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24-1 Reproduction in Flowering Plants. Parts of a Flower a. Receptacle - swollen base below the petals of the flower. b. Sepal – green leaf structures that are the outer most whorl that surrounds and protects the closed flower.( shapes the bud)
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24-1 Reproduction in Flowering Plants • Parts of a Flower a. Receptacle- swollen base below the petals of the flower. b. Sepal – green leaf structures that are the outer most whorl that surrounds and protects the closed flower.( shapes the bud) c. Petals – fragrant colorful structures that attract insects and protect the reproductive organs.
Incomplete Flower – Flowers that have only either male or female parts. • Complete Flower – Flowers that have both parts (male and female
d. Male Reproductive Parts • Stamen – 2 parts a). Filament – stalk like structure that supports the anther. b). Anther – top of filament, contains microsporangia which produce ( pollen grains).
Male StaMEN STAMEN ANTHER FILAMENT
e. Female Reproductive Parts 1. Pistil – 3 parts a). Stigma – sticky on top of it. b). Style – stalk like stem of pistil where the pollen tube travels. c). Ovary – enlarged base of pistil, contains ovules.
Female Pistil STAMEN PISTIL STYLE
III Pollen Grain Formation-Forms in the anther of the stamen A. Microspore Mother Cells- through meiosis produces 4 haploid microspore. B. Microspores divide by mitosis into two haploid cells. This 2 cells structure is the pollen grain
C. The larger of the 2, the Tube Cell, Forms the pollen tube . D. The other becomes the generative cells, which forms into 2 sperm.
II.Ovule Formation • Ovule consists of a megasporangium that is surrounded by Integument with two layers. The integument has an opening where the pollen tube penetrates and the 2 sperm enter called the micropyle. 1. Megaspore Mother Cell – through meiosis forms 4 haploid megaspores, one enlarges into the egg and 3 others called polar bodies die and have no purpose.
IV. Pollination/Fertilization • Pollination – Transfer of pollen to Stigma • Fertilization – Union of Gametes 1. Pollen reaches stigma 2. Pollen tube grows a tube down style. 3. Generative cell divides into 2 sperm. 4. Pollen tube penetrates micropyle of ovule. 5. First sperm fertilizes enlarged egg. 6. Second fertilizes POLAR NUCLEI which develop into the endosperm which provides the plant with nourishment. 7. Because 2 sperm are involved they call this DOUBLEFERTILIZATION