The Importance of Leaves
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.
• Leaves are arranged
in 3 different ways.
• 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
• 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
Leaf Cross Section
• 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.
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
Chapter 19.3 Notes
Food chain- always start with the sun…then a producer (green
Leaves are used for food, flavorings, spices, and making drugs…
Digitals-drug used to treat heart disease.
Common pigments colors in leaves
Why do leaves change color?
Flow of sap in the stem slows down
Chlorophyll breaks down
Other pigments show through
• “Food Chain”. December 12, 2006. http://salinaint.dearbornschools.org/COATT/foodchain2.JPG
• “Alder Leaf”. December 11,2006.
• “Leaf arrangement pictures (3)”. December 11, 2006.
• “Leaf cross section”. December 12, 2006.
• “Maple Leaves in Fall”. December 12, 2006.