Plant Anatomy Unit 1 Chapter 6 Lesson 4

Flowers, Fruits, & Seeds Flowers are pretty & contain nectar in order to attract insects Flowers are pretty & contain nectar in order to attract insects These insects fertilize the flower by pollination These insects fertilize the flower by pollination Pollination begins fruit and seed formation Pollination begins fruit and seed formation

Fruits & Seeds Fruits and seeds are eaten, collected, and spread out by animals and people Fruits and seeds are eaten, collected, and spread out by animals and people This reproduces the plant This reproduces the plant

Seeds Seeds have special devices to ensure propagation Seeds have special devices to ensure propagation Some seeds are sticky (thistles), some float in the wind (dandelions), others can survive stomach acid (cherry pits) Some seeds are sticky (thistles), some float in the wind (dandelions), others can survive stomach acid (cherry pits)

Flower Parts Flowers differ in shape, size, and color, but all have relatively the same parts Flowers differ in shape, size, and color, but all have relatively the same parts

Flower Parts cont. Seeds are the most common way plants reproduce in nature Seeds are the most common way plants reproduce in nature – Sexual process involving male and female parents A complete flower has both male and female parts A complete flower has both male and female parts Only one parent is needed if a plant is self- fruitful, or can pollinate itself Only one parent is needed if a plant is self- fruitful, or can pollinate itself

Flower Parts cont. 4 main parts 4 main parts – Sepals – Petals – Stamens – Pistil

The Sepals Green, leaf like parts of the flower that cover and protect the flower bud before it is open Green, leaf like parts of the flower that cover and protect the flower bud before it is open

Petals Are actually leaves Are actually leaves Generally the most striking part of the flower Generally the most striking part of the flower Bright colors are used to attract insects for pollination Bright colors are used to attract insects for pollination

The Stamens Male reproductive part Male reproductive part Each stamen consists of: Each stamen consists of: – Filament – Anther – contains the pollen (male sex cell)

The Pistil Located in the center Located in the center of the flower of the flower Female part Female part Produces female sex cells (eggs or ovules) Produces female sex cells (eggs or ovules) If fertilized, the eggs become seeds If fertilized, the eggs become seeds

Parts of the Pistil 3 main parts: 3 main parts: – Stigma – sticky, catches the pollen – Style – tube that leads to the ovary – Ovary – eggs develop here, after fertilization the ovary grows to become a fruit or seed coat

Flower Construction Insects looking for nectar have to climb over the anther and brush pollen on their legs Insects looking for nectar have to climb over the anther and brush pollen on their legs As they climb towards the center looking for food, they deposit pollen on the stigma As they climb towards the center looking for food, they deposit pollen on the stigma

Fertilization After an insect deposits pollen, fertilization begins! After an insect deposits pollen, fertilization begins! The pollen grain The pollen grain sprouts and sends sprouts and sends a long stalk (pollen a long stalk (pollen tube) down tube) down the style to the the style to the ovary ovary

Fertilization cont. The pollen sperm cell can then fertilize the female egg cells and seeds begin to develop The pollen sperm cell can then fertilize the female egg cells and seeds begin to develop The ovary enlarges into a seed coat or fruit The ovary enlarges into a seed coat or fruit

Pollen

Incomplete Flower Has ONLY male parts or female parts Has ONLY male parts or female parts Male flower – sepals, petals & stamens but no pistil Male flower – sepals, petals & stamens but no pistil Female flower – sepals, petals, & pistil, but no stamens Female flower – sepals, petals, & pistil, but no stamens Examples: Kiwi, Ginkgo Examples: Kiwi, Ginkgo

Flowers are Important! Many plants are grown only for their flowers Many plants are grown only for their flowers Floriculture industry in a multimillion dollar business!!! Floriculture industry in a multimillion dollar business!!!

What is the major function of flowers?

What is a fruit? A ripened flower ovary A ripened flower ovary Botanically, fruits = vegetables & vegetables = fruits Botanically, fruits = vegetables & vegetables = fruits In most plants, a fruit is formed following fertilization of the ovules In most plants, a fruit is formed following fertilization of the ovules They contain seeds They contain seeds

What about seedless fruit? Seedless fruit -- fruit that form without pollination or fertilization Seedless fruit -- fruit that form without pollination or fertilization These fruit are called PARTHENOCARPIC These fruit are called PARTHENOCARPIC Examples: Banana, navel orange Examples: Banana, navel orange

When the fruit ripens, the ovary wall thickens. When the fruit ripens, the ovary wall thickens. This is called the pericarp This is called the pericarp The pericarp has three sections: The pericarp has three sections: The endocarp The endocarp The mesocarp The mesocarp The exocarp The exocarp

Types of Fruits Aggregate fruits Aggregate fruits Multiple fruits Multiple fruits Simple fruits Simple fruits

Key Flower Terms Flower – Reproductive organ of the plant Pedicel – Flower stem Receptacle – Tip of the pedicel that holds the flower parts Sepals – Leaf-like structure that is the exterior portion of the flower

Key Flower Terms Calyx – The term for all of the sepals or a flower, collectively Corolla – The term for all of the petals of a flower, collectively Perianth – The term for the sepals and petals of a flower, together

Key Flower Terms Tepals – Term used when there is not a clear distinction between the petals and sepal of the flower Stamen – Male part of the flower – Made of anther and filament – Produces the pollen Pistil – Female part of the flower – Contains the stigma, style, and ovary – Produces the ovules (eggs) of the flower

Key Flower Terms Complete flower – Flowers that have sepals, petals, stamens, and a pistil Incomplete flower – A flower that lacks 1 or more of the parts of a complete flower Perfect flowers – Have both male and female parts Imperfect flowers – Flowers that lack 1 or more sex structures

Key Flower Terms Solitary flowers – Stem with only one flower on it Tulip, narcissus, rose Inflorescence – Plants with flower clusters Peduncle – Main stem of an inflorescence Determinate – When the first flower to open is at the apex with progression moving down the stem

Key Flower Terms Indeterminate – Last flower to open is at the apex as the flowering had an upward movement