Transcript Mader 11 ch 27 Reproduction in Flowering Plants

Chapter 27
Reproduction in Flowering Plants
Topics:
27.1
27.2
27.3
27.4
Sexual Reproductive Strategies
Seed Development
Fruits and Seeds
Asexual Reproductive Strategies
Read Textbook Ch 27 and pages 569-572
Read Cliffs AP Book
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
•
Life Cycle of flowering
Plant
– Alternation of generations
• Sporophyte (2n)
– Dominant in flowering
plants – plant we recognize
– Diploid – produces haploid
spore by meiosis
• Gametophyte (n)
– Haploid- produces diploid
zygote
– Small and not
independently living (is
independent in mosses and
ferns)
– (Dominant in mosses)
– Flowering plants’ sperm do
not require water to fertilize
egg – mosses and ferns do
Memory device:
meggagametophyte
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Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
• Flower parts
– “Female”-ovary and egg
• Pistil (some texts call a carpel)
– Stigma
– Style
– Ovary (with ovules)
– “Male” – produces pollen grain
• staMEN
– Anther (MANther)
– filaMENt
– Petals
– Sepals
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Pistils SEM
http://www.ulb.ac.be/sciences/bi
odic/ImDicot.html
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Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
• Wild peoni
– Many stamen and 3 pistils
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Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
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Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
• Three carpels fused to form a compound pistil
– When pistil contains only one carpel, then pistil and carpel
are synonymous
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Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
• A single pistil consisting of several fused carpels
(A) and several pistils each consisting of a single
carpel (B)
Carpel is ovule
bearing unit.
Ovary may have
one or more
carpels.
http://www.botany.uwc.ac.za/ecotree/flowers/flowerparts2.htm
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
•
•
Sporophyte (flower)
produces haploid spores
(microspore and
megaspore) by meiosis
Microspore produces
microgametophyte (pollen
grains “male”) and
megaspore produces
megagametophtye (eggs
“female”) by mitosis. (sometimes
also called macrogametophyte)
•
When pollen and egg come
together – fertilization –
diploid zygote is formedplant returns to sporophyte
stage
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
• Megaspore (female embryo
sac) development
Functional megaspore divides by
mitosis to become:
One egg cell
Two synergid cells
One central cell with two polar
nuclei
Three antipodal cells
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Angiosperm.html
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
Synergid cells – guide pollen tube
Polar nuclei – become endosperm
once fertilized
Ovum – egg  sporophyte
Antipodal nuclei- no known
function – degenerate eventually
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
• Microspore development (male pollen)
http://www.ualr.edu/~botany/pollendev.gif
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Pollen grain formation
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Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
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Pollen Sac (in anther) SEM
http://www.ulb.ac.be/sciences/biodic/ImDicot.html
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Allergenic Pollen (SEM x1,000).
This image is copyright Dennis Kunkel at www.DennisKunkel.com,
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
•
Pollination and Fertilization
–
–
–
–
–
–
–
–
Pollen usually wind blown (in flowering plants)
Pollen sticks on sticky stigma
Pollen grain contains one generative cell and one tube cell (each haploid)
Generative cell divides by mitosis to produce two sperm cells
Tube cell forms a tube that grows down to the megagametophyte (embryo sac)
One sperm joins with egg to form zygote
Other sperm joins with both polar nuclei to form triploid endosperm
This double fertilization is unique to flowering plants
Zygote becomes sporophyte
embryo
Ovule matures into seed and
seed coat
Ovary becomes the fruit
Fertilization animation
..\..\Biology\Biology Clipart Movies Animations Sounds\Biology animations\PlantFertilization.mov
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Fertilization
From: http://www.emunix.emich.edu/~ghannan/systbot/NewFiles/animation%203801.swf
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Chapter 27 Reproduction in Plants
27.1 Sexual Reproductive Strategies
• Pollination
– Animals, wind
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Chapter 27 Reproduction in Plants
27.2 Seed Development
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Chapter 27 Reproduction in Plants
27.2 Seed Development
•
Embryo Development – (seed development animation)
– Endosperm nucleus divides to become endosperm tissue
– Zygote divides into embryo (which will develop cotyledons) and
suspender which will transfer nutrients to the embryo
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Chapter 27 Reproduction in Plants
27.2 Seed Development
•
Cotyledons
– Monocot
• Has one
• Doesn’t store food just
passes it from the
endosperm to the
embryo
– Dicot
• Has two
• Store nutrients to feed
embryo
•
Epicotyl
– Area between
cotyledon(s) and first
leaves
•
Hypocotyl
– Below cotyledon(s) –
stem development
•
Radicle
– Contributes to root
development
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Embryo Development
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Chapter 27 Reproduction in Plants
27.3 Fruit Types and Seed Dispersal
•
Fruits and Seeds
–
Seeds
•
–
Fruit
•
•
–
Ovary and sometimes surrounding
floral parts
Fruit=mature ovary that usually
contains seeds.
Many types and varieties of fruits
•
•
•
–
–
embryo plus endosperm plus
surrounding ovule (seed coat)
Simple (derived from one ovarysimple or compound)– apples
peaches
Compound (develop from several
individual ovaries) – blackberry,
strawberry
Grains (corn, wheat,rice, beans,
nuts etc.) are dry fruits
Fruit animation
Good fruit type site:
http://www.botany.uwc.ac.za/ecotr
ee/fruit/fruittypeswin.htm
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Chapter 27 Reproduction in Plants
27.3 Fruit Types and Seed Dispersal
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Chapter 27 Reproduction in Plants
27.3 Fruit Types and Seed Dispersal
www.caosclub.org/ members/plan22.html
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants
27.3 Fruit Types and Seed Dispersal
• Seed dispersal
– Many varied ingenious
mechanisms
•
•
•
•
Explosive
Wind
Water
Animals
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Chapter 27 Reproduction in Plants
27.3 Fruit Types and Seed Dispersal
• Seed germination
– Needs sufficient water, warmth and oxygen
– Needs correct chemical regulators
– Some need mechanical actions (washing, bacteria, fire)
– Some need period of dormancy
Dicot- –if epicotyl
– All work together to have seed germinate when it is most likely to
bends – cotyledons
Dicot- –if hypocotyl
stay below ground. survive.
bends – cotyledons
come above ground.
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Chapter 27 Reproduction in Plants
27.3 Fruit Types and Seed Dispersal
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Chapter 27 Reproduction in Plants
27.3 Fruit Types and Seed Dispersal
• Germination in monocots and dicots
–
–
–
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Embryo breaks out of seed coat
Epicotyle bears young leaves called plumule
Monocot tip protcted by coleoptile – dicot bends
Phytochromes (ch 38) stimulate leaf growth
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Chapter 27 Reproduction in Plants
27.3 Fruit Types and Seed Dispersal
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Chapter 27 Reproduction in Plants
27.3 Fruit Types and Seed Dispersal
Germination movies:
Corn
..\..\Biology\Biology Clipart Movies Animations Sounds\Biology movies\Germination
corn.mov
Sunflower
..\..\Biology\Biology Clipart Movies Animations Sounds\Biology movies\Germination
sunflower.mov
Photomorphism in sunflowers:
Sunflowers in light
..\..\Biology\Biology Clipart Movies Animations Sounds\Biology movies\Germinating
sunflower dark.mov
Sunflowers in dark
..\..\Biology\Biology Clipart Movies Animations Sounds\Biology movies\Germinating
sunflower light.mov
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants
27.4 Asexual Reproduction Strategies
• Vegetative propagation
– Can occur naturally
– Can be “human induced”
• Tissue culture
• Capitalize on fact that
plant cells are totipotent
– This is possible because
plants contain non
differentiated meristematic
tissue
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Tissue Culture Animation
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Chapter 27 Reproduction in Plants
27.4 Asexual Reproduction Strategies
• Genetic engineering in
plants
– Previously, hybridization,
the crossing of different
varieties or species of plants,
was used to produce plants
with desirable traits.
– Now can just ‘insert the
gene”
– Can produce plants with
• Resistance to disease and
herbicides
• More nutritious
• Ability to make human
hormones, clotting factors
and antibodies
– The sky is the limit, but
some advise great caution
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Transgenic Plants
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Transgenic Plants- Gene Gun
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Evolutionary Overview
•
algae  mosses  ferns  gymnosperms angiosperms
– Ferns are over 360 million years old – were around way before the
dinosaur (about 220mya)
•
avascular seedless (mosses, liverworts, hornworts- which are all
bryophytes)  vascular seedless (ferns)  vascular with seeds
(gymnosperms and angiosperms)
•
gymnosperms (pine trees etc) with naked seeds  angiosperms
(flowering plants) with seeds inside ovaries
•
Mosses and ferns need water (externally) for fertilization, seeded
plants don’t
•
•
Gametophyte (haploid) generation dominant in mosses.
Sporophyte generation dominant in vascular plants (ferns,
angosperms and gymnosperms).
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants
•
In ferns and mosses, the sporophyte and gametophyte generations are
represented by two greatly different plants.
– Among mosses, a sporophyte consists of a long, rigid stalk with a
spore-producing container at the end, extending from the top of a soft,
leafy, green gametophyte. The sporophyte depends on the gametophyte
for food and water. When we think of the green carpet of mosses, it is
the gametophyte we are seeing.
– The ferns sporophytes have leaves which are much larger than the
gametophytes. They have clusters of sporangia, where the spores
develop, called sori form on the edges or underside of each leaf.
– After the spores ripen, they fall to the ground and grow into
gametophytes. A fern gametophyte produces both male and female
sex cells, and if enough moisture is present, a sperm cell swims to an
egg cell and unites with it.
– Once fertilized, the egg grows into an adult sporophyte.
•
From:
http://www.ecoworld.com/plants/EcoWorld_Plants_Home5.cf
m
Mills AP Bio 2003/2013
Gymnosperm Life Cycle Animation
Link to animation : http://bcs.whfreeman.com/thelifewire/content/chp30/30020.html
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Gymnosperm Life Cycle
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Chapter 27 Reproduction in Plants
Gametophyte (bottom) vs Sporophyte (top) in various “plants”
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Mosses (bryophytes)
avascular seedless
•
http://www.esu.edu/~milewski/intro_biol_two/lab_2_moss_ferns/MossandFern_Diversity.
html
In mosses, the sporophyte is small and at least partially erect, with very little specialization of cells
and tissues, specifically, no true leaves, stems, or roots.
The moss gametophyte has a shoot portion that appears leafy, and has rhizoids which emerge from
its base to attach it to the substratum upon which it grows.
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Mosses
avascular seedless
Sporophyte (diploid)
Gametophyte (haploid)
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Mosses
avascular seedless
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Life cycle of a Moss Animation
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Moss Life Cycle
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Ferns
The ferns sporophytes , which are much larger than the gametophyte, have
clusters of sporangia (inside sori), on their leaves, where the haploid spores
develop. After the spores ripen, they fall to the ground and grow into heart
shaped gametophytes.
A fern gametophyte produces both male and female sex cells, and if enough
moisture is present, a sperm cell swims to an egg cell and unites with it. Once
fertilized, the egg grows into an adult sporophyte
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Ferns
vascular seedless
Sporangia (in sori)
on underside of fern
leaf
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Ferns
vascular seedless
Sporophyte (diploid)
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Gametophyte with new
sporophyte growing
Heart shaped haploid
gametophyte
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Fern Life Cycle Animation
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Sporophyte (diploid)
Gametophyte
(haploid)
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Ferns
vascular seedless
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The End
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