Mills AP Bio 2003/2013 Chapter 27 Reproduction in Flowering Plants Topics: 27.1 Sexual Reproductive...
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Transcript of Mills AP Bio 2003/2013 Chapter 27 Reproduction in Flowering Plants Topics: 27.1 Sexual Reproductive...
Mills AP Bio 2003/2013
Chapter 27Reproduction in Flowering
Plants
Topics:27.1 Sexual Reproductive Strategies27.2 Seed Development27.3 Fruits and Seeds27.4 Asexual Reproductive Strategies
Read Textbook Ch 27 and pages 569-572Read Cliffs AP Book
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants27.1 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
Mills AP Bio 2003/2013
• 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
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Mills AP Bio 2003/2013
Pistils SEM
http://www.ulb.ac.be/sciences/biodic/ImDicot.html
Mills AP Bio 2003/2013
• Wild peoni– Many stamen and 3 pistils
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Mills AP Bio 2003/2013
• Three carpels fused to form a compound pistil– When pistil contains only one carpel, then pistil
and carpel are synonymous
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Mills AP Bio 2003/2013
• A single pistil consisting of several fused carpels (A) and several pistils each consisting of a single carpel (B)
http://www.botany.uwc.ac.za/ecotree/flowers/flowerparts2.htm
Carpel is ovule bearing unit. Ovary may have one or more carpels.
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Mills AP Bio 2003/2013
• 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 formed-plant returns to sporophyte stage
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Mills AP Bio 2003/2013
• Megaspore (female embryo sac) development
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/A/Angiosperm.html
Functional megaspore divides by mitosis to become:
One egg cellTwo synergid cellsOne central cell with two polar nucleiThree antipodal cells
Mills AP Bio 2003/2013
Synergid cells – guide pollen tube
Polar nuclei – become endosperm once fertilized
Ovum – egg sporophyte
Antipodal nuclei- no known function – degenerate eventually
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Mills AP Bio 2003/2013
• Microspore development (male pollen)
http://www.ualr.edu/~botany/pollendev.gif
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Mills AP Bio 2003/2013
Pollen Sac (in anther) SEM
http://www.ulb.ac.be/sciences/biodic/ImDicot.html
Mills AP Bio 2003/2013
Allergenic Pollen (SEM x1,000). This image is copyright Dennis Kunkel at www.DennisKunkel.com,
Mills AP Bio 2003/2013
• 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
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Fertilization
Mills AP Bio 2003/2013
From: http://www.emunix.emich.edu/~ghannan/systbot/NewFiles/animation%203801.swf
Mills AP Bio 2003/2013
• Pollination– Animals, wind
Chapter 27 Reproduction in Plants27.1 Sexual Reproductive Strategies
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants27.2 Seed Development
Mills AP Bio 2003/2013
• 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
Chapter 27 Reproduction in Plants27.2 Seed Development
Mills AP Bio 2003/2013
• 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
Chapter 27 Reproduction in Plants27.2 Seed Development
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013
• Fruits and Seeds– Seeds
• embryo plus endosperm plus surrounding ovule (seed coat)
– Fruit • Ovary and sometimes
surrounding floral parts• Fruit=mature ovary that
usually contains seeds.
– Many types and varieties of fruits
• Simple (derived from one ovary-simple 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/ecotree/fruit/fruittypeswin.htm
Chapter 27 Reproduction in Plants27.3 Fruit Types and Seed Dispersal
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants27.3 Fruit Types and Seed Dispersal
Chapter 27 Reproduction in Plants27.3 Fruit Types and Seed Dispersal
Mills AP Bio 2003/2013
www.caosclub.org/ members/plan22.html
Mills AP Bio 2003/2013
• Seed dispersal– Many varied ingenious
mechanisms• Explosive• Wind• Water• Animals
Chapter 27 Reproduction in Plants27.3 Fruit Types and Seed Dispersal
Mills AP Bio 2003/2013
• Seed germination– Needs sufficient water, warmth and oxygen– Needs correct chemical regulators– Some need mechanical actions (washing, bacteria, fire)– Some need period of dormancy– All work together to have seed germinate when it is most
likely to survive. Dicot- –if hypocotyl bends – cotyledons come above ground.
Dicot- –if epicotyl bends – cotyledons stay below ground.
Chapter 27 Reproduction in Plants27.3 Fruit Types and Seed Dispersal
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants27.3 Fruit Types and Seed Dispersal
Mills AP Bio 2003/2013
• Germination in monocots and dicots– 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
Chapter 27 Reproduction in Plants27.3 Fruit Types and Seed Dispersal
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants27.3 Fruit Types and Seed Dispersal
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013
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
Chapter 27 Reproduction in Plants27.3 Fruit Types and Seed Dispersal
Mills AP Bio 2003/2013
• 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
Chapter 27 Reproduction in Plants27.4 Asexual Reproduction Strategies
Mills AP Bio 2003/2013
• 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
Chapter 27 Reproduction in Plants27.4 Asexual Reproduction Strategies
Transgenic Plants- Gene Gun
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013
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.cfm
Gymnosperm Life Cycle
Mills AP Bio 2003/2013
Link to animation: http://bcs.whfreeman.com/thelifewire/content/chp30/30020.html
Gymnosperm Life Cycle Animation
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013
Chapter 27 Reproduction in Plants
Gametophyte (bottom) vs Sporophyte (top) in various “plants”
Mills AP Bio 2003/2013
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.
Mills AP Bio 2003/2013
Mossesavascular seedless
Gametophyte (haploid)
Sporophyte (diploid)
Life cycle of a Moss Animation
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013
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
Ferns
Mills AP Bio 2003/2013
Fernsvascular seedless
Sporangia (in sori) on underside of fern leaf
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013
Fernsvascular seedless
Sporophyte (diploid)
Mills AP Bio 2003/2013
Heart shaped haploid gametophyte
Gametophyte with new sporophyte growing
Fern Life Cycle animation
..\..\Biology\Biology Clipart Movies Animations Sounds\Biology animations\FernLifeCycle[1].mov
http://flightline.highline.edu/jbetzzall/BI100/animations/fern_life_cycle_v2.html
Mills AP Bio 2003/2013
Sporophyte (diploid)
Gametophyte (haploid)
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013
Mills AP Bio 2003/2013