1. Plant Structure, Reproduction, and Development
Chapter 31
Plant Structure, Reproduction, and Development

2. A Gentle Giant Gymnosperms Are one of two groups of seed plants
A Gentle Giant
Gymnosperms
Are one of two groups of seed plants
Bear seeds in cones

3. Angiosperms, or flowering plants
Are the most familiar and diverse group of plants

4. TALKING ABOUT SCIENCE
31.1 Plant scientist Natasha Raikhel studies the Arabidopsis plant as a model biological system
Natasha Raikhel
Is one of America’s most prominent plant biologists
Figure 31.1A

5. Dr. Raikhel works with Arabidopsis
A popular model organism for studying biological systems
Figure 31.1B

6. PLANT STRUCTURE AND FUNCTION
31.2 The two main groups of angiosperms are the monocots and the dicots
Monocots and dicots differ in
The number of seed leaves and in the structure of roots, stems, leaves, and flowers
Fibrous
root system
MONOCOTS
Seed leaves
Leaf veins
Stems
Flowers
Roots
One
cotyledon
Main veins usually parallel
Vascular bundles in
complex arrangement
Floral parts usually
in multiples of three
Two
cotyledons
Main veins usually branched
Vascular bundles arranged in ring
Floral parts usually in
multiples of four or five
Taproot
usually present
DICOTS
Figure 31.2

7. 31.3 A typical plant body consists of roots and shoots
A plant’s root system
Anchors it in the soil
Absorbs and transports minerals and water and stores food

8. The shoot system of a plant
Is made up of stems, leaves, and adaptations for reproduction, flowers

9. The body of a dicot Figure 31.3 Terminal bud Blade Leaf Flower Petiole
Axillary bud
Stem
Taproot
Root
hairs
Epidermal cell
Root hair
Internode
Node
Flower
Shoot
system
Leaf
Figure 31.3

10. 31.4 Many plants have modified roots, stems, and leaves
Some plants have unusually large taproots
That store food in the form of carbohydrates
Figure 31.4A

11. Many plants have modified stems
That store food or function in asexual reproduction
Strawberry plant
Potato plant
Stolon (runner)
Taproot
Rhizome
Tuber
Ginger plant
Root
Figure 31.4B

12. Other types of plants have modified leaves
That function in protection or climbing
Figure 31.4C

13. 31.5 Plant cells and tissues are diverse in structure and function
Most plant cells have three unique structures
Chloroplasts, the sites of photosynthesis
A central vacuole containing fluid
A cell wall that surrounds the plasma membrane
Chloroplast
Central
vacuole
Cell walls
Primary cell wall
Middle lamella
Secondary cell wall
Plasma
membrane
Cell walls of adjoining cells
Plasmodesmata
Pit
Plasma membrane
Microtubules
Ribosomes
Golgi
apparatus
Mitochondrion
Endoplasmic
reticulum
Nucleus
Figure 31.5A

14. Plants have five major types of cells
Parenchyma, which perform most of the metabolic functions
Collenchyma, which provide support
Primary cell wall (thin)
Pit
Starch-storing vesicles
LM 270
Figure 31.5B
Primary cell wall (thick)
LM 270
Figure 31.5C

15. Sclerenchyma, the main component of wood
Secondary cell wall
Pits
Fiber cells
Primary cell wall
Sclereid cells
Fiber
Sclereid
LM 266
LM 200
Figure 31.5D

16. Angiosperms have water-conducting cells Tracheids and vessel elements
Pits
Openings in end wall
Vessel element
Tracheids
Colorized SEM 150
Figure 31.5E

17. Are food-conducting cells
Sieve-tube members
Are food-conducting cells
Sieve plate
Companion cell
Primary cell wall
Cytoplasm
Figure 31.5F

18. Two kinds of vascular tissue are
Xylem, which conveys water and minerals
Phloem, which transports sugars

19. 31.6 Three tissue systems make up the plant body
Each plant organ is made up of three tissue systems
The dermal, vascular, and ground tissue systems
Vein
Guard cells
Cuticle
Upper epidermis
Mesophyll
Lower epidermis
Stoma
Xylem
Phloem
Dicot leaf
Dicot stem
Sheath
Vascular bundle
Cortex
Pith
Epidermis
Monocot stem
Vascular cylinder
Endodermis
Dicot root
Key
Dermal tissue system
Ground tissue system
Vascular tissue system
Figure 31.6

20. The dermal tissue system
Covers and protects the plant
The vascular tissue system
Contains xylem and phloem and provides long-distance transport and support
The ground tissue system
Consists of parenchyma cells and supportive collenchyma and sclerenchyma cells

21. 31.7 Primary growth lengthens roots and shoots
PLANT GROWTH
31.7 Primary growth lengthens roots and shoots
Meristems, areas of unspecialized, dividing cells
Are where plant growth originates

22. Initiate primary (lengthwise) growth by producing new cells
Apical meristems
Are located in the tips of roots and in the terminal and axillary buds of shoots
Initiate primary (lengthwise) growth by producing new cells
Figure 31.7A
Terminal bud
Axillary buds
Root tips
Arrows = direction of growth

23. Roots are covered with a root cap
That protects the cells of the apical meristem
Vascular cylinder
Root hair
Cortex
Epidermis
Zone of maturation
Zone of elongation
Zone of cell division
Root cap
Apical meristem region
Cellulose fibers
Key
Dermal tissue system
Ground tissue system
Vascular tissue system
Figure 31.7B

24. Axillary bud meristems Are found near the apical meristems
Leaves
Axillary bud meristems 1 2
LM 103
Figure 31.7C

25. 31.8 Secondary growth increases the girth of woody plants
Secondary growth arises from cell division
In a cylindrical meristem called the vascular cambium

26. The vascular cambium thickens a stem
By adding layers of secondary xylem, or wood, next to its inner surface
Year 1
Early Spring
Late Summer
Year 2
Growth
Primary xylem
Vascular cambium
Primary phloem
Cor tex
Epidermis
Secondary xylem (wood)
Cork
cambium
Secondary phloem
Bark
Shed epidermis
Secondary xylem (2 years’ growth)
Key
Dermal tissue system
Ground tissue system
Vascular tissue system
Figure 31.8A

27. The heartwood and sapwood Consist of different layers of xylem
Outside the vascular cambium, the bark consists mainly of
Secondary phloem, cork cambium, and protective cork cells
Heartwood
Sapwood
Rings
Wood rays
Vascular cambium
Secondary phloem
Cork cambium
Cork
Bark
Figure 31.8B

28. REPRODUCTION OF FLOWERING PLANTS
31.9 Overview: The sexual life cycle of a flowering plant
The angiosperm flower consists of
Sepals, petals, stamens, and carpals
Stigma
Style
Ovary
Anther
Filament
Stamen
Petal
Ovule
Sepal
Carpel
Figure 31.9A

29. Pollen grains develop in anthers
At the tip of stamens

30. The tip of the carpel, the stigma Receives pollen grains
The ovary, at the base of the carpel
Houses the egg-producing structure, the ovule
Ovary, containing ovule
Fruit, (mature ovary), containing seed
Mature plant with flowers, where fertilization occurs
Seedling
Germinating seed
Seed
Embryo
Figure 31.9B

31. 31.10 The development of pollen and ovules culminates in fer tilization
In the diploid sporophyte of an angiosperm
Haploid spores are formed within ovules and anthers

32. The spores in the anthers
Give rise to male gametophytes, pollen grains, which produce sperm
A spore in an ovule
Produces the embryo sac, the female gametophyte, which contains an egg cell

33. Pollination
Is the arrival of pollen grains onto a stigma
A pollen tube grows into the ovule
And sperm pass through it and fer tilize both the egg and a second cell in a process called double fer tilization

34. Gametophyte development and fertilization in an angiosperm
Development of male gametophyte (pollen grain)
Development of female gametophyte (embryo sac)
Anther
Cell within anther
Meiosis
Four haploid spores
Single spore
Wall forms
Mitosis
(of each spore)
Two cells
Pollen grain
released from anther
Ovary
Ovule
Surviving cell (haploid spore)
Pollen germinates
Embryo sac
Egg cell
Two sperm in pollen tube
Pollen tube enters embryo sac
Two sperm discharged
Triploid (3n) endosperm nucleus
Double fer tilization occurs
Diploid (2n)
zygote (egg plus sperm)
Pollination
Figure

35. Secondary xylem (wood)
31.11 The ovule develops into a seed
After fertilization, the ovule becomes a seed
And the fertilized egg within it divides and becomes an embryo
Growth
Secondary xylem (wood)
Cork
cambium
Secondary phloem
Shed epidermis
Triploid cell
Ovule
Zygote
Embryo
Endosperm
Shoot
Cotyledons
Seed coat
Seed
Root
Two cells
Figure A

36. The other fertilized cell
Develops into the endosperm, which stores food for the embryo

37. The internal structures of dicot and monocot seeds
Differ in a variety of ways
Figure B
Embryonic
leaves
root
Seed coat
Cotyledons
shoot
Common bean (dicot)
Cotyledon
leaf
Sheath
Fruit tissue
Endosperm
Shoot
Corn (monocot)

38. 31.12 The ovary develops into a fruit
Angiosperms form fruits
Which help protect and disperse the seeds 1 2 3
Figure A
Upper part
of carpel
Ovule
Sepal
Ovar y
wall
Seed
Pod
(opened)
Figure B

39. May differ in size and development
Angiosperm fruits
May differ in size and development
Figure C

40. 31.13 Seed germination continues the life cycle
A seed starts to germinate
When it takes up water and star ts to expand
The embryo resumes growth
And absorbs nutrients from the endosperm
An embryonic root emerges
And a shoot pushes upward and expands its leaves

41. In dicot germination, the root emerges first
Followed by the shoot, which is covered by a protective hook
Foliage leaves
Embryonic
shoot
root
Cotyledons
Figure A

42. In monocot germination
A protective sheath surrounding the shoot breaks the soil
Foliage
leaves
Protective sheath
enclosing shoot
Embryonic
root
Cotyledon
Figure B

43. 31.14 Asexual reproduction produces plant clones
Asexual reproduction can be achieved via
Bulbs, sprouts, or runners
Figure A
Figure B
Figure D
Figure C

44. 1.15 Asexual reproduction is a mainstay of modern agriculture
CONNECTION
1.15 Asexual reproduction is a mainstay of modern agriculture
Propagating plants asexually from cuttings or bits of tissue
Can increase productivity but can also reduce genetic diversity
Figure