2014 Pearson Education Inc 1 Stamen Stigma Anther

© 2014 Pearson Education, Inc. 1

Stamen Stigma Anther Carpel Style Filament Ovary Petal Sepal Ovule © 2014 Pearson Education, Inc. 2

Sepals Petals A B Stamens Carpels C A B gene activity B C gene activity (a) A schematic diagram of the ABC hypothesis Petal Stamen A gene activity Active genes: Carpel Sepal B B BB AACCCC AA BB B B CCCCCC CC AACCCC AA AA AA ABBAAB BA Mutant lacking B Mutant lacking C Whorls: Stamen Carpel Petal Sepal Wild type (b) Side view of flowers with organ identity mutations © 2014 Pearson Education, Inc. 3

Carpel Microsporangium Microsporocytes (2 n) Anther Mature flower on sporophyte plant (2 n) MEIOSIS Microspore (n) Ovule with megasporangium (2 n) Ovary Germinating seed MEIOSIS Male gametophyte (in pollen grain) (n) Megasporangium (2 n) Embryo (2 n) Endosperm (3 n) Seed coat (2 n) Female gametophyte (embryo sac) Nucleus of developing endosperm (3 n) Zygote (2 n) 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 Haploid (n) Diploid (2 n) © 2014 Pearson Education, Inc. Discharged sperm nuclei (n) 4

Abiotic pollination by wind Pollination by insects Common dandelion under normal light Hazel staminate flower (stamens only) Hazel carpellate flower (carpels only) © 2014 Pearson Education, Inc. Common dandelion under ultraviolet light 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 tube Pollen grain Ovule Two sperm Tube nucleus Polar nuclei Style Egg Ovary Polar Synergid nuclei Two sperm Egg Ovule Endosperm nucleus (3 n) (two polar nuclei plus sperm) Zygote (2 n) (egg plus sperm) 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 Suspensor © 2014 Pearson Education, Inc. Seed coat Endosperm 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 (cotyledon) Pericarp fused with seed coat Coleoptile Endosperm Epicotyl Hypocotyl Coleorhiza Radicle (c) Maize, a monocot © 2014 Pearson Education, Inc. 9

Foliage leaves Cotyledon Epicotyl Hypocotyl Cotyledon Radicle Seed coat (a) Common garden bean Foliage leaves Coleoptile (b) Maize © 2014 Pearson Education, Inc. Coleoptile Radicle 10

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 Stamen Receptacle Apple fruit (d) Accessory fruit 11

Dispersal by water Dispersal by wind Giant seed of the tropical Asian climbing gourd Alsomitra macrocarpa Winged fruit of a maple © 2014 Pearson Education, Inc. Coconut seed embryo, endosperm, and endocarp inside buoyant husk Dandelion fruit Dandelion “seeds” (actually one-seeded fruits) Tumbleweed 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 Thrum flower (b) Thrum and pin flowers © 2014 Pearson Education, Inc. Stamens Pin flower 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

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