root - underground axial element of the plant is the most important part of them, their main vegetative organs.Due to the plant roots in the soil is fixed and held there for the entire life cycle, and provides water and mineral nutrients contained therein.There are different kinds and types of roots.Each of them has its own distinctive characteristics.In this article we will look at the roots of existing types, the types of root systems.Also look at their characteristics.
What are the kinds of roots?
Standard root is characterized by a filamentary uzkotsilindricheskoy form.In many plants, in addition to the primary (main) roots, has developed other types of roots - lateral and adventitious.Let us examine what they are.
main root
This plant body develops from the embryonic root seed.The main root is always one (other plant roots are usually present in the plural Chile).He saved the plant over the entire life cycle.
to root characteristic positive geotropism, that is due to gravity, he delves into the substrate vertically downwards.
Adventitious roots
called paranasal types of plant roots, which are formed on their other organs.These authorities could be the stalks, leaves, twigs and so forth. For example, in cereals, there are so-called primary adventitious roots that are laid in the seed embryo stem.They develop in the course of germination of the seed substantially simultaneously with the main root.
also found leafy subordinate kinds of roots (resulting from rooting the leaves), stem or node (produced from rhizomes, aboveground or underground stem nodes) and so forth. In the lower nodes are formed strong roots, which are called air (or reference).
emergence of adventitious roots determines the ability of plants to vegetative reproduction.
Lateral roots
called Lateral roots, arising as a side branch.May be formed at both the primary and the adventitious roots.Furthermore, there may be branched, and from the side, resulting in formation of lateral roots of higher order (first, second and third).
large lateral cross geotropism characterized bodies, i.e. their growth occurs in substantially horizontal or at an angle to the soil surface.
What is called the root system?
root system called all kinds and types of roots available at one plant (ie their combination).Depending on the ratio of growth in the main, lateral and adventitious roots is defined by its look and character.
types of root systems
There are pivotal and fibrous root system.
If the main root developed very well and is noticeable among the roots of another species, which means that the plant has a core system.Inherent in it mainly dicots.
root system of this type is characterized deep germination in the soil.For example, the roots of some herbs can penetrate to a depth of 10-12 meters (sow thistle, alfalfa).The depth of penetration of tree roots in some cases can reach 20 meters.
If greater denominated adventitious roots developing in large quantities and is mainly characterized by slow growth, the root system is formed, which is called fibrous.
Such systems are characterized, as a rule, monocots and some of the grass.Despite the fact that the roots of fibrous system does not penetrate as deep as that of the core, they are better entwine soil particles adjacent to them.Many ryhlokustovye and rhizomatous grasses forming copious amounts fibrillose fine roots are widely used for securing the gullies, the soil on the slopes and so on. Some of the best grass-zaderniteley includes couch grass, brome, fescue, Kentucky bluegrass and others.
Modified roots
Besides typical outlined above, there are other kinds of roots and root systems.They are called modifications.
stocking up the roots
It is stored are roots and korneklubni.
root crop is a thickening of the main root in connection with the deposition of nutrients in it.It is also involved in the formation of root crop the lower part of the stem.It consists largely of stocking up the underlying tissue.Examples of root crops can serve as parsley, radishes, carrots, beets, and others.
If roots are thickened to stock up lateral and adventitious roots, they are called root tubers (cones).They developed the potato, sweet potato, dahlia, etc.
Aerial roots
This lateral roots growing in the aerial part.There are a number of tropical plants.They absorb water and oxygen from the air.There have tropical plants growing in a lack of minerals.
Breathing roots
This kind of lateral roots that grow upward, rising above the surface of the substrate, water.These types of roots are formed in plants grown too moist soils, in the conditions of the marshes.With such roots of the vegetation gets oxygen deficient air.
Support (plank-buttress) roots
These types of tree roots are characteristic of large species (beech, elm, poplar, tropical, and so on. N.) Is a triangular vertical protuberances formed lateral roots and extending from the surface of the soil orabove her.They also called plank-buttress, because they remind boards that leaned against a tree.
Roots-suckers (haustoria)
observed in parasitic plants who can not photosynthesize.The nutrients necessary for normal functioning, they are produced by growing into the stem or root of other plants.Thus they are introduced into the phloem and xylem.Examples of plant pests are dodder, broomrape, Rafflesia.
Haustorium plants semiparasites having photosynthetic ability, grow only in the xylem, taking the host plant only minerals (Ivan da Marya, mistletoe, and others.)
roots hooks
This kind of additional adventitious roots, developingon the stem of climbing plants.With their help, the plants are able to attach to a specific support and rise (trail) up.These roots are, for example, the tenacious ficus, ivy, and so on. N.
retractable (contractile) roots
characteristic plants, the root of which is sharply reduced in the longitudinal direction of the base.Examples are plants having bulbs.Retractable roots Roots and bulbs provide a depression in the soil.Moreover, their presence caused a snug fit sockets (e.g., dandelion) to the ground and the vertical position of an underground rhizome and root neck.
Mycorrhiza (gribokoren)
called mycorrhiza symbiosis (mutually beneficial co-existence) of the roots of higher plants with fungal hyphae, which entwine them, acting as the root hairs.Mushrooms provide the plants with water and nutrients dissolved in it.Plants, in turn, produce mushrooms necessary for their metabolic organic substance.
inherent many mycorrhizae roots of higher plants, especially woody.
bacterial nodules
This modified lateral roots, which are adapted to the cohabitation with symbiotic nitrogen-fixing bacteria.The formation of nodules is due to infiltration of nitrogen-fixing bacteria in the roots of the young.Such mutually beneficial co-existence allows plants to obtain nitrogen that the bacteria is transferred from the air in a form available to them.The bacteria also provides a special habitat in which they can operate, not compete with other types of bacteria.Furthermore, they use substances present in the roots of the vegetation.
characteristic for bacterial nodules of legumes, which are widely used as ameliorants in crop rotation in order to enrich the soil with nitrogen.The best nitrogen-fixing plants are considered with tap legumes grasses, such as alfalfa blue and yellow, clover pink, red and white clover, sainfoin, Lotus corniculatus and so forth.
addition to these metamorphoses, there are other kinds of roots such as root-backup (help to strengthenstem), stilted roots (help plants do not sink in the mud) and suckers (have adventitious buds and provide vegetative propagation).
