1. ALTERNATION OF GENERATIONS a defining feature of plants
Both cell divisions:
mitosis meiosis
2 forms of the plant:
sporophyte
gametophyte

2. IN ANGIOSPERMS – chapters 37 (5e), 42 (6e)
SPOROPHYTE GROWS via mitosis
DIPLOID CELLS UNDERGO MEIOSIS making haploid spores
PLANT A SEED
FERTILIZATION
HAPLOID CELLS DIVIDE in
mitosis
GAMETES MADE
GAMETOPHYTE FORMED

3. SPORES? Another type of reproductive cell
microscopic
here

4. IN ANGIOSPERMS it all happens in the flower
male female
stamen pistil/carpel
The flower is the sporophyte
The gametophyte is within the ovary at the base of pistil

5. pistil stamen petals sepals female male attract pollinators
Protect bud, ovary

6. Sticky stigma of pistil
Anther of stamen
with pollen containing
sperm nuclei
Sticky stigma of pistil
pollen
lands here

7. Pollen lands on stigma; sperm nuclei migrate to ovary via pollen tubes
1 sperm fertilizes an ovum (egg) in
ovule forming zygote
1 sperm fertilizes polar nuclei cells
forming nutritive endosperm
eggs within

8. Ovary
Three fused carpels make up this ovary
Ovules contain eggs

9. Fruit c.s Ovary becomes fruit/ovules become seeds Seeds
• protect embryo
• endosperm
nourishes embryo
Fruit for dispersal of seeds

10. Plants can undergo
asexual reproduction too
Meristem cells at nodes,
tips, of roots and shoots
are undifferentiated (pluripotent)

11. Fragmentation in Ludwigia
Strip leaves off
Bury most nodes
Roots and shoots after 10 days!