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Sexual Reproduction of Flowering Plants Topics: 2022D, 2022E, 2022F, 2022G Amanda Trutsch. Sexual Reproduction includes:. - Pollination. - Fertilization. - Seed production. *NOTE: Pollination and fertilization are separate processes! . Parts of a flower:.
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Sexual Reproduction of Flowering Plants Topics: 2022D, 2022E, 2022F, 2022G Amanda Trutsch
Sexual Reproduction includes: - Pollination - Fertilization - Seed production *NOTE: Pollination and fertilization are separate processes!
Parts of a flower: http://www.ualr.edu/~botany/flower_parts.jpg
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.
Self-pollination: - More effective - Almost guarantees pollination - Isn’t dependent on outside variables for pollination Cross-pollination: - Increases genetic variability
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)
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/cattail.jpg Examples include: Grasses, wheat or cattails
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/2003-09-10/2003-09-11--Red%20flower.jpg http://ppng.home.comcast.net/abc/Butterfly_Bush_Lavendar.jpg
Flowers that are pollinated by flies: - Brown or dark colored - Have a foul odor http://digital-picture-gallery.com/Orchids-LR-PO-SG/thm_Brown%20Spotted%20Orchid.jpg
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-annuals/pansy-flower.jpg
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_white_flowers_hp.jpg
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.
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.
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.
3 Essential Parts of a Seed: - Embryo - Embryonic root (radicle) - Shoot (plumule) - Food Reserve (endosperm in a monocot, cotyledon in a dicot) - Seed coat