Plant Reproduction

Plant Reproduction - Plant Reproduction v Focus on...

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Unformatted text preview: Plant Reproduction v Focus on angiosperm plants Ø >250,000 species or 90% of all plants ≈ Ø produce flowers and fruits Ø life cycle alternates between diploid haploid v Sporophyte: diploid plant v Gametophyte: haploid gametes Life Cycle of Angiosperm Union of gametophytes: form new sporophytes Meiosis: sporophyte production of gametophytes v Sporophte generation is dominant over gametophyte generation v Gametophytes are "housed" in sporophyte reproductive structure (flower) Angiosperm Reproduction In angiosperms, the dominant sporophyte Ø Produces spores that develop within anthers into male gametophytes (pollen grains) Ø Produces ovules that develop within the ovary into female gametophytes (embryo sacs) Figure 38.2a, b Anther at tip of stamen Filament Anther Pollen tube Germinated pollen grain ( n ) (male gametophyte) on stigma of carpel Ovary (base of carpel) Ovule Embryo sac ( n ) (female gametophyte) FERTILIZATIO N Egg ( n ) Sperm ( n ) Receptacle Style Ovary Key Haploid ( n ) Diploid (2 n ) (a) An idealized flower. (b) Simplified angiosperm life cycle. See Figure 30.10 for a more detailed version of the life cycle, including meiosis. Mature sporophyte plant ( 2n ) with flowers Seed (develops from ovule) Zygote (2 n ) Embryo (2 n ) (sporophyte) Simple fruit (develops from ovary) Germinating seed Seed Stigma Chamber for pollen production Chamber for egg production i i (determinate growth) Carpel (female) Stamen (male) Sepal Petal Four floral organs Flower Variations v Evolved over 140 million years of angiosperm history v Significance is flower arrangement effect on fruit and seed arrangement 3...
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This note was uploaded on 03/28/2008 for the course BIOL 212 taught by Professor Shen during the Spring '08 term at Iowa State.

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Plant Reproduction - Plant Reproduction v Focus on...

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