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Angiosperm Reproduction

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

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Angiosperm Reproduction

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  1. Angiosperm Reproduction Chapter 19

  2. 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 • Prokaryotic cell/autotrophic Place on the time scale, the following events: 1. Earth 2. Prokaryotes 3. Eukaryotes 4. Multicellular life 5. Vascular tissue 6. Seeds 7. Flowers Flowers - 140 mya Eukaryotic cell - 1,400 mya Multicellar plants - 1,000 mya • Vascular tissue - 430 mya • Needed on land - why? Seeds - 350 mya

  3. Flower variation • Complete • has all 4 whorls • Incomplete • lacks one or more of whorls (sepals, petals, stamens or carpels)

  4. Flower variation • Perfect • 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

  5. 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

  6. Sexual Reproduction Four events must occur for successful reproduction in angiosperms: • Pollination • Pollen grain growth to ovule • Successful fertilization • Successful seed development

  7. 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?

  8. Sexual Reproduction • Unisexual flowers • Monoecious plants • Dioecious plants

  9. Hibiscus Protandry Magnolia Epilobium (fireweed) Sexual Reproduction Bisexual flowers • Protandry - stamens mature before stigma • Protogyny- stigma matures before stamens • Heterostyly - physical separation between stigma and stamen

  10. Sexual Reproduction Bisexual flowers Self-incompatibility • Pollen grain-stigma surface: no germination • Pollen tube growth: tube “dies” • Fertilization: inviable zygotes Amarylis

  11. 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

  12. Fertilization: • Define: • combining of sperm + egg AND sperm + polar nuclei = double fertilization ovule

  13. Fertilization megagametophyte (female gametophyte) microgametophyte (male gametophyte) ovule

  14. Fertilization

  15. 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

  16. Seed germination & growth

  17. How might reproductive success be measured in an angiosperm?

  18. 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 plants • Male-sterile flowers on other plants

  19. 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

  20. What conclusions can be drawn?

  21. 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. • What conclusions can be drawn? • What is the role of gyno-dioecy in plant reproduction and reproductive success in Callirhoeinvolucrata?

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