Roots

Just as important as stems and

leaves…. Major Functions:

1. Serve as an anchor 2. Conduct nutrients and water 3. Store food(ex. sweet potatoes, carrots, radish, turnip, beet)

Roots

Root Functions

Root Development Primary root develops from

the embryo

1. If primary root becomes the main root=Taproot System

Root Development 2. If primary root stops growing

early on and new roots grow from the stem, it is a Fibrous Root System

Fibrous vs. Taproot

Root Hairs Grow from

epidermal cells of roots

Only occur in first ¼ of root tip

Only live about 10 days

Absorb water and nutrients from soil particles

Function of Root Hairs

Root Hairs

Specialized Roots

Food Storage Roots Most roots store some

food

Some are enlarged to store starch and other carbohydrates

Examples: sweet potato, carrot, beet, radish

Produced by plants in arid regions Can be quite large (159 lbs.!) Examples: Manroot

Water Storing Roots

Grows close to ground: perennial vineRoots can be several meters long and

over 100lbs.

Manroot

Extend above the surface of water

for plants that grow in swampy areas

Helps roots exchange gases

Example: Mangrove

Pneumatophores

Mangrove

Roots that occur above the surface of the soil Examples: prop roots in corn (support in high

wind)

Aerial Roots

Adventitious roots in ivy for

climbing

Aerial Roots Continued

Poison Ivy

Contractile Roots Help to pull the plant deeper

into the soil

Occurs from year to year

Examples: Lily, Dandelion

Peg-like projections penetrate

host’s stem Usually in plants that do not

contain chlorophyll (can’t make food)

Examples: pinedrops, dodder (one organisms benefits, one is

harmed)

Parasitic Roots

Pinedrops

—Not green!

Dodder: NO Chlorophyll

Huge roots near base of

trunk Usually in trees that grow in

shallow soil Rainforest environmentsExample: many tropical trees

Buttress Roots

Buttress Roots

Buttress Roots

Dicot Root Tip

Cross Section of Root

Modified Stems/Roots