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Seed Reproduction
Chapter 9 Notes
Seed Reproduction
• Plants need to reproduce to carry on their species.
• Plants reproduce due to the movement of pollen
and seeds.
Pollen
• Pollen contains the males sperm. It is
known as a gametophyte. When the pollen
reaches female plant parts, fertilization
occurs.
• After fertilization, seeds form. These seeds
are the plants offspring.
Seeds
– The seed contains an embryo, stored food (in the
cotyledon), and a protective coat.
Because the seed is so well protected and fed, the
plant grown from it will grow faster compared to
spores (seedless reproduction).
Why would the seed
want stored food and
a protective coat?
Two Types of Seed Reproducers
• Angiosperms
What’s the difference?
• Gymnosperms
Angiosperm
• Angiosperms produce flowers which are
used for sexual reproduction.
Parts of a Flower
Petal
Stigma
Anther
Style
Pistil
Filament
Stamen
Sepals
Ovary
Angiosperm
– The stamen is the male reproductive organ.
– The pistil, the female reproductive organ, contains the
ovary at its base.
Angiosperm
– The appearance of a plant’s
flower can give clues about
how the plant is pollinated.
– After pollination and
fertilization, a zygote forms
and grows into the plant
embryo.
– Parts of the ovule develop
into the seed coat and
store food for the embryo.
Angiosperm
• Some seeds store food in cotyledons.
• Other seeds store food in endosperm tissue
Where are seeds found?
• THE FRUIT. So…fruit is like the plant’s baby.
Fact: Fruits have
seeds. Vegetables
do not. A true
vegetable is usually
a root. (potato, carrots,
onion)
Angiosperm Life Cycle
A. Pollination happens when pollen
grains from the anthers land on the
sticky stigma of a pistil.
B. The pollen tube
grows from the pollen
grain down through
the style and into the
ovary at the ovule.
C. The sperm
travels down and
fertilizes the egg.
The zygote
develops.
Gymnosperm
• Gymnosperms develop seeds in cones.
Gymnosperm
– A pine tree or shrub is a
sporophyte plant that
produces male and female
cones.
– A female cone has two
ovules which produce eggs.
– Male cones produce and
release pollen.
Gymnosperm
– When pollen blows into a female cone, fertilization and
seed formation can occur.
– Seed released by a female cone can take two or three
years.
Seed Dispersal
• Seeds are dispersed by wind, gravity, animals, and
water. Some seeds have trapped air which helps
them float.
– Germination occurs when the seed coat swells
and breaks open.
– Environmental conditions affect germination.