Transcript Flowering Plants

Flowering Plants
Flower Function
Flowers make reproduction more
efficient
A flower is the location of sexual
reproduction in flowering plants
Flower Structure
Sepal- part of which encloses the bud before it
opens. Protects the flower
Petal- colored leaves on the flower. Attracts
pollinators
Stamen- consists of filament and anther (male
reproductive organ)
Anther- structure where male reproduction occurs
and pollen is made
Filament- thin, stem-like stalk, supporting anther
Pistil- ovary, stigma, and style (female reproductive
organ)
Ovary- base of pistil which holds the ovules (eggs)
Stigma- upper part of pistil where pollen is
deposited
Style- stalk between stigma and ovary
Complete Flower Structure
Pistil
Pollination
Flowering plants use the
wind, insects, bats, birds
and mammals to transfer
pollen from the male
(stamen) part of the flower
to the female (stigma) part
of the flower
A flower is pollinated when
a pollen grain lands on its
stigma
Pollen grains germinate on
the stigma, growing down
the style to reach an ovule.
The sperm cells enter the
ovule through an opening
called the micropyle
Pollination
Some flowers, such as grasses, do
not have brightly colored petals and
nectar to attract insects.
They do have stamens and pistils.
These flowers are pollinated by the
wind.
Fertilization
Double fertilization
Unique to angiosperms
Each pollen grain has two sperm cells (n)
One sperm (n) fertilizes one of six egg
cells(n) to form a diploid zygote (2n).
The other sperm (n) fuses with the
central cell (2n) to form a triploid cell
(3n)
This triploid cell becomes the endosperm of
the seed
Seeds and Fruits
Seed Formation
After fertilization most of the
flower parts die and seeds develop
The wall of the ovule becomes seed
coat
The zygote inside ovule develops
into plant embryo
Seeds and Fruits
Fruit Formation
The ovary enlarges and becomes
the fruit
The fruit contains the seeds
Types of fruits
Fleshy fruits– apples, grapefruit,
tomatoes
Dry fruits- peanuts, sunflower seeds
Seed Dispersal
Seeds are dispersed in many different ways:
Wind
Fruit is shaped for flight
So tiny floats on the air
Water
Float and drift away
Animals
Eat and excrete
Carry away and spit out
Clumsy and drop their collection
Bury and forget
Get stuck of fur
Seed germination
Seeds are dormant (inactive) until conditions
are favorable and germination can then
begin.
Germination is the beginning of development
of the new plant
Requirements for germination
Water
Oxygen
Favorable temperatures
Other
Acid of an animals digestive system
Period of freezing
Soaking in salt water
Exposure to fire
Seed Germination