1. The Importance of Leaves
Chapter #19
The Importance of Leaves

2. Chapter 19.1 Notes Blade- thin, flat part of leaf.
Stalk-usually joins the leaf to the stem.
Midrib-is the main vein of the leaf.
Blade
Midrib
Stalk

3. Leaves are arranged in 3 different ways. Alternate Opposite Whorled

4. Waxy layer- protective layer, protects from water loss & insects.
Epidermis-is the outer layer of cells of a plant.
Palisade layer- the layer of long, green cells below the upper epidermis (makes most of food).
Spongy layer- below palisade layer is a layer of round, green cells. Has air spaces.
Stoma- is a small pore or opening in the epidermis allows air and water to go in and out.
Guard cells- are green cells that change the size of stoma in a leaf. Found on either side of stoma.

5. Leaf Cross Section Waxy layer Epidermis Palisade Layer Spongy Layer
Stoma
Epidermis
Guard cells

6. Transpiration- the process of water passing out through the stomata of leaves.
Wilting- is when a plant loses water faster than it can be replaced.

7. Chapter 19.2 Notes
Photosynthesis- is the process in which plants use water, carbon dioxide, and energy from the sun to make food
6 CO2 + 6H2O C6H12O6 + 6O2
Carbon dioxide + water = sugar + oxygen
Sunlight
Final Product
Waste Product
Raw materials

8. Chapter 19.3 Notes
Food chain- always start with the sun…then a producer (green plant)
Leaves are used for food, flavorings, spices, and making drugs…
Digitals-drug used to treat heart disease.

9. Common pigments colors in leaves
Red
Yellow
Green
Why do leaves change color?
Flow of sap in the stem slows down
Temperature drops
Less sunlight
Chlorophyll breaks down
Other pigments show through

10. “Food Chain”. December 12, 2006. http://salina-int. dearbornschools
“Alder Leaf”. December 11,
“Leaf arrangement pictures (3)”. December 11,
“Leaf cross section”. December 12,
“Maple Leaves in Fall”. December 12,