Root

Root [ Botany ]

Dictionary of botanic terminology - index of names


	The roots are the axial system of vascular plants which don't bear leaves, bud and nodes and generally grow underground.

Their main function of roots is the anchorage, the absorption of water and minerals from the soil, and the transport of these substances to the rest of the plant. Water and minerals are transported upwards through the vascular system.

(Compare with other underground organs derived from stem modification like rhizome, tuber, corm etc... ).

Roots will generally grow in any direction where the correct environment of air, nutrients and water exists that meets that plant's needs. Roots will not grow in dry soil. How far roots penetrate the soil and how far they spread laterally is dependent upon several factors, including soil moisture, temperature and compositions.
Feeder roots, those actively involved in water and mineral uptake generally occur toward upper surface (15 cm) of the soil. Most roots spread laterally much more than deeply. However some tap roots may go to 50 meters deep.
Not all roots grows underground but they can also be aerial root ( i.e. entirely above the ground) or aerating root (i.e. rises above the ground, especially above water).

Origin and growth of the roots:
Roots originate from the radicle of the embryo during the germination of the seed and growth essentially at their tip for the activity of the root apical meristem

The growing tip of a root is divided into four regions:
1. Root cap – A cap that protects the apical meristem behind it.
2. Region of cell division - The growing point containing the meristem.
3. Region of elongation: The zone where cells increase and elongate in size..
4. Region of maturation: the zone where most of water uptake occurs through root hairs

Root systems:
A root system is the network off all the roots of a plant; the system of roots
and related organs that a plant develops.

Taproot system

The two basic types of root systems are the primary root systems and the adventitious root system.

The primary root systems is formed from the primary root.

Two primary root system types:

Taproot system - Single primary root dominates over branch roots
Fibrous (Diffuse) root system – A network of fine roots with no central dominant root.

The adventitious root system is typical of most Monocotyledons in which the primary root is ephemeral and sort living and adventitious root soon arise from stem or leaf tissue. (At the bottom of a grass plant, for example, are a number of these adventitious roots growing out from the nodes above the seed near the ground level. ) These roots and their lateral branches make up a fibrous root system.

Fibrous (diffuse)
root system

See also:

Absorbent root (Feeder root):
Contractile root: Pull the plants deeper into the ground as the stem elongates.
Aerial roots:
Adventitious roots:
Storage roots:

Rooting [ Botany - Horticulture ]


	The process of putting forth roots and beginning to grow.

To root ( verb ) [ Botany - Horticulture ]


	To develop a root or roots. To cause a plant to put out roots and grow. To become firmly established, settled.

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Holdfast roots [ Botany ]
Dictionary of botanic terminology - index of names

Some species of climbing plants develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place.

Climbing plants, like the poison ivy (Toxicodendron radicans), Boston ivy (Parthenocissus tricuspidata), and trumpet creeper (Campsis radicans), develop holdfast roots which help to support the vines on trees, walls, and rocks. By forcing their way into minute pores and crevices, they hold the plant firmly in place. Usually the Holdfast roots die at the end of the first season, but in some species they are perennial. In the tropics some of the large climbing plants have hold-fast roots by which they attach themselves, and long, cord-like roots that extend downward through the air and may lengthen and branch for several years until they strike the soil and become absorbent roots.

Major references and further lectures:
1) E. N. Transeau “General Botany” Discovery Publishing House, 1994