1. Roots
Section 12.4

2. Roots
Learning Goal: To explore the structure and function of plant roots.
Success Criteria:
I know I am succeeding when I can…
describe the features of taproot and fibrous root systems
explain the differences and similarities between monocot and eudicot roots
describe the nature, structure, and function of different specialized roots
list a variety of ways that humans use roots

3. Roots anchor the plant and keep it upright
absorb water and nutrients from the soil
may store water and carbohydrates

4. Types of Root Systems taproot system
has a large, thick, main root called a taproot, which grows straight downward
push deep into the soil
gymnosperms and angiosperm eudicots have taproot systems

5. Types of Root Systems Cont’d…
fibrous root system
has many small roots
tend to be shallower than taproots
occur in angiosperm monocots
Both root systems have root hairs and can have lateral branching

6. Structure of Roots the tip of the root contains:
root cap: a thick layer of cells that produce a slippery substance to help the root penetrate the soil, minimizing damage to the root cells
Meristem: produces new cells to increase the length of the root

7. Structure of Roots Cont’d…
root hairs above the root tip project out of the epidermis and increase the surface area for absorption
root cortex is a region of parenchyma cells beneath the epidermis that stores carbohydrates and helps transport water from the epidermis to the xylem
walls of the cells in the endodermis are wrapped with a wax-like substance, forming a continuous barrier called the Casparian strip

8. Structure of Roots Cont’d…
vascular cylinder contains the vascular tissue of roots
in gymnosperms and eudicots, the centre of the root contains xylem cells forming an “X” or star-shape in the centre of the vascular cylinder
the phloem cells are also in the centre of the root, around the xylem
arrangement of xylem and phloem within the vascular cylinder varies among the groups of angiosperms

9. Structure of Roots Cont’d…
in monocots the centre of the root contains parenchyma cells surrounded by a ring of xylem cells and a ring of phloem cells

10. Roots
Learning Goal: To explore the structure and function of plant roots.
Success Criteria:
I know I am succeeding when I can…
describe the features of taproot and fibrous root systems
explain the differences and similarities between monocot and eudicot roots
describe the nature, structure, and function of different specialized roots
list a variety of ways that humans use roots

11. Homework
Answer 12.4 questions #7, 9 & 10 on page 563