Chapter 6 Roots

Plant organ systems

What are the primary functions of roots?

Fibrous and taproot systems

Dicots Monocots

Dicot root, c.s.

Root structure

Root cap

Parenchyma Mucigel Perception of

gravity

Dicot root, l.s.

Region of cell division Region of elongation

Region of maturation

Monocot root, c.s.

Phloem

Xylem

Endodermis

Endodermis regulates mineral absorption

Secondary growth Growth in diameter Ex. Sweet potato Secondary growth occurs at the lateral

meristems, namely the vascular cambiu and cork cambium.

The former forms secondary xylem and secondary phloem, while the latter forms the periderm.

Specialized roots Storage roots

Camote root

Roots of carrots

Storage roots

Roots which store a portion of the energy/nutrients gathered or produced

by a plant, Potatoes , beets , ginger are some examples of them.

Aerial roots

Aerial roots (poison ivy)

Aerial roots Velamen (orchids)

Aerial roots – velamen (orchids)

AERIAL ROOTS

Type of roots above the ground. They are almost always adventitious.

Contractile roots

Roots of a corn

Contractile root Roots that pull bulbs or corms deeper

in the soil through expanding radially and contracting longitudinally. They

have a wrinkled surface.

Buttress roots

Prop roots

Prop roots

Prop roots – Mangrove swamp

Propagative roots

Pneumatophores

Cypress pneumatophores, Black River, NC

Pneumatophores

These specialized aerial roots enable plants to breathe air in habitats that have waterlogged soil. The roots may grow down from the stem, or up from typical roots. 

Mycorrhizae

A mutualistic fungal association with roots

Mycorrhizae

Root nodules

Root nodules

Root nodules

Nitrogen fixation research

Ammonia diffusion hypothesis of nitrogen transport into plants

Parasitic roots

Witchweed

Parasitic roots

Oscula of witchweed (Striga sp.)

Human uses of roots

yams

sweet potatoes

cassava

Rosemary's Root Beer Tonic

Ingredients (4 servings) 3 oz Sassafras Bark, dried 2 oz Sarsaparilla root, dried 1 oz Dandelion Root, dried 1 oz Burdock Root, dried 1/2 oz Ground Ginger root 1/2 oz Ground Cinnamon 1/4 oz Orange Peel, dried

Mix together all ingredients and store in a tightly closed container. In a large pot combine 1 quart of water and 4 tablespoons of dry mixture. Bring to a boil, cover and simmer for 15 to 20 minutes. Strain and sweeten with honey or stevia (also called "sweet herb") if desired. Source: Vegetarian Times, April 1993

link

Herbal medications

Ginger

Valerian extract, derived from the dried rhizomes and roots of the plant, has been used for thousands of years as a folk remedy, tranquilizer and calmative for several disorders such as restlessness, nervousness, insomnia, hysteria, menstrual problems, and as a sedative for "nervous" stomach. Valerian extracts are currently used in scores of compounds and teas in Europe.

Valeriana officinalis

Licorice (Glycyrrhiza glabra)

Rotenone comes from Derris root and Lonchocarpus species leaf (Family: Leguminosae) It is an insecticide and also used as a fish poison. Rotenone disrupts cellular respiration and death is relatively slow compared to most nerve toxins. Rotenone is extremely toxic to fish and is used as a fish poison bySouth American Indians and in water management programs.

Roots & erosion ErosionSeed.com

Root research CO2 concentration and root growth

Phytoremediation and molecular farming– Mercury detoxification– TNT detoxification

Root cap function

Root nematodes

Root nematodes

-disrupts the uptake of nutrients and water

-interferes with plant growth

-vector for viruses

Root nematodes

Root nematode damage

Root nematode damage

Root nematodes reduce crop productivity