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LECTURE 3 REPRODUCTIVE STRUCTURES Flowering Floral Induction Leaves Floral Stimulus Florigen Phloem Transport Floral Evocation Reproductive Apex Leaf Primordia → Floral Primordia Sepals (A) Petals (A+B) Stamens (B+C) Pistils (C) Vegetative Apex SAM Tunica Corpus
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Flowering • Floral Induction • Leaves • Floral Stimulus • Florigen • Phloem Transport • Floral Evocation • Reproductive Apex • Leaf Primordia → Floral Primordia • Sepals (A) • Petals (A+B) • Stamens (B+C) • Pistils (C)
Vegetative Apex • SAM • Tunica • Corpus • Leaf Primordia
Inflorescence Apex • Multiple Reproductive Apical Meristems • Floral Primordia • Sepals • Petals • Stamens • Pistils
Floral Primordia • Whorls • 1 - Sepals • 2 - Petals • 3 - Stamens • Anther • Filament • 4 - Carpels • Stigma • Style • Ovary
stigma style petal petals andcorolla anthers stigma filament anther hypanthium ovules ovary ovary filament sepal scar stigma anther style filament petal sepal ovary receptacle hypanthium Fig. 13-12, p. 203
bract umbel ray flowers disc flowers pedicel bract receptacle raceme panicle spike cyme head Fig. 13-13, p. 204
Alternation of Generations • Sporophyte (2N) • Diploid (2N) • Vegetative Phase • Mitosis • Gametophyte (1N) • Haploid (1N) • Reproductive Phase • Meiosis
Male Gametophyte • Stamen • Anther 4 Locules Attached to Filament Tapetal Cells • Microsporocytes (2N) Meiosis • Microspores (4 x 1N) Tetrads • Pollen Grains (1N) Complex Cell Wall Exine Intine Generative Nucleus 2 x sperm nuclei Tube Nucleus
filament anther Meiosis pollensac tapetum two-cell stage four-cell stage microsporocyte Pollen sac anther filament Mitosis germinated pollen grain tube cell generative cell pollen tube sperm cells tube nucleus stamen pollen grain (male gametophyte) microspores tube nucleus Fig. 13-2, p. 197
Female Gametophyte • Pistil • Stigma • Style • Ovary • Ovules • Megasporocyte (2N) • 4 Megaspores (1N) • 1 Cell Gametophyte • 2 Cell Gametophyte • 4 Cell Gametophyte • 8 Cell Gametophyte • 1 Egg Cell • 2 Synergids • 2 Polar Nuclei • 3 Antipodals
Fertilization • Pollination Compatable Stigma Genetic Regulation • Pollen Germination Environmental Regulation Humidity Temperature • Pollen Tube Growth down Style to Ovary into Ovule • Double Fertilization 2 Sperm Nuclei (2 x1N) 1 Sperm (1N) + Egg Cell (1N) Zygote (2N) - Sporophyte 1 Sperm (1N) + 2 Polar Nuclei (2 x 1N) Triploid Endosperm (3N)