In higher plants, which include flower crops, the forms of vegetative propagation are most diverse: by dividing the bush, tubers, bulbs, corms, rhizomes, cuttings. Reproduction by layering, offspring and grafting is less commonly used. The latter method is used for tree crops of roses, which, as beautifully flowering plants, are used in flower decoration (parterres, mixborders, borders). Vaccinations are also used in cactus culture. Vegetative propagation is used for perennial plants.
Dividing the bush. Herbaceous perennial flower crops, in their life form, belong to perennial polycarpic plants, in which the bush grows over time, sometimes breaking up into separate parts (gelenium), and a weakening of flowering is observed. Such large individuals are divided into parts and planted, taking into account the time of initiation and formation of flowers in a particular species: the division of bushes must be carried out outside this period. Plants that bloom in spring and summer (peony, primrose) are divided in July-August, and those that bloom in autumn (asters, solidago, late phlox) are divided in spring. Depending on the growth rate of the bush, division is carried out at different time intervals: perennial asters can be divided every year; once every 2 years - soapwort, horned violet, Korean chrysanthemums; once every 3-4 years, divide most perennials - asters, astilbe, helenium, gaillardia, carnations, delphinium, elecampane, bells, rudbeckia, solidago, phlox, etc.; After 5-6 years, you can divide well-growing and flowering aquilegia, maquea, bergenia, iberis, lily of the valley, daylily, monarda, hosta, black cohosh, etc. Some plants react painfully to division and replanting - they are stunted in growth and often die. These include aconite, gypsophila, dicletra (dicentra), lupine, oriental poppy, hellebore, eremurus, and ash. It is advisable not to disturb these plants, divide and replant them very carefully.
The technology for dividing bushes (peony, dahlia, phlox) is usually given when describing specific crops.
Division of rhizomes. This method is used for crops that have plagiotropic rhizomes - iris, cannas, lily of the valley. The division of rhizomes of iris and lily of the valley is carried out without germination after flowering in September, and the division of heat-loving cannas, stored in winter in the storage of cannas, is carried out after germination in February-March in greenhouses. The technology for dividing rhizomes is usually given when describing the corresponding crops.
Reproduction by tubers and their division. Anemones, tuberous begonia, gloxinia, caladiums, and buttercups are propagated by tubers and their division. When dividing a tuber, it is necessary that each part has at least one eye (bud). The cuts are sprinkled with crushed coal. In winter, tubers are stored in dry, cool rooms.
Propagation by bulbs. This method is used for bulbous plants (tulip, hyacinth, narcissus, scylla, muscari, lilies, hazel grouse), in which, in addition to the large mother bulb, small daughter bulbs are formed underground. These bulbs are separated and grown into adult, flowering bulbs. Bulbous plants also have unique ways of propagating bulbs. Thus, hyacinth is characterized by a method of violating the integrity of its bottom in various ways (a cross-shaped incision, scraping the bottom, punching the bottom with a tube) to living tissues, after which, with an optimal combination of temperature and humidity, many baby bulbs are formed on the living tissues of the bottom. For narcissus, there is a method of propagation by segments with two scales (cutting option) on a piece of bottom - baby bulbs are formed at the base of the scales in a warm and moist substrate.
Some lilies (bulbous, tiger, sulfur-yellow, etc.) are characterized by the formation of aerial bulblets on the flowering stem, in the axils of the leaves. When planted in the ground in the fall, they produce flowering plants after 3-4 years.
Reproduction by corms and their division. This method is typical primarily for gladiolus, crocus, and freesia. During the period of growth and development, small corms are formed at the base of the new corm: (babies), which grow to an adult flowering individual.
The corm has buds that allow it to be divided into parts with 1-2 eyes and grown as a regular plant. This method allows you to get more corms and children, which is especially important for varieties that produce few children, but are very valuable for their decorative properties.
Propagation by cuttings. A cutting is a section of a stem with leaves or buds, a root with adventitious buds, or a leaf separated from the mother plant. The cuttings are respectively stem, root and leaf.
In ornamental herbaceous plants, the stem cuttings are herbaceous. Only roses and azaleas are propagated by semi-lignified (green) cuttings. Herbaceous cuttings are used to propagate phlox, chrysanthemums, carnations, peonies, carpet plants, hydrangea, pelargonium, as well as many evergreen (indoor) plants - tetrastigma, ganura, scindapsus, Kalanchoe, bellflower, zebrina, peperomia, etc. Such perennials can be propagated by herbaceous cuttings annuals, such as ageratum, salvia, petunia, etc. Tetrastigma, columna, aucuba, beloperona, codiaum, monstera, philodendron, etc. are propagated by semi-lignified stem cuttings.
Peonies can be propagated by root cuttings - its long thickened roots, which fall off when dividing the bush, are divided into parts and rooted in boxes in open ground in a semi-shaded place. This method is suitable for the roots of old plants that may have adventitious buds. The best time is spring; by autumn the roots can give rise to young shoots. For peony, this method is more productive. Dracaenas, arrowroots, and aralias can be propagated by root cuttings.
Many species are propagated by leaf cuttings. This is most often used in begonia, achimenes, Uzumbara violet, and sansevieria. Adventitious roots of leaves are formed mainly on the morphologically lower side of the leaf, in places where large veins branch; buds and then shoots appear on the upper side of the leaf. Propagation of lilies by leaf cuttings is propagation by scales of bulbs (scales are metamorphosed leaves) and the actual leaves located on the peduncle. For propagation, young upper stem leaves are taken. The greatest effect is obtained when planting leaves in greenhouses. Leaves and leaf scales are planted at half their length.
An option for propagation by leaf cuttings is the option of propagation by a leaf with an axillary bud, for example in phlox, aucuba, hydrangea, roses. In evergreen indoor crops, it is important to take into account the phase of plant development, since leaf cuttings taken from a plant in the active growth phase develop vegetative buds, and those taken from a plant ready for flowering develop flowering buds (Achimenes). Technologies for propagation by leaf cuttings, as a rule, are given for specific plants.
Reproduction by grafting. This method is typical, as mentioned above, for roses and lilacs, which are cultivated for cutting indoors. In this case, they can be conditionally classified as flower crops, and not as open ground shrubs. These plants are propagated using types of grafting such as budding and “bark cuttings.” Budding is carried out at a time when the bark is well separated - during the period of active sap flow in the spring (ascending current) and in August (descending current). As a rootstock (plant on which to graft) for roses in the Non-Black Earth Region, dog rose is used (for plants grown for open ground and for rose crops in the greenhouse) and Indian rose (for rose crops in the greenhouse). Eyes and cuttings are taken from varietal plants. When budding, a T-shaped cut is made on the rootstock, into which an eye is inserted. When grafting “by the cutting by the bark,” the cutting, whose lower, basal end is cut obliquely, is inserted into a longitudinal cut made on the bark of the rootstock. In this case, the rootstock should be somewhat thicker than the cuttings. When vegetative propagation, especially when cuttings, cuttings from plants are cut in different ways, depending on the biology of the plants. Thus, cuttings of remontant carnation are collected all year round, breaking out young shoots from the leaf axils. At the same time, they always keep in mind that the quality of cuttings taken in summer and winter will be different - summer cuttings are more powerful and heavier. In azaleas, especially in difficult-to-root varieties, cuttings are cut from plants up to six months old at the first pinching in order to form a bush. Chrysanthemum cuttings are cut from the mother plant, which is in a long day mode. Evergreen, so-called indoor plants, are cut from spring or in the active growth phase.
For all types of cuttings taken from a plant at any time and in any way, it is necessary to create especially favorable environmental conditions. The temperature of the substrate in the rooting zone, where the basal part of the cutting is placed, should be 4-5 0 C higher than the temperature above the substrate in order to ensure the flow of nutrients into the basal part and thereby improve root formation, and in the air to reduce the transpiration of cutting tissue. If the substrate temperature is insufficient, under-shelf heating is turned on, which is provided in all modern greenhouses. The substrate temperature for most crops should be in the range of 20-25 0 C, and the ambient air temperature - 18 - 20 0 C. To reduce transpiration, the cuttings are covered with a waterproof film, stretching it over the frame over the cuttings. The optimal ratio of the listed factors affecting the rooting of cuttings is created under conditions of so-called artificial fog. Artificial fog is produced using special spraying units equipped with nozzles that provide droplet spray of water jets. In the State Botanical Garden of the Russian Academy of Sciences, the installation of artificial fog provides a very fine, mist-droplet spray (particle size 146 - 360 microns) and can operate continuously or intermittently (20 seconds on, 1 minute break). With artificial fog, 100% illumination is maintained, which is very important for photosynthesis of cuttings. With the help of artificial fog, high rooting of cuttings in difficult-to-root species is achieved. In principle, easily rooted species do not need artificial fog, but it is used to speed up rooting and improve the quality of the resulting root system.
1.4. Where is the vaccine used?
Introduction
Goal: find out what vegetative propagation is and study it.
1. Consider the basis of vegetative propagation.
2. Consider how vegetative propagation is carried out.
3. Study methods of artificial vegetative propagation.
4. Find out where vegetative propagation is used.
What is the basis of vegetative propagation?
Vegetative propagation - This is a property that distinguishes plant organisms from animals. The basis of vegetative propagation is the ability of plants to regenerate. Regeneration- This is the renewal of the whole organism from its parts due to cell division. As a result of vegetative propagation, a large number of identical descendants appear, which are a copy of the parent plant. All together they form clone - offspring that arises from one individual through vegetative propagation. Cloning allows a person to preserve the varietal characteristics of many cultivated plants. Today, a cell and tissue culture method has been developed, thanks to which plant clones are obtained by growing them on a nutrient medium from a single cell or group of cells. Cloning allows you to grow valuable or rare plants from individual cells (for example, growing ginseng), quickly obtaining a large plant mass to extract certain useful substances from it. So, the basis of vegetative propagation is regeneration.
1.2. How is natural vegetative propagation carried out?
As you already know, plants have modified organs - bulb., rhizome, tuber etc., by which vegetative propagation is carried out. Bulbs lilies, daffodils, tulips, etc. multiply. And plants such as wheatgrass, lily of the valley, sow thistle can quickly cover a large area with the help rhizomes The division and transformation of parts of the rhizome into independent plants can be facilitated by animals living in the soil (for example, moles, mice, beetles), etc. Some plants reproduce tubers(potatoes, corydalis, Jerusalem artichoke). Plants often reproduce by above-ground shoots. Thus, wild strawberries grow several creeping shoots during the summer - mustache, on the tops of which young shoots and adventitious roots develop. Over time, the tendrils dry out and die, and new plants begin to live on their own. Poplar, willow, and aspen can reproduce by rooting branches. The wind breaks the branch, carries it to damp soil - and now it has already taken root and given rise to a new plant. In many woody plants (for example, cherry, raspberry, lilac) reproduction is common root suckers. So, natural vegetative propagation occurs with the help of parts of vegetative organs and their modifications.
What are the methods for artificial vegetative propagation of cultivated plants?
For vegetative propagation of plants, people often choose the same methods by which wild species propagate: strawberries are propagated with a mustache, potatoes are propagated with tubers, etc. Lilacs and raspberries are propagated by root suckers, and berry crops are propagated by dividing a bush. In plant growing, special methods of vegetative propagation are also used - cuttings And vaccination.Cuttings -This is reproduction by parts of a shoot or root separated from the body. Handle called a part of a shoot or root with several buds. Stem cuttings, that is, by parts of a shoot with several buds, tradescantia, grapes, etc. are propagated. By parts of roots with several adventitious buds - root cuttings - Raspberries and plums are propagated. Plants such as begonia, lemon, propagate leaf cuttings - separate leaves on which there are adventitious buds that give rise to adventitious roots and shoots. Graft- Thisthe fusion of a cutting from one plant (scion) with another rooted plant (rootstock). There are about 100 different vaccination methods, which are divided into three types: inoculation(budding) - scion grafting, having only one bud, taken with a thin layer of bark (for example, roses); grafting by cuttings(copulation) - grafting obliquely a cut scion cutting with several buds (for fruit trees, etc.); grafting by proximity(ablation) - grafting in which the scion is not separated from the parent plant until it has completely fused with the rootstock (for example, in grapes). So, artificial vegetative propagation is carried out using parts of vegetative organs or their modifications, using special propagation methods- cuttings and grafting.
1.4 .Where is the vaccine used?
Fruit plants - apple trees, citrus fruits, grapes and many others - reproduce mainly vegetatively - by grafting. Plantations of such industrial crops: aromatic (mint), cinchona, are created thanks to the ability of these plants to reproduce vegetatively.
Forestry has also long used this feature of the propagation of woody plants. In place of felling of oak, birch, ash, maple, shoots appear the very next year, and after two or three years a young low-trunk forest is already growing.
Aspen conquers large territories, often displacing species such as oak, spruce, pine, etc., due to its ability to quickly reproduce with the help of root shoots. Species such as willows and poplars are propagated on large plantations exclusively by cuttings.
Conclusion
As a result of the work done, we learned what vegetative propagation is, learned methods of vegetative propagation and learned where it is used.
15. Seed and vegetative methods of propagation. The value of each method for growing ornamental plants.
Arboriculture. When growing ornamental tree species, seed and vegetative propagation methods are used. Seed propagation of most ornamental trees and shrubs remains the main method due to technological simplicity, the possibility of mechanization and overall cost-effectiveness. In addition, the seed propagation method is the only way of plant introduction, which has received the greatest development in green construction. The use of vegetative propagation methods in ornamental tree growing is due to the following:
the decorative features of a large number of ornamental and garden forms and varieties (roses, lilacs, clematis, rhododendrons, thujas, etc.) are not reproduced at all or are reproduced in a very small number of plants when propagated by seed;
the presence of species that are difficult to propagate by seed under production conditions due to the fact that their seeds quickly lose their viability (poplar, willow seeds) or are often of poor quality (seeds of mock orange, actinidia, grapes, some spirea and honeysuckle);
propagation of introduced species that do not set seeds at all;
to speed up the introduction into culture of plants that have not yet entered the fruiting season;
to extend the propagation period (terms) when using both seed and vegetative propagation methods for a specific species or variety.
The main and most valuable property of seed propagation is the ability to obtain plants based on individual variability that are more adapted to certain environmental conditions. This valuable property of seed progeny is also important during the introduction of plants. It should be noted that with prolonged vegetative propagation, degeneration of plants is possible. This happens if the material is taken from old mother plants. In plants from cuttings and grafts, long-term preservation of the age characteristics or developmental pattern of the mother plant is often observed. During generative reproduction, complete rejuvenation of the body occurs. The same phenomenon is observed when plants propagate by pieces of meristem tissue. On the contrary, when branches from old trees are used for propagation, a certain stage of development and aging continues without rejuvenation. However, plants, having plasticity and the ability to rejuvenate organs and tissues, can restore their vital functions to some extent. This is especially evident in the rejuvenation of plants by cutting branches to the basal part and subsequent propagation by cuttings or layering. It is this phenomenon that can explain that aspen plants obtained from leaf cuttings do not differ from seed plants.
Seed propagation. We should strictly avoid collecting seeds from random trees and shrubs that are not typical in terms of the clearly expressed qualities that interest us. Plants that are damaged as a result of diseases and adverse effects of the urban environment and are not resistant to pests should not be used for collecting seeds. Particular attention should be paid to the need to prohibit the use of seeds from trees with signs of degeneration and old age. The offspring obtained from them are characterized by fragility, poor growth, and poor resistance to pests and diseases.
During seed propagation of decorative forms, the heritability of individual traits depends on the meteorological conditions of the year and pollination conditions. With free pollination, the characteristic features of purple-leaved forms appear in 60% of plants, variegated - in 20% and dissected-leaved - in 30%. Therefore, a preliminary test for the transmission of certain characteristics to offspring can be established for individual species and forms only experimentally. Propagation of forms and species by seeds should be considered justified if the trait of interest appears in 40% of the plants.
Vegetative propagation. Vegetative propagation in ornamental plant growing primarily pursues the goal of obtaining plants with certain qualities: crown shape, color and shape of leaves, doubleness of flowers, etc., which are not transmitted to offspring during seed propagation or are transmitted to a very small number of specimens.
The yield of decorative forms can be increased if pollination is allowed only between plants of a given form, and in no case with plants of the main species. But when propagating varieties, this way is also ineffective: the diversity of offspring is very great. Therefore, in practice, only vegetative propagation methods are used to propagate forms and varieties.
The basis of vegetative propagation of plants is the natural ability to regenerate that part of the mother (uterine) plant that is used for vegetative propagation. Vegetative propagation - grafting and cuttings.
The essence of vegetative propagation is to obtain from individual vegetative organs of plants - roots, stems, leaves - or from their parts independent new plants with the characteristics and properties of the mother plant. The basis is the ability of living tissues to regenerate the whole plant, that is, to restore lost parts.
You can get new plants without separating parts (shoots, roots) from the mother plant before they take root and from separated small parts; Recently, plant propagation by culture of meristem tissue has become widespread.
Reproduction by unseparated parts : layering, root suckers, stolon suckers (rhizomatous, dividing bushes
Reproduction by parts separated from the plant: The separated parts of plants from which new independent plants must develop are called cuttings. Propagation by separated parts is carried out by root, lignified stem, semi-lignified (green) stem, and leaf cuttings. In ornamental tree growing, stem cuttings are used mainly, root cuttings are used less, and leaf cuttings are not used at all. New plants from stem cuttings are obtained by rooting them or grafting them onto other plants (rootstock).
Floriculture. One of the mandatory properties of a living organism is reproduction of offspring, reproduction. In nature, there are two ways of plant reproduction: sexual and asexual.
Sexual reproduction of plants is reproduction by seeds formed during the fusion of specialized cells - gametes. As a result, new individuals with richer hereditary capabilities appear. For many plants, seed propagation is the only method of propagation. This applies primarily to annual plants. But in the practice of growing flower products, many perennial plants grown as annuals are also obtained from seeds - ageratum, verbena, lobelia, petunia, etc. Many greenhouse and industrial crops are also propagated by seeds - cyclamen, cineraria, gloxinia, calceolaria, as well as open ground perennials - aquilegia, multileaf lupine, alyssum, lilies, primroses, etc. Modern heterotic F 1 hybrids are also propagated by seeds. The main disadvantage of seed propagation is that with it only self-pollinating plants retain their varietal qualities. In cross-pollinating varieties (zinnia, tagetes), the characteristics of the variety are not always preserved without special selection. The latter is also typical for hybrid plants, the same F 1 hybrids. At the same time, seed propagation makes it possible to obtain new valuable plants that differ in quality from the parent ones.
Asexual reproduction in botany is divided into two main forms: vegetative and actually asexual. An example of asexual reproduction itself is reproduction by spores in ferns. Vegetative propagation is very widespread in ornamental herbaceous plants in nature and in cultivated plants. In flower crops, vegetative propagation is carried out by parts of vegetative organs - roots, stems, leaves and metamorphosed organs (bulbs, rhizomes), as well as groups of cells (microclonal propagation, meristem culture). All these methods are specifically discussed for individual crops in the relevant sections. The advantage of vegetative propagation is that it allows you to recreate and preserve plants with certain decorative qualities inherent in the original maternal individual.
In higher plants, which include flower crops, the forms of vegetative propagation are most diverse: by dividing the bush, tubers, bulbs, corms, rhizomes, cuttings. Reproduction by layering, offspring and grafting is less commonly used. The latter method is used for tree crops of roses, which, as beautifully flowering plants, are used in flower decoration (parterres, mixborders, borders). Vaccinations are also used in cactus culture. Vegetative propagation is used for perennial plants.
Vegetative propagation is of great practical importance, as it guarantees the production of offspring that fully retain the properties and characteristics of the mother plant; Flowering in a number of species occurs earlier than during seed propagation; Some plants here do not produce seeds (Japanese anemone, etc.).
Methods of vegetative propagation .
1) Reproduction by rhizomes. This method is used to propagate rhizomatous plants - irises, larkspur, chrysanthemums, lilies of the valley, goldenrod, etc. The rhizome is an underground stem; it has dormant buds that give rise to new shoots. Rhizomatous plants therefore grow very quickly, take root well after transplantation and develop well. The dug up bush is cut into pieces with a shovel or knife, or you can break it with your hands, trying to cause as little injury to the plant as possible. Each part of the bush should have 3-4 buds and its own roots. Plants that bloom in spring are best divided in autumn, those that bloom in summer and those that bloom in autumn are best divided into spring.
2) Reproduction by tubers. Tubers are of stem origin (modified stems) and root origin - modified roots. A distinctive feature of stem tubers from root ones is the presence of dormant buds on them, which allows them to be propagated by division (artichoke - tubers die off after a year; tuberous begonia, cyclamen - tubers live for several years). Root tubers that do not bear buds are separated from the part of the root collar where dormant buds (dahlias) are located.
3) Reproduction by bulbs and corms. Bulb plants are divided into 2 groups based on the structure of the bulbs: the first has scaly bulbs (lilies), the second has filmy bulbs (tulips, daffodils, hyacinths, etc.). In filmy and scaly bulbs, baby bulbs are formed from the axillary buds, with which plants reproduce. Lilies can also be propagated by bulb scales, and some species form aerial bulbs in the leaf axils.
Gladioli and crocuses reproduce by corms; they can be divided into parts, each of which should have 1-2 buds.
4) Reproduction by mustache(stem shoots growing horizontally and forming new rooting plants at the nodes) is typical for Indian strawberry, periwinkle, tenacious, fragrant violet, etc. Rooted specimens in spring or autumn are separated from the mother ones and planted in a new place.
5) Root suckers propagated by plants on the roots of which there are adventitious buds capable of developing into above-ground shoots (bindweed, dracaena, hops, etc.). The offspring are separated from the mother plant and planted.
6)Cuttings- one of the most common methods of plant propagation. Any part separated from a plant intended for vegetative propagation is called a cutting. Cuttings are divided into stem, root and leaf. Stem cuttings, in turn, are: green, harvested with immature wood and unformed leaves, intended for propagation of biennials, perennials, potted crops and certain types of shrubs; semi-lignified, characterized by formed leaves and incompletely ripened wood (roses, lilacs, indoor jasmine, fuchsia, etc.); lignified, characterized by durable, well-formed wood without leaves (willow, jasmine, spirea, etc.).
Most rhizomatous plants (peonies, phlox, irises, oriental poppy, etc.) are propagated by root and rhizomatous cuttings. In most cases, greenhouse plants (Rex begonia, gloxinia, sanseveria, echeveria, etc.) are propagated by leaf cuttings.
It is better to carry out cuttings in greenhouses, greenhouses or in a specially protected area with well-fertilized and treated soil. Planting is carried out in autumn or spring. The cuttings are covered for the winter. In the first year of plant life, flowers and inflorescences are plucked out, giving the opportunity to better develop vegetative organs.
7) Reproduction by grafting– transplanting a cutting or eye from one plant (scion) to another (rootstock). This method is used to propagate roses, azaleas, lemons, cacti, etc. For grafting to be successful, it is necessary to combine living cells capable of dividing, i.e. at least in some areas, the cambium (tissue between the phloem and the wood) of the scion should coincide with the cambium of the rootstock.
Vaccination should be carried out during the period when the scion buds are dormant. There are several methods of vaccination. They are quite widely described in the horticultural literature. The most commonly used method is budding (by eye). It is performed in the spring (with the germinating eye) and in the summer (July - August) with the dormant eye.
Vegetative propagation involves separating the viable parts of the vegetative body of plants. The isolated part lives independently for a certain time and creates new organs, primarily those that are missing (roots form on the isolated part of the above-ground shoot, above-ground parts develop on underground shoots).
In fact, vegetative propagation is somehow connected with regeneration. In some cases, senile decay of an individual may occur, when the parts that have separated do not develop new growths and parts of the clone quickly die off, showing low viability. This phenomenon should not be considered vegetative propagation.
The ability for vegetative reproduction is very characteristic of plants at all levels of organization (as well as fungi and lichens), in contrast to animals, where this form is found only in some groups of lower organisms. During vegetative propagation, the hereditary characteristics of the mother plant are completely transmitted to the daughter plants. The set of new individuals that arose from the original maternal vegetative path is called a clone. When a clone is formed, daughter individuals, as a rule, bear the imprint of the age state of the mother plant and, when separated, are in the same age state as it. However, especially in the presence of special organs of vegetative propagation, significant rejuvenation of parts of the clone occurs. Vegetative propagation is possible primarily due to the presence of axillary or accessory buds and the pronounced ability of shoots to form additional roots. The frequency of natural vegetative propagation in different plant species is different - more often annually or once every two to three years, sometimes vegetative propagation can be repeated after a long period (for example, the pine tree reproduces vegetatively once every five years, linden - once every 100-150 years).
Natural vegetative propagation can be carried out in various ways. The simplest way is to divide the cell into two, which is typical for unicellular and separate groups of colonial organisms. In lower plants, vegetative propagation also occurs due to fragmentation or disintegration of the plant. In some types of algae, vegetative reproduction can be carried out by bubbles. Vegetative reproduction of fungi can occur by hyphae and oidiames, and lichens - by isidiums and sorediames. Vegetative propagation of higher plants is carried out by brood buds, layering, root suckers, rhizomes, tubers, bulbs, and above-ground shoots.
Brood buds are specialized organs of vegetative propagation in some ferns and flowering plants. They are formed in large numbers in the leaf axils, on leaves, in inflorescences, etc. and fall off even before development or fall onto the soil already in the form of seedlings, reminiscent of seedlings that develop from seeds (such buds, for example, appear in each notch of a Kalanchoe Degremon leaf, on the leaves of sundews). In some cases, brood buds can turn into bulbs, for example, in the cibulinum lily, bulbista, and spring millet. In the knotweed viviparous, the brood buds are modified into vesicles of pagonal origin and immediately germinate into small plants. This phenomenon is sometimes called a false live birth.
In some species, flowers in inflorescences turn into specialized organs of vegetative reproduction. Many types of wild onions produce bulbs instead of flowers, which fall off and form new plants. Bulbs appear instead of ears and in Thin-legged bulbous, which immediately turn into small vegetative shoots.
Specialized organs of vegetative propagation are overwintering buds or hibernaculae, characteristic of some aquatic plants (for example, arrowhead, water cutter, gillweed, blister). They form at the ends of underwater shoots, which rot in the fall. Hibernaculas overwinter at the bottom of reservoirs, and in the spring they emerge and grow into new plants.
Vegetative propagation of flowering plants most often occurs with the help of long or short rhizomes, above-ground creeping shoots - lashes, tendrils, stolons, as well as bulbs and corms. The internodes of above-ground shoots gradually die off and new plants, losing connection with the mother, separate and become independent independent plants. Creeping shoots serve primarily to capture territory.
The simplest way of vegetative propagation is to separate shoots from the mother plants that develop into a new individual (for example, in the spring, from several copies of duckweed, a small aquatic plant that overwintered and began to intensively reproduce vegetatively, such a number of new individuals are formed that in a matter of weeks they cover the surface of a reservoir with an area of 0 .5 ha).
In root-parous plants (for example, poplar, lilac, willow, plum, milkweed, thistle, dandelion, raspberry), the organs of vegetative propagation are adventitious buds that develop into above-ground shoots - root shoots. After the roots that connect the root shoots to the mother plants die off, the new plants become independent.
All natural methods of vegetative propagation are used in the artificial propagation of cultivated plants. Artificial vegetative propagation is used if you need to quickly propagate a particular plant or its individual variety, while maintaining its properties, and obtain a large number of planting material. Such propagation is also used when a plant under cultural conditions does not form seeds or produces few or poor quality ones. Artificial vegetative propagation is most appropriate for the reproduction of complex hybrid varieties (for many cultivated plants it is the only way to preserve valuable varietal characteristics and properties).
In the practice of artificial vegetative propagation, several common methods are used.
The division of bushes is the closest to natural and is widely used in floriculture, horticulture and gardening. Ornamental shrubs and perennial herbs are propagated by dividing bushes and rhizomes. To speed up the natural process of decay of the bush, it is cut into pieces and transplanted to new places. Some stone fruit (for example, cherry, plum) and ornamental (for example, bird cherry) trees and berry bushes (for example, raspberries) are propagated by root suckers. Their sprouts, which look like young plants, are dug up and transplanted to new places. Certain types of woody plants reproduce by transplanting - rooted branches that are bent in an arc to the soil and covered so that the tip of the shoot remains above the soil surface. Sometimes cuts are made on the branches, thereby causing the accelerated formation of additional roots, and the cut branches are passed through pots with soil. After rooting, the branches are cut off and planted in new places. Gooseberries, currants, hazels, grapes, azaleas, etc. are propagated by transplanting. Plants can be propagated using cuttings. Live is any part of the plant cut off from the plant that is used for vegetative propagation. Many fruit and ornamental plants are propagated by cuttings in open and closed ground. Cuttings can be parts of rhizomes, shoots, leaves or parts thereof. Pagon-like cuttings can be propagated, for example, currants, willow, poplar, ficus, fuchsia; rhizome cuttings can be used to propagate root and parsnip plants, for example, raspberries, horseradish, roses; For example, begonias, gloxinias and Saintpaulias propagate well from leaf cuttings. In many plants, at the lower end of the cuttings, a growth of parenchyma tissue called callus is first formed. Here the traumatic meristem is formed, and later the cambium. Thanks to it, additional roots develop. After rooting of pagon-like cuttings, new shoots develop from axillary buds; in the case of rhizomatous and leaf cuttings, the development of new shoots occurs from adventitious buds.
Various methods of grafting or transplantation are widely used. Grafting is the transplantation of a part of a living plant with one or more buds to another with subsequent fusion. The part of the plant that is transplanted is called a scion. The plant being grafted onto is called a rootstock or wildflower. In grafted plants, the scion receives water with minerals, as well as organic substances, from the rootstock. Grafting is used in the propagation of fruit trees, which are very difficult to form adventitious roots, and when propagated by seeds they lose valuable varietal properties. Practitioners know more than 100 methods of grafting, but in all cases, cuttings or buds are taken from the mother plant. Clothes use the already existing, well-developed root system of the rootstock, which is often wildflowers grown from seeds, but it can also be adult plants with damaged crowns. Annual branches are most often used as cuttings. Live grafting with the same diameter as the rootstock is called copulivannyam. In this case, the live bait and the rootstock are cut obliquely, tightly applied and tied. When the diameter of the rootstock is larger than that of the scion, grafting is carried out in the appendices, behind the bark, or in the root chip in different ways. Budding is the transplantation of a bud or eye of a scion under the bark of a rootstock, on which a T-shaped incision is made. The eye is taken from the middle part of the shoot along with the remains of bark and wood. In addition to the cell, they leave the petiole of the cut leaf in the axil of which it formed. Budding is one of the most used grafting methods in horticulture (up to 90-95% of all scions are obtained by budding). This method requires less material for grafting, it is a simpler technique, gives a higher percentage of survival rate, and is faster in merging parts. A prerequisite for successful grafting is the combination, at least partial, of the cambium of the scion and the rootstock. To do this, the scion is tightly tied to the rootstock, and the contact area is covered with garden pitch to prevent microorganisms from entering the wound. A close exchange of substances and mutual influence are established between the rootstock and the scion. The plant obtained by grafting cannot be absolutely identical to the mother plant, but it is not very changed, and generally retains its varietal characteristics and qualities well. The survival rate of the scion and rootstock largely depends on the compatibility of tissues, the relationship of plants, and their systematic proximity. The best results are achieved when grafting plants of similar varieties or forms within the same species; grafting species from the same genus is more difficult, and even more difficult is grafting between families.
In recent decades, such an effective and cost-effective method of vegetative propagation as clonal micropropagation of plants in culture has become increasingly widespread. It is a mass non-sexual propagation of plants in cell and tissue culture, in which all descendants are genetically identical to the original specimen. The method is based on the ability of cells to give rise to a whole plant organism. There are two types of clonal micropropagation of plants in in vitro culture: activation of the development of apical meristems of dormant buds and the production of organized structures (buds or somatic embryos) anew from individual cells and tissues, which are previously isolated from certain plant organs and cultivated for a long time on artificial sterile sources. Isolated one or more cells acquire the characteristics and properties of cells. Even single cells are isolated using tissue culture, from which whole plants are grown on artificial nutrient media, flower and bear fruit. This method makes it possible to obtain several thousand times more ideal homogeneous planting material in a short period than with traditional vegetative propagation. At the same time, the planting material is completely revitalized, since the cell culture is devoid of the presence of pathogenic microorganisms. Product quality also improves. The tissue culture method makes it possible to propagate plants that are difficult or impossible to reproduce vegetatively (for example, ginseng).