Vegetative propagation of cultivated and wild plants. What are the methods for artificial vegetative propagation of cultivated plants? What is the basis of vegetative propagation
Vegetative propagation is propagation by parts of plants: shoots, roots, leaves, or groups of somatic cells of these organs. Such reproduction is one of the adaptations for the formation of offspring where sexual reproduction is difficult.
The essence of vegetative propagation
The vegetative method is based on the regenerative ability of plants. This type of propagation is widespread in nature and is often used in crop production. During vegetative propagation, the offspring repeat the genotype of the parent, which is very important for preserving the characteristics of the variety.
In nature, vegetative propagation occurs by root suckers (cherry, aspen, sow thistle, thistle), layering (macrum, wild grapes), tendrils (strawberries, creeping buttercup), rhizomes (wheat grass, reed), tubers (potatoes), bulbs (tulip, onion ), leaves (bryophyllum).
All natural methods of vegetative propagation of plants are widely used by humans in the practice of plant growing, forestry and especially horticulture.
Natural methods of reproduction
Reproduction by layering used for growing currants, walnuts, grapes, mulberries, azaleas, etc. To do this, a one- or two-year-old shoot of the plant is tilted into a specially dug groove, pinned and covered with earth so that the end of the shoot remains above the soil surface.
Even without a groove, you can lay out the shoots in radii on a leveled soil surface, pin them and cover them with earth. Rooting goes better if cuts are made in the bark under the bud. Inflow to cuts nutrients stimulates the formation of adventitious roots. Rooted shoots are separated from the mother plant and planted.
Berry bushes are also propagated by dividing the bush into several parts, each of them is planted in a new place.
Root suckers they propagate roses, lilacs, quince, rowan, hawthorn, raspberries, blackberries, cherries, plums, horseradish, etc. By deliberately injuring the roots, gardeners cause increased formation of root suckers. They are replanted with part of the mother plant.
Artificial ways
Cuttings called parts of a shoot, root, or leaf cut off for this purpose. Stem cuttings are one- and two-year-old shoots 20-30 cm long. Cut cuttings are planted in the soil. At their lower end, adventitious roots grow, and new shoots grow from the axillary buds. To increase survival rate, before planting, the lower ends of the cuttings are treated with solutions of growth stimulants. Many varieties of currants, gooseberries, grapes, roses, etc. are propagated by cuttings.
Leaf cuttings Begonias, Uzambara violets, lemon, etc. are propagated. The leaf cut with the cuttings is placed with the underside on wet sand, making an incision on the large veins to accelerate the formation of adventitious roots and buds.
Root cuttings- sections of lateral roots 10-20 cm long are harvested in the fall, stored in sand and planted in greenhouses in the spring. Used for propagation of cherries, plums, raspberries, chicory, apple trees, roses, etc.
Propagation by grafting is widely used in gardening.. Grafting is the merging of a bud or cutting of one plant with the stem of another growing in the soil. The cutting, or bud, is called the scion, and the plant with the root is called the rootstock.
Budding called grafting a bud with a piece of wood. In this case, an L-shaped incision 2-3 cm long is made on the stem of a one- or two-year-old seedling, and a horizontal one - no more than 1 cm. Then the edges of the bark are carefully folded back, and a peephole cut with a piece of wood is inserted under the bark. The peephole is pressed tightly against the wood with bark flaps. The grafting site is tied with a washcloth, leaving the bud open. After fusion, the stem of the rootstock above the eye is removed. Budding is carried out in summer and spring.
Copulation- grafting a one-year-old cutting with several buds. In this case, the scion and rootstock should be the same thickness. They make identical oblique cuts. The scion is applied to the rootstock so that their tissues coincide (the matching of the cambium is especially important) and carefully tied with a washcloth. If the thickness of the rootstock and scion is different, grafting is done into the split, behind the bark, into the butt, etc.
Importance in Agriculture
Artificial vegetative propagation of plants has great importance V agriculture. It makes it possible to quickly obtain a large amount of planting material, preserve the characteristics of the variety and propagate plants that do not form seeds.
Since vegetative propagation involves mitotic division of somatic cells, the offspring receives the same set of chromosomes and completely retains the characteristics of the mother plants.
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 graftings, long-term preservation is often observed age characteristics or the developmental pattern of the mother plant. 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 open pollination characteristic features purple-leaved forms appear in 60% of plants, variegated - in 20% and dissect-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. Should be considered justified propagation by seeds forms and species if the trait of interest appears in 40% of 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 from seeds, many perennials, bred as annuals - ageratum, verbena, lobelia, petunia, etc. Many greenhouse and industrial crops are also propagated by seeds - cyclamen, cineraria, gloxinia, calceolaria, as well as perennials open ground- 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 widely represented in ornamental plants. herbaceous plants in nature and 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.
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, reproduction vegetable crops 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 top part bulbs are “shoulder-deep”; in the cross section you will see the rudiments, into which you will need to disassemble the bulb. When they have dried 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 good harvest shallots, stacked onions and garlic: Before sowing the bulbs, size them 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 form 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.
Reproduction of such vegetable plants as potatoes, Jerusalem artichoke and stachys is carried out by dividing the tubers, based on biological features 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.
Practicing plant propagation 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 root formation, use heteroauxin, for which dissolve 2 tablets in a glass 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.
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 obtain 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 take over large area by using 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, humans often choose the very methods by which they reproduce. wild species: 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 the 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.
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. Phlox, chrysanthemums, carnations, peonies are propagated by herbaceous cuttings, carpet plants, hydrangea, pelargonium, as well as many evergreen (indoor) plants - tetrastigma, ganura, scindapsus, kalanchoe, bellflower, zebrina, peperomia, etc. Perennial annuals such as ageratum, salvia, petunia, etc. can be propagated by herbaceous cuttings. Tetrastigma, Columnea, Aucuba, Beloperona, Codium, Monstera, Philodendron, etc. are propagated by 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 a special favorable conditions external environment. 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, the under-rack heating is turned on, which is provided to 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.
