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37
Chapter 24 Reproduction in Plants Lecture Outline Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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Page 1: Bio 100 Chapter 24

Chapter 24Reproduction

in PlantsLecture Outline

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 2: Bio 100 Chapter 24

Alternation of generations Sporophyte

Dominant in flowering plants Bears flowers – reproductive structure Diploid or 2n Produces haploid microspores and megaspores by meiosis

Gametophyte Haploid or 1n Produces gametes Microspore undergoes mitosis and become a pollen grain, a male

gametophyte Megaspore undergoes mitosis to become embryo sac, a female

gametophyte

Upon fertilization, the cycle returns to the 2n sporophyte

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Page 3: Bio 100 Chapter 24

Plant Reproduction, cont.

Once a sperm fertilizes an egg, the zygote becomes an embryo, still within an ovule

Ovule develops into a seed, which contains the embryo and stored food surrounded by a seed coat

Ovary becomes a fruit, which aids in dispersing the seeds

When a seed germinates, a new sporophyte emerges and, through mitosis and growth, becomes a mature organism

Sexual life cycle of flowering plants is adapted to land

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Page 4: Bio 100 Chapter 24

24-4

Figure 24.1A Alternation of generations in flowering plants

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

mitosis

mitosis

diploid (2n)

haploid (n)

1

2

5

6

7

8

seed

zygote

sporophyte

ovaryovule

FERTILIZATION

egg

Female gametophyte(embryo sac)

Male gametophyte(pollen grain)

anther

3

4

microspore

MEIOSIS

megaspore

sperm

Page 5: Bio 100 Chapter 24

Flowers are unique to angiosperms Produce spores, protect gametophyte, attract

pollinator, produce fruits

Exs. of pollinators: birds, beetles, flies, butterflies, bats

Typical flower 4 whorls of modified leaves attached to a receptacle

1. Sepals – protect bud

2. Petals – attract pollinators

3. Stamens – Male Portion (anther & filament)

4. Carpel – Female Portion (stigma, style & ovary)

24-5

Page 6: Bio 100 Chapter 24

Figure 24.1B Anatomy of a flower

24-6

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

carpelstamen

antherfilament

petal

sepal receptacle

stigmastyleovaryovule

Page 7: Bio 100 Chapter 24

Figure 24.1C b. Azaleas are eudicots Eudicots have flower parts in fours or fives (p = petal; s = sepal)

24-7

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

a: © Farley Bridges; b: © Pat Pendarvis

b.

carpelstamen

petal

p3

p4

p5

p1

p2

Page 8: Bio 100 Chapter 24

24-8

Figure 24.1D A corn plant is monoecious (flowers that are only male or only femalea. The staminate flowers produce pollen that is carried by wind to b. the carpellate flowers, where ears of corn develop.

Page 9: Bio 100 Chapter 24

24-9

Figure 24B Butterflies, birds, and bats are adapted for acquiring nectar from certain flowers. Flowers that attract beetles produce much pollen and those that attract flies have the smell of rotting flesh

Page 10: Bio 100 Chapter 24

Sexual reproduction involves1. Production of pollen grains (male gametophytes) in

the anthers of stamens

2. Production of an embryo sac (female gametophyte) in an ovule located within the ovary of a carpel

Pollination Pollen transferred from anther to stigma so an egg

within female gametophyte is fertilized

Most angiosperms use animals to carry out pollination

24-10

Page 11: Bio 100 Chapter 24

Figure 24.2A Life cycle of flowering plants

24-11

Stamenanther

filament

Carpelstigmastyle

ovary

ovule

SporophyteMitosis

fruit(mature ovary)seed(mature ovule)

seedcoat

embryo

endosperm (3n)

Seed

diploid (2n)MEIOSIS MEIOSIS

microsporemother cell

Ovulepollen sac

Anther

Carpel

stigma

style

ovary

megasporemothe rcell

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 12: Bio 100 Chapter 24

Figure 24.2A Life cycle of flowering plants (cont.)

24-12

haploid (n)Pollen grain Microspores

(all survive)

Mitosis

MEIOSIS

Megaspores(one survives)

degeneratingmegaspores

Ovule

Mitosis

Embryosac(mature female gametophyte)

eggDOUBLE FERTILIZATION

(mature malegametophyte)

sperm

pollentube

sperm andpolar nucleifuse

sperm andegg fuse

generative cell

POLLINATION

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 13: Bio 100 Chapter 24

Figure 24.2B Wind pollination of a grass, with SEM of pollen grains

24-13

Page 14: Bio 100 Chapter 24

Coevolution As one species changes, the other changes too, so that

in the end, the two species are suited to one another

24-14

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

nectar guides

As a bee sees itAs we see it(both): © Heather Angel/Natural Visions

Page 15: Bio 100 Chapter 24

Double fertilization is unique in angiosperms Results in not only a zygote but also a food source for

the developing zygote Endosperm – nutritive tissue developing embryonic

sporophyte uses as energy source

Mature seed contains Embryo – will develop into the plant Stored food – endosperm Seed coat – develops from ovule wall for protection

24-15

Page 16: Bio 100 Chapter 24

Figure 24.2D The parts of a bean seed, a eudicot

24-16

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Embryo

Seed coat

immatureleaves

hypocotyl

Cotyledon(stored food)

radicle

(right): © Dwight Kuhn

Page 17: Bio 100 Chapter 24

24.4 The ovary becomes a fruit, which assists in sporophyte dispersal

Fruit = a ripened ovary

Protects and helps disperse the plant (“marketing for the seeds”)

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Page 18: Bio 100 Chapter 24

24.4 The ovary becomes a fruit, which assists in sporophyte dispersal

Fleshy Versus Dry Fruits

Dry fruits Exs: peas, maples

Fleshy fruits Exs: apples, strawberries, tomatoes, corn

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Page 19: Bio 100 Chapter 24

Figure 24.4 Fruit diversity

24-19

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

1

pea flower pea pod

stigma

ovary wall

ovule

pericarp(fruit wall)

Pea pods are a dry, dehiscent (can open to reveal seeds) fruit.

seed

Page 20: Bio 100 Chapter 24

Figure 24.4 Fruit diversity (Cont.)

24-20

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2 Maple tree fruits are dry, in dehiscent.

wing

seed covered by pericarp

© James Mauseth

Page 21: Bio 100 Chapter 24

Simple Versus Aggregate & Multiple Fruits Simple fruits are derived from the simple ovary of a

single carpel Exs: grapes, tomatoes Accessory fruits form from other flower parts in

addition to ovary Exs: strawberry, apple Aggregate and multiple fruits are examples of

compound fruits derived from several individual ovaries Strawberry – aggregate fruit, each ovary becomes a one-

seeded fruit called an achene Pineapple – a multiple fruit derived from many individual

flowers, each with its own carpel

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Page 22: Bio 100 Chapter 24

Figure 24.4 Fruit diversity (Cont.)

24-22

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

3

one fruit

flesh is fromreceptacle

Strawberries are a fleshy aggregate fruit.© Corbis RF

Page 23: Bio 100 Chapter 24

Figure 24.4 Fruit diversity (Cont.)

24-23

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

4 Raspberries are an aggregate fruit.

fruits fromovaries ofone flower

one fruit

© C Squared Studios/Getty RF

Page 24: Bio 100 Chapter 24

Figure 24.4 Fruit diversity (Cont.)

24-24

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

5

one fruit

Pineapple is a multiple fruit.

fruits fromovaries ofmany flowers

© BJ Miller/Biological Photo Service

Page 25: Bio 100 Chapter 24

Germination – seeds form into a seedling

Doesn’t usually take place until there is sufficient water, warmth, and oxygen to sustain growth

For seeds, dormancy is the time during which no growth occurs, even though conditions may be favorable for growth

24-25

Page 26: Bio 100 Chapter 24

Figure 24.5A Structure and germination of a common bean seed

24-26

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Embryo:epicotyl-plumule

hypocotyl

radicle

Seed coat

Cotyledon(stored food)

Cotyledon(two)

Bean seed(right): © Ed Reschke

Page 27: Bio 100 Chapter 24

Figure 24.5A Structure and germination of a common bean seed (Cont.)

24-27

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

seedcoat

first true leaves(primary leaves) epicotyl

with red cotyledons

hypocotylcotyledons

(two)

hypocotylsecondary

root

primaryroot

primary root

Page 28: Bio 100 Chapter 24

Figure 24.5B Structure and

germination of a corn kernel

24-28

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Seed coat

endosperm

cotyledon(one)coleoptile

Embryo:

radicle

coleorhiza

coleoptile

true leaf

prop root

pericarp

plumule

Corn kernel

first leaf

coleoptile

primary root

adventitiousroot

coleorhiza

radicle

(Top right): © James Mauseth

Page 29: Bio 100 Chapter 24

24.6 Plants have various ways of reproducing asexually

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Also called vegetative reproduction Type of cloning – offspring exactly like parent Plants can grow from axillary buds of above or

below ground stems Rhizome – underground horizontal stem (iris, many

grasses) Tuber – enlarged portion of rhizome (potato) Corm – bulbous underground stems (onion)

Page 30: Bio 100 Chapter 24

Figure 24.6 Asexual reproduction in plants 24-30

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Asexually produced offspring

stolon

© G.I. Bernard/Animals Animals

Page 31: Bio 100 Chapter 24

Figure 24.6 Asexual reproduction in plants (cont.) 24-31

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Rhizome

rhizome

adventitious roots

tuber

axillarybud

Tuber Corm

paperyleaves

rhizome

branch

adventitious roots

corm

axillarybud

Page 32: Bio 100 Chapter 24

24.7 Cloning of plants in tissue culture assists agriculture

Tissue culture Growth of a tissue in an artificial liquid or on agar

3 methods Somatic embryogenesis – technique that uses hormones to

cause plant tissues to generate small masses of cells Meristem tissue culture – many new shoot tips from a single

shoot tip Anther tissue culture – produces haploid plantlets or

chromosomal doubling chemically induced

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Page 33: Bio 100 Chapter 24

Figure 24.7A Somatic embryogenesis

24-33

(both): Courtesy Prof. Dr. Hans-Ulrich Koop, from Plant Cell Reports, 17:601-604

b. Cell wall regenerationa. Protoplasts, naked cells

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 34: Bio 100 Chapter 24

Figure 24.7A Somatic embryogenesis (Cont.)

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c. Aggregates of cells d. Callus, undifferentiated mass

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

(both): Courtesy Prof. Dr. Hans-Ulrich Koop, from Plant Cell Reports, 17:601-604

Page 35: Bio 100 Chapter 24

Figure 24.7A Somatic embryogenesis (Cont.)

24-35(both): Courtesy Prof. Dr. Hans-Ulrich Koop, from Plant Cell Reports, 17:601-604

e. Somatic embryo f. Plantlet

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Page 36: Bio 100 Chapter 24

24-36

Figure 24.7B Producing whole plants from meristem tissue

Page 37: Bio 100 Chapter 24

Connecting the Concepts:Chapter 24

Life, as we know it, would not be possible without vascular plants

Although we now live in an industrialized society, we are still dependent on plants and have put them to many more uses We grow plants for food, shelter, beauty and substances for

industry Half of all pharmaceutical drugs have their origin in plants

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