Methods of asexual reproduction

1) Division in two(amoeba and ciliates are divided by transverse division, green euglena is divided by longitudinal division).

2) Sporulation

• Spores are specialized haploid cells. Spores of fungi and plants serve for reproduction. Fungal spores are formed by mitosis, and plant spores are formed by meiosis.
• Sp bacterial pores do not serve for reproduction, because One spore is formed from one bacterium. They serve to survive unfavorable conditions and dispersal (by wind).

3) Budding: daughter individuals are formed from outgrowths of the body of the mother organism (buds) - in coelenterates (hydra, sea anemone, corals, jellyfish), yeasts - unicellular fungi

4) Fragmentation: The mother organism is divided into parts, each part turns into a daughter organism. (Spirogyra, coelenterates, starfish.) Based on regeneration.

5) Vegetative propagation of plants: reproduction using vegetative organs:

• roots – raspberries
• leaves - violet
• specialized modified shoots:
• bulbs (onion, tulip)
• rhizome (wheatgrass, iris, lily of the valley)
• tuber (potato, Jerusalem artichoke)
• mustache (strawberry)

Methods of sexual reproduction

1) With the help of gametes, sperm and eggs. Hermaphrodite is an organism that produces both female and male gametes (most higher plants, coelenterates, flatworms and some annelids, mollusks).

2) Conjugation green algae Spirogyra: two filaments of spirogyra come together, copulation bridges are formed, the contents of one filament flow into the other, one filament is formed from zygotes, the second from empty shells.

3) Conjugation in ciliates: two ciliates approach each other, exchange reproductive nuclei, and then separate. The number of ciliates remains the same, but recombination occurs.

4) Parthenogenesis: a child develops from an unfertilized egg (in aphids, daphnia, bee drones).

Are the statements true?

Sporulation is characteristic of hydra. -

Green euglena reproduces by cell division. +

Asexual reproduction involves one individual. +

A hermaphrodite is a bisexual organism. +

Mosses and ferns reproduce by budding. -

In asexual reproduction, the offspring are genetically very different from the parent organisms. –

Protozoa are characterized by halving. +

Reproduction is the process of reproducing others like themselves. +

Hydra reproduces by budding. +

Grapes, currants, gooseberries, and willows are propagated by cuttings. +

Asexual reproduction involves one individual. +

37 tests on the topic (Zubrominim website)

1. During parthenogenesis, the organism develops from
A) zygotes
B) vegetative cell
B) somatic cell
D) n unfertilized egg

2. In agricultural practice, vegetative propagation of plants is often used to
A) get a high yield
B) increase their resistance to pests
C) increase their resistance to disease
D) get mature plants faster

3. The daughter organism is most similar to the parent during reproduction
A) sexual
B) seed
IN ) asexual
D) with alternating generations

4. In agricultural practice, the vegetative method of plant propagation is often used to
A) to achieve the greatest similarity of the offspring with the parent organism
B) achieve the greatest difference between the offspring and the original forms
C) increase plant resistance to pests
D) increase plant resistance to diseases

5. The daughter organism is more different from the parent organisms during reproduction
A) vegetative
B) using spores
B) sexual
D) budding

6. Gametes with a haploid set of chromosomes participate in reproduction
A) using spores
B) vegetative
IN) sexually
D) budding

7. The method of reproduction of aphids, ants, wasps, in which a daughter organism develops from an unfertilized egg, is called
A) parthenogenesis
B) spore
B) budding
D) vegetative

8. Reproduction, in which a daughter organism appears without fertilization from the cells of the body of the mother organism, is called
A ) parthenogenesis
B) sexual
B) asexual
D) seed

9. Parthenogenesis is characteristic of
A ) aphids
B) worms
B) bacteria
D) protozoa

10. Parthenogenesis is the process of development of an organism from
A) unfertilized egg
B) somatic cells of the mother
B) haploid spores
D) a zygote formed as a result of the fusion of gametes

11. The method of propagating raspberries using root suckers is called
A) generative
B) budding
IN) vegetative
D) seed

12. The reproduction of some insects through parthenogenesis promotes
A) increasing the viability of offspring
B) improving adaptation to the environment
C) enrichment of the heredity of offspring
G) rapid increase in animal numbers

13. Gametes are specialized cells with the help of which
A) sexual reproduction
B) vegetative propagation
B) budding
D) regeneration

14. The sexual method of reproduction includes the process
A ) parthenogenesis in bees
B) budding in yeast
B) spore formation in mosses
D) regeneration in freshwater hydra

15 During the sexual reproduction of organisms, offspring experience
A) complete reproduction of parental characteristics and properties
B) p recombination of traits and properties of parent organisms V
C) maintaining the number of females
D) predominance of males

16. During sexual reproduction, as opposed to asexual
A) the daughter organism develops faster
B) population numbers increase
C) more females are born
G ) genetic diversity of offspring increases

17 Asexual reproduction occurs in
A) flowering plants with seeds
B) birds laying eggs
IN) hydr budding
D) coniferous plants with seeds

18 The set of genes in a daughter organism differs significantly from the set of genes in parent organisms during reproduction
A) vegetative
B) disputes
IN ) sexual
D) budding

19. Reproduction carried out by the fusion of gametes is called
A) asexual
B) vegetative
IN) sexual
D) controversial

20 Parthenogenesis is characterized by
A) partial exchange of hereditary information through the cytoplasm
B) development of an embryo from an unfertilized egg
B) death of sperm after penetration into the egg
D) development of the egg due to the genetic material of sperm

21. The great importance of sexual reproduction for evolution is that
A) During fertilization, new combinations of genes may arise in the zygote
B) the daughter organism is an exact copy of the parent organisms
C) due to the process of mitosis, an embryo is formed from the zygote
D) the development of a new organism begins with the division of one cell

22. As a result of sexual reproduction in populations
A) various somatic mutations occur
B) the number of individuals of the species increases rapidly
C) the genotype identical to the maternal one is preserved
G) the genetic diversity of individuals in the population increases

23. Reproduction of humans, animals, plants, in which the fusion of two specialized cells occurs, is called
A) budding
B) parthenogenesis
B) asexual
G) sexual

24. Parthenogenesis is
A) reproduction by development of an adult from an unfertilized egg
B) reproduction of hermaphrodites that have both testes and ovaries
B) reproduction by budding
D) artificial fertilization of an egg (in vitro)

25. What type of reproduction is parthenogenesis?
A) sexually mu
B) vegetative
B) budding
D) asexual

26. In plants obtained by vegetative propagation
A) adaptation to new conditions increases
B) the set of genes is identical to the parent
B) combinative variability appears
D) many new signs appear

27. Which animal reproduces by budding?
A) white planaria
B) freshwater hydra
B) earthworm
D) big pond snail

28. What mushrooms reproduce by budding?
A) mukor
B) penicillium
IN) yeast
D) champignons

29. The exchange of hereditary information occurs in the process
A) sporulation of Escherichia coli
B) budding of freshwater hydra
C) vegetative propagation of strawberries
G) conjugation between individuals of ciliates-slippers

30. How does a fungal spore differ from a bacterial spore?
A) represented by only one cell
B) performs the function of reproduction
B) carried by the wind over a long distance
D) serves as an adaptation to unfavorable conditions

31 The basis of asexual reproduction of unicellular animals is
A) cyst formation
B) parthenogenesis
B) meiotic division
G) mitotic division

32. The sexual method includes reproduction
A) m honey bee parthenogenesis
B) freshwater hydra by budding
B) ciliates-slippers dividing in two
D) white planaria with body fragments

33. Parthenogenesis is a method of reproduction by
A) budding
B) regeneration
B) sporulation
G) sexual

34. Bacteria as opposed to fungi
A) do not reproduce by spores
B) form specialized germ cells
B) consist of a variety of tissues
D) have a cell wall

35. Sexual reproduction is more progressive because it
A) provides a larger number of offspring compared to asexual
B) maintains the genetic stability of the species
IN) provides greater genetic diversity in offspring
D) inhibits excessive fertility of the species

36. Participates in asexual reproduction
A) moss spores
B) rat sperm
B) elephant eggs
D) mature human erythrocytes

37. Participate in sexual reproduction
A) blastomeres
B ) gametes
B) kidneys
D) disputes

Introduction

Like all living organisms, plants reproduce. This physiological process of reproduction of similar organisms ensures the continuity of the existence of the species and its distribution in the environment.

As a result of reproduction, the number of individuals of the species increases, and plants occupy new territories. When the ability to reproduce is lost, species become extinct, which has happened many times during the evolution of the plant world.

There are three types of reproduction in plants: sexual, asexual and vegetative.

Sexual reproduction is fundamentally different from vegetative and asexual. The sexual process in the plant world is extremely diverse and often very complex, but essentially comes down to the fusion of two sex cells - gametes, male and female.

During asexual reproduction in plants, special cells (spores) are formed, from which new independently living individuals grow, similar to the mother. This method of reproduction is characteristic of some algae and fungi.

Vegetative propagation is carried out by the development of new individuals from vegetative organs or parts thereof, sometimes from special formations that appear on stems, roots or leaves and are specially designed for vegetative propagation. Both lower and higher plants have varied methods of vegetative propagation. Vegetative propagation has reached its most complex and varied forms in higher plants and especially in flowering plants. They are characterized by reproduction using vegetative organs: parts of the shoot, root, rhizome, leaf.

I.V. Michurin attached great importance to vegetative propagation of plants. He believed that from any plant, through prolonged exposure to it, it is possible to obtain offspring that can be easily propagated by cuttings.

The purpose of this essay was to obtain a complete and comprehensive understanding of the vegetative propagation of plants, since it plays a very important role in nature and is widely used by humans. Many cultivated plants are propagated almost exclusively by vegetative means - only in this case their valuable varietal qualities are preserved.

TYPES OF VEGETATIVE REPRODUCTION OF PLANTS

Natural vegetative propagation

The vegetative propagation of plants is based on their widespread ability to regenerate, that is, to restore lost organs or parts, or even to develop the entire plant from individual parts of the body. In animals, the lower the animal is in the system, the higher the ability to regenerate.

Among plants of lower groups, the ability to regenerate is also great; for example, in many mosses, almost all the cells of their body are potentially capable of developing a new plant. Moreover, in more rare cases, renewal occurs directly at the site of injury; more often, a new formation occurs somewhere near the injury, or the injury causes the growth of organs that have already been formed, but were in their infancy.

In unicellular plants, their reproduction by cell division can be considered vegetative reproduction.

Multicellular and large noncellular algae, fungi, and lichens often reproduce vegetatively, by randomly, but undoubtedly often occurring, breaking off individual sections from their thallus, which, thanks to their extraordinary ability to regenerate, develop into new plants. In mushrooms, mosses, mosses, and selaginella, in the simplest cases, vegetative propagation consists of the fact that the old parts of the thallus or shoot die off, while its younger branches separate and become independent. In ferns and horsetails, in a similar way, old sections of underground rhizomes die off and young ones separate from them with above-ground shoots that develop from them. In addition, in some of these higher spore plants, vegetative reproduction occurs with the help of so-called brood buds - accessory buds on the leaves, which, falling off the mother plant, germinate and give rise to new individuals.

Among seed plants, only annuals and biennials do not reproduce vegetatively under natural conditions. Among perennials, almost all herbaceous and all woody ones are capable of vegetative propagation in one way or another.

In the simplest cases, in relatively few cases, this occurs by separating shoots from the mother plant that develop into a new individual. In duckweeds, in this way, from several overwintered specimens, offspring are formed in a few weeks, covering an area of ​​​​half a hectare. In this regard, duckweed probably blooms extremely rarely. In the villain, each easily broken off piece of the stem can develop into a new plant.

The most widespread vegetative propagation in seed plants is through rhizomes, above-ground creeping and rooting shoots, bulbs, and adventitious buds on the roots.

Aboveground creeping shoots (lashes, tendrils, stolons) represent a transition from typical vertical stems to rhizomes. Creeping along the surface of the earth, they form adventitious roots at the nodes, and here, in the axils of the leaves, buds that produce vertical, leafy shoots. The internodes of creeping shoots die off, and new plants lose contact with the mother plant. This is how strawberries reproduce. drupes, some cinquefoils, etc. From one strawberry plant, after two years, 200 plants can be formed in this way, occupying a considerable area.

Vegetative propagation occurs by rhizomes in most perennial grasses. On some herbs, the buds are close together, resulting in crowded above-ground shoots. On long rhizomes, the buds are not crowded, and the above-ground shoots formed from them are not close together. As the old rhizomes rot, new plants become completely independent. Growing in all directions, long-rhizome grasses quickly colonize a large area.

Thanks to vegetative propagation by rhizomes, the species composition of our meadows, usually mowed during the flowering of cereals, remains almost unchanged. Some rhizomatous plants (for example, creeping wheatgrass, grass, etc.) in crops are difficult to eradicate weeds.

Many herbaceous, mainly monocotyledonous plants from the lily and amaryllis families (onions, garlic, tulips, hyacinth, narcissus, lilies, goose onions, etc.) reproduce by bulbs. In some, bulbs are also formed in the axils of the leaves of above-ground stems (in chives), or in inflorescences (garlic); in the latter case, significantly fewer flowers are formed or there are no flowers at all.

Tubers used for vegetative propagation are of root and stem origin, both of which can be underground or aboveground.

Vegetative propagation by adventitious buds formed on the roots and developing into above-ground shoots, the so-called root shoots, is very common. New plants become completely independent after the roots that connected them to the mother ones die off.

Many plants form such root shoots.

In some plants, small leafy shoots form in the leaf axils, which then fall off the mother plant and take root. Sometimes such plants are called viviparous, since previously it was mistakenly believed that their seeds germinate on the mother plant. They are distributed mainly in polar, high-mountain and steppe areas, where, due to the short growing season, the seeds may not ripen. These include steppe bluegrass, rush grass, some Arctic fescue, etc.

In the fall of many aquatic, mainly floating plants, special wintering buds are formed on the tops of the stems or on special side shoots, which are filled with starch and sink to the bottom either together with the mother plant, or separated from it. In the spring, after the mother plant has rotted, they float to the top due to the development of air cavities and develop into new plants. This is how overwintering and vegetative propagation occur in bladderwrack, teloresis, frogwort, rue, some pondweeds, etc.

Artificial vegetative propagation

It is impossible to draw a sharp line between natural and artificial vegetative propagation.

Conventionally, we can call artificial propagation something that does not take place in nature, since it is associated with the surgical separation of its parts used for propagation from the plant. Reproduction of propagated plants by tubers or baby bulbs separated from the mother plant occupies an intermediate position between natural and artificial vegetative propagation. Artificial vegetative propagation is resorted to if a plant under given cultural conditions does not produce seeds, or produces few of them, of poor quality, if propagation by seeds does not preserve the properties of the variety, which is usually the case with hybrids, or if it is necessary to quickly propagate a given plant or a given variety.

There are two main types of propagation of any plants - generative and vegetative.

Vegetative propagation of plants

This type includes division of rhizomes and bulbs of plants, propagation by tubers, grafting, the use of layering and cuttings - a method that allows you to grow a seedling from a small part of the parent plant. This method is not only popular among vegetable growers, but there are many plants that reproduce only in this way.

What plants are propagated vegetatively

It is necessary to propagate plants vegetatively if:

• They do not form seeds (multi-tiered onions, horseradish);
• When sowing with seeds, next year they will form small-sized productive organs - sets (onions, potatoes);
• When propagated using seeds, the characteristics of the variety are split - in size, appearance and color (for example, rhubarb);
• have small seeds that germinate poorly, and it takes more than 70 days to grow seedlings (crops such as artichoke, tarragon and rosemary).

Plant propagation by dividing bulbs is often used in vegetable growing. Some types of onions grow 3-12 children, which then only need to be divided and can then be planted in the garden. And in order for the planted onions to grow and develop evenly, you will need to calibrate the children and plant them in the garden, taking into account their size.

Herbs and perennials (lovage, mint and asparagus) are easy to propagate if you divide the mother rhizome. It contains a sufficient supply of nutrients necessary for the initial growth of young plants. It is best to carry out this operation in the fall or spring and immediately plant the plant in the garden bed.

Reproduction by tuber parts and eyes

Every gardener knows that potatoes are planted in the garden as tubers. But in the same way, stakhis and Jerusalem artichoke are planted. A tuber in its essence is a transformed shoot for this reason, a potato. Unlike ordinary carrots or beets, it must be called a tuber, and not a root vegetable, with buds, the bulk of which are collected on the upper part of the tuber, for example, out of 12 eyes available, approximately 6 will be in the upper part, 1-2 in the middle, and 3-4 at the bottom of the tuber. If you need to cut a large tuber before planting, you must not forget that any lobe must have several normal eyes.

There are still ways to propagate a rare variety of potatoes; they are used mainly if there is little planting material:

1) Using eyes - you need to cut them out of the tubers, with a small piece of pyramid-shaped potato, leave them in the air until the cuts dry, then put them in a box and keep them in a cool room until planting. During planting, distribute the eyes among the holes so that each hole contains 2-3 eyes;

2) Using layering that sprouts from tubers during vernalization. Place the selected tubers in a bright place at a temperature of 15-17 degrees. After a month, strong sprouts form, the tubers are placed in a box, covered with rotted peat or good humus. After 6-8 days, roots will form on the sprouts; carefully break off the sprouts and plant them in an area of ​​20 X 50 cm; such plantings are cared for like regular potatoes.

Grafting vegetables

Every summer resident knows that many plants are propagated using grafting, but Michurin was the first to use this method for vegetables. Thus, you can graft a tomato onto a potato bush, and a cucumber onto a growing pumpkin. This method is used mainly in plant breeding, and this method is not very common among summer residents.

Cuttings are used in gardening, but they are also used in vegetable growing. It is only necessary to trim the stepson and top of the plant, root it, and plant it in the soil next to the rootstock. When cuttings, it is difficult to maintain the viability of cuttings without a root system. It is necessary to organize a suitable water, temperature and light regime for the plant (this is best achieved in a greenhouse), and provide the culture with sterile soil (it is good to use vermiculite or perlite). In addition, it is necessary to choose the right cuttings for grafting (too young ones have difficulty growing roots, old ones dry out quickly, since a lot of substances are spent on the vital activity of the leaves). Cuttings must be free from diseases and pests. To speed up root formation, use heteroauxin.

Artichoke and horseradish are best propagated by root cuttings; they are harvested in the fall, 15 cm long, and covered with sand, stored in the basement until spring. Planted by removing the central bud. Artichoke cuttings are collected near the parent plant, for this reason it is only necessary to separate them and plant them on the site.

Artificial vegetative propagation is called the propagation of plants, which does not take place in nature, as it is associated with surgical separation from the planthisparts necessary for reproduction.

Wherein propagation of plants by tubers or baby bulbs, separated from the mother plant, occupies an intermediate position between natural and artificial vegetative propagation.

Artificial vegetative propagation is resorted to if a plant under given cultural conditions does not form seeds or produces few or poor quality ones, if propagation by seeds does not preserve the properties of the variety, which is usually the case with hybrids, or if it is necessary to quickly propagate a given plant or a given variety.

Closest to natural propagation by dividing bushes, which is often used in various ornamental herbaceous perennials (primroses, daisies, rudbeckias, phlox, delphiniums andothers), less often - in some perennial vegetable plants (chives, spring onions, sorrel, rhubarb) and in some shrubs and trees.

Herbaceous perennials that have formed many shoots (“bush”, “clump”) from rhizomes are dug out of the ground, individuals with their own roots are separated by hand or with a knife, and they are transplanted to new places.

Close to dividing bushes reproduction by offspring when, when the daughter plants are separated, the mother plant is not pulled out of the ground. This method is used in various shrubs and trees that form from adventitious buds on the roots root suckers (root shoots), dug up and transplanted to new places.

This is how raspberries, blackberries, plums, cherries, bird cherry, sea buckthorn and other plants are propagated.

In the same way, but only stem shoots(“whiskers”), they propagate strawberries and strawberries; Young plants that have developed on creeping, rooting above-ground shoots are separated and transplanted.

When propagated by stem shoots, the mother plant itself, without any human influence, produces rooting shoots, and when propagation by layering he is forced to do it. The branches of the plant are bent in an arched manner to the ground and they are usually covered so that the top of the shoot remains above the ground. After some time, adventitious roots develop on the section of the branch covered with soil, after which the cuttings can be transplanted to another place. Promotes rooting cutting the branch: it impedes the movement of plastic substances, promotes their accumulation at the incision site and more rapid formation of roots and new shoots. Sometimes the entire branch to be branched is spread on the ground and several branches are obtained from the nodes. Branches from thick trunks are “taken away” by tying to them a pot cut on the side and filled with soil into which they take root. Other variations of abduction methods are also used.

Tree propagation by layering passed through pots of soil:

Propagation by layering is used in gooseberries, mulberries, hazels, grapes, oleander, azaleas, some carnations, dracaena, ficus (Ficus elastica), yucca and other plants.

Plant propagation by layering bent to the ground:

Propagation by cuttings:

In the broad sense, cuttings are any parts of plants cut from them and used for vegetative propagation; these can be parts of the stem (shoots), roots or leaves. In a narrower sense, when they talk about cuttings, they mean stem cuttings. They are herbaceous (green) and woody (lignified, semi-lignified).

In the lower part of the cutting planted in the ground, adventitious roots are formed endogenously from the cambium. Often their formation is preceded by the development of an influx ( callus) from parenchymal tissue, covering the wound from the edges. Rooting occurs, depending on the type of plant, after a few days (willow, poplar, tradescantia), weeks or even months. Rooted cuttings are transplanted into various nurseries, ridges, or directly to their final location. New shoots on cuttings develop from axillary buds, but adventitious buds are usually not formed on them.

Propagation by stem cuttings widely used in many ornamental perennials, medicinal and industrial plants, some tree species (roses, grapes, willows, poplars, thujas, currants and others), sometimes in some vegetable plants (tomatoes, cucumbers, melons, eggplants, red peppers, potatoes).

Two willow cuttings, sprouted in limbo in a dark, damp space:

In a number of difficult-to-root plants, it is possible to accelerate the formationadventitious rootson cuttings, treating them with certain substances, the so-called growth substances or auxins. Such substances are also produced in the body of plants.

Of these, the most commonly used indolyl oil, and naphthylacetic acid. In aqueous solutions of these kilotonsfor some time (12-24 hours)withstand the lower ends of the cuttings, whichaccelerates the appearancein plantsadventitious roots andincreases their number. The use of growth hormones is promising in viticulture, fruit growing (for example, citrus fruits), forestry, and floriculture.

Some plants, such as irises (orcas), perennial phlox and others, propagate segments of rhizomes having buds (eyes).

Root cuttings They propagate plants that are capable of quickly forming adventitious buds on the roots - horseradish, rose hips, roses, dracaenas, paulownia, some varieties of raspberries, sometimes cherries, plums and others. Cuttings are taken 5-15 cm long and 0.5-2 cm thick; placed obliquely in the ground to a depth of 2-6 cm.

Leaf cuttings , that is, with leaves or even pieces of them, few plants are able to reproduce - gloxinia, gesneria, some begonias, purslane, tomatoes and others. Planted on wet sand, they form adventitious roots and adventitious buds that develop into new plants; cuts in the leaf blade in places where large veins branch accelerate the formation of roots and buds in these places.

Vaccination, or transplantation , is the transplantation of a part of a living plant, equipped (in higher plants) with a bud or buds, to another plant with which the first grows together. The transplanted plant is called scion, and the one on which they are transplanted (vaccinated), rootstock or wild. Grafting is possible not only in higher, but also in lower thallus plants. In grafted higher plants, the scion does not form its own roots, but receives water and inorganic salts from the roots of the rootstock, while the latter receives organic substances from the scion.

Reproduction by grafting(“ennoblement”) is used mainly in fruit trees, which have difficulty producing adventitious roots and cannot be propagated by cuttings and layering, and when propagated by seeds, being complex hybrids, they split and do not reproduce the varieties of the mother plant. Sometimes grafting is done to fill bare spots in a tree where branches have broken off, or to save a tree that is partially damaged in the lower part, etc.

Practice has developed over a hundred different methods of vaccination.

With conventional grafting methods, a small shoot with several buds is cut from the scion - stalk - or one bud with a piece of bark and usually wood - peephole - and transplanted onto the rootstock.

In woody plants, annual branches are usually cut into cuttings in late autumn or at the end of winter, stored in a cold place and grafted in early spring, when the buds of the cuttings have hardly begun to grow or have started to grow less than the buds of the rootstock. Grafting with herbaceous cuttings is also carried out in the summer.

Copulation called the fusion of a cutting with a rootstock that has the same thickness as it. Both are cut obliquely so that their cut planes coincide, they are applied tightly to each other, tied and sometimes coated with a special garden varnish. Particular care must be taken to match the cambium. For greater strength of the connection and better fusion, various cuts are often made on the rootstock and corresponding cuts on the scion - the so-called grafting with “tongues”, etc.

When the rootstock is thicker than the scion, which happens most often, they do side-by-side vaccination , for the bark into the cleft in various options.

Various methods of vaccination:

1 - ordinary copulation; 2 - grafting in the butt; 3 - grafting into cleft.

When grafting with cuttings it affects plant polarity phenomenon: you need to splice the opposite ends of the rootstock and scion, that is, the morphologically upper end of the rootstock with the morphologically lower end of the scion; with the reverse connection, fusion either will not occur, or it will be bad and ugly.

Budding called transplantation of the bud (eye) of the scion under the bark of the rootstock, on which a T-shaped incision is made. Eyes are usually takenfrom the middlestrong shoots together with pieces of bark, preferably with wood, otherwise the conducting bundle of the eye often breaks off far in its depths, and the eye does not take root. Most often budding is used at the end of summer with dormant buds formed in the current year, which will develop in the next year. In the year of budding, only the fusion of the eye with the rootstock occurs; It begins to grow the next year, after which the rootstock above it is cut off.

Budding:

In fruit growing, budding is the most common method of grafting. In nurseries, at least 90-95% of fruit trees are grafted by budding: it requires less grafting material, is simpler in technique and speed of work, the wound during budding is smaller than with other grafting methods, and the fusion of the scion with the rootstock occurs faster.

When grafting, the individual characteristics of the mother plant, as well as the age and position on the mother plant of the cutting or eye taken for grafting, are of great importance.

Cuttings or eyes for grafting in gardening, it should be taken from completely healthy, already fruit-bearing plants, in which all the characteristics of the variety that are desirable in cultivation are expressed to the best extent.

The shoots and buds (eyes) on a plant are not uniform, but are individualized, depending on their location on the plant, and are able to retain these characteristics for a long time.

A stalk, or peephole, taken from the blooming zone, usually produces a profusely flowering scion, and the taken from a zone of strong vegetative growth givesgood growingscion, but with a small number of flowers.

The quality of the cutting, or eye, depends on the age of the plant from which it is taken, on the age of the cutting, or eye, itself, and on the degree to which it has passed through certain stages of development.

A very important condition for all vaccinations is, as already indicated, coincidence of the cambium of the rootstock and scion . Usually, between the rootstock and the scion, a yellow-brown layer of tissue that has died due to wounding is first formed. Then it is gradually destroyed by resorption and by breaking through its newly formed parenchyma cells of both components, which grow into each other and close together. The main role in the formation of these cells that give fusion belongs to the cambium. Even later, the conducting tissues of the rootstock and scion are connected by special conducting strands, arising either from parenchyma cells or from the cambium newly formed here. Often, especially in woody plants, an external influx (callus) is formed at the place of fusion, strengthening their common connection.

For the success or failure of vaccination, the specific characteristics of a given species or group and systematic proximity (phylogenetic relationship) of grafted plants , if they belong to more than one species.

In monocots, for example, grafting is difficult, which is quite possibly due to the random arrangement of their vascular bundles and the absence of a cambium. Among dicotyledons The closer the relationship of the grafted plants is, the easier it is in general to graft; varieties or races within the same species are grafted onto each other more easily than species within a genus; Intergeneric vaccinations are even more difficult to achieve; until recently, interfamily vaccinations were considered incredible, although indications of them had been found for a long time; Recently, successful interfamily graftings have been carried out, for example, Asteraceae on Solanaceae (chamomile on tomato), purslane on cactus, fava bean on sunflower, buckwheat on peas, nasturtium on faba bean and others.

Available there are many exceptions to the rule about the relatedness of the grafted components. There are examples when a given species or genus can only serve as a rootstock or only a scion for another, and not vice versa.

So, vaccinations are applied for vegetative propagation of plants that do not easily form adventitious roots and cannot be propagated by cuttings. In addition, they are sometimes used to increase productivity, to increase frost resistance, to ensure cross-pollination in dioecious plants (grafting male branches onto female specimens in ginkgo, pistachio), to replace broken branches, to create various decorative original effects, etc.

Interesting questions arise in connection with vaccinations influence of the rootstock on the scion, and vice versa. In some cases, the rootstock and scion do not noticeably affect each other. When a tomato is grafted onto a potato, the first forms its usual edible fruits, and the second - underground tubers; When grafting earthen pear and sunflower, the inulin characteristic of earthen pear does not pass into the sunflower. When grafting two types of mimosa, which react to irritation by folding their leaves and transmit this irritation throughout their body at different speeds (2-3 cm and 5-8 cm per second), the irritation passes through the fusion site and is transmitted to another component, but the speed of its spread is each component remains the one that is characteristic of this species.

In dioecious plants, each of the grafted components retains its sex.

Sometimes several different varieties are grafted onto one apple tree, and they retain their characteristics.

On this basis, many scientists believe that there is no mutual influence between the rootstock and scion and the qualities of both remain unchanged. They especially categorically insist that even if there is some influence of the rootstock on the scion, and vice versa, then these changes are by no means transmitted by inheritance when propagated by seeds.

Meanwhile, numerous and not random, but constant cases of the influence of the rootstock on the scion have long been known. This phenomenon is most often expressed in a change in the power of development, a shift in the timing of flowering and fruiting, a change in yield and even quality of fruits, resistance to unfavorable climatic conditions, and some changes in growth functions.

Often this influence of the rootstock can be explained by quantitative changes in nutrition. For example, strongly growing forms grafted onto weakly growing ones with a poorly developed root system(for example, a pear - on a quince, a common apple tree - on a paradise apple tree or paradise, cherry and sweet cherry - on a steppe cherry) turn out to be dwarf, less hardy and short-lived, but bearing fruit earlier, often with sweeter fruits. Their dwarfism is explained by insufficient root nutrition from the weak root system of the rootstock; early fruiting and high sugar content of the fruit - by the rapid and significant accumulation of assimilates that are not consumed by the underdeveloped root system of the rootstock or, perhaps, by a more difficult outflow of assimilates; less longevity - due to early death of the roots of the rootstock. On the contrary, pistachio from seeds lives no more than 150 years, but grafted onto another, more durable species of the same genus (Pistacia terebinthus) lives up to 200 years.

In some cases, with skillful choice of rootstock it is possible to increase the frost resistance of the scion, for example, when grafting ordinary apple trees onto a frost-resistant Siberian tree, when grafting tangerines onto a more frost-resistant three-leaf orange (Poncirus trifoliata), melons onto pumpkins, etc. Some such cases were explained only by the frost resistance of the roots of the rootstock, but often frost resistance is obtained in the shoots of the scion, as, for example, in a cherry grafted on another species of the same genus, the so-called antipka (Cerasus mahaleb).

The influence of the rootstock on the scion is visible, for example, in the fact that a cutting from a turnip inflorescence grafted onto a one-year turnip root produces a leafy shoot, while a cutting grafted onto a biennial root develops into a flower shoot.

I. V. Michurin and his followers the relationship between the rootstock and the scion is understood differently. They believe that the influence of the rootstock on the scion, and vice versa, is not only of the nature of quantitative changes in the interacting components, but also in such a way that in some cases, under certain conditions, the resulting changes are transmitted to the offspring.

I.V. Michurin, in his work on breeding new varieties of fruit trees, widely used the influence of the rootstock on the scion, and vice versa. He explained the reason for the persistent preservation of the hereditary characteristics of the scion, observed during conventional grafting in fruit growing, and also established under what conditions this stability is violated.

The scion is always taken from a tree that has already bear fruit several times, and, moreover, an old cultivated variety; therefore, it has such a strong heredity that a young (2-3-year-old) wildflower (stock) usually cannot change. If you take a young hybrid seedling, unstable like a young organism, and also with heredity shaken by hybridization, and graft it into the crown of an old fruit-bearing tree, then this hybrid seedling, under the powerful influence of the rootstock, will gradually change, and, moreover, in a directional direction - towards closer according to properties to the rootstock.

The reverse method was widely used by I.V. Michurin - influence of scion on rootstocks. In this case, he grafted cuttings of the resistant variety whose properties he wanted the hybrid to have into the crown of a young hybrid entering the period of fruiting. The grafted cuttings influenced the hybrid (rootstock) and transferred to it some of their properties, which were fixed and subsequently transmitted during vegetative propagation.

In the experiments described, the component that transferred its properties (as the most powerful) “educated” the other component was called a mentor.

Also, I. V. Michurin called the method of influencing young hybrids with loose, unfixed heredity in the desired manner by an old variety mentor method. It is clear that the mentor can be either a scion (cuttings of an old variety in the last example) or a rootstock (in the first example).

In the works of I. V. Michurin signs, transferred from the rootstock to the scion, or vice versa, inherited only during vegetative reproduction. So, if cuttings of a variety obtained by the mentor method are rooted or grafted onto rootstocks, then trees with the characteristics of this variety will grow from the cuttings. A particularly interesting example is a variety obtained by grafting a bud from a young apple seedling ( Antonovka one and a half pound) into the crown of a wild pear. On the scion (subsequently bent to the ground and rooted at the place of its fusion with the pear, where there was a large influx), pear-shaped fruits were formed: the stalk was not in a funnel, like in apple trees, but on an elevation and somewhat shifted to the side, like in pears bergamots This new variety was named by I.V. Michurin Renet bergamot. During vegetative propagation, it retained this fetal shape feature. Further Renet bergamot crossed with various varieties of apple trees, and some of the new hybrids produced fruits that already inherited the fruit type during seed propagation Reneta bergamot, resembling a pear.

The rootstock is also capable of changing under the influence of the scion. The nature of the root system of the rootstock, the number, location and thickness of the roots, the number and size of wood vessels, etc. change. In potatoes, the shape and color of the tubers and the percentage of starch content in them changed; these changes persisted during vegetative propagation. When tobacco was grafted onto potatoes, a certain amount of alkaloids characteristic of tobacco accumulated in the tubers of the latter.

Evidence was obtained of the transfer of some biochemical characteristics of the rootstock to the scion. When grafting tomatoes, dope, and nightshade onto tobacco, an alkaloid from the rootstock, unusual for them, appears in the leaves of the scion - nicotine. With back-vaccinations, tobacco often does not contain nicotine. In a number of experiments where alkaloid scions from various families (Solanaceae, Legumes - lupine and others) were grafted onto alkaloid-free rootstocks close to them, the scion, as well as the rootstock, did not contain alkaloids or there were few of them. In the opposite cases (alkaloid rootstock), the scion became alkaloid (This is explained by the fact that the synthesis of alkaloids occurs only in the roots, and from there they move up the stem).

The production of plants from cells or pieces of plant tissue is called tissue culture. This method is based on the ability of a plant cell to form a whole plant.
Tissue culture is grown in special laboratories on nutrient media while maintaining a certain temperature and air humidity, and the required lighting.
A new plant can be obtained from living cells of any tissue. Pieces of tissue from the tip of a root or shoot, leaf or stem are sterilized and transferred to a nutrient medium. In the presence of the necessary substances, the cells grow quickly and are transferred to test tubes, where young plants are formed, ready for independent life.

In tissue culture, cells form miniature young plants. Thanks to this method of propagation, in a short period of time you can obtain a lot of plants with the desired properties. Thus, from one mother plant of rose, strawberry or potato, more than 1 million daughter plants can be obtained per year.

Reproduction is one of the characteristic features of all living organisms, along with respiration, nutrition, movement and others. Its importance is difficult to overestimate, because it ensures the very existence of life on planet Earth.

In nature, this process is carried out in different ways. One of them is asexual vegetative reproduction. It is found mainly in plants. The importance of vegetative propagation and its varieties will be discussed in our publication.

What is asexual reproduction

The school biology course defines vegetative propagation of plants (grade 6, section “Botany”) as one of the asexual types. This means that germ cells are not involved in its implementation. And, accordingly, recombination of genetic information is impossible.

This is the most ancient method of reproduction, characteristic of plants, fungi, bacteria and some animals. Its essence lies in the formation of daughter individuals from maternal ones.

In addition to vegetative, there are other methods of asexual reproduction. The most primitive of them is cell division in two. This is how plants and bacteria reproduce.

A special form of asexual reproduction is the formation of spores. Horsetails, ferns, mosses and mosses reproduce in this way.

Asexual vegetative reproduction

Often with asexual reproduction, a new organism develops from a whole group of parent cells. This type of asexual reproduction is called vegetative.

Reproduction by parts of vegetative organs

The vegetative organs of plants are the shoot, consisting of a stem and a leaf, and the root, an underground organ. By splitting off their multicellular part or petiole, a person can carry out vegetative propagation.

What is cuttings for example? This is the method of the mentioned artificial vegetative propagation. So, in order to increase the number of currant or gooseberry bushes, you need to take part of their root system with buds, from which a shoot will be restored over time.

But stem petioles are suitable for propagating grapes. Of these, after some time the root system of the plant will be restored. A necessary condition is the presence of buds on any type of petiole.

But leaves are often used for propagation of many indoor plants. Surely, many people bred Uzambara violet in this way.

Reproduction by modified shoots

Many plants develop modifications of vegetative organs that allow them to perform additional functions. One of these functions is vegetative propagation. We will understand what special modifications of shoots are if we consider rhizomes, bulbs and tubers separately.

Rhizome

This part of the plant is located underground and resembles a root, but, despite the name, it is a modification of the shoot. It consists of elongated internodes from which adventitious roots and leaves extend.

Examples of plants that reproduce using rhizomes are lily of the valley, iris, and mint. Sometimes this organ can also be found in weeds. Everyone knows how difficult it can be to get rid of wheatgrass. When pulling it out of the ground, a person, as a rule, leaves parts of the overgrown wheatgrass rhizome underground. And after a certain time they sprout again. Therefore, in order to get rid of the named weed, it must be carefully dug up.

Bulb

Leeks, garlic, and narcissus also reproduce using underground modifications of shoots called bulbs. Their flat stem is called the bottom. It contains juicy, fleshy leaves that store nutrients and buds. They are the ones that give rise to new organisms. The bulb allows the plant to survive a difficult period for reproduction underground - drought or cold.

Tuber and mustache

To propagate potatoes, you do not need to sow seeds, although they produce flowers and fruits. This plant reproduces by underground modifications of shoots - tubers. To propagate potatoes, it is not even necessary that the tuber be whole. A fragment of it containing buds is enough, which will sprout underground, restoring the entire plant.

And after flowering and fruiting, strawberries and wild strawberries form ground lashes (whiskers), on which new shoots appear. By the way, they should not be confused with the tendrils of grapes, for example. In this plant they perform another function - the ability to attach to a support for a more comfortable position in relation to the sun.

Fragmentation

Not only plants are able to reproduce by separating their multicellular parts. This phenomenon is also observed in animals. Fragmentation as vegetative propagation - what is it? This process is based on the ability of organisms to regenerate - restore lost or damaged body parts. For example, from a part of the body of an earthworm, a whole individual can be restored, including the integument and internal organs of the animal.

Budding

Budding is another method of reproduction, but vegetative buds have nothing to do with it. Its essence is as follows: a protrusion forms on the body of the mother’s body, it grows, acquires the features of an adult organism and splits off, beginning an independent existence.

This budding process occurs in freshwater hydra. But in other representatives of the coelenterates, the resulting protrusion does not break off, but remains on the mother’s body. As a result, bizarre reef shapes are formed.

An increase in the amount of dough that is prepared using yeast, by the way, is also the result of their vegetative propagation through budding.

The importance of vegetative propagation

As you can see, vegetative propagation in nature is quite widespread. This method leads to a rapid increase in the number of individuals of a certain species. Plants even have a number of adaptations for this, in the form of shoots.

Using artificial vegetative propagation (which this concept implies has already been said earlier), a person propagates plants that he uses in his economic activities. It does not require an individual of the opposite sex. And for the germination of young plants or the development of new individuals, the familiar conditions in which the mother’s organism lives are sufficient.

However, all varieties of asexual reproduction, including vegetative ones, have one feature. Its result is the emergence of genetically identical organisms that are an exact copy of the maternal one. To preserve the biological species and hereditary characteristics, this method of reproduction is ideal. But with variability, everything is much more complicated.

Asexual reproduction, in general, deprives organisms of the opportunity to develop new characteristics, and therefore one of the ways to adapt to changing environmental conditions. Therefore, most species in nature are capable of sexual intercourse.

Despite this significant drawback, when breeding cultivated plants, the most valuable and widely used is still vegetative propagation. A person is satisfied with this method due to the wide variety of possibilities, short periods of time, and the number of organisms that reproduce in the described way.