membranes of epidermal cells or through spaces between cells.

10. Roots: Cortex
The cortex layer is made up of parenchyma cells. What is the main function of these cells?
Endodermis separates the cortex from the vascular cylinder.

11. Roots: vascular cylinder
Casparian strip around endodermis cells controls water movement. Why?
Pericycle: layer of parenchyma cells, inside of endodermis, from which branch roots can arise.

12. Roots: vascular cylinder
Vascular cylinder contains:
Phloem: what does phloem do?
Xylem: What does xylem do?

13. Stems

14. Stems: Epidermis
In herbaceous plants and young woody plants, the stem is covered with epidermis.
Epidermis secretes cuticle, has stomata, and may be photosynthetic.

15. Stems: Cortex and Pith
Cortex layer contains parenchyma cells and vascular bundles.
Pith makes up the center of the stem, and is absent in hollow stems.

16. Stems: vascular tissue
Vascular bundles are in the cortex.
Between the xylem and phloem is the vascular cambium, a meristem layer. What is it for?

17. Stems: Secondary growth
Secondary growth is seen in woody plants.
This kind of growth produces stronger, thicker stems from the vascular cambium and cork cambium.

18. Stems: wood and bark
What tissue makes up the wood of a tree trunk? (hint: water flows there.)
What tissue makes up the “green bark?” (hint: sap flows there.)
Dead cork cells make up the bark.

19. Stems: Annual Rings
Trees in temperate zones grow at different rates in different seasons, causing annual rings to form.
In some parts of the tropics, if seasons vary little, tree rings are indistinct.