Plant Anatomy and Physiology What are the parts of the plant, and how do they work?

Flowering Plants Angiosperms meaning “flower plant” Most successful and abundant plants today Extremely diverse and well adapted At least 300,000 species known Vascular plants Reproduce sexually by forming flowers and seeds within fruits through double fertilization

Why are they important? Extremely important for human survival! All major food crops are flowering plants Rice, wheat, corn, barley Coffee, chocolate Lumber, medicines, Rubber, etc all provided by plants

How are they different from other plants? Angiosperms are unique because they contain ovules within an ovary Ovules: structures that contain egg cells that eventually develop into seeds after fertilization Ovary: enlarged base of a carpel that eventually becomes the fruit

What is a Flower? A flower may look pretty, but it is the reproductive component of a plant The flower attracts organisms to help spread pollen to other plants The flower also is where fertilization occurs and new plants are born Flowers normally have four kinds of organs for the flower-sepals, petals, stamens, carpels

Parts of a Flower Peduncle: the end of a flower stalk just before the stem Inflorescence: a cluster of flowers forming from one peduncle Receptacle: the tip of the peduncle that enlarges and holds some of the flower parts

Flowers Flower Parts -- Male Stamen: Male part of the flower. The filament and anther make up the stamen Filament: Stalk like in the stamen that holds up the anther Anther: Sack-like structure that contains pollen. Pollen Grains: transferred from the anther to the carpel of another flower to have sexual reproduction. One pollen grain has two cells. One produces two sperm cells and the other produces a pollen tube for the sperm to travel and reach the ovule.

Flowers Flower Parts – Female Pistil: Female part of the flower. The stigma, style, and ovary make up the pistil. Stigma: Sticky part of the pistil that is receptive to pollen. Style: Rod shaped middle part that has a swollen base (ovary) containing eggs Ovary: a large swollen structure that contains ovules. The ovary can develop into a fruit if fertilization occurs. Ovules: structures that are able to develop into seeds if fertilized.

Flowers Flower Parts – Neither male or female Petals: colorful leaf-like structures which attract animals and insects. Corolla: When all of the petals are fused together. Sepals: Green leaves that protect the flower before it opens. Calyx: When all of the sepals are fused together.

Flowers Flower Types: Perfect Flower: Has both male and female parts. Imperfect Flower: A flower that is missing either male or female parts. Complete Flower: Flowers that have sepals, petals, pistils, and stamens.

Flowers Flower Types: Incomplete Flowers: When a flower is missing sepals, petals, pistils, or stamen. Imperfect Flowers are always incomplete. Incomplete flowers may or may not be imperfect

Flowers Sexual Reproduction in Plants: Two parents #1 The stamen releases pollen. #2 Pollen is carried by wind, gravity, animals, or insects to the stigma of another flower. (This is when pollination occurs)

Pollination Pollination: the transfer of pollen grains from anther to stigma Self-pollination: pollination within the same flower or within a different flower on the same plant Cross-pollination: when pollen grains are transferred to a flower on another individual of the same species

Types of Pollination Insects Birds Have a well-developed sense of smell Flowers normally have strong scents that can be pleasant or foul to humans Example: Carrion flower smells like rotting flesh Usually flowers are red, orange, yellow because of birds being able to see these regions of visible light better than others Not normally scented, but have nectar for animal

Types of Pollination Bats Wind Feed at night and do not see well Normally night blooming flowers Normally have dull white petals and usually smell of fermented fruit Grasses, ragweed, maples, and oaks use this method Produce small flowers and large amounts of pollen to spread

Flowers Sexual Reproduction in Plants: #3 The pollen moves from the stigma down through in a pollen tube the style depositing sperm in the ovary. #4 When the sperm has been deposited in the ovary fertilization has occurred. #5 When the eggs have been fertilized, the ovary and surrounding tissue start to enlarge to become a fruit and the fertilized eggs become seeds.

Fertilization When pollen grains have been transferred from anther to stigma, the tube cell (one of the two cells in the pollen grain) grows a pollen tube down through the style into an ovule in the ovary The other cell moves down the pollen tube and enter the ovule causing fertilization and the seed develops

Seed A young plant embryo containing stored nutrients Nutrients are used by plant embryos to germinate, but also are eaten by animals This causes plants to want to protect this seed that will help diversify their species. They protect it through a fruit!

Seed Dispersal Wind, animals, water all means of moving seeds Dispersal has allowed plants to spread geographically Some plants have special structures for dispersal of seeds (ex: burs get stuck in animal fur, maple trees grow “winged” seeds)

Types of Fruit Simple Single carpel or several fused carpels Can be fleshy or dry Aggregate Fruit that develops from a single flower with several to many pistils Multiple Fruit that develops from the ovaries of a group of flowers Accessory Composed of nonovarian tissue

Types of Fruit Berry (simple fruit) Drupe (simple fruit) Simple, fleshy fruit Fruit wall (outside) is soft throughout Example: tomato Simple, fleshy fruit Inner wall is a hard stone Example: Peach

Types of Fruit Nut (simple fruit) Legume (simple fruit) Simple, dry fruit Stony wall and is large Does not split open at maturity Example: Oak Simple, dry fruit Splits open along two sutures to release seeds Example: green bean

Types of Fruit Aggregate Multiple Single flower with several pistils form these fruits Example: Blackberry Fruit develops from ovaries of a group of flowers Example: pineapple

Types of Fruit Accessory Composed of nonovarian tissue Examples: Apple (made mostly of floral tube), strawberries (made mostly of plant waste products)