Transcript Plant Reproduction PPT

Happy [almost]
Please do the following:
• pick up the handouts
• have out a sharpened pencil for today’s lab
Reproduction in
Plants
Sexual Reproduction of the
Flowering Plant
Structure of the flower
Function of floral parts
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Sepal : To protect the
flower (and to prevent it
from drying out
Petals : To attract
insects to the flower for
pollination
Function of floral parts

Stamen : To produce
the pollen grains in the
anthers. (Each pollen
grain produces two
male gametes/sperm,
one of which can
fertilize an egg cell)
Function of floral parts -Stamen
Anther
• Produces pollen
Filament
• Holds the anther in place
Function of floral parts

Pistil : To produce the
ovules (Each ovule
contains an egg cell
inside an embryo sac)
Function of floral parts - Pistil
Stigma
• Where pollen lands
after pollination
Style
• Pollen travels down this
Ovary
• Contains ovules (eggs)
Pollination
Transfer of pollen from the anther to the stigma of
a flower of the same species
Pollination
Self pollination
Cross pollination
• Transfer of pollen from
an anther to a stigma
of the same plant
• Transfer of pollen from
the anther to the stigma
of a different plant of
the same species
Animal (insect) pollination
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Petals brightly colored,
scented with nectar
Small amounts of sticky
pollen
Anthers inside petals
Stigmas sticky, inside
petals
Wind pollination
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Petals small, not
colored brightly
Anthers outside petals
Stigmas large, feathery
and outside petals
Pollen large numbers,
light, dry and small
Fertilization
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Fertilization is the
fusion of the male (n)
and female (n)
gametes to produce
a zygote (2n)
The pollen grain
produces the male
gametes
Embryo sac
produces an egg cell
Seed Formation in Flowering Plants
• Sperm + Egg  Zygote
• The zygote grows
repeatedly by mitosis to
form an embryo which is
found within a seed
Fruit Formation
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The ovule becomes the seed
The ovary becomes the fruit
Fruit Formation

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A fruit is a mature
ovary that may contain
seeds
The process of fruit
formation is stimulated
by growth regulators
produced by the seeds
Fruit and Seed Dispersal

Need for dispersal
 Minimizes competition
for light, water etc.
 Avoids overcrowding
 Colonizes new areas
 Increases chances of
survival
Types of Dispersal
1.
2.
3.
4.
Wind
Water
Animal
Self
Germination
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The re-growth of the
embryo after a period of
dormancy, if the
environmental conditions
are suitable
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Water
Oxygen
Suitable temperature
Events in germination
cease when the plants
leaves have developed
and the plant has started
to photosynthesize
Review of the stages of sexual
reproduction in plants…
4
Asexual Reproduction in Plants
Asexual reproduction
 Does not involve gametes, flowers, seeds or
fruits
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examples: binary fission, fragmentation, spore
formation and budding
It involves only one parent and offspring are
genetically identical (have the same genetic
content) to the parent
So what happens?
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Part of the plant becomes separated from the parent
plant and divides by mitosis to grow into a new plant
Plant Reproduction via Spores
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Spore - a reproductive cell capable of developing
into a new individual without fusion with another
reproductive cell
Spores are different than seeds, they do not contain
plant embryos or food stores
A structure called sporangia produce the very tiny
spores
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When the sporangia break open, the spores are released
and dispersed by water or wind…if the spore lands in a
suitable environment, it can grow into a tiny plant
Found in non-seed bearing plants such as mosses
and ferns