biology 23.2

23.2 ROOTS

TAPROOT

The primary root found in some plants that

grows longer and thicker than other roots

FIBROUS ROOT

Part of a root system in which roots branch to

such an extent that no single root grows

larger than the rest

ROOT HAIR

Tiny project from the outer surface, or

epidermis, of a root

CORTEX

Spongy layer of ground tissue just inside the

epidermis of a root

ENDODERMIS

A layer of cells that completely encloses

vascular tissue

VASCULAR CYLINDER

central region of a root that includes the

vascular tissue—xylem and phloem

ROOT CAP

Structure that protects a root as it forces its

way through the soil

CASPARIAN STRIP

Waterproof strip that surrounds plant

endodermis cells

KEY CONCEPT

The two main types of roots are

taproots, which are found mainly in

dicots, and fibrous roots, which are

found mainly in monocots.

KEY CONCEPT

A mature root has an outside layer,

the epidermis, and a central

cylinder of vascular tissue. Between

these two tissues lies a large area

of ground tissue.

KEY CONCEPT

Roots anchor a plant in the ground

and absorb water and dissolved

nutrients from the soil.