Flowers, Fruit and Seeds

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Transcript Flowers, Fruit and Seeds

INTRODUCTION
Science 3001
Science II: Earth & Life Sciences I
Mr. Kishore Lal
Living Things
Lesson 3A – Flowers, Fruits and Seeds
Flowers, Fruits and Seeds
Reproduction in plants
• Life cannot exist
without plants.
• There are three
methods of
reproduction in
plants:
• From seeds.
• From spores.
• Vegetative
propagation
(from body
parts)
Flowers, Fruits and Seeds
Parts of the Flower
• Flowers are important
in producing seeds.
• While flowers can be
different, there are
some parts that are
found in many flowers.
• Some flowers can be
small and dull looking
like tiny leaves
e.g.plum, or
pommecythe, while
others can be quite
conspicuous as single
flower or bunches of
flowers.
Flowers, Fruits and Seeds
Parts of the Flower.
• Stamen - the male part.
• Anther - produces male
gametes (pollen).
• Filament - supports
anther.
• Pistil - the female part.
• Stigma - sticky portion
at the top of the style
where pollen grains
usually land.
• Style - the narrow elongated part of the pistil between
the ovary and the stigma. The pollen tube grows into the
style to reach the ovule for fertilization.
• Ovary - contains ovules After fertilization, the ovary may
become the fruit.
• Ovule - the female gamete (egg)which become seeds.
Flowers, Fruits and Seeds
Parts of the Flower.
• Petal (corolla) - often
conspicuously colored and
may attract insects.
• Pedicel - the stalk of a
flower.
• Sepal (calyx) - external
covering of flower bud.
(often green and leaflike).
• Stalk - supports the
flower
• Receptacle - the part of a flower stalk where the other
parts of the flower are attached.
• Meiosis is the process of cell division that produces
gametes (sex cells) in the ovary and anther
Flowers, Fruits and Seeds
Seed and Fruit Formation.
• When the pollen lands on the sticky stigma it
begins to grow a pollen tube towards the ovary.
• This allows its nucleus to fertilize a single
ovule.
• The outer cell layers of ovule form seed coat.
• Seed coat forms slows down metabolic
activities and protects young plant when it’s
the most vulnerable.
• Seed has stored food for germination to
postpone development until favorable
conditions.
• The fruit develops from the ovary.
• Germination can’t start until water/oxygen
reaches embryo and other appropriate
conditions (e.g. heat, available nutrients,
chemicals, pass through animal intestines, etc).
Flowers, Fruits and Seeds
Main Parts of a Seed
• Testa – (Seed Coat) i.e. the
protective covering which
protects the baby plant
inside the seed.
• It has a tiny hole through
which the seed gets water.
• Cotyledons (Seed Leaves) They contain food for a
growing baby plant.
• Embryo – the parts that will
become the shoot and root
• Plumule – this becomes
the shoot
• Radicle – this becomes
the root
Flowers, Fruits and Seeds
• Germination is the
development of a
seed into a
seedling (baby
plant).
• The seed needs
• oxygen,
• water and
• warmth (from
sunlight) for
germination.
Germination - From the emergence of
the plumule and radicle to the first true
leaves.
Flowers, Fruits and Seeds
Stages of growth
• Seed absorbs water
from the soil.
• Seed coat becomes soft
and it breaks up and the
baby root (radicle)
emerges followed by the
baby shoot (plumule).
• Root grows down into the soil.
• Baby shoot develops and grows towards the sunlight.
• Tiny leaves appear on the shoot. As the leaves grow, they
start making their own food (photosynthesis).
• The new plant produces flowers which grow into fruits.
• Fruits contain seeds.
• Given suitable condition of air, water and warmth, these
seeds germinate and grow into new plants.
• In this way the cycle of reproduction in plants continues.
Flowers, Fruits and Seeds
Dispersal of seeds
• Dispersal helps the seeds to reach
the suitable place where they get
enough air, water and warmth
needed for their germination.
• It prevents the competition of
seeds growing near the mother
plant.
Flowers, Fruits and Seeds
Dispersal of seeds
• Seeds need to be scattered away
from the mother plant.
• Dispersal of seeds is accomplished
by agents like
• animals, birds, human beings
• air
• Water
• explosion.
END