1. Part 3: Reproduction in Seed Plants
Unit 7 Plants
Part 3: Reproduction in Seed Plants

2. Alternation of Generations…
Two stages
Haploid gametophyte phase
Diploid sporophyte phase
Book pg. 609!

3. Life Cycle in Gymnosperms
Components/Process
Reproduction takes place in cones
Pollen cones = male gametophytes
Seed cones = female gametophytes
Cones produced by mature sporophyte plant

4. Life Cycle in Gymnosperms
Pollination
Spring: Male cones release pollen grains
Pollen carried by wind
Sticks to female seed cones

5. Life Cycle in Gymnosperms
Fertilization & Development
Pollen grain lands near ovule (of seed cone)
Grain splits + grows pollen tube
Pollen tube extends to fertilize egg
Produces diploid zygote
Grows into embryo  Becomes a seed

7. Life Cycle in Angiosperms
Structure of Flowers
Reproductive organs
Petals  Vary in color; attract pollinators
Sepal  Outermost circle; resemble leaves; enclose the bud

8. Life Cycle in Angiosperms
Structure of Flowers
Stamen  Male parts of the flower
Filament: stalk
Anther: oval sac where pollen grains are made via meiosis
Anther
Filament

9. Life Cycle in Angiosperms
Structure of Flowers
Carpels/pistils  Female parts of the flower
Ovary: Contains ovule, where female gametophytes are made via meiosis
Style: stalk
Stigma: sticky area at top of style

10. Life Cycle in Angiosperms

11. Life Cycle in Angiosperms
Components/Process
Reproduction takes place in flowers
Mature sporophyte produces flowers
Each flower has male and female parts (some exceptions: pumpkins, melons)

12. Life Cycle in Angiosperms
Components/Process
Pollen released from anther deposits on stigma
Pollen grain splits and travels down the style (pollen tubes within)
Double fertilization:
Sperm 1 fertilizes egg in embryo sac
Sperm 2 fuses with other nuclei in sac to form endosperm
New sporophyte (seedling) develops and is nourishes by endosperm.

14. Life Cycle in Angiosperms
Pollination
Carried by wind
Carried by animals (more efficient)
Bees, birds, butterflies

15. Life Cycle in Angiosperms
Seed and Fruit Development
Ovary walls thicken to form fruit
Encloses developing seeds
If it contains a seed, it’s a fruit!

16. Seeds Dispersal Dormancy Germination Animals Wind & water
Embryo is alive but not growing
Needs right temp and moisture to grow
Germination
Early growth stage
Absorb water  Cracks seed coat and young root emerges