Vegetative propagation of plants by timing. Vegetative propagation of indoor plants

13.09.2023

Methods of vegetative propagation of plants

Vegetative propagation of plants is carried out using various methods: rhizomes, cuttings, tendrils or bulbs. The cuttings option is the most common when it comes to house plants.

What does the concept of vegetative propagation mean?

Vegetative propagation is one of the methods of propagation that involves growing a new plant using its mother part. The second name for this technique is asexual reproduction. It has a number of advantages, the main one of which is the complete preservation of all generic characteristics of the mother plant.

Source: Depositphotos

Vegetative propagation of plants is possible in several ways

The most popular methods of vegetative propagation:

Seeds.
Dividing the bush.

Scheme 1 Reproduction using air layering. 1 - Maternal branch; 2 - Formation of roots at the site of bark removal;
3 - The transplant process itself.

Air layering (see diagram 1.) To carry out this type of propagation, make an incision on a branch 1.5 cm long. Lubricate the area where the bark was removed with phytohormone. The plastic film is well fixed on the stem of the plant and sphagnum moss or other substrate is poured. Tie the other end of the film and wait for the roots to form.

Vaccination (see diagram 2)

Offspring (see diagram 3).

Scheme 4. Reproduction by tendrils or ground stolons contributes to the rapid rooting of a young plant

Whiskers or ground stolons (see diagram 4)
Leaves.

Since the simplest method is dividing the bush, let's talk about this method in more detail.

Dividing a bush as a method of vegetative propagation

Scheme 5. Dividing a bush is a simple method of vegetative propagation. 1 - main plant; 2 - the process of dividing a plant bush.

Dividing a bush is the most primitive, simple and cheapest propagation method. Dividing is very easy:

Carefully remove the plant from the pot and shake off the soil mixture.
Divide the plant into 2 equal parts. Please note that each part must have young buds.
Transplant both parts into different pots with previously prepared soil.

Nothing else is needed to successfully divide the bush. With the right approach to propagation, both plants will take root well in new pots, and all you have to do is regularly care for them.

Vegetative propagation by leaf cuttings

There is also nothing difficult about this breeding technique. It is suitable for mature healthy plants with developed fleshy leaves. Reproduction is done like this:

Lightly press a healthy, dense leaf into wet sand.
When the leaf sprouts roots, plant it in previously prepared soil.
Until the leaf gets stronger, water it with a sprayer twice a day. Cover the cutting with a plastic cup, creating greenhouse conditions.

When the plant becomes noticeably stronger, remove the glass and begin caring for it as usual.

Propagation by cuttings

Most often in nature, plants reproduce by cuttings - when the wind breaks the shoots, the roots remaining in the soil become tied into new young stems. Propagation by cuttings is carried out as follows:

Separate a twig with several buds from the mother shoot.
Place the twig in clean water at room temperature.
When adventitious roots form on the branch, transplant it into a plastic cup with a damp substrate.
When the plant gets stronger, transplant it to a permanent place.

Vegetative or asexual propagation is practiced for both indoor plants and outdoor trees, flowers and shrubs. This is a universal technique that allows you to experiment with the characteristics of varieties, create hybrid varieties, or develop new plants previously unknown to science. This is also the safest propagation option - the risk of accidentally harming the plant is minimal.

Vegetative propagation

the formation of a new organism from a part of the maternal one. The methods of V. r. observed in nature are varied. The simplest of them is the restoration of the organism from one vegetative cell as a result of its sequential division and differentiation of the resulting cells.

V. r. characteristic of microorganisms, low-organized animals, and almost all plants. In animals V. r. carried out by budding (for example, in sponges, coelenterates, bryozoans) or division (for example, in protozoa); in unicellular plants (algae, fungi, etc.) - more often by division, less often by budding; in lower multicellular plants, by disintegration of the body into separate sections capable of regeneration(recovery). Higher plants can reproduce by rhizomes, suckers, bulbs, tubers, and other vegetative organs (See Vegetative Organs). In many cultivated plants, V. r. - the only possible way to preserve valuable varietal characteristics and properties.

In higher plants, reproduction occurs by layering (fir, rhododendrons, wild forms of grapes, etc.), that is, by parts of organs whose connection with the mother plant is maintained until they begin to feed on their own; lashes or mustaches (strawberries - rice. 1 , blackberries, sweet potatoes, creeping buttercups, budra, etc.); root suckers (many deciduous and coniferous trees and grasses - mountain ash, rose, alder, tausagyz, field sow thistle, etc.). Many vegetable and ornamental plants (onions, tulips, lilies, potatoes, sweet potatoes and many others) reproduce by bulbs and tubers; as a rule, perennial plants (lily of the valley, mint, asparagus, bamboo and many weeds) reproduce by rhizomes. In plant growing, propagation by cuttings (stem, root and leaf) is widespread. Natural reproduction by leaves is characteristic of bryophyllum, in which the shoots formed on the leaf blades fall off and take root in the soil.

In fruit growing, own-root methods of V. r. are used. (propagation by layering and cuttings) and grafting (see Grafting in plant growing) . Layering is a part of a ground stem with buds that is not separated from the mother plant during the rooting period. Stems to be rooted are hilled. Rooted stems are separated from the mother plant, cut into pieces (having roots) and immediately planted on a plantation or grown in a nursery (1-2 years). Many types of agricultural products and ornamental plants (blackberry, ivy, sumac, mackerel, rhododendron, etc.) are propagated by natural layering ( rice. 2 ). In fruit growing, propagation by vertical and horizontal layering is most often used; This is how many varieties of gooseberries, some apple tree rootstocks are propagated, and in ornamental gardening - lilac, viburnum, honeysuckle, etc. Many varieties of blackberries and blackberry-like raspberries are propagated by apical layering.

When cuttings, parts of the plant (cuttings) are used that, under certain conditions, are capable of restoring roots (on stems), or buds (on roots), or buds and roots (on leaves). There are stem, leaf and root cuttings. Stem cuttings can be without leaves (winter), with leaves (summer, or green), herbaceous and woody. Leafless cuttings are usually harvested in the fall, often from annual shoots, which are cut into pieces 20-30 in length. cm, planted in autumn or spring, keeping them buried in the basement, in the snow. Winter cuttings are used to propagate grapes, some varieties of gooseberries, some types of apple and plum rootstocks, quince, fig, pomegranate, spirea, jasmine, poplar, willow, etc. For green cuttings, leafy shoots are used, cutting them into pieces 5-10 in length cm, sometimes a part of the bark with wood and one bud (leaf cuttings) is cut from the stem. Green cuttings are used to propagate gooseberries, cherries, plums, quince, sea buckthorn, olives, many ornamental shrubs and herbaceous flowering plants - chrysanthemum, geranium, carnation, dahlia, phlox, etc. The process of root formation in green cuttings of many plants is stimulated with the help of growth substances (See. Growth substances). In cherries, plums, lilacs, etc., green cuttings take root more easily during the period when the cuttings are in a phase of intensive growth in length; in apple trees, gooseberries, etc. - at the end of this phase, and in black currants and some varieties of gooseberries - during the entire growth phase. Temperature (optimal 20-25°C), air and substrate humidity, and light conditions are of great importance when propagating from green cuttings. For green cuttings, artificial fog is used, created by automated systems above the rooting site of the cuttings. In an atmosphere of fog, the rooting rate of cuttings increases sharply, and labor costs are reduced by 2-3 times.

A leaf stalk is a leaf or part of a leaf. The leaf is planted in the rooting medium (usually sand) with the petiole or laid with the underside, slightly cutting the convex veins of the leaf. Then lightly sprinkle with sand and water. Begonia, sedum, Uzambara (African) violet, etc. are propagated by leaf cuttings.

Root cuttings are parts of the root; They are usually harvested in the fall, 10-15 in length cm, stored buried in sand and peat, planted in fertile soil in the spring. Root cuttings are used to propagate raspberries (red), blackberries, young apple tree seedlings, some varieties of cherries, plums, etc.

Lit.: Krenke N.P., Plant regeneration, M. - L., 1950; Turetskaya R. X., physiology of root formation in cuttings and growth stimulants, M., 1961; Hartman X. T., Kester D. E., Reproduction of garden plants, trans. from English, M., 1963; Zhukovsky P. M., Botany, 4th ed., M., 1964.

M. T. Tarasenko.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

There are several main ways to propagate plants: they can be sown in the ground (open or closed) with seeds or seedlings can be obtained from them, bulbs, tubers or rhizomes can be divided. There are also less common options - propagation of vegetables by cuttings, layering and grafting. Vegetative methods of plant propagation are those that involve parts of crops.

They are resorted to for a number of reasons:

there are crops that do not produce seeds, for example garlic, horseradish, multi-tiered onions;
some vegetables (potatoes, spicy varieties of onions), sown with seeds, form small productive organs in the first year - such as sets;
gardeners cultivate plants that, when grown from seeds, produce strong splitting (as when sowing seeds collected from hybrids), for example rhubarb;
There are crops that have very small seeds that are difficult to germinate, and it takes 70-90 days to grow seedlings. These include artichoke, rosemary, tarragon, etc. Therefore, it is simply more convenient to grow them using the vegetative method of propagating cultivated plants.

Different methods of propagating vegetable crops

In practice, propagation of vegetable crops by dividing bulbs is common. For example, a multi-bud onion forms a fairly large number of bulbs - 3-12 pieces, into which it can be divided and then planted in beds. You can divide the bulbs not only by the number of children, but also into parts - by the number of embryos. Using this method of plant propagation, cut off the upper part of the bulb “up to the shoulders”; on the cross section you will see the rudiments, into which you will need to disassemble the bulb. When they dry out a little in the air, plant them in the same way as sets (bulbs grown from seeds and having a diameter of 1.5-2.2 cm) or selections (bulbs with a diameter of 3-4 cm).

There is a rule that, if followed, will allow you to grow a good harvest of shallots, multi-tiered onions and garlic: before sowing the bulbs, calibrate them by size and plant them at a depth that is 3 times their height. Then the plants will develop equally and at the same time produce a harvest.

What other methods of plant propagation do gardeners use? Perennial crops, such as asparagus, rhubarb, lovage, mint, thyme, etc., reproduce by dividing the rhizomes. It contains a sufficient supply of nutrients to support the vital activity of young plants until they develop their own root system. Divide the rhizomes into parts in the fall or spring and immediately plant them in a garden bed where they will grow for several years.

Artichoke and lemon balm provide root shoots. But their root system is quite weak, so in order for it to take root after the separation of the daughter plant from the mother plant, it must be grown in a nursery.

Vegetable plants such as potatoes, Jerusalem artichoke and stachys are propagated by dividing the tubers, based on the biological characteristics of these crops. A tuber is a modified thickened shoot, so potatoes are not a root crop, like carrots or beets (their fruit is a thickened root), but a tuber crop. At its top there are buds - eyes, which are unevenly distributed throughout the tuber. With 12 eyes 6-7 pcs. will fall on the top third, on the middle third - 1-2 pieces, on the bottom third - 2-3 pieces. When cutting the tuber, make sure that there are several eyes for each part.

How else does a person propagate cultivated plants that have tubers? Potatoes can also be propagated by eyes and sprouts (layers). In the first case, cut out the eyes in the form of cones, and the tubers themselves can be used for food. Leave the eyes in the air for several hours so that they wilt a little, pour them into a box in a small layer and store at a temperature of 3-4 ° C. During planting, place 2-3 eyes in each hole. By providing optimal care, you will get a good potato harvest.

Using this method of propagating vegetable plants, potatoes must undergo vernalization to produce sprouts. To do this, leave the tubers in the light for about 30 days at a temperature of 16-17 ° C. After the formation of sprouts 10-15 cm long on them, lay the potatoes in layers, alternating each of them with humus or peat. After 4-6 days, the root system will develop on the sprouts. Separate them from the tuber (try not to damage the eyes) and plant them in a plot (at a distance of 20 cm from each other, and there should be 50 cm between rows) or in a nursery for growing (this is how sweet potatoes are usually cultivated). Further care does not differ from the generally accepted one.

When practicing plant propagation in different ways, experienced gardeners use grafting. Reproduction by grafting is a method better known in fruit growing. It was first applied to vegetables by I.V. Michurin. Of course, grafting is not so common in vegetable growing, however, tomatoes can be grafted onto potatoes, sunflowers onto Jerusalem artichokes, cucumbers and melons onto pumpkins. This method is used to the greatest extent in breeding, but it is not found in the practice of amateur vegetable growing.

Method of propagating vegetable plants by cuttings

What other methods of plant propagation are there, and how to use them? Tomatoes can be propagated by cuttings, especially if the plants are very elongated or if there are not enough seeds. Cut off the top and shoots of the seedling and root. From such cuttings, completely conditioned bushes will grow. At the same time, the mother plant planted in the ground will also develop normally and bear fruit.

Using the method of propagating plants by cuttings is associated with one difficulty - maintaining viability until they develop a full-fledged root system. This can only be achieved if they are provided with heat, light and moisture, which is possible in a greenhouse. In the process of propagating various cultivated plants by cuttings, he will need boxes filled with perlite or vermiculite, that is, sterile, light and loose substrates that can create optimal conditions for a new root system. You can use compost, humus, and rotted sawdust pre-treated with fertilizers.

In addition to tomatoes, stem cuttings are used for potatoes, lovage, marjoram, and tarragon. In this case, it is important to choose the right cuttings, which should not be too young (they do not give roots well) or too old (they dry out, since a large amount of nutrients is used to maintain the developed vegetative organs - leaves). Therefore, choose healthy shoots, free from pests and diseases, that are just beginning to become lignified. To stimulate the formation of roots, use heteroauxin, for which dissolve 2 tablets in a glass of hot water, pour in water at room temperature, bringing the amount to 10 liters, and keep the cuttings in the liquid for 6 hours.

The survival rate of cuttings will increase if you soak them in a 0.005% sodium humate solution. To obtain a liquid of this concentration, dilute 10 g of the drug in 150 ml of water and leave for 1 day, then drain the solution, and pour 20 ml of sediment into 10 liters of water.

Cuttings come not only from stems, but also from roots. This is how artichokes, rosemary and horseradish are grown. For example, prepare horseradish cuttings 15-20 cm long in the fall and store them in the basement in the sand until the next season. Before planting, wipe them with a cloth, removing all the buds in the middle. And in artichoke, root cuttings are grouped around the mother plant; they can simply be separated with a knife and planted in a permanent place.

Vegetative propagation plants- this is the development of new plants from vegetative organs or their parts. Vegetative propagation is based on the plant’s ability to regenerate, i.e., to restore a whole organism from a part. During vegetative propagation, new plants are formed from shoots, leaves, roots, tubers, bulbs, and root suckers. The new generation has all the qualities that the mother plant has.

Vegetative propagation of plants occurs naturally or with human help. People widely use vegetative propagation of indoor, ornamental, and vegetable plants. For this, first of all, those methods that exist in nature are used.

Wheatgrass, lily of the valley, and kupena reproduce by rhizomes. Rhizomes have adventitious roots, as well as apical and axillary buds. The plant, in the form of a rhizome, overwinters in the soil. In spring, young shoots develop from the buds. If the rhizomes are damaged, each piece can produce a new plant.

Some plants reproduce from broken branches (willow, poplar).

Reproduction by leaves occurs less frequently. It is found, for example, in meadow heart. In moist soil, an adventitious bud develops at the base of the broken leaf, from which a new plant grows.

Potatoes are propagated by tubers. When planting a club, part of the buds develops into green shoots. Later, from another part of the buds, underground shoots, similar to rhizomes, are formed - stolons. The tops of the stolons thicken and turn into new tubers (Fig. 144).

Onions, garlic, and tulips reproduce by bulbs. When planting bulbs in the soil, adventitious roots grow from the bottom. Daughter bulbs are formed from axillary buds.

Many shrubs and perennial herbs are propagated by dividing the bush, for example peonies, irises, hydrangeas, etc.

Scientists have developed methods of vegetative propagation that are extremely rare in nature (cuttings) or do not exist at all (grafting).

Cutting-forging

When cuttings, part of the mother plant is separated and rooted. A cutting is a part of any vegetative organ - a shoot (stem, leaf), root. The cuttings usually already have buds, or they may appear under favorable conditions. A new plant grows from the cuttings, completely similar to the mother one.

Many indoor plants, tradescantia, pelargonium, and coleus, are propagated by green leafy shoot cuttings (Fig. 145). Gooseberries, currants, nil, willow and other plants are propagated by leafless cuttings (a section of a young stem with several buds).

Begonia, glock blue, Uzambara violet, sansevieria (pike tail) and many other indoor plants are propagated by leaf cuttings. To do this, a separate leaf is planted in damp sand, covered with a glass cap, or placed in water (Fig. 146).

Raspberries are propagated by root cuttings.

Layerings

Layerings are used for propagating gooseberries, currants, and linden. In this case, the lower branches of the bush are bent to the ground, pressed and sprinkled with soil. It is recommended to make cuts on the underside of the bent branch to stimulate the formation of adventitious roots. After rooting, the cutting branch is separated from the mother plant and transplanted to a permanent place (Fig. 147).

Plant grafting

Apple trees, pears and other fruit plants, when grown from seeds, do not retain the valuable qualities of the original plant. They become wild, so such plants are propagated by grafting. The plant that is grafted onto is called the rootstock, and the plant that is grafted onto is called the scion. A distinction is made between grafting with an eye and grafting with a cutting (Fig. 148).

Inoculation

Eye grafting is carried out as follows. In the spring, during sap flow, a T-shaped cut is made on the bark of the rootstock. Then the corners of the bark are folded back and a bud cut from the scion with a small area of bark and wood is inserted under it. The bark of the rootstock is pressed, and the wound is bandaged with a special adhesive tape. The part of the rootstock located above the scion is removed.

Grafting with cuttings

Grafting with cuttings is done in different ways: by butt (cambium on cambium), split, under the bark. With all methods, it is important to observe the basic condition: the cambium of the scion and the cambium of the rootstock must match. Only in this case will fusion occur. As with kidney grafting, the wound is bandaged. The sites of correctly performed grafting quickly grow together. Material from the site

Plant tissue culture

In recent decades, such a method of vegetative propagation as tissue culture has been developed. The essence of the method is that a whole plant is grown from a piece of educational (or other) tissue or even from one cell on a nutrient medium under careful observation of lighting and temperature conditions. At the same time, it is important to prevent the plant from being damaged by microorganisms. The value of the method is that, without waiting for seeds to form, you can get a large number of plants.

Vegetative propagation of plants is of great biological and economic importance. It promotes fairly rapid dispersal of plants.

During vegetative propagation, the new generation has all the qualities of the mother’s organism, which allows the preservation of plant varieties with valuable traits. Therefore, many fruit crops reproduce only vegetatively. When propagated by grafting, the new plant immediately has a powerful root system, which allows it to provide young plants with water and minerals. Such plants turn out to be more competitive compared to seedlings emerging from seeds. However, this method also has disadvantages: with repeated repetitions of vegetative propagation, “aging” of the original plant occurs. This reduces its resistance to environmental conditions and diseases.

Diaspores formed during vegetative propagation are represented by parts of the vegetative organs of plants or their metamorphoses. All groups of plants are capable of propagating vegetatively. Angiosperms have the greatest ability for vegetative propagation; they also exhibit the greatest diversity of diaspores. There are natural and artificial (with the help of humans) vegetative propagation of plants.

Natural vegetative propagation plays a very important role in the life of plants. It allows plants to quickly capture new territories, especially in those conditions where seed propagation is difficult or does not occur at all. Typically, angiosperms reproduce using specialized organs of vegetative reproduction: rhizomes (iris, wheatgrass, cornflower), tubers (yam, potato, Jerusalem artichoke), bulbs (lily, onion, tulip), corms (gladiolus, crocus), bulbill (tiger lily), basal rosettes (strawberry, saxifrage).

The totality of all vegetative descendants of one plant, developed from a seed or spore, called a clone. Clones can be represented by a huge number of individuals. It is difficult to even imagine how many individuals a clone of some popular potato, strawberry or tulip variety in the world is represented by.

As noted above (see 5.7.1), many plants produce highly specialized shoots of vegetative propagation with a pronounced stolon part, providing distancing and fast department daughter plant from the mother plant. Potatoes, the most important food crop in the world, also reproduce with the help of such shoots. It is grown from tubers. The methods being developed for its seed propagation have not yet become widespread. Morphogenesis (shaping process) of potato plants during their development from a tuber proceeds as follows (Fig. 103).

Aboveground shoots of renewal are formed from the apical and axillary buds of the tuber. The first metameres of these shoots are in the soil, so their leaves are small and scale-like. After the shoots emerge to the soil surface, they begin to form photosynthetic leaves of the middle formation - simple, intermittently unpaired pinnately dissected, without stipules. The emergence of renewal shoots to the soil surface coincides with the beginning of the formation of Fig. 103. Development of a potato plant (Solarium tuberosum) from a tuber (according to O.A. Korovkin, 1979):

1 - planted tuber;
2 - above-ground shoots of renewal, formed from the apical and axillary buds of the tuber;
3 - stolons developing from the lower axillary buds of renewal shoots;
4 - young tubers;
5 - nodal adventitious roots

formation of shoots of vegetative propagation from buds in the axils of their lower scale-like leaves. On each renewal shoot, from three to ten shoots of vegetative propagation are formed (more in late-ripening varieties). The development of shoots of vegetative propagation begins with the formation of their stolon part. Stolons grow quickly and can branch - lateral stolons of the next order are formed from their axillary buds. In cultivated varietal plants, the length of the stolons is small - 5-20 cm, which makes harvesting easier (in plants of wild species it can reach 2 m!). The beginning of the formation of buds in aboveground shoots coincides with the beginning of the formation of the tuberous part in shoots of vegetative propagation. It is formed after the stolon part and differs from it in the short and thick internodes of the stem. Small scale-like leaves can be seen only on the upper metameres of young tubers - they quickly die and fall off. If adventitious roots develop on stolon nodes, adventitious roots never form on potato tubers. In the educational literature you can find the statement that the tuber is formed due to the thickening of the stem at the top of the stolon. This is incorrect: the boundary between the stolon and tuber parts of the shoot of vegetative propagation is very clear - the stolon metamers do not take part in the formation of the tuber.

Young tubers of all varieties are white and covered with epidermis. As they ripen, they become covered with periderm and acquire varietal coloring. Most of the tuber is represented by storage parenchyma; conductive tissues are poorly expressed. After the stolon part dies, the tubers become isolated from the mother plant and from each other. On their lower part there is a clearly visible trace of the dead stolon, which in plant growing is called the umbilical cord. After overwintering, the third part of the shoot of vegetative propagation is formed from the apical bud of the tuber next spring - the above-ground photosynthetic part. The development of a vegetative propagation shoot will end with the formation of an apical inflorescence - a double curl. Thus, a shoot of vegetative propagation goes through its ontogeny in two growing seasons, i.e. it is dipyclic. In the first year, the stolon and tuber parts are formed, and in the second year, the above-ground photosynthetic part is formed. In the second year of life, the direction of shoot growth also changes - from plagiotropic to orthotropic. Since the annual renewal of plants occurs only due to shoots of vegetative propagation, it can be stated that the potato clone (the totality of all vegetative descendants) is represented by a set of shoots of vegetative propagation of increasing order (Fig. 104). In the form of the same clones, there are other economically valuable stolon-forming plants with tubers of shoot origin: Jerusalem artichoke, Siebold's stachys, tuberous sorrel, and common arrowhead.

Rice. 104. Scheme of the structure of the shoot system of a potato clone (Solarium tuberosum)(according to O.A. Korovkin, 2005):

L- main shoot; B, C, D- shoots of vegetative propagation of increasing order: 1 - cotyledon node; 2-4- shoot vegetative propagation (2 - stolon; 3 - tuber; 4 - aboveground photosynthetic part);

5 - renewal shoot, developed from the lateral bud of the tuber;
6 - continuation escape; 7- apical inflorescence

Artificial vegetative propagation carried out to obtain descendants from valuable cultivated plants that themselves cannot reproduce asexually. Vegetative propagation makes it possible to preserve in daughter plants the valuable qualities of the parent, which are lost during sexual (seed) propagation. Artificial vegetative propagation of plants is called cloning. Plants are usually propagated by cuttings, grafting, and layering.

By cuttings, As a rule, fruit and ornamental plants are propagated. A shoot cutting is a part of a shoot, usually consisting of two or three metamers. On the lower section of the cuttings immersed in the substrate, wound meristems form and callus, from which adventitious roots and buds are formed. In many plants, adventitious roots arise directly on the lower part of the stem of the cutting, and shoots develop from its axillary buds. Grapes, currants, gooseberries, pelargonium, phlox, roses, etc. are propagated by shoot cuttings. “Green cuttings” have become widespread - growing plants from cuttings obtained from young shoots with non-lignified stems under special conditions (growth regulators, artificial fog, etc.). d.). This method has significantly expanded the list of cultivated plants propagated vegetatively.

Many ornamental plants (begonia, gloxinia, saintpaulia, etc.) are propagated by leaves - leaf cuttings. From the callus formed at the end of the petiole, adventitious buds and roots develop. Root shoot plants (cherry, sea buckthorn, lilac, plum) can be propagated root cuttings.

By layering - currants, gooseberries, spirea and other shrubs are propagated by bent to the ground and rooted shoots. This method of vegetative propagation can also be observed in nature: lodging branches of willow, linden, bird cherry, and fir take root easily.

Graft consists of grafting a cutting from one plant onto another plant. The grafted plant is called scion, and that to which one is grafted - rootstock. There are many methods of grafting, differing in timing, grafted material (cutting or one bud), and method of connecting the scion to the rootstock.

In the middle of the 20th century. An unusual method of cloning plants began to be actively developed - the method cell and tissue culture. Scientists have managed to learn how to grow entire plants from a group of cells, or even from a single cell, placed in a medium containing nutrients and essential hormones. The method is based on totipotency

cells. Each of them contains a complete set of genes of the organism, which allows, under certain conditions, to fully implement the genetic program of its development. New organisms are usually obtained from cells of apical meristems. The propagation of plants using tissue culture is called clonal micropropagation. This method turned out to be especially relevant for the improvement of plants when they are damaged by pathogenic viruses. It turned out that in a plant infected with viruses, only the cells of the apical meristem are free from them, where the viruses do not have time to penetrate. From these cells, healthy plants are grown, which are then propagated vegetatively using a more traditional method - cuttings. One plant can produce over 1 million genetically identical healthy plants per year. This is how valuable varieties of cloves, strawberries, potatoes, etc. are freed from viral infection. Considerable costs are paid off by a sharp increase in yield from healthy plants. Clonal micropropagation is also used for faster propagation of especially valuable plants.