1. PLANT STRUCTURE AND FUNCTION
PLANT STRUCTURE AND FUNCTION
Life - Plants
Copyright © 2009 Pearson Education, Inc.

2. Evolution and types of plants
Since the earth was once covered in water, plants had to make three adaptations to survive on land
The ability to prevent water loss
The ability to reproduce in the absence of water
The ability to absorb and transport nutrients
Plants can be placed under two groups
Vascular- having true roots, leaves, and stems
Ex. ferns, conifers, flowering plants
Nonvascular- not having true roots, leaves, and stems
Ex. mosses, liverworts, hornworts

3. Vascular Plants can be divided into two groups
Seedless Plants
Seed Plants
Made up of ferns and plants closely associated with ferns
Two types of seed plants
Gymnosperms- which includes pine trees, produce seeds that are not encased in fruit
Angiosperms- aka flowering plants, produce seeds within a protective fruit

4. The two main groups of angiosperms are the monocots and the dicots
Monocots (Ex. Lilies, onions, corn, grasses, wheat)
One cotyledon
Parallel leaf venation
Scattered vascular bundles
Flower parts in 3s or multiples of 3
Fibrous roots
Student Misconceptions and Concerns
1. Students often fail to see the specific applications of fundamental principles of biology. For example, many structural adaptations increase the surface-to-volume ratio in plants and animals. The divisions within the human lung, as well as microvilli, leaves, and root hairs, are examples. Increased surface areas are typically found where something is exchanged: gases exchanged at respiratory surfaces, nutrients absorbed by microvilli, light absorbed by leaves, and water and minerals absorbed by root hairs. If this chapter is one of the final topics addressed in your course, illustrating these broad principles with examples from a variety of subjects can serve as a unifying review.
Teaching Tips
1. Figure 31.2 provides a visually simple but important comparison of monocots and eudicots. By referring to this figure in class, students will be able to absorb more details during lecture that they can then review at their leisure.
2. Consider bringing living examples of monocots and eudicots to class or taking a short trip outside during a related lab to quickly compare examples.

5. The two main groups of angiosperms are the monocots and the eudicots
Dicots—most plants are eudicots (Ex. Trees)
Two cotyledons
Branched leaf venation
Ring of vascular bundles
Flower parts in 4s or 5s (or multiples)
Taproot system
Student Misconceptions and Concerns
1. Students often fail to see the specific applications of fundamental principles of biology. For example, many structural adaptations increase the surface-to-volume ratio in plants and animals. The divisions within the human lung, as well as microvilli, leaves, and root hairs, are examples. Increased surface areas are typically found where something is exchanged: gases exchanged at respiratory surfaces, nutrients absorbed by microvilli, light absorbed by leaves, and water and minerals absorbed by root hairs. If this chapter is one of the final topics addressed in your course, illustrating these broad principles with examples from a variety of subjects can serve as a unifying review.
Teaching Tips
1. Figure 31.2 provides a visually simple but important comparison of monocots and eudicots. By referring to this figure in class, students will be able to absorb more details during lecture that they can then review at their leisure.
2. Consider bringing living examples of monocots and eudicots to class or taking a short trip outside during a related lab to quickly compare examples.

6. A typical plant body contains three basic organs: roots, stems, and leaves
Plants absorb water and minerals from soil through roots
Plants absorb the sun’s energy and carbon dioxide from the air through shoots (stems and leaves)
Plant roots depend on shoots for carbohydrates produced via photosynthesis
Plant shoots depend on roots for water and minerals
Teaching Tips
1. Challenge your students to suggest circumstances when apical growth is more adaptive for a plant, and other situations in which branching would be more favorable.
Copyright © 2009 Pearson Education, Inc.

7. A typical plant body contains three basic organs: roots, stems, and leaves
Plant roots
Anchor plant
Absorb water and minerals
Store food
Plant shoots
Stems, leaves, and reproductive structures
Stems provide support
Leaves carry out photosynthesis
Teaching Tips
1. Challenge your students to suggest circumstances when apical growth is more adaptive for a plant, and other situations in which branching would be more favorable.
Copyright © 2009 Pearson Education, Inc.

8. Terminal bud Blade Leaf Flower Petiole Axillary bud Stem Shoot system
Node
Internode
Root
hair
Root
hairs
Figure 31.3 The body plan of a flowering plant (a eudicot).
Taproot
Root
system
Epidermal cell

9. Many plants have modified roots, stems, and leaves
Modifications of plant parts are adaptations for various functions
Food or water storage
Asexual reproduction
Protection
Climbing
Photosynthesis
Teaching Tips
1. The modifications of the three plant organs described in Module 31.4 reveal the remodeling nature of evolution. As Francois Jacob noted, evolution works more like a tinkerer than an engineer. The common ancestry of eudicots is revealed by the diverse modifications of three basic plant organs derived from the shared ancestors. Your students’ appreciation of the enormous evidence in support of evolution will grow if you note such examples frequently throughout your course.
Copyright © 2009 Pearson Education, Inc.

10. Many plants have modified roots, stems, and leaves
Root modifications
Food storage
Large taproots store starches
Examples include carrots, turnips, sugar beets, sweet potatoes
Teaching Tips
1. The modifications of the three plant organs described in Module 31.4 reveal the remodeling nature of evolution. As Francois Jacob noted, evolution works more like a tinkerer than an engineer. The common ancestry of eudicots is revealed by the diverse modifications of three basic plant organs derived from the shared ancestors. Your students’ appreciation of the enormous evidence in support of evolution will grow if you note such examples frequently throughout your course.

11. Many plants have modified roots, stems, and leaves
Stem modifications
Stolon—asexual reproduction
Rhizomes—storage, asexual reproduction
Tubers—storage, asexual reproduction
Cactus stem—water storage and photosynthesis
Teaching Tips
1. The modifications of the three plant organs described in Module 31.4 reveal the remodeling nature of evolution. As Francois Jacob noted, evolution works more like a tinkerer than an engineer. The common ancestry of eudicots is revealed by the diverse modifications of three basic plant organs derived from the shared ancestors. Your students’ appreciation of the enormous evidence in support of evolution will grow if you note such examples frequently throughout your course.

12. Many plants have modified roots, stems, and leaves
Leaf modifications
Protection
Cactus spine, Thorns
Climbing
Pea plant tendril
Teaching Tips
1. The modifications of the three plant organs described in Module 31.4 reveal the remodeling nature of evolution. As Francois Jacob noted, evolution works more like a tinkerer than an engineer. The common ancestry of eudicots is revealed by the diverse modifications of three basic plant organs derived from the shared ancestors. Your students’ appreciation of the enormous evidence in support of evolution will grow if you note such examples frequently throughout your course.

13. Three tissue systems make up the plant body
Dermal tissue
tightly packed epidermis cells
First line of defense
Waxy layer called cuticle
reduces water loss
Teaching Tips
1. Module 31.5 can be particularly problematic for students with limited backgrounds in plant biology. The basic structures and functions of tissues and subtypes of plants are introduced, and monocots and eudicots are compared. The terminology is extensive. Students may benefit most by creating their own mini-glossary for quick reference and study before, during, and after related lectures.
2. The functions of human epidermis have some analogues in plants. As in plants, our epidermis serves as a defense against physical damage and infectious organisms. In addition, oils on our skin help us retain water (and keep the epidermis flexible).

14. Three tissue systems make up the plant body
Vascular tissue
Composed of xylem and phloem
Xylem transports water from roots to leaves
Phloem transports glucose made in leaves to nonphotosynthetic parts of the plant
Arranged in bundles
Ground tissue
Leaf ground tissue is called mesophyll
Bulk of plant body
Food production and storage (because it contains chloroplasts)
Teaching Tips
1. Module 31.5 can be particularly problematic for students with limited backgrounds in plant biology. The basic structures and functions of tissues and subtypes of plants are introduced, and monocots and eudicots are compared. The terminology is extensive. Students may benefit most by creating their own mini-glossary for quick reference and study before, during, and after related lectures.
2. The functions of human epidermis have some analogues in plants. As in plants, our epidermis serves as a defense against physical damage and infectious organisms. In addition, oils on our skin help us retain water (and keep the epidermis flexible).

15. Review of 3 types of tissues

16. Plant cells and tissues are diverse in structure and function
Plants cells have three structures that distinguish them from animals cells
Chloroplasts used in photosynthesis
A large, fluid-filled vacuole
A cell wall composed
of cellulose
Student Misconceptions and Concerns
1. Students may not understand turgor, although they encounter it in their lives. The shape of a water balloon is different from the shape of an uninflated balloon due to internal fluid pressure (turgor). A plant in need of water may have drooping leaves, a consequence of decreased turgor.
Teaching Tips
1. Cellulose is the most abundant organic compound on Earth. Students often find this fact worth remembering.
2. Students will remember the function of phloem more easily if you remind them that both phloem and food start with an “F” sound.
For the BioFlix Animation Tour of a Plant Cell, go to Animation and Video Files.

17. Transpiration
Transpiration – water is absorbed through roots (specifically root hairs); as water evaporates from the stomata openings it pulls water up through the plant from a combination of cohesion (water attracted to itself) and adhesion (water attracted to the tree)
Transpiration demo

18. PLANT GROWTH
Copyright © 2009 Pearson Education, Inc.

19. Primary growth lengthens roots and shoots
Plant growth is indeterminate
Growth occurs throughout a plant’s life
Plants are categorized based on how long they live
Annuals complete their life cycle in one year
Biennials complete their life cycle in two years
Perennials live for many years
Animal growth is determinate
Growth stops after a certain size is reached
Student Misconceptions and Concerns
1. Students often expect determinate growth in plants, because it is characteristic of humans. However, most plant species show indeterminate growth and are capable of growing as long as they can live.
Teaching Tips
1. Lobsters are one of the few animals that show indeterminate growth.
Copyright © 2009 Pearson Education, Inc.

20. Primary Growth and Secondary Growth
Primary growth is the vertical growth of a plant (shoot growing up and root growing down).
Secondary growth is an increase in diameter of roots and shoots (getting thicker).
This growth does not occur at all parts of the body like in animals. This is because not all cells in a plant divide.
Meristem – small, unspecialized cells that divide continually

21. Meristem There are two types of meristem cells.
Apical meristem – located at the tips of roots and shoots
Responsible for primary growth
Lateral meristem – cells responsible for creating more xylem / phloem and bark
Responsible for secondary growth

22. Primary growth allows roots to push downward through the
soil and shoots to grow upward
Terminal bud
Axillary buds
Figure 31.7A Locations of apical meristems, which are responsible for primary growth.
Arrows =
direction
of growth
Root
tips

23. Vascular tissue system
Secondary growth increases the girth of woody plants
Year 1
Early Spring
Year 1
Late Summer
Year 2
Late Summer
Key
Dermal tissue system
Ground tissue system
Vascular tissue system
Shed
epidermis
Growth
Growth
Growth
Primary
xylem
Epidermis
Secondary
xylem (wood)
Cork
Vascular
cambium
Figure 31.8A Secondary growth of a woody eudicot stem.
Cortex
Secondary xylem
(2 years’ growth)
Cork
cambium
Bark
Primary
phloem
Secondary
phloem

24. Secondary growth increases the girth of woody plants
Vascular cambium produces cells in two directions
xylem produces wood toward the interior of the stem
The xylem is responsible for water transport in plant
Moves water through transpiration
phloem produces the inner bark toward the exterior of the stem
Living tissue of the tree that is responsible for moving sugar throughout the plant

25. Secondary growth increases the girth of woody plants
Cork cambium produces the outer bark, which is composed of cork cells
Student Misconceptions and Concerns
1. Students typically expect that as a tree grows taller, the trunk will “stretch” upward along its entire length. This expectation arises naturally from the experience of our own growth as humans. However, as a tree grows, the entire trunk does not increase in size. Instead, growth occurs at the upper ends and through expansion of the trunk. Therefore, initials carved into the trunk of a tree will remain at that height as long as the tree is upright and healthy.
Teaching Tips
1. Students may not realize that the cork used to seal a wine bottle is the same cork that is discussed in Module 31.8.
2. Students may not appreciate the many important functions of tree bark. Carving into bark, or peeling it away from a trunk, exposes the inner tissues to pathogens. In many ways, the functions of human skin and bark are similar.
Copyright © 2009 Pearson Education, Inc.

26. Secondary growth increases the girth of woody plants
Wood annual rings show layers of xylem
In temperate regions, periods of dormancy stop growth of secondary xylem
Rings occur in areas when new growth starts each year
The bark (phloem and cork) is sloughed off over time
Student Misconceptions and Concerns
1. Students typically expect that as a tree grows taller, the trunk will “stretch” upward along its entire length. This expectation arises naturally from the experience of our own growth as humans. However, as a tree grows, the entire trunk does not increase in size. Instead, growth occurs at the upper ends and through expansion of the trunk. Therefore, initials carved into the trunk of a tree will remain at that height as long as the tree is upright and healthy.
Teaching Tips
1. Students may not realize that the cork used to seal a wine bottle is the same cork that is discussed in Module 31.8.
2. Students may not appreciate the many important functions of tree bark. Carving into bark, or peeling it away from a trunk, exposes the inner tissues to pathogens. In many ways, the functions of human skin and bark are similar.

27. Secondary growth increases the girth of woody plants
Part of the Xylem
Sapwood transports water
Heartwood stores resins and wastes
Student Misconceptions and Concerns
1. Students typically expect that as a tree grows taller, the trunk will “stretch” upward along its entire length. This expectation arises naturally from the experience of our own growth as humans. However, as a tree grows, the entire trunk does not increase in size. Instead, growth occurs at the upper ends and through expansion of the trunk. Therefore, initials carved into the trunk of a tree will remain at that height as long as the tree is upright and healthy.
Teaching Tips
1. Students may not realize that the cork used to seal a wine bottle is the same cork that is discussed in Module 31.8.
2. Students may not appreciate the many important functions of tree bark. Carving into bark, or peeling it away from a trunk, exposes the inner tissues to pathogens. In many ways, the functions of human skin and bark are similar.