Flowers and Fruits

Flower anatomy

Flower anatomy• Sepals– Green leaves that protect the flower before it

opens• Peduncle– stem

Flower anatomy• Petals– Colorful leaf-like structures– Attract animals and insects

• Calyx– All sepals fused

together

Flower anatomy• Male: Stamen– Filament• Stalk-like structure that hold up anther

– Anther• Sack-like structure that holds pollen

– Pollen• Contains

reproductive cells

Flower anatomy• Female: Pistil – Stigma

• Sticky part of pistil• Receives pollen

– Style• Rod that holds up

stigma– Ovary

• Holds eggs– Ovule

• Reproductive cell (eggs) that become seeds once fertilized

Types of Flowers• Perfect flower– Contains male and female parts

• Imperfect flower– Contains only male or only female parts

• Complete flower– Contain sepals, petals, pistil, and stamen

• Incomplete flower– Missing either sepals, petals, pistil, or stamen

Imperfect flowers are always incompleteIncomplete flowers are not always imperfect

Pollination and fertilization• Sexual reproduction in plants

• Stamen releases pollen• Pollen is carried to a stigma– Does it have to be a different plant’s stigma?– Can it be?– How does it get there?

• Pollination occurs when the pollen reaches a stigma

Pollination and fertilization• Pollen moves down the style depositing

sperm into the ovary• Fertilization occurs when that sperm

reaches an ovule inside the ovary• Once fertilized eggs become seeds and the

ovary will swell and become fruit

Types of Fruits• How can fruit be different? • Name some different fruits

• What is the purpose of a fruit?

Types of Fruits• It is the fertilized ovary of a plant that

grows to produce and protect seed.• Once fertilization occurs, the flower is no

longer needed and dries up.• Seed are formed within fruit.• Fruit must be sufficiently mature for the

seed to be viable.

Types of Fruits• Good fruit formation is essential for

farmers and other producers– Why?

• The fruit that is often the most valuable product of a plant

• Fleshy fruit– Fibrous structure that surrounds the seed– Pome• Several seeds

– Drupe• Single seed

Types of Fruits

Types of Fruits• Dry fruit– Formed in a pod or hull– Caryopsis• Thin wall

– Samara• Wings attached

– Pod• Definite seam

– Hull• No seam

Seeds• Container of new life

• Good pollination is essential to creating lots of new seeds

seeds• What is their purpose?– Reproduce plants– Protect embryo– Provide food for new plant to grow

• Human uses– Food production

seeds• Corn, soybeans, and wheat – We want lots of seed from these plants– Most valuable part of the plant

• Grapes, oranges, and watermelons– We want few seeds from these plants– The fruit without seeds is more valuable

seeds• Seed structure– External • Protect and nourish internal parts

– Internal• Embryo and food supply

• Monocots vs. Dicots– Very similar– Significant differences

Dicots• External– Seed coat• Hold seed together• Protection

– Hilum • Seed scar• Attachment to fruit

– Micropyle • Tiny opening• Pollen entered

this opening

seeds• Internal– Cotyledons

• Fleshy parts that contain food– Radicle

• Forms root– Hypocotyl

• Connects cotyledonsto radicle

– Epicotyl• Forms stem

– Plumule• Above ground part

of plant

monocot• External– Seed coat• Protects and shapes seed

– Seed scar• Attachment point

– Silk scar• Point that silk was

attached to ovule

seeds• Internal

– Endosperm• Stored food

– Radicle• Forms root

– Hypocotyl• Connects radicle

to food – Epicotyl

• Forms stem– Cotyledon

• Absorbs food andmoves it to cotyledon

– Plumule• Develops leaves and stem