Sexual Reproduction of Flowering Plants

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Sexual Reproduction of Flowering Plants Topics
2022D, 2022E, 2022F, 2022G Amanda Trutsch
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Sexual Reproduction includes
- Pollination
- Fertilization
- Seed production
NOTE Pollination and fertilization are
separate processes!
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Parts of a flower
http//www.ualr.edu/botany/flower_parts.jpg
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Pollination is the process of moving the pollen
grain from the anther of a stamen (male organ) to
the stigma of a carpel (female organs). Pollen
contains sperm cells.
Self-pollination is the transfer of pollen from
the anther of a flower to the stigma of the same
flower, or to different flowers on the same plant.
Cross-pollination is the transfer of pollen from
the anther of a flower to the stigma of a flower
on a different plant.
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Self-pollination - More effective - Almost
guarantees pollination - Isnt dependent on
outside variables for pollination
Cross-pollination - Increases genetic variability
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Methods of Pollen Distribution
- Wind pollen grains are carried by wind from
one flower to another
- Animals Birds (hummingbirds) Insects
(moths, butterflies, bees, flies) Mammals
(bats)
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Flowers of wind pollinated plants are
- Small
- Greenish or brown
- No fragrance
- Small or no petals
- No nectar
http//www.epa.gov/owow/wetlands/types/images/catt
ail.jpg
Examples include Grasses, wheat or cattails
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Flowers that are pollinated by hummingbirds and
butterflies are
- Tube shaped
- Fragrant for butterflies, no fragrance for
hummingbirds
- Brightly colored, usually red attracts
hummingbirds

- Produce nectar which is an attractive snack
http//www.indirectsunlight.com/images/scotland/20
03-09-10/2003-09-11--Red20flower.jpg
http//ppng.home.comcast.net/abc/Butterfly_Bush_La
vendar.jpg
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Flowers that are pollinated by flies
- Brown or dark colored
- Have a foul odor
http//digital-picture-gallery.com/Orchids-LR-PO-S
G/thm_Brown20Spotted20Orchid.jpg
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Flowers that are pollinated by bees are
- Fragrant (nectar as a reward)
- Brightly colored with nectar guides visibly
only with UV light that bees can see, which
directs bees to the center of the flower
- Sweet fragrance
- Produce nectar
http//www.mooseyscountrygarden.com/flowering-annu
als/pansy-flower.jpg
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Flowers that are pollinated by bats or moths
- Tube shaped
- Fragrant
- White or yellow which can be seen easily at
night
- Sometimes only open at night
http//fcbs.org/images/Tillandsia/t_streptocarpa_w
hite_flowers_hp.jpg
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Fertilization process of sperm reaching the egg
- Cells of many plant flowers are diploid (two
sets of chromosomes). Represented by 2n
- Some of these cells undergo a process of cell
division called miosis. This process causes the
chromosomes number to be halved and the result
are the daughter cells.
- The daughter cells are haploid (one set of
chromosomes). Represented by 1n
- The daughter cells undergo another process of
cell division called mitosis, which produce more
haploid egg or sperm cells.
- When these cells come together (fertilization)
they form the zygote, which is then diploid.
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zygote.swarthmore.edu/ plantfig10.gif
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Process of Fertilization
- After the pollen grain lands on the stigma, it
develops a pollen tube which travels down the
style.
- The pollen grain releases a sperm cell, in some
cases 2 sperm cells.
- The sperm travel down the pollen tube and reach
the ovary then enter the ovule.
- If there are 2 sperm cells, one fertilizes the
egg while the other fuses with another cell and
produce the endosperm. This is called double
fertilization.
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http//www.saburchill.com/images04/0107.jpg
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Development of Seed
- The diploid zygote forms the embryo. These
cells will later divide and form parts of the
seed.
- Cells in the outer layer of the ovule harden
and become the seed coat.
- The endosperm grows and becomes the food source
for the growing seed.
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3 Essential Parts of a Seed
- Embryo
- Embryonic root (radicle) - Shoot (plumule)
- Food Reserve (endosperm in a monocot, cotyledon
in a dicot)
- Seed coat
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www.huntersponyfarm.com/ garden/seeds_di_mono.gif
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www.huntersponyfarm.com/ garden/seeds_di_mono.gif