angiosperm reproduction
DESCRIPTION
Angiosperm Reproduction. Chapter 19. Vascular tissue. Earth Forms. Prokaryotic Cells. Eukaryotic Cells. Multicellular Plants. Flowers. 5,000 mya. 4,000 mya. 3,000 mya. 2,000 mya. 1,000 mya. Seeds. Major Evolutionary Advances. Life - 3,800 mya - PowerPoint PPT PresentationTRANSCRIPT
Angiosperm Reproduction
Chapter 19
Major Evolutionary Advances
Flowers - 140 mya
5,000mya
4,000mya
3,000mya
2,000mya
1,000mya
EarthForms
ProkaryoticCells
EukaryoticCells
MulticellularPlants
Vascular
tissue
Seeds
Flowers
Life - 3,800 myaProkaryotic cell/autotrophic
Eukaryotic cell - 1,400 myaMulticellar plants - 1,000 myaVascular tissue - 430 mya
Needed on land - why?Seeds - 350 mya
Place on the time scale, the following events:
1. Earth2. Prokaryotes3. Eukaryotes4. Multicellular life5. Vascular tissue6. Seeds7. Flowers
Flower variation
Complete• has all 4 whorls
Incomplete• lacks one or more
of whorls (sepals, petals, stamens or carpels)
Flower variationPerfect
• both androecium and gynoecium
Imperfect• carpellate or
staminate flower only• if both carpellate and
staminate flowers are on same plant called monoecious
• if on different plants called dioecious
Fertilization
• Pollination: transfer of pollen grains from anther to pistil
• Pollen grain onto stigma• Germination - tube cell
produces pollen tube, generative cell divides to form 2 sperm cells
• Double Fertilization:• 2 sperm enter
embryo sac: • 1 sperm fertilizes egg to form zygote• other sperm fertilizes polar nuclei to
form endosperm
Sexual Reproduction
Four events must occur for successful reproduction in angiosperms:
1. Pollination2. Pollen grain growth to ovule3. Successful fertilization4. Successful seed development
Sexual Reproduction
• Inbreeding• Result of self-pollination & self-fertilization• Results in inbreeding depression
• Outcrossing• Result of cross-pollination & cross-fertilization• Results in hybrid vigor
• What process is “best”? Why?• How do plants promote this?
Sexual Reproduction• Unisexual flowers• Monoecious plants
• Dioecious plants
Sexual ReproductionBisexual flowers
• Protandry - stamens mature before stigma
Hibiscus
MagnoliaEpilobium (fireweed)
Protandry
• Protogyny - stigma matures before stamens
• Heterostyly - physical separation between stigma and stamen
Sexual ReproductionBisexual flowers
Self-incompatibility• Pollen grain-
stigma surface: no germination• Pollen tube
growth: tube “dies”• Fertilization:
inviable zygotes
Amarylis
Pollination• Define:• transfer of pollen to stigma
• How is self-fertilization prevented (or reduced) through pollination mechanisms?• unisexual flowers (monoecious plants)• unisexual flowers (dioecious plants)• protandry• protogyny• heterostyly
Fertilization:
ovule
• Define:• combining of sperm + egg AND sperm +
polar nuclei = double fertilization
Fertilization
megagametophyte(female gametophyte)
microgametophyte(male gametophyte)
ovule
Fertilization
Fertilization
• What occurs after double fertilization?• embryo development
• next generation• endosperm development
• nourishment for embryo• What structure is
formed?• seed
• embryo• endosperm• seed coat
• Where is the seed housed?• inside ovary• matures into a fruit
• ovary wall = pericarp
Seed germination & growth
How might reproductive success be measured in an angiosperm?
Funk, Lisa. 1997. A comparison of reproduction in self and outcrossed purple poppy mallow flowers (Callirhoe involucrata). Results presented at the 1997 Nebraska Academy of Sciences Annual Meeting.
Gyno-dioecious species
Hermaphroditc flowers on some plantsMale-sterile flowers on other plants
Funk, Lisa. 1997. A comparison of reproduction in self and outcrossed purple poppy mallow flowers (Callirhoe involucrata). Results presented at the 1997 Nebraska Academy of Sciences Annual Meeting.
4 Treatments• Selfed• Outcrossed • Pollinator excluded• Control
Fruit set measured
What conclusions can be drawn?
• What conclusions can be drawn?• What is the role of gyno-dioecy in
plant reproduction and reproductive success in Callirhoe involucrata?
Funk, Lisa. 1997. A comparison of reproduction in self and outcrossed purple poppy mallow flowers (Callirhoe involucrata). Results presented at the 1997 Nebraska Academy of Sciences Annual Meeting.