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Part 4
Parts of a Flower
(A.K.A.
Pistil)
Structure & Function
of Flowers

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Flowers are the reproductive organs
of many angiosperms and vary
greatly in shape, color and size.
A typical flower has both male &
female gametes.
Structure & Function of Flowers

Flowers typically are composed of four
types of specialized leaves:
 pistil (carpel)
Listed from
inner most to
 stamen
outer most
layer
 petals
 Sepals
Structure & Function of
Flowers
The outermost layer,
or whorl, of a flower
is called the sepals,
which in many plants
are green and closely
resemble regular
leaves.
Structure & Function of
Flowers

Petals are the often
brightly colored
structures that are
found just inside
the sepals and are
used to attract
pollinators like
insects and birds.
Structure & Function of
Flowers

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The male part of the
flower is called the
stamen, which consists
of the anther and the
filament.
Stamen
The anther of a flower
is where pollen is
located. Pollen is
basically plant sperm.
Structure & Function of
Flowers

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The female part of a
flower is called the
carpel (or pistil),
which consists of 3
parts: the stigma, the
style and the ovary.
The ovary contains
the female eggs that
pollen travel to after
landing on the stigma.
Structure & Function of Flowers

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After fertilization, the ovules develop into
seeds, while the ovary enlarges into the
fruit.
If a flower has only one ovule, the
fruit will contain one seed, as in a peach.
The fruit of a flower with many ovules, such
as a tomato, will have many seeds.
Flower Pollination and Fertilization
Pollen Grains



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A pollen grain contains a
sperm cell that fertilizes
an egg.
If fertilization is
successful, a seed is
produced.
The pollen grains of
each species are unique.
The pollen grains shown
here are about 1000
times their actual size.
Plant Responses & Adaptations

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There are many ways that plants have adapted
to their various environments and have
developed to assist in their growth and
development.
Plants have hormones, which are chemical
substances that control a plant’s pattern of
growth and development, as well as its’
response to environmental conditions.
Plant Responses & Adaptations

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Many plants lay dormant when cold
weather approaches and turn off
their photosynthetic pathways until
warmer weather returns.
Other plants have adapted to living
in aquatic environments, extremely
salty environments or very dry
environments.
Plant Responses & Adaptations

Venus fly trap

Some plants that have
specialized structures for
obtaining nutrients include
carnivorous plants and
parasitic plants.
Many plants defend
themselves against insect
attack by making
compounds that ward off
potential predators.
Poison ivy
Plants As Food

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Many plants are used as food sources in
many countries.
Cereals such as rice, wheat, and corn are
important sources of food.
Cereals produce dry fruits calls grains,
which contain a single seed that is paced
with energy-rich endosperm.
Plants As Food

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Though wheat’s
primary use is to make
flour, it is also used in
brewing & distilling,
for livestock feed and
even as a coffee
substitute.
Rice, corn & wheat are
the 3 most important &
widely used cereal
crops.
Legumes

Legumes, such as beans and peas, are
important foods because they provide
essential amino acids that grains lack.
Root crops


Root crops, like potatoes & yams, are
a major source of calories.
They are used to inexpensively fill
stomachs in poor countries (cassava).
Other uses of Plants
While many plants are consumed primarily for
food, other plants are utilized for other reasons.
Wood

Wood, an important plant resource, is
found in thousands of products, from
lumber used to build houses, to wood
that is ground into pulp to make
fabrics (rayon) and paper.
Other uses of Plants

Besides rayon,
plants are also
used to make other
textiles like cotton,
rubber and latex.
Plants as
Medicine

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Plants are the sources of many
important medicines that are used to
treat diseases and other ailments.
Some examples: Aspirin, cancer
treatment drugs & cortisone.
Impact of Plants
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Though the first plants appeared on land only
about half a billion years ago, today they account
for, by far, the largest proportion of the Earth's
biomass.
Plants provide life on Earth with oxygen and
shelter, as well as serving as the foundation of the
food web.
Plants frequently determine the appearance of
other organisms that depend on them in a variety
of different habitats.
Impact of Plants
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Plants have laid the foundation that
provides power for industrial society.
Plants have supplied sufficient oxygen
to the atmosphere to support the
evolution of higher animals.
Impact of Plants

Plants have modified the terrain of the
Earth, making its’ surface habitable to
maintain many different life forms.
Impact of
Plants

From towering redwood trees to the
microscopic duckweed plant,
Kingdom Plantae is an extraordinarily
diverse and long-lived group that
makes the life of animals, fungi and
other organisms possible.
PLANT TEST COMING
SOON!! You will be tested
over what you have learned
about plants on:
A  Friday 5/13
B  Wednesday 5/18