Unit 3Parts of the Plant and Their

Functions• Plant life is essential for life on earth.

-Plants provide food, oxygen, and enjoyment

Plants are made up of four basic parts

1. Leaves 2. Stems

3. Roots 4. Flowers

Leaves

• Leaves are the food factory of the plant.

• External Leaf Structure• Petiole - leaf stalk

• Blade - usually the flat part

• Veins – structural frame

• Margin-edge of leaf

Parts of a leaf

Leaves help in the identification of horticulture plants.

• Internal Leaf Structure• Epidermis-skin of the leaf

• Chloroplasts-process food

– Photosynthesis - is the process by which carbon dioxide and water in the presence of light are converted to sugar and oxygen.

Carbondioxide+water+sunlight=sugar+oxygen

6CO2 + H2O + Sunlight = C6H12O6 + 6O2

• Guard Cells– Open and Close stoma to allow the leaf to

exchange gases

Stems• 2 Main Functions

– Movement of materials– Support the leaves and reproductive

structures– Also used for food storage, reproduction

methods

• External Stem Structure– Terminal Bud– Axillary Bud– Bud Scale Scar– Lenticle

• Internal Stem Structure• Phloem – manufactured food travels down

• Xylem – water and minerals travel up

• Cambium – produces the new stems

Cross Section of a Stem

RootsFunctions

• Anchor the plant and hold it Upright

• Absorb water and minerals from the soil and conduct them to the stem

• Store large quantities of plant food

• Propagate or reproduce some plants

Flowers• Complete Flower –

– Both Male and Female Parts– Incomplete Flower – has only the male or

female parts.

•4 Main Parts–Sepals – protect the flower bud–Petals – leaves (attract insects)–Stamens – Male reproductive parts–Pistil – Female Parts