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