Roots

Vascular Cambium, Tissues produced by -

Secondary Xylem Secondary Phloem Tracheids Vessel Elements Companion Cells Sieve Cells Fibers

Region of elongation

Usually about 1cm. from the tip of the root. Here, cells become several times longer and somewhat wider.

Xylem

Vascular tissue, MADE UP OF DEAD CELLS - vessels and tracheids. Transports water up through plant.

Cucumbers and Water Melons

Water storage roots

Root Region 2

Where root growth takes place. Where apical meristem develops.

Root Cap Functions

*Protects tissues behind it *Secretes slimy substance (mucilage) that helps roots slide through soil. Mucilage provides a beneficial bacteria that roots take up through the plant. *Senses gravity, so the root grows downward.

Buttress Roots

Large, column-like roots that extend out from the base of the tree to provide support

Phloem

MADE UP OF LIVING CELLS. Pulls good/sugars down from the leaves for storage. Made of sieve plates, sieve tube elements and sieve cells. The younger layers, nearest the cambium, transport, via their sieve cells, sugars and other substances, in solution, to various parts of the plant.

Cortex

Many parenchyma cells thick. Where food storage take place in the root.

Lignin

Natural polymer that combines with suberin to form casparian strips in endodermal layer.

Region of Elongation

Root Region 3. Cells produced by apical meristem grow longer, helping to push the root through the soil

Region of Maturation

Root Region 4. (The root hair zone). Cells have stopped growing in this region. Root hairs develops from epidermal cells in this region.

Adventitious

Roots that develop from stems or leaves, but not from the root system

Aerial Roots

Roots that grow down from the branches until they contact the soil. (Ex: English Ivy)

Contractile Roots

Roots that pull the plant deeper into the soil to a depth where relatively stable temperatures are reached.

Just above the root cap

Region of cell division

Root hair region

Region of maturation

Apical Meristem

3 parts *Protoderm *Ground Meristem *Procambium

Seed

A Mature Ovule containing an embryo.

Taproot

A straight tapering root growing vertically downward and forming the center from which subsidiary rootlets spring

Root Cap Cell Division Elongation Maturation

All four root regions

Where root growth is taking place

Apical Meristem. Region of cell division

Mycorrhiza

Beneficial fungus associated with the roots around it. Help with water uptake, and breakdown of phosphorus. Present in more than 95% of land plants.

Region of cell division

Composed of the apical meristem, in the center of the root tip. Cells in this region produce the surrounding root cap.

Lignin and Suberin

Constituents that combine to form casparian strips.

Vascular Cambium

Develops from the procambium of the apical meristem. On its outer surface, forms new layers of phloem, and on its inner surface, new layers of xylem. The growth of these new tissues causes the diameter of the stem to increase

May develop from adventitious roots

Fibrous roots

Casparian Strip

Formed by endodermal cells. Works with plasma membrane to ensure entry of water and minerals into endodermal cells and not into cortex.

Endodermis

Full of suberin and lignin; a cylinder one cell thick that forms the boundary between the cortex and the vascular cylinder. Its cells form bands of Casparian Strips.

Determinate Growth

Growth that stops after organ has fully developed or reach a certain size.

Suberin

Highly hydrophobic (water-proof) waxy substance found in endodermal and cork layers.

Cohesion

Hydrogen bonds that hold water molecules together and facilitate movement of water through plants.

Radicle

In monocots, this dies off and emerges as one leaf.

Root Crops

Include sugar beets, beets, turnips, rutabagas, parsnips, carrots, sweet potatoes, yams and cassava.

Root Hairs

Increase surface area of epidermal layer to increase water and mineral uptake. Only live a few days. New ones produced constantly.

Indeterminate Growth

Occurs in trees and perennials that don't stop growing

Protoderm

Part of the apical meristem that becomes the epidermis of the root.

Procambium

Part of the apical meristem that develops Xylem and Phloem (Vascular Tissue).

Ground Meristem

Part of the apical meristem that produces ground tissues for storage of water and nutrients.

Transpiration

Process by which moisture is carried through plants from roots to stomata on the underside of leaves, where it changes to vapor and is released to the atmosphere.

Radicle

Produced from the lower side of the embryo. Develops into an apical meristem. This becomes the first root of the plant, which evolves into a tapered taproot or produces many adventitious roots that become a fibrous root system.

Cells in this region are produced in the meristematic region.

Region of Elongation

Where cells become long and push the apical meristem down. Cells grow larger and make the root longer.

Region of Elongation

Human uses of roots

Shade, Food, Spices, Food Flavorings, Dyes, Fiber for Rope or twine, Fuel, Oils, Soaps and Colognes, Insect repellants, Drugs, Tobacco, Beverages, Insecticides, Waxes.

Root Nodules

Small forms of growth along roots. Convert nitrogen from the air into forms the plant can use.

Pneumatophores

Spongy roots which extend above the water's surface and enhance gas exchange between the atmosphere and the subsurface roots to which they are connected.

Root Cap

The 'tip' of the root, made up of a mass of parenchyma cells.

Root Cap Cell Division Elongation

The 3 root regions that constitute the ROOT TIP.

Germination

The beginning of growth

Pericycle

The outermost layer of the vascular cylinder. Along the inside wall of the endodermis. Develops lateral roots and helps in development of the vascular cambium

Taproot

The primary root