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Sexual Reproduction in Plants

Sexual Reproduction in Plants. Sexual Reproduction includes:. Pollination Fertilization Seed Production Sexual reproduction also known as seed reproduction because it involves using seeds to produce new plants. Seeds. Seeds contain all the genetic characteristics of the parent plant

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Sexual Reproduction in Plants

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  1. Sexual Reproduction in Plants

  2. Sexual Reproduction includes: • Pollination • Fertilization • Seed Production • Sexual reproduction also known as seed reproduction because it involves using seeds to produce new plants.

  3. Seeds • Seeds contain all the genetic characteristics of the parent plant • However, the characteristics of the plant grown from seeds may vary from parent plant.

  4. Reasons for Seed Propagation Most Economical Allows a grower to produce a larger number of plants. Most widely used method

  5. Parts of the Flower

  6. Parts of the Flower • Pistil – Female reproductive part of the flower • Stigma- Sticky surface to capture the pollen • Style- Tube that connects the stigma to the ovary • Ovary-contains the ovules. • Stamen- Male reproductive part of the flower • Anther- produces the pollen grains • Filament- supports the anther.

  7. Pollination • When a flower opens, the stamens mature and become fully developed. • The anthers on the stamen then release hundreds of pollen grains • Pollen grains are the male sex cell • Each pollen grain contains genetic characteristics of the plant.

  8. Pollination • Flower ovary contains one or more ovules, which are the female sex cells • Each ovule contains genetic information of the plant as well. • Pollination occurs when the pollen grains come into contact with the sticky surface of the stigma.

  9. Types of Pollination • Self Pollination: • The transfer of pollen from the anther of a flower to the stigma of the same flower., or to a different flower on the same plant. • Cross Pollination • The transfer of pollen from the anther of a flower to the stigma of a flower on a different plant.

  10. Self Pollination • More Effective • Almost guarantees pollination • Isn't’ dependable on outside variables for pollination

  11. Cross Pollination • Increases genetic variability • Accomplished through • Wind • Bees • Birds

  12. 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)

  13. Flowers of wind pollinated plants are: • Small • Greenish or brown • No fragrance • Small or no petals • No Nectar Examples Include Grasses, wheat and cattails

  14. Flowers that are pollinated by hummingbirds and butterflies are: • Tube shaped • Fragrant fro butterflies, no fragrance for hummingbirds • Brightly colored, usually red attracts hummingbirds • Produce nectar which is an attractive snack.

  15. Flowers that are pollinated by flies • Brown and dark colored • Have foul odor

  16. 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

  17. Flowers that are pollinated by bats and moths • Tube Shaped • Fragrant • White or yellow which can be seen easily at night • Sometimes only open at night

  18. Fertilization • 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 meiosis. This process causes the chromosomes number to be halved and the result are “daughter cells”. • The daughter cells are haploid (one set of chromosomes) represented by 1n

  19. Fertilization • 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 a diploid

  20. 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 two sperm cells, one fertilizes the egg while the other fuses with another cell and produces the endosperm. This is called double fertilization.

  21. 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

  22. 3 essential parts of the seed. • Embryo- Embryonic Root (Radical) • Endosperm/Cotyledon- Food Reserve • Seed Coat

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