1. Review How are tissues distributed in plant roots2. Apply Concepts Why is it important that the root

endodermis permits only a one way passage of materials

3. Classify Draw and label a diagram to show how roots absorb water and nutrients- also include a brief description

CH 23 PLANT STRUCTURE AND FUNCTION23.2 Roots

Types of Root Systems

Taproot systems Fibrous root systems.

Taproot Systems

Taproot Long and thick primary root

Smaller branch roots Mainly found in dicots.

Fibrous Root System

Many equally sized branch roots that grow separately from the base of the stem

Begins with one primary root Help hold topsoil in place Found mainly in moncots.

Root Tissues

Dermal tissue Ground tissue Vascular tissue Apical meristem.

Dermal Tissue

Also called Epidermis Protection Absorption Root hairs to increase surface

area.

Ground Tissue

Cortex is one portion of ground tissue

Directly inside of epidermis Water and minerals move

through to get to center of root

Store photosynthesis products (starch).

Ground Tissue

Endodermis Completely encloses the

vascular cylinder Plays essential role in

moving water and minerals to the center of root.

Vascular Tissue

Vascular cylinder Region made up of Xylem

and Phloem.

Apical Meristem

Root cap Protects meristem Secrets slippery substance

to help root move through soil

Cells constantly being scraped away and replaced.

Root Functions

Uptake nutrients Transport nutrients Support plant Anchor in ground Store nutrients.

Uptake Nutrients Need inorganic nutrients Also trace minerals.

Transport Nutrients

Active transport brings mineral ions across the epidermis

High mineral ions concentration causes water molecules to move into the plant by osmosis.

Transport Nutrients

Water and dissolved minerals pass through the cortex and move toward the vascular cylinder.

Transport Nutrients

Vascular cylinder is enclosed by the endodermis and a special waterproof zone called a Casparian strip.

Casparian Strip

Forces water and minerals through the cell membranes of the endodermis rather than in between the cells

Controls water and minerals entering vascular cylinder doesn’t allow to leak back out.

Root Pressure

Water is forced in by osmosis due to active transport of minerals

Water enters through casparian strip and is forced up.

Root Pressure

Glass tube replaced stem and leaves of carrot.