Transcript Chapter 24: Reproduction of Seed Plants

Chapter 24:
Reproduction of
Seed Plants
Biology- Kirby
Ch. 24-Reproduction of Seed Plants
• Seedless plants need water to carry
their gametes from plant to plant.
• Seed plants do not need water to
transport their gametes.
• Plants alternate between the
sporophyte and gametophyte phases
in their life cycle.
Ch. 24-Reproduction of Seed Plants
• Gymnosperms:
• Reproduction occurs in cones, which
are made by the sporophyte plant.
• Pollen cones- male cones- produce
male gametophytes called pollen.
• Seed cones- produce female
gametophytes- ovules are located at
the base of the scales.
Ch. 24-Reproduction of Seed Plants
• Gymnosperms:
• Pollination- male cones are released
and stick to the female cones.
• If a pollen grain lands near an ovule,
the grain opens and grows a pollen
tube (2 haploid sperm).
• When the tube reaches the ovule, the
sperm nuclei join with the female
gametophyte.
Ch. 24-Reproduction of Seed Plants
• Structure of Flowers:
• Sepals- enclose the bud before it
opens.
• Petals- brightly colored to attract
insects to the flower.
• Male parts:
– Stamen- the anther and the filament.
– Filament- long, thin stalk that supports
the anther.
– Anther- produces male pollen grains.
Ch. 24-Reproduction of Seed Plants
• Female parts:
– Carpel (Pistil)- produce female
gametophytes.
– Ovary- base of the pistil.
– Style- stalk of the pistil.
– Stigma- top of the style where
pollen lands.
Ch. 24-Reproduction of Seed Plants
Ch. 24-Reproduction of Seed Plants
• Angiosperms:
• Reproduction occurs in the flower.
• Most are pollinated by insects/animals.
• When the pollen lands on the stigma it
grows a pollen tube which grows down
the style to the ovary.
• One sperm nuclei fuses with the egg
and the other fuses with polar bodies.
• This makes endosperm- nourishes the
embryo.
Ch. 24-Reproduction of Seed Plants
• Seed germination- early growth stage of
the plant embryo.
• The seed absorbs water, cracking the
seed coat open.
• The root emerges and begins to grow.
• Then the stem emerges and begins to
grow exposing the cotyledon (first leaf).