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BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
CHAPTER 17
Plants, Fungi, and the
Colonization of Land
Modules 17.1 – 17.3
From PowerPoint® Lectures for Biology: Concepts & Connections
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Plants and Fungi—A Beneficial Partnership
• Mutually beneficial associations of plant roots
and fungi are common
– These associations are called mycorrhizae
– They may have enabled plants to colonize land
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• Citrus growers face a dilemma
– They use chemicals to control disease-causing
fungi
– But these also kill beneficial mycorrhizae
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17.1 What is a plant?
• Plants are multicellular photosynthetic
eukaryotes
– They share many characteristics with green
algae
– However, plants evolved unique features as they
colonized land
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PLANT
LEAF
performs
photosynthesis
CUTICLE
reduces water
loss; STOMATA
allow gas exchange
STEM
supports plant
(and may perform
photosynthesis)
Surrounding water
supports the alga
ROOTS
anchor plant;
absorb water and
minerals from
the soil (aided
by mycorrhizal
fungi)
ALGA
WHOLE ALGA
performs
photosynthesis;
absorbs water,
CO2, and
minerals from
the water
HOLDFAST
anchors the alga
Figure 17.1A
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• Unlike algae, plants have vascular tissue
– It transports water and nutrients throughout the
plant body
– It provides internal support
Figure 17.1B
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PLANT EVOLUTION AND DIVERSITY
17.2 Plants evolved from green algae called
charophyceans
• Molecular studies indicate that green algae
called charophyceans are the closest relatives of
plants
Figure 17.2A, B
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• Cooksonia was one of the earliest vascular land
plants
Sporangia
Figure 17.2C
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17.3 Plant diversity provides clues to the
evolutionary history of the plant kingdom
• Two main lineages arose early from ancestral
plants
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Gymnosperms
(e.g., conifers)
Seedless vascular plants
(e.g., ferns, horsetails)
Bryophytes (e.g., mosses)
Charophyceans (a group of green algae)
CENOZOIC
MESOZOIC
PALEOZOIC
Radiation of
flowering plants
First seed plants
Early vascular plants
Origin of plants
Figure 17.3A
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• One lineage gave rise to bryophytes
– These are plants that lack vascular tissue
– Bryophytes include mosses, which grow in a low,
spongy mat
Figure 17.3B
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• Vascular plants are the other ancient lineage
• Ferns and seed plants were derived from early
vascular plants and contain
– xylem and phloem
– well-developed roots
– rigid stems
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• Ferns are seedless plants whose flagellated
sperm require moisture to reach the egg
Figure 17.3C
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• A major step in plant evolution was the
appearance of seed plants
– Gymnosperms
– Angiosperms
• These vascular plants have pollen grains for
transporting sperm
• They also protect their embryos in seeds
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• Gymnosperms, such as pines, are called naked
seed plants
– This is because their seeds do not develop inside
a protective chamber
• The seeds of angiosperms, flowering plants,
develop in ovaries within fruits
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ALTERNATION OF GENERATIONS AND
PLANT LIFE CYCLES
17.4 Haploid and diploid generations alternate in
plant life cycles
• The haploid gametophyte produces eggs and
sperm by mitosis
– The eggs and sperm unite, and the zygote
develops into the diploid sporophyte
– Meiosis in the sporophyte produces haploid
spores, which grow into gametophytes
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Gametophytes
(male and female)
n
Spores
n
Meiosis
Gametes
(sperm and eggs)
n
HAPLOID
Fertilization
DIPLOID
Zygote
2n
Sporophyte
2n
Figure 17.4
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17.5 Mosses have a dominant gametophyte
• Most of a mat of moss consists of gametophytes
– These produce eggs and swimming sperm
– The zygote stays on the gametophyte and
develops into the less conspicuous sporophyte
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5 Mitosis and
Sperm (n) (released from
their gametangium)
development
Spores
(n)
1
Gametangium
containing the egg (n)
(remains within
gametophyte)
Gametophytes
(n)
Egg
HAPLOID
Meiosis
Fertilization
DIPLOID
Sporangium
Stalk
2
4
Zygote
(2n)
Gametophyte
(n)
3 Mitosis and
development
Sporophytes (growing from gametophytes)
Figure 17.5
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17.6 Ferns, like most plants, have a dominant
sporophyte
• Ferns, like mosses, have swimming sperm
• The fern zygote remains on the small,
inconspicuous gametophyte
– Here it develops into the sporophyte
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5
Sperm (n)
Mitosis and
development
Spores
(n)
1
Gametophyte (n)
(underside)
Egg (n)
HAPLOID
Meiosis
Sporangia
Fertilization
DIPLOID
2
4
Zygote
(2n)
3 Mitosis and
development
Sporophyte (2n)
New sporophyte growing
out of gametophyte
Figure 17.6
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17.7 Seedless plants formed vast “coal forests”
• Ferns and other seedless plants once dominated
ancient forests
– Their remains formed coal
Figure 17.7
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• Gymnosperms that produce cones, the conifers,
largely replaced the ancient forests of seedless
plants
– These plants remain the dominant
gymnosperms today
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17.8 A pine tree is a sporophyte with tiny
gametophytes in its cones
• Sporangia in male cones make spores that
develop into male gametophytes
– These are the pollen grains
• Sporangia in female cones produce female
gametophytes
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4
Female gametophyte (n)
Haploid spore cells in
ovule develop into
female gametophyte,
which makes egg.
5 Male gametophyte (pollen)
Egg (n)
grows tube to egg and
makes and releases sperm.
Sperm (n)
Male gametophyte
(pollen grain)
HAPLOID
DIPLOID
MEIOSIS
Ovule
Fertilization
Scale
Sporangium
(2n)
Seed
coat
3 Pollination
HAPLOID
Pollen grains
(male
gametophytes)
(n)
Embryo
(2n)
Integument
1 Female cone
bears ovules.
6 Zygote develops
MEIOSIS
into embryo, and
ovule becomes
seed.
2 Male cone produces
spores by meiosis;
spores develop into
pollen grains
Zygote
(2n)
7
Sporophyte
Seed
Seed falls to
ground and germinates,
and embryo grows into tree.
Figure 17.8
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17.9 The flower is the centerpiece of angiosperm
reproduction
• Most plants are angiosperms
– The hallmarks of these plants are flowers
Pollen grains
Anther
Stigma
CARPEL
Ovary
STAMEN
PETAL
Ovule
SEPAL
Figure 17.9A, B
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Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
17.10 The angiosperm plant is a sporophyte with
gametophytes in its flowers
• The angiosperm life cycle is similar to that of
conifers
– But it is much more rapid
– In addition, angiosperm seeds are protected and
dispersed in fruits, which develop from ovaries
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2 Haploid spore in each
Stigma
Egg (n)
ovule develops into
female gametophyte,
which produces egg.
3 Pollination
Pollen
grain
and
growth
of pollen
tube
Ovule
Pollen
tube
1 Haploid spores
in anthers develop
into pollen grains:
male gametophytes.
Sperm
Pollen (n)
HAPLOID
Meiosis
Fertilization
DIPLOID
4
Zygote
(2n)
Food supply
Seed
coat
Seeds
7 Seed
Ovary
germinates,
and embryo
grows into plant.
Ovule
Sporophyte
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6 Fruit
5 Seed
Embryo
(2n)
Figure 17.10
Figure 31.10
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BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
CHAPTER 31
Plant Structure, Reproduction,
and Development
Modules 31.1 – 31.4
From PowerPoint® Lectures for Biology: Concepts & Connections
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
PLANT STRUCTURE AND FUNCTION
31.2 The two main groups of angiosperms are the
monocots and the dicots
• Angiosperms, or flowering plants, are the most
familiar and diverse plants
• There are two main types of angiosperms
– Monocots include orchids, bamboos, palms,
lilies, grains, and other grasses
– Dicots include shrubs, ornamental plants, most
trees, and many food crops
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• Monocots and dicots differ in seed leaf number
and in the structure of roots, stems, leaves, and
flowers
SEED LEAVES
LEAF VEINS
STEMS
FLOWERS
ROOTS
MONOCOTS
One
cotyledon
Main veins
usually parallel
Vascular bundles in
complex arrangement
Floral parts usually
in multiples of three
Fibrous
root system
DICOTS
Two
cotyledons
Main veins
usually branched
Vascular bundles
arranged in ring
Floral parts usually in
Taproot
multiples of four or five usually present
Figure 31.2
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31.3 The plant body consists of roots and shoots
• Root system
– Provides anchorage
– Absorbs and transports minerals and water
– Stores food
• Root hairs increase the surface area for
absorption
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• Shoot system
– Consists of stems, leaves, and flowers in
angiosperms
– Stems are located above the ground and support
the leaves and flowers
– Leaves are the main sites of photosynthesis in
most plants
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Terminal bud
Blade
Leaf
Flower
Petiole
Axillary bud
Stem
SHOOT
SYSTEM
Node
Internode
Taproot
ROOT
SYSTEM
Root
hairs
Figure 31.3
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• The terminal bud is located at the tip of a stem
– It is the growth point of the stem
• Axillary buds can give rise to branches
• In apical dominance, the terminal bud produces
hormones that inhibit the growth of axillary
buds
– This results in a taller plant that has greater
exposure to light
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31.4 Many plants have modified roots and shoots
• Roots and stems are adapted for a variety of
functions
– Storing food
– Asexual reproduction
– Protection
• Plant breeders have improved
the yields of root crops by
selecting varieties, such as
the sugar beet plant, with
very large taproots
Figure 31.4A
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• Modified stems
include
STRAWBERRY
PLANT
– runners, for
asexual
reproduction
Runner
POTATO
PLANT
– rhizomes, for
plant growth and
food storage
– tubers, for food
storage in the
form of starch
Rhizome
IRIS
PLANT
Rhizome
Tuber
Taproot
Root
Figure 31.4B
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• Modified leaves include tendrils and spines
– Tendrils help plants to climb
– Spines may protect the plant from plant-eating
animals
Figure 31.4C
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31.6 Three tissue systems make up the plant body
• Roots, stems, and
leaves are made
of three tissue
systems
Leaf
Stem
– The epidermis
– The vascular
tissue system
– The ground
tissue system
Root
Epidermis
Ground
tissue system Vascular
tissue system
Figure 31.6A
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• The epidermis covers and protects the plant
– The cuticle is a waxy coating secreted by
epidermal cells that helps the plant retain water
• The vascular tissue contains xylem and phloem
– It provides support and transports water and
nutrients
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• The ground tissue system functions mainly in
storage and photosynthesis
– It consists of parenchyma cells and supportive
collenchyma and sclerenchyma cells
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• The ground tissue system of the root forms the
cortex
– The cortex consists mostly of parenchyma tissue
• The selective barrier forming the innermost
layer of the cortex is the endodermis
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VASCULAR
TISSUE
SYSTEM
Xylem
Phloem
Epidermis
GROUND
TISSUE
SYSTEM
Cortex
Endodermis
Figure 31.6B
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• These microscopic cross sections of a dicot and
a monocot indicate several differences in their
tissue systems
Figure 31.6C
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• The three tissue systems in dicot leaves
– The epidermis consist of pores called stomata
(singular, stoma) flanked by regulatory guard
cells
Figure 31.6D
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– The ground tissue system of a leaf is called
mesophyll and is the site of photosynthesis
Figure 31.6D
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– The vascular tissue consists of a network of
veins composed of xylem and phloem
Figure 31.6D
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PLANT GROWTH
31.7 Primary growth lengthens roots and shoots
• Most plants exhibit indeterminate growth
– They continue to grow as long as they live
• In contrast, animals are characterized by
determinate growth
– They cease growing after reaching a certain size
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• Annuals complete their life cycle in a single year
or growing season
– Examples: wheat, corn, rice, and most
wildflowers
• Biennials complete their life cycle in two
years, with flowering occurring in the second
year
– Examples: beets and carrots
• Perennials live and reproduce for many years
– Examples: trees, shrubs, and some grasses
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• Growth in all plants originates in tissues called
meristems
– Meristems are areas of unspecialized, dividing
cells
• Apical meristems are located at the tips of
roots and in the terminal buds and axillary
buds of shoots
– They initiate primary growth, lengthwise
growth by the production of new cells
– Roots and stems lengthen further as cells
elongate and differentiate
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Terminal bud
Axillary buds
Arrows =
direction
of growth
Root
tips
Figure 31.7A
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Cortex
Epidermis
DIFFERENTIATION
Vascular
cylinder
CELL
DIVISION
ELONGATION
Root hair
Cellulose
fibers
Apical meristem
region
Root
cap
Figure 31.7B
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Leaves
Apical
meristem
Axillary bud
meristems
1
2
Figure 31.7C
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31.8 Secondary growth increases the girth of
woody plants
• An increase in a plant's girth results from
secondary growth
• Secondary growth involves cell division in two
cylindrical meristems
– Vascular cambium
– Cork cambium
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• Vascular cambium thickens a stem by adding
layers of secondary xylem, or wood, next to its
inner surface
– It also produces the secondary phloem, which
is a tissue of the bark
• Cork cambium produces protective cork cells
located in the bark
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Figure 31.8A
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• Everything external to the vascular cambium is
considered bark
– Secondary phloem
– Cork cambium
– Protective cork cells
• Heartwood in the center of the trunk consists
of older, clogged layers of secondary xylem
• Sapwood consists of younger, secondary xylem
that still conducts water
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• A woody log is the result of several years of
secondary growth
Sapwood
Rings
Wood
rays
Heartwood
Sapwood
Vascular cambium
Secondary phloem
Bark
Cork cambium
Cork
Heartwood
Figure 31.8B
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PLANT REPRODUCTION
31.9 Overview: The sexual life cycle of a flowering
plant
• The angiosperm
flower is a
reproductive shoot
consisting of
Anther
Carpel
Stigma
Ovary
– sepals
– petals
Stamen
– stamen
Ovule
– carpels
Sepal
Petal
Figure 31.9A
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• Sepals are usually green and resemble leaves in
appearance
– Sepals enclose and protect the flower bud
before the flower opens
• Petals are often bright and colorful
– They attract insects (pollinators)
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• Stamens are the male reproductive organs of
plants
– Pollen grains develop in anthers, at the tips of
stamens
• Carpels are the female reproductive organs of
plants
– The ovary at the base of the carpel houses the
ovule
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• The life cycle of an angiosperm involves several
stages
Ovary, containing
ovule
Embryo
Fruit,
containing seed
Seed
Mature plant with
flowers, where
fertilization occurs
Seedling
Germinating seed
Figure 31.9B
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31.10 The development of pollen and ovules
culminates in fertilization
• The plant life cycle alternates between diploid
(2n) and haploid (n) generations
• Double fertilization is unique to plants
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Figure 31.10
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31.11 The ovule develops into a seed
• After fertilization, the ovule becomes a seed
– The fertilized egg within the seed divides to
become an embryo
– The other fertilized cell develops into the
endosperm, which stores food for the embryo
• A resistant seed coat protects the embryo and
endosperm
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Triploid cell
OVULE
Zygote
Two cells
Cotyledons
Endosperm
Seed coat
Shoot
Embryo
Root
SEED
Figure 31.11A
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• Seed dormancy is an important evolutionary
adaptation in which growth and development
are suspended temporarily
– It allows time for a plant to disperse its seeds
– It increases the chance that a new generation of
plants will begin growing only when
environmental conditions favor survival
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• Comparison between dicot and monocot seeds
Seed coat
Embryonic
shoot
Embryonic
leaves
Embryonic
root
Cotyledons
COMMON BEAN (DICOT)
Fruit tissue
Cotyledon
Seed coat
Endosperm
Embryonic
leaf
Embryonic
shoot
Sheath
Embryonic
root
CORN (MONOCOT)
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Figure 31.11B
31.12 The ovary develops into a fruit
• The ovary develops into a fruit which helps
protect and disperse the seeds
Figure 31.12A
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• There is a correspondence between flower and
fruit in a pea plant
– The wall of the ovary becomes the pod
– The ovules develop into the seeds
Upper part
of carpel
Ovule
Seed
Ovary
wall
Sepal
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Pod
(opened)
Figure 31.12B
– The small, threadlike structure at the end of the
pod is what remains of the upper part of the
flower's carpel
– The sepals of the flower stay attached to the
base of the green pod
Upper part
of carpel
Ovule
Seed
Ovary
wall
Sepal
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Pod
(opened)
Figure 31.12B
• Simple fruits develop from a flower with a
single carpel and ovary
– Apples, pea pods, cherries
• Aggregate fruits develop from a flower with
many carpels
– Raspberries
• Multiple fruits develop
from a group of flowers
clustered tightly together
– Pineapples
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Figure 31.12C
BIOLOGY
CONCEPTS & CONNECTIONS
Fourth Edition
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor
CHAPTER 33
Control Systems in Plants
Modules 33.1 – 33.5
From PowerPoint® Lectures for Biology: Concepts & Connections
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
PLANT HORMONES
33.1 Experiments on how plants turn toward light
led to the discovery of a plant hormone
• Hormones coordinate the
activities of plant cells
and tissues
• The study of plant
hormones began with
observations of plants
bending toward light
– This phenomenon is
called phototropism
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Figure 33.1A
• Phototropism results from faster cell growth on
the shaded side of the shoot than on the
illuminated side
Shaded
side of
shoot
Light
Illuminated
side of
shoot
Figure 33.1B
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• Experiments carried out by Darwin and others
showed that the tip of a grass seedling detects
light and transmits a signal down to the
growing region of the shoot
Light
Control
Figure 33.1C
Tip
removed
Tip covered
by opaque
cap
Tip
covered
by transparent cap
DARWIN AND DARWIN (1880)
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Base
covered
by opaque
shield
Tip
separated
by gelatin
block
Tip
separated
by mica
BOYSEN-JENSEN (1913)
• It was discovered in the 1920s that a hormone
was responsible for the signaling Darwin
observed
– This hormone was dubbed auxin
– Auxin plays an important role in
phototropism
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Shoot tip placed on agar block.
Chemical (later called auxin)
diffuses from shoot tip into agar.
Agar
Control
Block with
chemical
stimulates
growth.
Offset blocks with
chemical stimulate
curved growth.
Other controls:
Blocks with no
chemical have
no effect.
NO LIGHT
Figure 33.1D
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33.2 Five major types of hormones regulate plant
growth and development
• Hormones regulate plant growth and
development by affecting
– cell division
– cell elongation
– cell differentiation
• Only small amounts of hormones are
necessary to trigger the signal-transduction
pathways that regulate plant growth and
development
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Table 33.2
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