Ce diaporama a bien été signalé.
Nous utilisons votre profil LinkedIn et vos données d’activité pour vous proposer des publicités personnalisées et pertinentes. Vous pouvez changer vos préférences de publicités à tout moment.

Unit 4, Lesson 4.2 - Parts of a Flower

Unit 4, Lesson 4.2 - Parts of a Flower

Lesson Outline:
1. Introduction: Sexual Reproduction
2. Flowering Plants
3. Parts of a Flower

  • Identifiez-vous pour voir les commentaires

Unit 4, Lesson 4.2 - Parts of a Flower

  1. 1. Parts of a Flower Unit Four, Lesson 4.2 By Margielene D. Judan
  2. 2. Lesson Outline  Introduction: Sexual Reproduction  Flowering Plants  Parts of a Flower
  3. 3. Reproduction  Reproduction is the creation of “new individuals” from existing individuals.
  4. 4. Two Types of Reproduction  Sexual – involves sex cells (egg, sperm)  Asexual – does not involve sex cells
  5. 5. Refer to p.125 In asexual reproduction, the parent cell is SINGLE AND DIVIDING. (ex. amoeba, hydra, fungi, bacteria, etc.)
  6. 6. Refer to p.125 In sexual reproduction, the offspring are genetically identical (exact clones) to their parents. (ex. humans, elephants, dogs, fishes, plants, etc.)
  7. 7. Sexual Reproduction  Involves union of gametes  Gametes = sperm (male) + egg (female)  Trivia: The egg is the largest cell in the human body while the sperm is the smallest.
  8. 8. Sexual Reproduction  Sperm – mobile and small  Egg – immobile and large  During fertilization, they unite (n + n) to form a diploid (2n) zygote (fertilized egg)
  9. 9. Nonflowering Plants  They are called gymnosperms (we will not discuss them).
  10. 10. Flowering Plants  Comprises 90% of plant species  Classified as either: 1. Angiosperms – have seeds enclosed in ovary 2. Anthophytes – plants that produce flowers. They have an ovary that’s part of the flower
  11. 11. Flowers  Reproductive organs/structures of a plant  Most flowers are hermaphrodites (contains both male and female sex organs)
  12. 12. Parts of a Flower  Corolla  Calyx  Stamen (male)  Pistil (female)  Receptacle  Peduncle (Be sure to be able to memorize and label each part)
  13. 13. Accessory Parts – function mainly for support, protection and attraction • Corolla • Calyx • Receptacle • Peduncle
  14. 14. Corolla  Comprises of the petals  Have various shapes, sizes, and colors  Function: protection, attraction
  15. 15. Calyx  Comprises of sepals (typically green)  Leaf-like  Function: Protect the flower when it was still young sepal
  16. 16. Receptacle  Also called torus  Function: Supports the entire flower (base of the flower) receptacle calyx
  17. 17. Peduncle  Also called stalk  Function: Connects the flower to the branch or stem. peduncle
  18. 18. Reproductive Parts – for reproduction; main parts of a flower 1. Stamen (male) 2. Pistil (female)
  19. 19. Stamen  The male reproductive organ  Collectively called androecium (collective noun)  Composed of two parts: 1. Anther 2. Filament
  20. 20. Anther  Expanded lobular structure at the end of the filament  Function: Produces pollen (male sex cell)
  21. 21. Filament  Function: Stalk that supports and holds the anther
  22. 22. Pistil or carpel  The female reproductive organ  Collectively called gynoecium (collective noun)  Composed of three parts: 1. Stigma 2. Style 3. Ovary
  23. 23. Stigma  Swollen tip of the pistil  Function: Covered by sticky substance for pollen grains to adhere (stick) to stigma Pollen grains (purple dots)
  24. 24. Style  Function: Long, slender tube that connects the stigma to the ovary  Acts as a conveyor (carrier from one place to another) of pollen grains style
  25. 25. Ovary  Enlarged basal portion of the pistil  Function: Houses the ovule  The ovule houses the egg cell
  26. 26. Ovary In cross section, internal parts of the ovary can be seen: Carpel Locule Ovule Funiculus Placenta
  27. 27. Ovary Carpel – segment or partition that comprises an ovary Ovary wall – supports the ovary Ovary with 3 carpels
  28. 28. Ovary Locule – space or cavity within the carpel An ovary with 3 carpels has also 3 locules room-like locules
  29. 29. ovules (2 ovules per locule) Cross-section of a plant ovary carpel
  30. 30. Ovary Ovary core – solid structure at the center Placenta – the edge of the core; nourishes the egg core (yellow); placenta (green) Visual representation core placenta placenta core
  31. 31. Ovary Finuculus – short stalk that connects the ovule and placenta finiculus finiculus
  32. 32. Ovary Ovule – produces the egg (2 ovules per lenticel) ovule ovule ovule
  33. 33. Cross-section of an ovule The ovule has the following parts: 1. Integument - 2 layer protective coat 2. Nucellus – mass of tissue consisting of meristematic (dividing) cells 3. Funiculus 4. Embryo sac – contains the egg
  34. 34. (ovary sac) (ovary sac)
  35. 35. Development of Gametophytes (Egg) Two Stages 1. Megasporogenesis (genesis = beginning/creation) – creation of megaspores 2. Megagametogenesis – creation of the gametes (egg)
  36. 36. Development of Gametophytes (Egg) 1. Megasporogenesis A. Ovule produces megaspore mother cell (2n). B. Megaspore mother cell (2n) produces 4 megaspores (n) via a two- time meiosis. C. 3 megaspores die and only one is left to continue. 2n n n meiosis n n meiosis n n meiosis
  37. 37. Development of Gametophytes (Egg) 1. Megagametogenesis A. The surviving megaspore divides via mitosis 3 times, forming 8 haploid (n) cells) n megaspore n n n n n n nnnnnnnn mitosis mitosis mitosis mitosismitosismitosismitosis 8 haploid (n) cells
  38. 38. Egg Development in Ovule B. Among the eight cells:  3 cells migrate near the micropyle. The one at the center becomes the egg while the other two becomes the synergid cells.  The other 3 migrate on the opposite pole and become antipodal cells.  The remaining 2 cells are naked (no membrane) and remains at the center to become the polar nuclei. micropyle egg synergidsynergid antipodal polar nuclei
  39. 39. Egg Development in Ovule C. These 8 cells form the inside of the embryo sac and are ready to be fertilized by a pollen (from the male).
  40. 40. Pollen Development in the Anther (Male) Like egg development, pollen development undergoes meiosis and mitosis to produce pollen grains. The product is 2 pollen grains. 1. Microsporogenesis – creation of microspore 2. Microgametosgenesis – creation of male gametes (pollen)
  41. 41. Assignment: p. 143 (Check Your Knowledge A: #s 1-10)
  42. 42. Sources:  Science Links 7

×