Dev. Bio

  1. Centroradiulus (CEN) gene
    • found in snapdragon:
    • prevents terminal flower formation
    • suppresses FLO
  2. Floricaula (FLO)
    • specifies floral meristem:
    • stimulates CEN to prevent terminal flowers from forming
  3. Short day plants
    flowering plants that are regulated by photoperiod (day length)
  4. 2 types of soluble photoreceptors that travel throughout plant
    • phytochromes-respond to red light (day)
    • cryptochromes-respond to blue light (night)
  5. Short day/long night plants like poinsettia's require:
    8 hours or less of light
  6. Long day/short night plants require:
    12 to 16 hours of light
  7. Perfect flower contains 4 whorls
    • Whorl 1 (W1)-Sepals (Se)
    • Whorl 2 (W2)-Petals (Pe)
    • Whorl 3 (W3)-Stamens (St)
    • Whorl 4 (W4)-Carpels (Ca)
  8. W1-Sepals
    Green "leaves" at base of flower
  9. W2-Petals
    Petals of flower around W3 and W4
  10. W3-Stamens
    Within the flower on outside of pistil:

    • Anther-contains pollen sacs that produce mail gametes
    • Filament
  11. W4-Carpels (pistil)
    Very center of flower that is comprised of:

    • Stigma-top of pistil
    • Style-neck of pistil
    • Ovary with eggs-body of pistil
  12. 3 floral meristem identity genes that are responsible for the switch from inflorescent ot floral:
    • leafy (lfy)
    • apetala (ap1)
    • cauliflower (cal)
  13. leafy (lfy)
    • A homolog of flo
    • A transcription factor
    • Moves between cells in meristem before activating other flower genes

    ap1 and cal are closely related and redundant-would need a double mutant to resemble broccoli/cauliflower
  14. ABC model for organ identity genes in Arabidopsis
    • Perfect flower:
    • A required for sepals
    • A+B required for petals
    • B+C required for stamen
    • C required for carpel
  15. 7 mutants in ABC model
    • 1-ABC gives leafs only
    • 2-A mutants yield carpal and stamen
    • 3-B mutants yield sepals and carpal
    • 4-C mutants yield sepals and petals
    • 5-B+C mutants yield all sepals
    • 6-A+B mutants yield all carpals
    • 7-A+C mutants yield hybrid petal and stamen 
  16. Sporophyte vs. Gametophyte generations-1
    • sporophyte-diploid, makes spores
    • gametophyte-haploid, makes gametes
  17. Sporophyte vs. Gametophyte generations-2
    Circle starting at bottom:

    Fertilization-Mitosis-Sporophytes-Spore mother cell-Meiosis-Spores-Mitosis-Gametophytes-Gametes
  18. Sporophyte-Angiosperm
    • sporophyte-makes spores
    • dominant generation in angiosperm
    • zygote produces seed (zygotes found in carpal)
    • carpal becomes fruit
    • fruit possibly eaten by animal
    • seeds deposited/seeds germinate
    • plant grows/plant produces flowers
  19. Gametophyte-Microspores
    • minor generation
    • stamen produce pollen grains (microspores)
  20. Pollen grain
    • Tube cell (n)-haploid, allows digestion of enzymes, allows for formation of generative cell
    • Generative cell (n)-located inside tube cell
    • Lands on stigma of pistil (may contain multiple carpals)
  21. Gametophyte-Megaspores
    • One or more ovules attached by a "placenta" to the ovary wall
    • Fully developed ovules called seeds
    • Ovules produce 4 megaspores (n) (unequal cytokinesis)
  22. 4 Megaspores produced
    • 3 of 4 will degenerate
    • 4th megaspore (the largest) will mitotically divide producing 8 nuclei in 7 cells (embryo sac)
  23. The cell with the 2 nuclei will fuse with a sperm cell and form:
    the endosperm-this becomes the food source
  24. Another of the 6 remaining cells with fuse with another sperm cell to form:
    an embryo
  25. Ovules contain 3 things:
    • Stalk-attachment
    • Nuclellus-nutritive tissue
    • Integaments-exclose the nuclellus

    (Didn't go over much in class)
  26. Embryo development:
    • Dicots have 2 cotyldons
    • Monocots have 1 cotyldon
    • Suspensor-support tissue (will get squashed)
    • Protoderm-epidermal layer of embryo
Card Set
Dev. Bio
Plants 2