Chapter 27: pp. 493 - 509
Outline
BIOLOGY
10th Edition
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
!  Reproductive
Sylvia S. Mader
Flowering Plants:
Reproduction
Strategies
Alternation of generations
!  Adaptation to a land environment
!  Flowers
!
!
!
Pollination
Fertilization
!  Seed
Development
!  Fruit
!  Seed
Germination
!  Asexual Reproduction
!  Tissue Culture
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1
PowerPoint® Lecture Slides are prepared by Dr. Isaac Barjis, Biology Instructor
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2
Alternation of Generations
in Flowering Plants
Reproductive Strategies
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
!  All
plants have a two-stage, alternating life
cycle
!  Sporophyte
8
produces haploid spores by
anther
1
7
meiosis
!  Spores divide mitotically to become haploid
gametophytes
!  Gametophytes produce gametes
!  Gametes fuse to produce zygote
!  Zygote divides mitotically to become diploid
sporophyte
sporophyte
seed
2
diploid (2n)
6
zygote
FERTILIZATION
ovule
ovary
MEIOSIS
haploid (n)
3
egg
sperm
5
microspore
megaspore
4
Male gametophyte
(pollen grain)
Female gametophyte
(embryo sac)
3
4
Reproductive Strategies
!  Flower
!
!
Flowers
produces two types of spores
!  Flower
develops in response to
environmental signals such as day length
Microspore - Male gametophyte
!
Undergoes mitosis
!
Becomes pollen grain
!  In
monocots, flower parts occur in threes and
multiples of three
!  In eudicots, flower parts occur in fours or fives
and multiples of four or five
Megaspore - Female gametophyte
!
Undergoes mitosis
!
Becomes embryo sac within an ovary, within an ovule
!
Ovule becomes seed
5
Anatomy of a Flower
Monocot vs. Eudicot Flowers
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stamen
anther
filament
petal
6
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
carpel
stigma
style
ovary
ovule
stamen
s1
p2
carpel
s2
p1
petal
p3
sepal
s3
a. Daylil y , Hemerocallis sp.
p3
p2
carpel
stamen
p4
sepal
receptacle
petal
p1
p5
peduncle
b. Festive azalea, Rhododendron sp.
a: © Farley Bridges; b: © Pat Pendarvis
7
8
Flowers
Flowers
!  Leaf-like
sepals protect the bud
!  Open flower has whorl of petals
!  Stamens
!  Anther
!  Four
whorls of modified leaves attached to a
receptacle at the end of a flower stalk
are male portion of flower
- Saclike container
!  Filament
!  Carpel
!  Receptacle
with a single flower is a peduncle
!  Receptacle with several flowers is a pedicle
is female portion of flower
!  Stigma
!  Style
- Slender stalk
- Enlarged sticky knob
- Slender stalk
!  Ovary
- Enlarged base enclosing ovules
9
10
Corn Plants are Monoecious
Flowers
!  Complete
vs. incomplete flowers:
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Complete flowers have sepals, petals, stamens,
and a carpel
!  Incomplete flowers missing one or more of above
!
!  Bisexual
!
!
vs. unisexual flowers:
Bisexual flowers have both stamens and carpel
Unisexual flowers have one but not the other
!  Monoecious
vs. dioecious plants
Monoecious plants have staminate flowers and
carpellate flowers on the same plant
!  Dioecious plants have all staminate or all
carpellate flowers
!
a. Staminate flowers
b. Carpellate flowers
a: © Arthur C. Smith III/Grant Heilman Photography, Inc.; b: © Larry Lefever/Grant Heilman Photography, Inc.
11
12
Life Cycle of Flowering Plants
From Spores to Fertilization
!  Male
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
anther
Mature Seed
Development of the male
gametophyte:
In pollen sacs of the anther , a
microspore mother cell undergoes
meiosis to produce 4 microspores
each
seed coat
The ovule
develops into a
seed containing
the embryonic
sporophyte and
endosperm.
are produced in anthers
!  Each anther has four pollen sacs, each with
many microsporocytes
anther
mitosis
ovule
ovary
Pollen sac
ovary
Ovule
embryo
microspore
mother cell
endosperm (3n)
Sporophyte
Seed
MEIOSIS
egg
!  Undergoes
meiosis to produce microspores
!  Mitosis produces pollen grains
pollen
tube
Microspores
Pollination
occurs;
a pollen grain
germinates and
produces a pollen
sperm
tube
cell
nucleus
sperm
ovule
wall
tube cell
Development of
the sporophyte:
Mature male
gametophyte
polar nuclei
MEIOSIS
haploid (n)
Pollination
During double
fertilization, one
sperm from the
Male gametophyte
Will fertilize the
egg; another
Sperm will join with
polar nuclei to
produce the 3n
endosperm.
megaspore
mother cell
diploid (2n)
DOUBLE FERTILIZATION
generative cell
Megaspores
ovule
wall
Pollen grain
(male gametophyte)
antipodals
polar nuclei
egg cell
Microspores
develop into male
gametophytes
(pollen grains).
One megaspore
becomes the
embryo sac
(female
gametophyte).
Gametophytes
!  Microspores
Development of the female
gametophyte:
In an ovule within an ovary, a
megaspore mother cell
undergoes meiosis to
Produce 4 megaspores.
megaspore
3 megaspores
disintegrate
integument
micropyle
synergids
Embryo sac
(mature female gametophyte)
(Top): Courtesy Graham Kent; (Bottom): © Ed Reschke
13
Pollination
14
Pollination
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
!  Pollination
is the transfer of pollen from an
anther to the stigma of a carpel
!  Self-pollination
occurs if the pollen is from the
same plant
!  Cross-pollination occurs if the pollen is from a
different plant
a.
b.
118 µm
c.
8 µm
a: © George Bernard/Animals Animals/Earth Scenes; b: © Simko/Visuals Unlimited; c: © Dwight Kuhn
15
16
Pollinators
Pollinators
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
a.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
b.
Aa: © Steven P. Lynch; Ab: © Robert Maier/Animals/Animals/Earth Scenes
a.
b.
Ba: © Anthony Mercieca/Photo Researchers, Inc.; Bb: © Merlin D. Tuttle/Bat Conservation International;
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Production of Female Gametophyte
!  Ovary
18
Fertilization
!  When
pollen grain lands on stigma, it
germinates forming a pollen tube
!  Passes between the stigma and style to
reach the micropyle of the ovule
!  Double fertilization occurs
contains one or more ovules
!  Ovule
has mass of parenchyma cells
!  One cell enlarges to become megasporocyte
!  Undergoes
meiois and becomes four haploid
megaspores
!  Functional megaspore divides mitotically until there
are eight nuclei of a female gametophyte
!  One
sperm nucleus unites with the egg
nucleus, producing a zygote
!  Other sperm nucleus unites with the polar
nuclei, forming a 3n endosperm cell
19
20
Development of an Eudicot Embryo
Seed Development
!  Development
of eudicot embryo
!  After
double fertilization, endosperm nucleus
begins to divide asymmetrically
!  Small cell is destined to become the embryo
!  Larger cell divides repeatedly to become a
suspensor
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Arabidopsis thaliana
endosperm
endosperm nucleus
A. thaliana
A. thaliana
endosperm
cotyledons appearing
Capsella
shoot apical
meristem
zygote
1
bending
cotyledons
hypocotyl
(root axis)
epicotyl (shoot
apical meristem)
seed
coat
embryo
endosperm
suspensor
zygote
Capsella
root
apical
meristem
radicle
(root apical
meristem)
cotyledons
basal cell
Zygote stage: Double
fertilization results in zygote
(true green) and endosperm.
2
Proembryo stage: Embryo
(green) is multicellular and
the suspensor (purple) is
functional.
3 Globular stage:
Embryo is globe
shaped.
4
Heart stage: Embryo is
heart shaped.
5 Torpedo stage: Embryo is
torpedo shaped; the
cotyledons are obvious.
6
Mature embryo stage: The
epicotyl will be the shoot
system; the hypocotyl will
be the root system.
(Proembryo): Courtesy Dr. Chun-Ming Liu; (Torpedo): © Biology Media/Photo Researchers, Inc.; (Mature embryo): © Jack Bostrack/Visuals Unlimited
21
Monocot vs. Eudicot
22
Development of Eudicot Embryo
!  During
cells
!  Outermost cells will become dermal tissue
!  Embryo is heart shaped when cotyledons
appear
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seed coat
plumule
pericarp
hypocotyl
endosperm
coleoptile
radicle
cotyledon
embryo
embryo
plumule
cotyledon
!  Epicotyl
is portion between cotyledons
contributing to shoot development
!  Hypocotyl is portion below that contributes to
stem development
!  Radicle contributes to root development
radicle
coleorhiza
a.
globular stage, prembryo is ball of
b.
a: © Dwight Kuhn; b: Courtesy Ray F. Evert/University of Wisconsin Madison
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24
Fruit Types and Seed Dispersal
!  Simple
Simple Fruits
Fruits
!  Fleshy
!  Simple
fruits are derived from single or several
united carpels
!  Legumes
Drupe
Berry
Pome
are fruits that split along two sides when
mature
!
!
!  Dry
Follicle
Legume
Capsule
Achene
Nut
Grain
Dehiscent - Split open
Indehiscent - Fail to split open
25
26
Fruits
Simple Fruits
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!
Dispersal
Drupe
True Berry
exocarp
!
Many seeds are dispersed by wind
chamber of
ovary has
many seeds
pericarp
exocarp (skin)
mesocarp (flesh)
endocarp (pit
contains seed)
!
Woolly hairs, plumes, wings
a. A drupe is a fleshy fruit with a pit containing a single seed produced
from a simple ovary.
b. A berry is a fleshy fruit having seeds and pulp produced from a
compound ovary.
Samara
Legume
!
Fleshy fruits - Attract animals and provide them
with food
seed covered by pericarp
wing
pericarp
seed
c. A legume is a dry dehiscent fruit produced from a simple ovary .
!
d. A samara is a dry indehiscent fruit produced from a simple ovary .
Aggregate Fruit
Peaches, cherries, tomatoes
Multiple Fruit
fruit from many
ovaries of a
single flower
!
Accessory fruit - Bulk of fruit is not from ovary, but
from receptacle
!
e. An aggregate fruit contains many fleshy fruits produced from simple
ovaries of the same flower.
one fruit
fruits from ovaries
of many flowers
Apples
f. A multiple fruit contains many fused fruits produced from simple
ovaries of individual flowers.
a, b: © Kingsley Stern; c: © Dr. James Richardson/Visuals Unlimited; d: © James Mauseth; e: Courtesy Robert A. Schlising; f: © Ingram Publishing/Alamy
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Fruit Dispersal by Animals
Compound Fruits
!  Compound
fruits develop from several
individual ovaries
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!  Aggregate
Fruits
!  Ovaries
are from a single flower
!  Blackberry
!  Multiple
Fruits
!  Ovaries
are from separate flowers clustered
together
a.
b.
a: © Marie Read/Animals Animals/Earth Scenes; b: © Scott Camazine/Photo Researchers, Inc.
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Seed Germination
30
Seed Germination
!  When
seed germination occurs, the
embryo resumes growth and metabolic
activity
!  Length of time seeds retain their viability is
quite variable
!  Environmental
requirements for seed
germination
!  Availability
of oxygen for metabolic needs
!  Adequate temperature for enzyme activity
!  Adequate moisture for hydration of cells
!  Light (in some cases)
!  Some
seeds do not germinate until they have
been through a dormant period
!  Respiration
and metabolism continue
throughout dormancy, but at a reduced
level
!  Temperate
zones - Cold Weather
!  Deserts - Rain
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Eudicot and Monocot Seed
Structure and Germination
Asexual Reproduction in Plants
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
!  Plants
endosperm
cotyledon
(one)
coleoptile
hypocotyl
radicle
plumule
seed coat
radicle
cotyledon
coleorhiza
Corn kernel
Seed structure
true leaf
first true leaves
(primary leaves)
seed
coat
tissue
!  Allows them to reproduce asexually by
vegetative propagation
!  Plant hormone auxin:
pericarp
cotyledons
plumule (two)
cotyledons
(two)
epicotyl
withered
cotyledons
!  Can
be used to cause roots to develop
!  Expands the list of plants that can be
propagated from cuttings
first leaf
hypocotyl
coleoptile
coleoptile
prop root
radicle
hypocotyl
primary
root
secondary
root
adventitious
root
coleorhiza
primary
root
contain nondifferentiated meristem
primary root
Corn germination and growth
b.
Bean germination and growth
a.
a: © Ed Reschke; b: © James Mauseth
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Asexual Reproduction in Plants
34
Tissue Culture of Plants
!  Tissue
culture is the growth of a tissue in an
artificial liquid or solid culture medium
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!
Plant cells are totipotent
!  Meristem
!
Parent plant
Auxins and cytokinins allow many new shoots to
develop from a single shoot tip
!
stolon
culture
Virus-free clonal plants
!  Suspension
Asexually produced offspring
!
Culture
Rapidly growing calluses are cut into small pieces
and shaken into a liquid nutrient medium
!
Single cells or small clumps break off and form a
suspension
© G.I. Bernard/Animals Animals/Earth Scenes
35
36
Tissue Culture in Plants
Genetic Engineering
!  Traditionally,
hybridization was used to
produce plants with desirable traits
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a. Protoplasts, naked cells
!
b. Cell wall regeneration
Crossing different varieties of plants
!  Transgenic
plants can now be produced by
placing foreign genes into a plant
c. Aggregates of cells
d. Callus, undifferentiated mass
!
Agricultural plants with improved traits
!
!
e. Somatic embryo
Commercial products
!
f. Plantlet
(All): Courtesy Prof. Dr. Hans-Ulrich Koop, from Plant Cell Reports, 17:601-604
Pest or insecticide resistant
Human hormones, antibodies
37
Review
38
Chapter 27: pp. 493 - 509
Strategies
Flowering Plants:
Reproduction
Alternation of generations
!  Adaptation to a land environment
!  Flowers
!
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Pollination
!  Fertilization
!
!  Seed
Development
!  Fruit
Germination
!  Asexual Reproduction
!  Tissue Culture
10th Edition
Sylvia S. Mader
!  Reproductive
BIOLOGY
!  Seed
© Royalty-Free/Corbis
PowerPoint® Lecture Slides are prepared by Dr. Isaac Barjis, Biology Instructor
39
Copyright © The McGraw Hill Companies Inc. Permission required for reproduction or display
40