After studying this chapter you will be able to: Describe how the plant life cycle is modified in angiosperms; identify and describe the function of a sepal, petal, stamen (filament and anther), carpel (style, ovary, ovule, and stigma), seed coat, hypocotyl, radicle, epicotyl, endosperm, cotyledon;. | Chapter 38 Angiosperm Reproduction and Biotechnology Overview: To Seed or Not to Seed The parasitic plant Rafflesia arnoldii Produces enormous flowers that can produce up to 4 million seeds Figure Concept : Pollination enables gametes to come together within a flower In angiosperms, the dominant sporophyte Produces spores that develop within flowers into male gametophytes (pollen grains) Produces female gametophytes (embryo sacs) An overview of angiosperm reproduction Figure , b Anther at tip of stamen Filament Anther Stamen Pollen tube Germinated pollen grain (n) (male gametophyte) on stigma of carpel Ovary (base of carpel) Ovule Embryo sac (n) (female gametophyte) FERTILIZATION Egg (n) Sperm (n) Petal Receptacle Sepal Style Ovary Key Haploid (n) Diploid (2n) (a) An idealized flower. (b) Simplified angiosperm life cycle. See Figure for a more detailed version of the life cycle, including meiosis. Mature sporophyte plant (2n) with flowers Seed (develops from ovule) Zygote (2n) Embryo (2n) (sporophyte) Simple fruit (develops from ovary) Germinating seed Seed Carpel Stigma Flower Structure Flowers Are the reproductive shoots of the angiosperm sporophyte Are composed of four floral organs: sepals, petals, stamens, and carpels Many variations in floral structure Have evolved during the 140 million years of angiosperm history Bilateral symmetry (orchid) Sepal Radial symmetry (daffodil) Fused petals Semi-inferior ovary Inferior ovary Superior ovary Lupine inflorescence Sunflower inflorescence Maize, a monoecious species Dioecious Sagittaria latifolia (common arrowhead) REPRODUCTIVE VARIATIONS SYMMETRY OVARY LOCATION FLORAL DISTRIBUTION Figure Gametophyte Development and Pollination In angiosperms Pollination is the transfer of pollen from an anther to a stigma If pollination is successful, a pollen grain produces a structure called a pollen tube, which grows down into the ovary and discharges sperm near the embryo sac Pollen Develops from . | Chapter 38 Angiosperm Reproduction and Biotechnology Overview: To Seed or Not to Seed The parasitic plant Rafflesia arnoldii Produces enormous flowers that can produce up to 4 million seeds Figure Concept : Pollination enables gametes to come together within a flower In angiosperms, the dominant sporophyte Produces spores that develop within flowers into male gametophytes (pollen grains) Produces female gametophytes (embryo sacs) An overview of angiosperm reproduction Figure , b Anther at tip of stamen Filament Anther Stamen Pollen tube Germinated pollen grain (n) (male gametophyte) on stigma of carpel Ovary (base of carpel) Ovule Embryo sac (n) (female gametophyte) FERTILIZATION Egg (n) Sperm (n) Petal Receptacle Sepal Style Ovary Key Haploid (n) Diploid (2n) (a) An idealized flower. (b) Simplified angiosperm life cycle. See Figure for a more detailed version of the life cycle, including meiosis. Mature sporophyte plant (2n) with flowers Seed (develops from ovule)
