Classify Which plant structures are male sexual organs and which are female sexual organs Apply Concepts Relate the characteristics of angiosperms reproduction to angiosperm success Review Define vegetative reproduction Compare and Contrast Make a compare contrast table comparing alternation of generations in flowering plants and green algae (22.2)

Ch 24 Plant Reproduction and Response 24.1 Reproduction in Flowering Plants

Structure of Flowers Reproductive organs that are composed of four kinds of specialized leaves: Sepals, petals, stamens, and carpels.

Sepals Outermost circle of floral parts Enclose the bud before it opens Protect the flower while it is developing.

Petals Found just inside the sepals Colors, number, and shapes of such petals attract insects and other pollinators to the flower.

Stamen Male parts of the flower Consists of a stalk called a filament with an anther at its tip Anther Structure that produces pollen grains.

Carpels Produce and shelter the female gametophytes and seeds Ovary Contains one or more ovules where female gametophytes are produced.

Carpels Style Stigma Stalk of carpel Sticky or feathery portion at tip of carpel to capture pollen.

Carpel Pistil Single carpel or several fused carpels.

Angiosperm Life Cycle Fertilization in angiosperms is distinct from other plants Two fertilization events take place- one produces the zygote and the other a tissue, called endosperm, within the seed.

Angiosperm Life Cycle Alternation of generations between a diploid sporophyte phase and a haploid gametophyte stage Male and female gametophytes live within the tissues of the sporophyte.

Development of Male Gametophytes The male gametophytes (pollen grains) develop inside anthers Meiosis produces four haploid spore cells.

Development of Male Gametophytes Each spore undergoes one mitotic division to produce the two haploid nuclei of a single pollen grain Two nuclei are surrounded by a thick wall that protects the male gametophyte.

Development of Female Gametophytes Develop inside each carpel of a flower Ovules (future seeds) are enveloped in a protective ovary (future fruit).

Development of Female Gametophytes Single diploid cell goes through meiosis to produce four haploid cells, three of which disintegrate.

Development of Female Gametophytes Remaining cell undergoes mitosis, producing eight nuclei Embryo sac Eight nuclei and the surrounding membrane.

Development of Female Gametophytes Cell walls form around six of the eight nuclei One of the eight nuclei near the base of the gametophyte, is the nucleus of the egg (female gamete) Will fuse with male gamete, form zygote and become sporophyte if fertilization occurs.

Pollination Transfer pollen to the female portions of the flower Can use wind or an animal pollinator Wind pollination is less efficient Relies on favorable weather and sheer numbers of pollen grains.

Animal Pollinated Plants Variety of adaptations to attract and reward animals Such as bright colors and sweet nectar Animals have evolved body shapes to reach nectar deep within certain flowers Insect pollination Plant benefits- efficient pollination Insect benefits- source of food.

Fertilization Pollen grain lands on the stigma of a flower Pollen tube begins to grow Pollen grain has two cells Cell divides and forms two sperm cells Cell becomes the pollen tube.

Pollen tube grows into the style Reaches the ovary Enters an ovule.

Double Fertilization One of the sperm nuclei fuses with the egg nucleus to produce a diploid zygote Other sperm nucleus fuses with two polar nuclei in the embryo sac to form a triploid (3N) cell or endosperm Endosperm Food-rich tissue known which nourishes the seedling as it grows.

Flowering plant spends very little in the way of food resources on producing seeds from ovules until double fertilization has actually taken place Make more seeds.

Vegetative Reproduction Asexual reproduction Enables a single plant to produce offspring genetically identical to itself by mitosis Enables a single plant to produce offspring genetically identical to itself by mitosis.

New plants may grow from roots, leaves, stems, or plantlets Single plant can reproduce quickly.

Good Single plant produces genetically identical offspring, enabling well-adapted individuals to rapidly fill a favorable environment.

Bad Does not produce new combinations of genetic traits, which may be valuable if conditions in the physical environment change.

Grafting Method to reproduce seedless plants and varieties of woody plants that cannot be propagated from cuttings Plants need to be closely related.