© 2014 Pearson Education, Inc. 1 Stigma Stamen Anther Carpel Style Filament Ovary Petal Sepal Ovule © 2014 Pearson Education, Inc. 2 Sepals Petals Stamens A Carpels B C C gene activity B + C (a) A schematic diagram A B Carpel + gene of the ABC hypothesis gene activity activity Petal A gene Stamen activity Sepal Active B B B B B B B B A A A A genes: A A C C C C A A C C C C C C C C A A C C C C A A A B B A A B B A Whorls: Carpel Stamen Petal Sepal Wild type Mutant lacking A Mutant lacking B Mutant lacking C (b) Side view of flowers with organ identity mutations © 2014 Pearson Education, Inc. 3 Carpel Anther Microsporangium Microsporocytes (2n) Mature flower on sporophyte plant MEIOSIS Microspore (2n) (n) Ovule with Generative cell megasporangium (2n) Tube cell Male gametophyte (in pollen Pollen Germinating Ovary grain) (n) seed MEIOSIS grains Stigma Pollen tube Megasporangium (2n) Sperm Embryo (2n) Surviving Tube nucleus Endosperm (3n) Seed megaspore Seed coat (2n) (n) Antipodal cells Integuments Style Female Polar nuclei gametophyte in central cell (embryo sac) Pollen Synergids tube Zygote (2n) Egg (n) Sperm Nucleus of Egg (n) developing nucleus (n) endosperm (3n) FERTILIZATION Key Haploid (n) Diploid (2n) Discharged sperm nuclei (n) © 2014 Pearson Education, Inc. 4 Abiotic pollination by wind Pollination by insects Common dandelion Common dandelion under normal light under ultraviolet Hazel staminate light flower (stamens only) Hazel carpellate flower (carpels only) © 2014 Pearson Education, Inc. 5 Pollination by bats or birds Long-nosed bat feeding on cactus flower at night Hummingbird drinking nectar of columbine flower © 2014 Pearson Education, Inc. 6 Stigma Pollen Endosperm grain nucleus (3n) Pollen tube (two polar nuclei plus sperm) Two sperm Ovule Tube Polar nucleus nuclei Style Egg Ovary Synergid Polar Zygote (2n) Ovule nuclei Two sperm (egg plus sperm) Egg Micropyle © 2014 Pearson Education, Inc. 7 Ovule Endosperm nucleus Zygote Integuments Zygote Terminal cell Basal cell Proembryo Suspensor Basal cell Cotyledons Shoot apex Root apex Seed coat Suspensor Endosperm © 2014 Pearson Education, Inc. 8 Seed coat Epicotyl Hypocotyl Radicle Cotyledons (a) Common garden bean, a eudicot with thick cotyledons Seed coat Endosperm Cotyledons Epicotyl Hypocotyl Radicle (b) Castor bean, a eudicot with thin cotyledons Scutellum Pericarp fused (cotyledon) with seed coat Coleoptile Endosperm Epicotyl Hypocotyl Coleorhiza Radicle (c) Maize, a monocot © 2014 Pearson Education, Inc. 9 Foliage leaves Cotyledon Epicotyl Hypocotyl Cotyledon Hypocotyl Hypocotyl Cotyledon Radicle Seed coat (a) Common garden bean Foliage leaves Coleoptile Coleoptile Radicle (b) Maize © 2014 Pearson Education, Inc. 10 Stigma Style Carpels Stamen Flower Petal Ovary Stamen Stamen Sepal Stigma Ovary (in Ovule receptacle) Ovule Pea flower Raspberry flower Pineapple inflorescence Apple flower Each segment Carpel Remains of develops (fruitlet) stamens and styles Stigma from the Sepals Seed carpel Ovary of one flower Stamen Seed Receptacle Pea fruit Raspberry fruit Pineapple fruit Apple fruit (a) Simple fruit (b) Aggregate fruit (c) Multiple fruit (d) Accessory fruit © 2014 Pearson Education, Inc. 11 Dispersal by water Coconut seed embryo, endosperm, and endocarp inside Dispersal by wind buoyant husk Giant seed of the tropical Asian climbing gourd Dandelion fruit Alsomitra macrocarpa Dandelion “seeds” (actually one-seeded fruits) Winged fruit of a maple Tumbleweed © 2014 Pearson Education, Inc. 12 Dispersal by animals Fruit of puncture vine (Tribulus terrestris) Squirrel hoarding seeds or fruits underground Ant carrying seed with attached “food body” Seeds dispersed in black bear feces © 2014 Pearson Education, Inc. 13 (a) Staminate flowers (left) and carpellate flowers (right) of a dioecious species Stamens Styles Styles Stamens Thrum flower Pin flower (b) Thrum and pin flowers © 2014 Pearson Education, Inc. 14 Asexual reproduction in aspen trees © 2014 Pearson Education, Inc. 15 (a) (b) (c) Developing root Laboratory cloning of a garlic plant © 2014 Pearson Education, Inc. 16 © 2014 Pearson Education, Inc. 17 © 2014 Pearson Education, Inc. 18 .