Plant Reproduction

Plantstart! 11/5

• Why do plants make flowers?Write your answer based on what you already know.

Yes – I know I still have your Journals – take out a piece of paper!

LOTS OF KINDS OF PLANTS...

Plant Reproduction

Angiosperms (flowering plants)• Plants that protect their seeds within the body

of a fruit.

• Make up ¾’s of all plants, including:

–Trees, shrubs, herbs,

grasses, water plants…

Which plants make fruit?

• Orange tree? • Avocado tree?• Pumpkin plant?• Zucchini plant?• Tomato plant?• Wheat plant?

The Stamen:Male Reproductive Structure

Consists of two parts: Anther and Filament

The filament is a stalk that supports the anther

The anther is where meiosis occurs to produce pollen

Each pollen grain contains sperm cells.

The Pistil:Female Reproductive Structure

Consists of the stigma, style and ovary

The sticky stigma receives the pollen from the anther

The pollen grows a tube down through the style

Each ovule contains an egg cell.

Male Parts Female Parts Stamen consists of: 1. Anther 2. Filament

Pistil consists of: 1. Stigma 2. Style 3. Ovary (ovules inside)

Antherstart! 11/6

• Name the two parts of the male reproductive structure of the plant.

• Name the three parts of the female reproductive structure.

Reproductive Structures

• Petals: colorful

structures that attract pollinators.

• Sepals: surround and protect the flower bud.

Sepals: protect immature buds

Pollination

Wind, insects or other animals transfer pollen from the anther of one flower to the stigma of another

Flowers vary depending on pollination mechanism

Pollination VectorsWind Pollination: Dull, scentless flowers with reduced petalsBees/Butterfly Pollination: Brightcolor, nectaries, scent. They sip nectar, get pollen on coats, transfer pollen from flower to flower

Bird Pollination: Nectaries, brightcolors, tube-like flowers

Moth Pollination: White petals, open at night

Fly Pollination:Rank odor, fleshcolored petals

Tip of a tulip stamen with many grains of pollen.

Scanning electron microscope image of pollen grains from a variety of common plants: sunflower, morning glory, prairie hollyhock, oriental lily, evening primrose, and castor bean.

• Pollen Grain • Anther Sac

Pollen grains contain two haploid cells produced through meiosis.

1- The Tube cell – will grow the pollen tube. 2- The Generative cell – will go through meiosis to create two sperm cells.

tube cell

generative cell

Seed and Fruit Development After fertilization,

the petals and sepals fall off flower

Ovary “ripens” into a fruit

The ovule develops into a seed

See Fig 13 on page 139 Life Science Text

Seed Dispersal Mechanisms-Allow plants to colonize new areas and avoid

shade of parent plant

Wind Dispersal - Flight mechanisms, like parachutes, wings, etc. Ex. Dandelion, maples, birch

Animal Dispersal - Fleshy fruits which animals eat, drop undigested seeds in feces or burrs which stick to animals’ coats

Gravity Dispersal - Heavy nuts fall to ground and rollex. acorns

Water Dispersal - Plantsnear water create floating fruitsex. coconuts