Root- the main vegetative organ of a plant, which in a typical case performs the function of soil nutrition. The root is an axial organ that has radial symmetry and grows in length indefinitely due to the activity of the apical meristem. It differs morphologically from the shoot in that leaves never form on it, and the apical meristem is always covered by a root cap.

In addition to the main function of absorbing substances from the soil, the roots also perform other functions:

1) the roots strengthen (“anchor”) the plants in the soil, make it possible to grow vertically and shoot up;

2) various substances are synthesized in the roots, which then move to other organs of the plant;

3) reserve substances can be deposited in the roots;

4) roots interact with the roots of other plants, microorganisms, fungi that live in the soil.

The totality of the roots of one individual forms a single morphological and physiological relation root system.

The composition of root systems includes roots of various morphological nature - main root, lateral and adnexal roots.

main root develops from the germinal root. Lateral roots are formed on the root (main, lateral, subordinate), which in relation to them is designated as maternal. They arise at some distance from the apex, in the direction from the base of the root to its top. Lateral roots are laid endogenously, i.e. in the internal tissues of the maternal root. If branching occurred at the apex itself, it would make it difficult for the root to move through the soil. adventitious roots can occur on stems, and on leaves, and on roots. In the latter case, they differ from lateral roots in that they do not show a strict order of initiation near the apex of the maternal root and may appear in old root areas.

By origin, the following types of root systems are distinguished ( rice. 4.1):

1) main root system represented by the main root (first order) with lateral roots of the second and subsequent orders (in many shrubs and trees, most dicotyledonous plants);

2)adventitious root system develops on stems, leaves; found in most monocotyledonous plants and many dicotyledons that reproduce vegetatively;

3)mixed root system formed by the main and adventitious roots with their lateral branches (many herbaceous dicots).

Rice. 4.1. Types of root systems: A - main root system; B - system of adventitious roots; C - mixed root system (A and C - tap root systems; B - fibrous root system).

Distinguished by shape rod and fibrous root systems.

AT pivotal In the root system, the main root is strongly developed and is clearly visible among the other roots. AT fibrous root system, the main root is invisible or absent, and the root system is composed of numerous adventitious roots ( rice. 4.1).

The root has potentially unlimited growth. However, under natural conditions, the growth and branching of roots is limited by the influence of other roots and soil environmental factors. The bulk of the roots is located in the upper soil layer (15 cm), the richest in organic matter. The roots of trees deepen on average by 10-15 m, and in width they usually spread beyond the radius of the crowns. The root system of corn goes to a depth of about 1.5 m and about 1 m in all directions from the plant. The record depth of root penetration into the soil was noted in the desert mesquite shrub - more than 53 m.

In one rye bush grown in a greenhouse, the total length of all roots was 623 km. The total growth of all roots in one day was approximately 5 km. The total surface of all the roots of this plant was 237 m 2 and was 130 times larger than the surface of the above-ground organs.

Zones of the young root ending - these are parts of a young root that are different in length, perform different functions and are characterized by certain morphological and anatomical features ( rice. 4.2).

The tip of the root is always covered from the outside root cap protecting the apical meristem. The sheath consists of living cells and is constantly updated: as old cells are shed from its surface, the apical meristem forms new young cells to replace them from the inside. The outer cells of the root cap flake off while still alive, producing a copious mucus that facilitates the root to move through the hard soil particles. The cells of the central part of the cap contain many starch grains. Apparently, these grains serve statoliths, i.e., they are able to move in the cell when the position of the root tip in space changes, due to which the root always grows in the direction of gravity ( positive geotropism).

Under the cover is dividing zone, represented by the apical meristem, as a result of which all other zones and tissues of the root are formed. The division zone has dimensions of about 1 mm. The cells of the apical meristem are relatively small, multifaceted, with a dense cytoplasm and a large nucleus.

Following the division zone is located stretch zone, or growth zone. In this zone, cells almost do not divide, but strongly stretch (grow) in the longitudinal direction, along the axis of the root. The volume of the cells increases due to the absorption of water and the formation of large vacuoles, while high turgor pressure pushes the growing root between the soil particles. The stretch zone is usually small and does not exceed a few millimeters.

Rice. 4.2. General view (A) and longitudinal section (B) of the root end (scheme): I – root cap; II - zones of division and stretching; III - suction zone; IV - beginning of the conduction zone: 1 - growing lateral root; 2 - root hairs; 3 - rhizoderm; 3a - exoderm; 4 - primary bark; 5 - endoderm; 6 - pericycle; 7 - axial cylinder.

Next comes absorption zone, or suction zone. In this zone, the integumentary tissue is rhizoderma(epiblema), the cells of which bear numerous root hairs. The stretching of the root stops, the root hairs tightly cover the soil particles and, as it were, grow together with them, absorbing water and mineral salts dissolved in it. The absorption zone extends up to several centimeters. This area is also called zone of differentiation, since it is here that the formation of permanent primary tissues occurs.

The life span of the root hair does not exceed 10-20 days. Above the suction zone, where the root hairs disappear, begins holding area. Through this part of the root, water and salt solutions absorbed by the root hairs are transported to the overlying organs of the plant. Lateral roots are formed in the conduction zone (Fig. 4.2).

The cells of the suction and conduction zones occupy a fixed position and cannot move relative to the soil areas. However, the zones themselves, due to constant apical growth, continuously move along the root as the root ending grows. Young cells are constantly included in the absorption zone from the side of the stretching zone and at the same time aging cells are excluded, which pass into the composition of the conduction zone. Thus, the suction apparatus of the root is a mobile formation that continuously moves in the soil.

In the same way, internal tissues appear consistently and naturally in the root ending.

The primary structure of the root. The primary structure of the root is formed as a result of the activity of the apical meristem. The root differs from the shoot in that its apical meristem deposits cells not only inward, but also outward, replenishing the cap. The number and location of initial cells in the root apexes vary considerably in plants belonging to different systematic groups. Derivatives of initials already near the apical meristem differentiate into primary meristems – 1) protodermis, 2) main meristem and 3) procambium(rice. 4.3). From these primary meristems, three tissue systems are formed in the suction zone: 1) rhizoderma, 2) primary cortex and 3) axial (central) cylinder, or stele.

Rice. 4.3. Longitudinal section of the tip of an onion root.

rhizoderma (epiblema, root epidermis) is an absorbent tissue formed from protoderms, the outer layer of the primary root meristem. In functional terms, the rhizoderm is one of the most important plant tissues. Through it, water and mineral salts are absorbed, it interacts with the living population of the soil, and through the rhizoderm, substances that help soil nutrition are released from the root into the soil. The absorbing surface of the rhizodermis is greatly enlarged due to the presence of tubular outgrowths in some of the cells - root hairs(Fig. 4.4). The hairs are 1-2 mm long (up to 3 mm). In one four-month-old rye plant, approximately 14 billion root hairs were found with a absorption area of ​​401 m 2 and a total length of more than 10,000 km. In aquatic plants, root hairs may be absent.

The wall of the hair is very thin and consists of cellulose and pectin. Its outer layers contain mucus, which helps to establish closer contact with soil particles. Mucus creates favorable conditions for the settlement of beneficial bacteria, affects the availability of soil ions and protects the root from drying out. Physiologically, the rhizoderm is highly active. It absorbs mineral ions with the expenditure of energy. The hyaloplasm contains a large number of ribosomes and mitochondria, which is typical for cells with a high level of metabolism.

Rice. 4.4. Cross section of the root in the suction zone: 1 - rhizoderma; 2 - exoderm; 3 - mesoderm; 4 - endoderm; 5 - xylem; 6 - phloem; 7 - pericycle.

From main meristem formed primary cortex. The primary cortex of the root is differentiated into: 1) exoderm- the outer part, lying directly behind the rhizoderm, 2) the middle part - mesoderm and 3) the innermost layer - endoderm (rice. 4.4). The bulk of the primary cortex is mesoderm, formed by living parenchymal cells with thin walls. The cells of the mesoderm are located loosely, the gases necessary for cell respiration circulate along the system of intercellular spaces along the axis of the root. In marsh and aquatic plants, the roots of which lack oxygen, the mesoderm is often represented by aerenchyma. Mechanical and excretory tissues may also be present in the mesoderm. The parenchyma of the primary cortex performs a number of important functions: it participates in the absorption and conduction of substances, synthesizes various compounds, reserve nutrients, such as starch, are often deposited in the cells of the cortex.

The outer layers of the primary cortex, underlying the rhizoderm, form exoderm. The exoderm arises as a tissue that regulates the passage of substances from the rhizoderm to the cortex, but after the death of the rhizoderm above the absorption zone, it appears on the root surface and turns into a protective integumentary tissue. The exoderm is formed as a single layer (rarely several layers) and consists of living parenchymal cells tightly closed together. As the root hairs die, the walls of the exoderm cells are covered on the inside with a layer of suberin. In this respect, the exoderm is similar to the cork, but unlike it, it is primary in origin, and the cells of the exoderm remain alive. Sometimes in the exoderm, pass cells with thin, non-corked walls are preserved, through which selective absorption of substances occurs.

The innermost layer of the primary cortex is endoderm. It surrounds the stele in the form of a continuous cylinder. Endoderm in its development can go through three stages. At the first stage, its cells fit tightly to each other and have thin primary walls. Thickenings in the form of frames are formed on their radial and transverse walls - Caspari belts (rice. 4.5). The belts of neighboring cells are closely connected with each other, so that a continuous system of them is created around the stele. Suberin and lignin are deposited in Caspari bands, which makes them impermeable to solutions. Therefore, substances from the cortex to the stele and from the stele to the cortex can pass only along the symplast, i.e., through the living protoplasts of endoderm cells and under their control.

Rice. 4.5. Endoderm at the first stage of development (scheme).

At the second stage of development, suberin is deposited over the entire inner surface of endoderm cells. However, some cells retain their original structure. it check cells, they remain alive, and through them the connection between the primary cortex and the central cylinder is carried out. As a rule, they are located opposite the rays of the primary xylem. In roots that do not have secondary thickening, the endoderm can acquire a tertiary structure. It is characterized by a strong thickening and lignification of all walls, or more often the walls facing outward remain relatively thin ( rice. 4.7). Passage cells are also preserved in the tertiary endoderm.

Central(axial) cylinder, or stele formed in the center of the root. Already close to the division zone, the outermost layer of the stele forms pericycle, the cells of which retain the character of the meristem and the ability for neoplasms for a long time. In a young root, the pericycle consists of a single row of thin-walled living parenchymal cells ( rice. 4.4). The pericycle performs several important functions. In most seed plants, lateral roots are laid in it. In species with secondary growth, it participates in the formation of the cambium and gives rise to the first layer of the phellogen. In the pericycle, the formation of new cells often occurs, which are then included in its composition. In some plants, the adventitious buds also appear in the pericycle. In old roots of monocots, the cells of the pericycle are often sclerified.

Cells behind the pericycle procambia, which differentiate into primary conductive tissues. Phloem and xylem elements are laid in a circle, alternating with each other, and develop centripetally. However, the xylem in its development usually overtakes the phloem and occupies the center of the root. On a transverse section, the primary xylem forms a star, between the rays of which there are sections of phloem ( rice. 4.4). This structure is called radial conducting beam.

A xylem star can have a different number of rays - from two to many. If there are two, the root is called diarchic, if three - triarchal, four - tetrarch, and if there are many polyarchal (rice. 4.6). The number of xylem rays usually depends on the thickness of the root. In the thick roots of monocot plants, it can reach 20-30 ( rice. 4.7). In the roots of the same plant, the number of xylem rays can be different; in thinner branches, it is reduced to two.

Rice. 4.6. Types of structure of the axial cylinder of the root (scheme): A - diarch; B - triarch; B - tetrarch; G - polyarchy: 1 - xylem; 2 - phloem.

Spatial separation of strands of primary phloem and xylem, located at different radii, and their centripetal laying are characteristic features of the structure of the central cylinder of the root and are of great biological importance. The elements of the xylem are as close as possible to the surface of the stele, and it is easier for them, bypassing the phloem, to penetrate the solutions coming from the bark.

Rice. 4.7. Cross section of the root of a monocot plant: 1 – remains of rhizoderm; 2 - exoderm; 3 - mesoderm; 4 - endoderm; 5 - through cells; 6 - pericycle; 7 - xylem; 8 - phloem.

The central part of the root is usually occupied by one or more large xylem vessels. The presence of a core is generally atypical for a root, however, in the roots of some monocots, there is a small area of ​​mechanical tissue in the middle ( rice. 4.7) or thin-walled cells arising from procambium (Fig. 4.8).

Rice. 4.8. Cross section of a corn root.

The primary root structure is characteristic of young roots of all plant groups. In spore and monocotyledonous plants, the primary structure of the root is preserved throughout life.

Secondary structure of the root. In gymnosperms and dicotyledonous plants, the primary structure does not last long and above the absorption zone is replaced by a secondary one. Secondary root thickening occurs due to the activity of secondary lateral meristems - cambium and phellogen.

Cambium arises in the roots from meristematic procambial cells in the form of a layer between the primary xylem and phloem ( rice. 4.9). Depending on the number of phloem cords, two or more zones of cambial activity are formed simultaneously. At first, the cambial layers are separated from each other, but soon the cells of the pericycle, lying opposite the rays of the xylem, divide tangentially and connect the cambium into a continuous layer surrounding the primary xylem. The cambium lays down layers secondary xylem (wood) and out secondary phloem (bast). If this process lasts a long time, then the roots reach a considerable thickness.

Rice. 4.9. The establishment and beginning of the activity of the cambium in the root of the pumpkin seedling: 1 - primary xylem; 2 - secondary xylem; 3 - cambium; 4 - secondary phloem; 5 - primary phloem; 6 - pericycle; 7 - endoderm.

The areas of the cambium that have arisen from the pericycle consist of parenchymal cells and are not capable of depositing elements of conducting tissues. They form primary core rays, which are wide areas of the parenchyma between the secondary conductive tissues ( rice. 4.10). Secondary core, or beams of wood appear additionally with prolonged thickening of the root, they are usually narrower than the primary ones. The core rays provide a link between the xylem and phloem of the root, and radial transport of various compounds occurs along them.

As a result of the activity of the cambium, the primary phloem is pushed outward and squeezed. The primary xylem star remains in the center of the root, its rays can persist for a long time ( rice. 4.10), but more often the center of the root is filled with secondary xylem, and the primary xylem becomes invisible.

Rice. 4.10. Cross section of pumpkin root (secondary structure): 1 - primary xylem; 2 - secondary xylem; 3 - cambium; 4 - secondary phloem; 5 - primary core beam; 6 - plug; 7 - parenchyma of the secondary cortex.

The tissues of the primary cortex cannot follow the secondary thickening and are doomed to death. They are replaced by secondary integumentary tissue - periderm, which can be stretched on the surface of a thickening root due to the work of phellogen. fellogen is laid in the pericycle and begins to lay out cork, and inside phelloderma. The primary bark, cut off by a cork from the internal living tissues, dies and is discarded ( rice. 4.11).

Phelloderm cells and parenchyma, formed by cell division of the pericycle, form parenchyma of the secondary cortex surrounding conductive tissues (Fig. 4.10). Outside, the roots of the secondary structure are covered with periderm. The crust is rarely formed, only on old tree roots.

Perennial roots of woody plants often thicken greatly as a result of prolonged activity of the cambium. The secondary xylem of such roots merges into a solid cylinder, surrounded on the outside by a cambium ring and a continuous ring of secondary phloem ( rice. 4.11). Compared with the stem, the boundaries of annual rings in the wood of the root are much less pronounced, the bast is more developed, and the medullary rays are, as a rule, wider.

Rice. 4.11. Cross section of a willow root at the end of the first growing season.

Specialization and metamorphoses of roots. Most plants in the same root system have distinctly different growth and sucking endings. Growth endings are usually more powerful, quickly elongate and move deep into the soil. Their elongation zone is well defined, and the apical meristems work vigorously. Sucking endings, which appear in large numbers on growth roots, elongate slowly, and their apical meristems almost stop working. The sucking endings, as it were, stop in the soil and intensively “suck” it.

Woody plants have thick skeletal and semi-skeletal roots on which short-lived root lobes. The composition of the root lobes, continuously replacing each other, includes growth and sucking endings.

If the roots perform special functions, their structure changes. A sharp, hereditarily fixed modification of an organ, caused by a change in functions, is called metamorphosis. Root modifications are very diverse.

The roots of many plants form a symbiosis with hyphae of soil fungi, called mycorrhiza("mushroom root"). Mycorrhiza is formed on sucking roots in the absorption zone. The fungal component makes it easier for the roots to obtain water and mineral elements from the soil; fungal hyphae often replace root hairs. In turn, the fungus receives carbohydrates and other nutrients from the plant. There are two main types of mycorrhiza. gifs ectotrophic mycorrhiza form a sheath that envelops the root from the outside. Ectomycorrhiza is widespread in trees and shrubs. Endotrophic mycorrhiza is found mainly in herbaceous plants. Endomycorrhiza is located inside the root, hyphae are introduced into the cells of the bovine parenchyma. Mycotrophic nutrition is very widespread. Some plants, such as orchids, cannot exist at all without symbiosis with fungi.

On the roots of legumes, special formations appear - nodules in which bacteria from the genus Rhizobium settle. These microorganisms are able to assimilate atmospheric molecular nitrogen, converting it into a bound state. Part of the substances synthesized in the nodules are absorbed by plants, bacteria, in turn, use the substances found in the roots. This symbiosis is of great importance for agriculture. Legumes are rich in protein due to the additional source of nitrogen. They provide valuable food and fodder products and enrich the soil with nitrogenous substances.

Very widespread hoarding roots. They are usually thickened and strongly parenchymatized. Strongly thickened adventitious roots are called root cones, or root tubers(dahlia, some orchids). Many, more often biennial, plants with a tap root system develop a formation called root crop. Both the main root and the lower part of the stem take part in the formation of the root crop. In carrots, almost the entire root crop is composed of a root; in turnips, the root forms only the lowest part of the root crop ( rice. 4.12).

Fig.4.12. Root vegetables of carrots (1, 2), turnips (3, 4) and beets (5, 6, 7) ( xylem black on transverse sections; the horizontal dotted line shows the border of the stem and root).

Root crops of cultivated plants arose as a result of long-term selection. In root crops, the storage parenchyma is highly developed and mechanical tissues have disappeared. In carrots, parsley, and other umbellifers, the parenchyma is strongly developed in the phloem; in turnips, radishes and other cruciferous plants - in xylem. In beets, reserve substances are deposited in the parenchyma formed by the activity of several additional layers of cambium ( rice. 4.12).

Many bulbous and rhizomatous plants form retractors, or contractile roots ( rice. 4.13, 1). They can shorten and draw the shoot into the soil to the optimum depth during the summer drought or winter frosts. Retracting roots have thickened bases with transverse wrinkling.

Rice. 4.13. root metamorphoses: 1 - corm of gladiolus with retracting roots thickened at the base; 2 - respiratory roots with pneumatophores in Avicenna ( etc- tidal zone); 3 - aerial roots of an orchid.

Rice. 4.14. Part of a cross section of an aerial root of an orchid: 1 - velamen; 2 - exoderm; 3 - checkpoint.

Respiratory roots, or pneumatophores (rice. 4.13, 2) are formed in some tropical woody plants living in conditions of lack of oxygen (taxodium, or swamp cypress; mangrove plants that live along the swampy shores of ocean coasts). Pneumatophores grow vertically upwards and protrude above the soil surface. Through a system of holes in these roots, connected with the aerenchyma, air enters the underwater organs.

In some plants, to maintain shoots in the air, additional support roots. They depart from the horizontal branches of the crown and, having reached the soil surface, branch intensively, turning into columnar formations that support the crown of the tree ( columnar banyan roots) ( rice. 4.15, 2). stilted roots extend from the lower parts of the stem, giving the stem stability. They form in mangrove plants, plant communities that develop on tropical ocean shores flooded at high tide ( rice. 4.15, 3), as well as in corn ( rice. 4.15, 1). Ficus rubbery are formed plank-shaped roots. Unlike columnar and stilted, they are by origin not adventitious, but lateral roots.

Rice. 4.15. supporting roots: 1 - stilted corn roots; 2 - columnar banyan roots; 3 - stilted roots of rhizophora ( etc- tidal zone; from- ebb zone; silt- the surface of the muddy bottom).

The roots of a plant are its vegetative organs that are underground and conduct water and, accordingly, minerals to the rest, terrestrial, plant organs - stems, leaves, flowers and fruits. But the main function of the root is still to fix the plant in the ground.

On the distinctive features of root systems

Common in different root systems is that the root is always divided into main, lateral and adnexal. The main root, the root of the first order, always grows from the seed, it is he who is most powerfully developed and always grows vertically downwards.

Lateral roots depart from it and are called roots of the second order. They can branch, and adventitious roots, called third-order roots, depart from them. They (adventitious roots) never grow on the main, but in some plant species they can grow on stems and leaves.

This whole set of roots is called the root system. And there are only two types of root systems - rod and fibrous. And our main question concerns how the taproot and fibrous root systems differ.

The tap root system is characterized by the presence of a pronounced main root, while the fibrous root system is formed from adventitious and lateral roots, and its main root is not expressed and does not stand out from the total mass.

In order to better understand how the tap root system differs from the fibrous one, we propose to consider a visual diagram of the structure of one and the second systems.

Such plants as roses, peas, buckwheat, valerian, carrots, maple, birch, currants, watermelon have a tap root system. The urinary root system is found in wheat, oats, barley, onions and garlic, lilies, gladiolus and others.

Modified shoots underground

Many plants underground, in addition to the roots, have so-called modified shoots. These are rhizomes, stolons, bulbs and tubers.

Rhizomes grow mostly parallel to the soil surface, they are needed for vegetative propagation and storage. Outwardly, the rhizome looks like a root, but in its internal structure it has fundamental differences. Sometimes such shoots can come out of the ground and form a regular shoot with leaves.

Underground shoots are called stolons, at the end of which bulbs, tubers and rosette shoots are formed.

A bulb is a modified shoot, the storage function of which is carried out by fleshy leaves, and adventitious roots extend from a flat bottom below.

A tuber is a thickened shoot with axillary buds that performs the function of storage and reproduction.

The root system of a plant is formed by roots of various nature. Allocate the main root, which develops from the germinal root, as well as lateral and adventitious. The lateral ones are a branch from the main one and can form on any of its sections, while the adventitious roots most often begin their growth from the lower part of the plant stem, but can even form on the leaves.

Tap root system

The tap root system is characterized by a developed main root. It has the shape of a rod, and it is because of this similarity that this type got its name. The lateral roots of such plants are extremely weakly expressed. The root has the ability to grow indefinitely, and the main root in plants with a tap root system reaches an impressive size. This is necessary to optimize the extraction of water and nutrients from soils where groundwater occurs at a considerable depth. Many species have a tap root system - trees, shrubs, as well as herbaceous plants: birch, oak, dandelion, sunflower,.

fibrous root system

In plants with a fibrous root system, the main root is practically not developed. Instead, they are characterized by numerous branching adventitious or lateral roots of approximately the same length. Often, in plants, the main root grows first, from which the lateral ones begin to depart, but in the process of further development of the plant, it dies off. A fibrous root system is characteristic of plants that reproduce vegetatively. Usually it is found in - coconut palm, orchids, ferns, cereals.

Mixed root system

Often, a mixed or combined root system is also distinguished. Plants belonging to this type have both a well-differentiated main root and multiple lateral and adventitious roots. Such a structure of the root system can be observed, for example, in strawberries and strawberries.

Root modifications

The roots of some plants are so modified that it is difficult at first glance to attribute them to any type. These modifications include root crops - thickening of the main root and lower part of the stem, which can be seen in turnips and carrots, as well as root tubers - thickening of the lateral and adventitious roots, which can be observed in sweet potato. Also, some roots may not serve to absorb water with salts dissolved in it, but for respiration (respiratory roots) or additional support (stilted roots).

tap root system- a root system characterized by the most powerful development of the main root compared to lateral roots, for example. Dandelion officinalis (Taraxacum officinale) Plant anatomy and morphology

ROOT ROOT SYSTEM- a root system consisting of the main and lateral roots of different orders, and the main root noticeably exceeds the lateral ones in its development (for example, in Onobrychis tanaitica Spreng.) ...

ROOT SYSTEM- a set of roots of one Plant. With the predominant growth of the main root, the tap root system (in lupine, cotton), with a strong development of adventitious roots, is fibrous (in buttercup, plantain, all monocots). Plants with developed ... ... Big Encyclopedic Dictionary

root system- a set of roots of one plant. With the predominant growth of the main root, the tap root system (in lupine, cotton), with a strong development of adventitious roots, is fibrous (in buttercup, plantain, all monocots). Plants with developed ... ... encyclopedic Dictionary

ROOT SYSTEM- the totality of the roots of one plant, the general shape and nature of the cut are determined by the ratio of the growth of the main, lateral and adventitious roots. With the predominant growth of ch. root is formed rod To. (lupine, cotton, etc.), with weak growth or ... Biological encyclopedic dictionary

root system- plants: 1 - rod; 2 - fibrous; 3 - mixed type. root system, a set of roots of one plant, formed as a result of their branching. Distinguish the system of the main root (mostly pivotal in shape), ... ... Agriculture. Big encyclopedic dictionary

ROOT SYSTEM- a set of roots of one rii. With the predominant growth of ch. root rod K. s. (in lupine, cotton), with a strong development of adventitious roots, fibrous (in buttercup, plantain, all monocots). R niya with developed K. page. used for... ... Natural science. encyclopedic Dictionary

ROOT SYSTEM- a set of roots of one plant, formed as a result of their branching. Distinguish the system of the main root (b.ch. rod in form), to paradise it develops from the root of the embryo and consists of ch. root and lateral roots of different orders (in most ... Agricultural Encyclopedic Dictionary

ROOT SYSTEM- a set of underground roots in plants. In flowering plants, there are two main types of K. s .: taproot (consists of the main and lateral roots) and fibrous, or carpal (the main root is poorly developed or dies off early, adventitious roots ... ... Glossary of botanical terms

Root- I Root (radix) is one of the main vegetative organs of leafy plants (with the exception of mosses), which serves to attach to the substrate, absorb water and nutrients from it, the primary transformation of a number of absorbed substances, ... ... Great Soviet Encyclopedia

TAPROOT

TAPROOT, the first ROOT of the plant that develops from the PRIMARY ROOT. The taproot grows straight down and remains the main root of the plant, spreading lateral roots to expand the spread of the root system. In biennial plants, whose leaves and stems usually die off in the first winter, the root is kept alive underground, ready to sprout new leaves the next year. In some vegetable crops (such as beets, carrots and parsnips), the taproot develops into a fleshy organ - a root crop in which STARCH accumulates. These roots are edible for both animals and humans.

Scientific and technical encyclopedic dictionary.

See what "ROOT ROOT" is in other dictionaries:

The main main part of the root system of many plants, which is a direct continuation of the stem in the ground and develops from the original root of the seed germ. In some plants, as, for example, in oaks, the taproot or main root ... ...

A postmodern metaphor that captures the presumption of axiologically colored perception of depth, characteristic of classical metaphysics, as a symbol of the location of the essence and the source of the phenomenon rooted in it, which is associated with the interpretation ... ... History of Philosophy: Encyclopedia

See beginning, reason, origin uproot, take root... Dictionary of Russian synonyms and expressions similar in meaning. under. ed. N. Abramova, M .: Russian dictionaries, 1999. root, beginning, reason, origin; radical; spine, stem, ... ... Synonym dictionary

This term has other meanings, see Root (meanings) ... Wikipedia

Axial root, underground vegetative organ of higher plants, with unlimited growth in length and positive geotropism. The root fixes the plant in the soil and ensures the absorption and conduction of water with dissolved ... ... Wikipedia

Axial root, underground vegetative organ of higher plants, with unlimited growth in length and positive geotropism. The root fixes the plant in the soil and ensures the absorption and conduction of water with dissolved ... ... Wikipedia

Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron

- (Radix). This part in most plants is expressed very clearly and differs well from the rest, but there are also many that are either completely devoid of K. or represent transitions to the stem and generally have non-typical K. Not to mention the lower, ... ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron

pivotal- see rod; a / i, o / e. The tap root of a shrub. Rod / th question. Rod / th transformer (with rod) Mixture (used in the manufacture of rods) ... Dictionary of many expressions