1. Classify Which plant structures are male sexual organs and which are female sexual organs

2. Apply Concepts Relate the characteristics of angiosperms reproduction to angiosperm success

3. Review Define vegetative reproduction4. 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 Stalk of carpel

Stigma 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

1. Cell divides and forms two sperm cells

2. 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.