Transcript Ch 23 Plant Structure and Function

1.
2.
3.
Review How are tissues distributed in plant roots
Apply Concepts Why is it important that the root
endodermis permits only a one way passage of
materials
Classify Draw and label a diagram to show how
roots absorb water and nutrients- also include a
brief description
CH 23 PLANT STRUCTURE AND FUNCTION
23.2 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.