8 – 1
Chapter 8
Plant Organs: Leaves
CHAPTER OUTLINE
Leaf form and structure
Epidermis, mesophyll, xylem, and phloem are the major tissues of the leaf
Leaf structure differs in eudicots and monocots
Leaf structure is related to function
Plants and the Environment: The Effects of Air Pollution on Leaves
Plants and the Environment: Trees, Transpiration, and Climate
Plants and People: Important Edible Leaf Crops
CHAPTER OBJECTIVES
1. Describe the major tissues of the leaf (epidermis, mesophyll, xylem, and phloem) and relate
the structure of the leaf to its function of photosynthesis.
2. Contrast leaf structure in eudicots and monocots.
LECTURE OUTLINE
I. Leaves are variable in form and arrangement
A. What are the two parts of a typical leaf?
B. Distinguish between simple, pinnately compound, and palmately compound
leaves.
C. Distinguish between alternate, opposite, and whorled leaf arrangement.
D. Distinguish between parallel, palmately netted, and pinnately netted venation.
II. What is the primary function of a leaf?
A. Describe the tissues found in a typical leaf.
B. Describe the position of the epidermal layer.
1. What is the major substance found in the cuticle, and what is the cuticle’s
function?
C. Distinguish between palisade and spongy mesophyll, both in location and function.
D. What tissues are found in the veins?
1. What materials are transported in vein tissues?
2. What cells usually surround the veins?
E. How do monocot leaves differ from eudicot leaves?
F. How is leaf structure related to the leaf’s primary function?
III. What internal and external factors affect the opening and closing of stomata?
A. How is water lost from leaves?
V. What is transpiration?
A. How do plants reduce the rate of transpiration?
B. What environmental factors effect transpiration rate?
C. In what ways is transpiration beneficial?
D. What happens when the rate of transpiration exceeds the rate of water uptake?
VI. What special leaf structures are associated with guttation?
A. Under what environmental conditions does guttation occur?
VII. What is leaf abscission?
KEY TERMS
abscission, p. 166
air pollution, p. 161
alternate, p. 152
facilitated diffusion, p. 162
forest decline, p. 161
guard cells, p. 154
proton gradient, p. 162
simple leaf, p. 152
spine, p. 169
TEACHING TIPS
1. Three–dimensional models are useful to help students comprehend the arrangement of tissues in
2. Save an hour of lab time to cook and sample a variety of leaf foods. Select things that may be
new to at least some of the students. Many people have never eaten bok choy, New Zealand
3. Bring in several plants that you have allowed to wilt (impatiens or coleus work well) and water
4. Collect a variety of different leaf adaptations to pass around the room (make use of your school
greenhouse). Lead into a discussion of how leaf morphology shows adaptations to climate.
5. Take the students on a walk around the campus and have them perform tree identification
using a taxonomic key to local species. Be careful to identify the trees first and use the
6. Bring in an assortment of plants to class and have the students determine their leaf type,