12.4 Roots

Pages 558-563

Roots

Ta Phrohm temple in Cambodia

Function

• Anchor plant• Absorb water and nutrients• Store water and carbohydrates

Types of Roots

Taproot Fibrous roots

Root hairs

• Microscopic hair-like outgrowth from an epidermal cell.

• Increase surface area for absorption

Root cap

• Thick layer of cells produces a slippery substance allowing root to penetrate soil

• Meristem

Cortex

• Parenchyma• Stores carbohydrate• Water passes through cortex

Endodermis

• Wrapped with a wax-like substance.• Form a barrier called the Casparian strip

Vascular cylinder

• Eudicot Monocot• Gymnosperms

Root Specializations

• 80% of plants have mutualistic relationships with mycorrhizal fungi

• Also, nitrogen-fixing bacteria such as Rhizobia are found in the root nodules of legumes

Roots continued…

• Tuberous roots: lateral roots used for storage• For example: yam• Adventitious root: prop root

Uses of roots

• Food• Medicine• Erosion control