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