Types of roots and root systems. Types and types of roots

The root is an underground axial element of plants, which is their most important part, their main vegetative organ. Due to the root, the plant is fixed in the soil and retained there throughout the life cycle, and is also provided by water, mineral and nutrients contained in it. There are different types and types of roots. Each of them has its own distinctive characteristics. In this article we will consider the existing types of roots, types of root systems. Also get acquainted with their characteristics.

What are the types of roots?

The standard root is characterized by filamentary or narrow-cylindrical shape. In many plants, in addition to the main (main) root, other types of roots are also developed - lateral and accessory. Let us consider in more detail what they are.

Main root

This plant grows from the embryonic root of the seed. The main root is always one (other types of plant roots are usually present in the plural chile). It is preserved by the plant throughout the life cycle.

The root is characterized by positive geotropism, that is, due to gravity, it deepens into the substrate vertically downwards.

Assimilative roots

Pridatichnymi called species of plant roots, which are formed on their other organs. These organs can be stems, leaves, shoots, etc. For example, cereals have the so-called primary accessory roots, which are embedded in the stalk of the embryo of the seed. They develop in the process of germination of the seed practically simultaneously with the main root.

Also there are leaf accessory kinds of roots (formed as a result of rooting of leaves), stem or nodal (formed from rhizomes, aboveground or underground cauline nodes), etc. At the lower nodes, powerful roots are formed, which are called air (or supporting) roots.

Appearance of accessory roots determines the plant's ability to vegetatively propagate.

Lateral roots

Lateral roots are known as lateral branches. They can be formed both on the main and on the accessory roots. In addition, they can branch off from the lateral, resulting in the formation of lateral roots of higher orders (first, second and third).

Large lateral organs are characterized by transverse geotropism, that is, their growth occurs in a practically horizontal position or at an angle to the soil surface.

What is the root system?

The root system refers to all types and types of roots that are present in one plant (that is, their aggregate). Depending on the ratio of the growth of the main, lateral and accessory roots, its shape and character is determined.

Types of Root Systems

Distinguish between the core and the fibrous root systems.

If the main root is developed very well and is noticeable among the roots of another species, this means that the plant has a core system. It inherits mainly dicotyledons.

The root system of this type differs by deep germination in the soil. So, for example, the roots of some herbs can penetrate to a depth of 10-12 meters (sow, alfalfa sowing). The depth of penetration of the roots of trees in some cases can reach 20 m.

If the subordinate roots are more pronounced, developing in large numbers, and the main one is characterized by slow growth, then a root system is formed, which is called lobed.

Such a system is characterized, as a rule, monocotyledonous plants and some of the grassy ones. Despite the fact that the roots of the fibrous system do not penetrate as deep as the rod, they better braid the particles of the soil adjacent to them. Many loamy-bush and rhizome grasses, forming an abundant number of ragged thin roots, are widely used for fixing ravines, soils on slopes, etc. Among the best herb-extracts are grasshoppers, creepers, fescue, meadow grass , etc.

Modified Roots

In addition to the typical, described above, there are other types of roots and root systems. They are called mutated.

Resourceful roots

To the root are root crops and root crops.

Root is a thickening of the root in connection with the deposition of nutrients in it. Also, the lower part of the stem participates in the formation of the root crop. It consists mainly of the reserve main tissue. Examples of root crops are parsley, radish, carrots, beets, etc.

If the thickened root stocks are lateral and accessory roots, they are called root tubers (cones). They are developed in potatoes, sweet potatoes, dahlias, etc.

Air Roots

These are lateral roots growing in the aerial part. Are present in a number of tropical plants. Water and oxygen are absorbed from the air. There are tropical plants that grow in conditions of a lack of mineral substances.

Breathing roots

This is a kind of lateral roots that grow up, rising above the surface of the substrate, water. Such types of roots are formed in plants growing on too moist soils, under marsh conditions. With the help of such roots vegetation receives from the air the missing oxygen.

Reference (plank) roots

These types of tree roots are characteristic of large breeds (beech, elm, poplar, tropical, etc.). These are triangular vertical outgrowths formed by lateral roots and passing at the surface of the soil or above it. They are called still board-like, because they resemble boards that are leaning against a tree.

Roots-suckers (haustoria)

Observed in parasitic plants that do not know how to photosynthesize. Nutrients necessary for normal functioning, they are obtained by ingrowing into the stem or root of other plants. At the same time, they are introduced into phloem and xylem. Examples of plant parasites are dodder, broomrape, rafflesia.

Haustorium plants, semi-parasites with photosynthetic abilities, grow only in xylem, taking away only the mineral substances from the host plant (ivan-da-marya, mistletoe, etc.)

Roots-hooks

This is a kind of additional accessory roots developing on the stem of climbing plants. With their help, plants have the ability to attach to a specific support and climb upwards. Such roots are available, for example, in the fricative tibia, ivy, etc.

Retractable (contractile) roots

Characteristic for plants, the root of which sharply decreases in the longitudinal direction at the base. An example is plants with bulbs. The retractive roots provide a bulge to the bulbs and root crops in the soil. In addition, their presence is caused by a tight fit of the rosettes (for example, in the dandelion) to the ground, as well as the underground position of the vertical rhizome and the root neck.

Mycorrhizas (mushrooms)

Mycorrhiza is a symbiosis (mutually beneficial cohabitation) of the roots of higher plants with fungal hyphae, which braid them, fulfilling the functions of root hairs. Mushrooms provide plants with water and nutrients dissolved in it. Plants, in turn, give mushrooms the organic substances necessary for their vital activity.

The presence of mycorrhizas is the root of many higher plants, especially woody plants.

Bacterial nodules

These are modified lateral roots, which are adapted to symbiotic cohabitation with nitrogen fixing bacteria. The formation of nodules occurs due to the penetration of nitrogen-fixing bacteria inside the young roots. Such mutually beneficial cohabitation allows plants to obtain nitrogen, which bacteria are transferred from the air in a form that is accessible to them. Bacteria are given a special habitat, where they can function without competing with other types of bacteria. In addition, they use substances present in the roots of vegetation.

Characteristic are bacterial nodules for plants of the Bobov family, which are widely used as ameliorants in crop rotations to enrich the soil with nitrogen. The best nitrogen-fixing plants are rod-root bean grasses, such as alfalfa blue and yellow, clover pink, red and white, sweet clover, sainfoin, horned lagoon, etc.

In addition to the above metamorphosis, there are other types of roots, such as root-supports (help strengthen the stem), stilted roots (help plants not to sink in mud) and root offspring (have adnexal buds and provide vegetative reproduction).