Mycorrhizal mushrooms. Mycorrhiza of tree species Which mushroom does not have mycorrhiza

In the natural environment, seemingly impossible interactions between different kinds animals or birds, insects and plants. One of them, namely the interaction between plants and fungi, we will consider today: fungus root or mycorrhiza, what is it ?.

Did you know? Mushrooms are interesting works of nature: they are eaten, they are made of extracts for medicines, and cosmetics are produced. Yves Rocher launched a line of cosmetics for middle-aged women based on an extract from shiitake mushrooms. The active substances of these fungi, penetrating into the skin cells, nourish them and accelerate regeneration.

Mycorrhiza - what is it

To understand what a fungus root is, it is necessary to consider the structure of the fungus. The fruiting body of the fungus consists of a cap and a leg, but the most interesting are hyphae or thin filaments, which intertwine form a mycelium (mycelium). This organ of the fungus serves both for nutrition and for reproduction (formation of spores), as well as for the formation of mycorrhiza.

What is mycorrhiza? It is just a combination of fungal mycelium with the root system of plants. Mushroom roots and plant roots are intertwined, sometimes the fungus is introduced into the root system of plants, which is done for fruitful cooperation of both parties.

What is mycorrhiza by definition? This is a symbiotic habitat of fungi on the surface of the root system or in the tissues of the roots of higher plants.

To better understand the action of mycorrhiza, consider its types. There are three main types of mycorrhiza: ectotrophic, endotrophic and ectoendotrophic. In its biological essence, the first type is the external or superficial enveloping of the roots with mycelium, the second type is characterized by penetration into the root tissue, and the third type is a mixed interaction.

So, we have found out what mycorrhiza is in biology and now we know that such cooperation is typical for almost all plants: herbaceous, trees, shrubs. The absence of such a symbiosis is rather an exception to the general rules.

Properties of mycorrhiza for growing plants

Let's take a closer look at what mycorrhiza is and what its functions are useful for plants. Mushroom mycelium is capable of producing special proteins that are some kind of catalysts in nature. In addition, the mycelium digests and breaks down nutrients in the soil, from plant residues to organic and inorganic elements from humus. Plants are capable of absorbing only readily soluble humus elements and here they have many competitors: these are weeds and microbes that live in the soil.

–it is a mutually beneficial symbiosis of plants and fungi. Plants receive nutrients and water, while mushrooms receive carbohydrates produced by plants. Without carbohydrates, mushrooms are unable to multiply and grow fruit bodies. Plants give up to 40% of carbohydrates.

The role of mycorrhiza in plant life cannot be overestimated. Mycorrhiza supplies them with vitamins, minerals, enzymes and hormones. Thanks to mycelium root system plants increases the area of absorption of beneficial elements such as phosphorus, potassium and other stimulating substances. Moreover, it not only serves as a food provider, but also doses it correctly.

Plants grow more actively, during the flowering period they form more inflorescences with fruitful flowers and, accordingly, fruiting increases. Plants gain immunity to stress and weather conditions: drought, heavy rainfall, sudden temperature changes. Fungi, forming mycorrhiza with plant roots, act as defenders against some of the latter's diseases, such as, for example, fusarium or late blight.

Due to its ability to digest and break down organic and inorganic humus compounds, mycorrhiza cleans the soil for plants from excess salts and acids.

Did you know? In nature, there are predatory fungi that feed on living organisms, worms. These mushrooms grow mycelium in the form of rings that act as traps. The adhesive-backed rings contract like a loop when the victim is caught in them. The more the prey twitches, the tighter the trap is tightened.

Mycorrhizal vaccinations

Fungi rarely form mycorrhiza, because this symbiosis has existed since the beginning of the development of flora on earth. Unfortunately on summer cottages mycorrhiza is often destroyed as a result long-term use chemical preparations, mycorrhiza also perishes during construction. Therefore, to help their plants, gardeners are vaccinating.

Mycorrhiza vaccine - it is a preparation in the form of a powder or liquid, which contains particles of live mycelium of fungi. After a kind of grafting of the soil, the bacteria of the fungi begin to cooperate with the root system of plants, which forms a natural mycorrhiza.

Mycorrhizal vaccines are popular today for indoor flowers, there are big choice for vegetables, garden flowers and herbaceous plants, as well as conifers such as hydrangeas, rhododendrons, heather and roses. When vaccinating, remember that the root system of very old trees is too deep and not suitable for mycorrhiza.

Important! The mycorrhizal vaccine is administered once in a plant's life, and each plant interacts and forms mycorrhiza with certain fungi. There is no mycorrhiza suitable for all plants.

Features of the use of mycorrhiza for plants

The mycorrhiza preparation is applied by watering or spraying crops, and directly into the soil. When vaccinating in the soil, make several shallow holes directly in the ground near the plant and inject the vaccine there.

Many are interested in the question "Which plants do not form mycorrhiza and with which fungi, this symbiosis is also impossible?" Today, few plants are known that perfectly do without mycorrhiza: these are some species of the Cruciferous, Amaranth and Marevaceae family. Mushrooms that do not form mycorrhiza - umbrellas, oyster mushrooms, champignons, dung beetles, honey mushrooms.

The mycorrhiza preparation should be used after harvest, that is, in the fall. During the winter, the fungi form mycorrhiza with the roots of dormant plants, and the results will already be noticeable in the spring. Unlike plants, mushrooms do not go into hibernation in winter and continue to be active. If you use the drug in the spring, its active effect will be noticeable next year.

The use of mycorrhiza is important when transplanting crops to a new or permanent place after rooting of seedlings. The action of the drug will reduce the stress of the plant and accelerate its adaptation. After inoculation with mycorrhiza preparations, there is a significant growth and more accelerated development of crops.

Important!-it is not a fertilizer, and combine with chemicals it is not recommended as it could be destroyed by them. Top dressing is carried out exclusively with organic fertilizers.

When using mycorrhiza for indoor plants there are also a few rules:

Powder preparations for indoor plants are introduced into the potting soil, then watering is carried out. The composition in the form of an emulsion is drawn into a syringe and injected directly onto the root system into the soil.
After grafting, the plant is not fertilized for two months. Fungicides are not used during the same period.
More effective for flowerpots are vaccinations containing particles of live mycelium, and not fungal spores. These include gel formulations with live mycelium, which form mycorrhiza immediately, while spores do not have the conditions for development in a closed pot.

Advantages and disadvantages of using mycorrhiza in plant life

The main advantages of using mushroom root:

Mycorrhiza is a symbiosis between the plant and the mycelium of the fungus that live in the soil. Certain types of fungi cooperate with specific types of plants. In natural conditions, allies are on their own. In the garden, we must help them with this by applying the appropriate "vaccines" applied to the soil.

What is mycorrhiza?

Mycorrhiza, (from Greek mykos (μύκης) - mushroom and riza (ρίζα) - root) - the phenomenon of mutually beneficial coexistence between living plant cells and non-pathogenic (not causing diseases) fungi that populate the soil. The definition of mycorrhiza literally means " mushroom root«.

Mycorrhiza is a commonwealth between plants and fungi leading to mutual benefit. Mushrooms use the products of plant photosynthesis to obtain plant sugars that they cannot produce themselves. Plants, in turn, receive much more benefits from mycorrhiza.

Mycelium hyphae penetrate into the cells of the root cortex ( Endomycorrhiza) or remain on the surface of the root, braiding it with a dense network ( Ectomycorrhiza), thereby increasing the ability to absorb moisture and mineral salts from the soil. Plants begin to grow stronger, form more flowers and fruits. They also become much more resistant to unfavorable conditions - drought, frost, inappropriate pH or excessive soil salinity. Mycorrhiza protects plants from diseases (,).

Where is mycorrhiza found?

Mycorrhiza has existed in nature for millions of years.- more than 80% of all plants remain in symbiosis with mycorrhizal fungi. On the household plots, unfortunately, rarely occurs, since it was destroyed as a result of intensive cultivation and the use of chemical fertilizers and plant protection products.

The naked eye (without a microscope) will not be able to check if there is mycorrhiza in the garden soil. Mycorrhizal fungi very often die during the construction of a house. Deep pits, ground left on the surface, rubble and lime residues are the main reasons for the absence of mycorrhiza in the garden.

A noticeable effect of the action of mycorrhiza

The most popular and most visible result of mycorrhiza is Forest mushrooms ... These are the fruiting bodies of ectomycorrhizal fungi. Even a beginner in mushroom picking, after the first mushroom picking, will notice that specific mushrooms grow only in the immediate vicinity of specific trees.

Chanterelles grow both under deciduous and under conifers, mushrooms under pines, spruces and firs. Porcini mushrooms can be found in not too dense forests, mainly under oaks, beeches, as well as pines and spruces. It is better to look for flywheels under spruce and pine trees, as well as in deciduous forests, under oak and beech trees. In the birch groves and under the spruce trees grow stumps, and boletus grows under birches, hornbeams and oaks.

Mycorrhizal preparations - vaccines

Mycorrhizal vaccines contain live fungal hyphae or fungal spores... For different plants specific, adapted mixtures of mycorrhiza are intended (they also include edible varieties, however, on personal plots, they rarely form fruit bodies).

You can buy mycorrhizal preparations for indoor plants (the most popular is mycorrhiza) and balcony plants. Much larger selection of vaccines for garden plants- for, and deciduous plants, vegetables, for heather, roses, and even for.

The roots of old trees go very deep, and by the tree itself there are only skeletal roots that are not suitable for mycorrhization. It should be remembered that in plants, both young and adult, the youngest roots are relatively shallow underground, within 10-40cm. In the case of planting trees dug directly from the ground, with an open root system, the vaccine should be added to a few of the youngest, living roots before planting.

5 rules for the use of mycorrhiza vaccine

Preparations in powder form are added to the substrate in flower pot and then watered. Vaccines in the form of a suspension are injected into pots or into the soil (directly to the roots) using a syringe or a special applicator.
It is enough to plant the roots of plants once in order to bind with it and be useful throughout life.
There is no universal mycorrhiza suitable for all plant species! Each plant (or group of plants - for example, heathers) remains in the mycorrhiza only with certain types of fungi.
Mycelium containing hyphae are much better. Vaccines containing fungal spores are unreliable because spores often do not have suitable conditions for germination. Mycorrhiza of live mycelium, in contrast to dry preparations, after watering, is ready for an immediate reaction with the plant. In the form of a gel suspension, it is stable even for several years, at a temperature of about 0⁰C, and loses its vitality upon drying.
After the introduction of live mycelium, the plants should not be fertilized for 2 months. Also, do not use any fungicides.

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Granular butter dish - forms mycorrhiza with Scots pine and other pines

Mycorrhiza formers (symbiotrophic macromycetes, mycorrhizal fungi, symbiotrophs) - fungi that form mycorrhiza on the roots of trees, shrubs and herbaceous plants... This is a specialized ecological group of fungi isolated within the framework of modern mycology with late XIX century. This group of fungi is specific in that its representatives enter into a symbiosis with higher plants, do not have enzymes for the decomposition of cellulose and lignin, and exhibit an energy dependence on the symbiont, which is the plant. The term mycorrhiza ("mushroom root") was introduced by the German researcher of fungi A. V. Frank in 1885.

Mycorrhiza

Mycorrhiza - the formation of symbiosis of a fungus and a plant. It manifests itself in the fact that the mycelium (mycelium), which is in the soil, intertwines and envelops the roots and root hairs of plants. The roots of the plant are transformed, but this does not harm the owner. Mycorrhiza allows both the fungus and the plant to get the missing nutrients from the soil. In modern mycology, exotrophic and endotrophic mycorrhiza are distinguished. With exotrophic mycorrhiza (ectomycorrhiza), the mycorrhiza hyphae entwine outside the plant roots, and with endotrophic mycorrhiza (endomycorrhiza), the hyphae penetrate into the intercellular space of the roots and into the cells of the root parenchyma. Ectoendotrophic mycorrhiza (ectoendomycorrhiza) combines the features of both ectomycorrhiza and endomycorrhiza. The phenomenon is described in 1879-1881. Russian scientist F.M. Kamensky and he also gave the first attempt to explain it scientifically, the term was introduced by the German scientist A.V. Frank in 1885.

Differences between mycorrhiza formers and saprotrophs

Both mycorrhiza formers and saprotrophs use dead organic matter for their nutrition, and therefore, within the framework of mycology, there is a problem of distinguishing between these groups.

The mycorrhiza-forming agent receives carbohydrates from the plant, which is used by the fungus as an energy source, and the plant receives from the fungus elements of mineral nutrition, which the mycelium transforms into a form assimilable by the plant. At the same time, mycorrhiza formers are similar to saprotrophs in the absence of a plant with which symbiosis is formed or in the stage of free-living mycelium.

L. A. Garibova in the book "The Mysterious World of Fungi" distinguishes the following differences, which indicate a difference in the biochemistry of these ecological groups of fungi:

only mycorrhiza formers form indole compounds (some saprotrophs also form them, but in a significantly smaller amount);
mycorrhiza formers form growth substances of the auxin type;
mycorrhiza formers have almost no antibiotic properties;
mycorrhiza formers do not participate in the destruction of cellulose and are not able to develop on it without carbon sources available to them;
most mycorrhiza formers do not have hydrolytic enzymes, in particular, they do not synthesize laccase, which is needed for the oxidation of lignin;
mycorrhiza formers have a more complete amino acid composition.

Symbiotrophs in the kingdom of mushrooms

Boletus is a tubular fungus that forms mycorrhiza with aspens and other tree species

Amanita muscaria - forms mycorrhiza mainly with birch and spruce

Ascomycetes, basidiomycetes and zygomycetes are mycorrhiza-forming organisms.

So, mycorrhiza formers are all tubular (boletal mushrooms), many of which are edible and collected by humans for human consumption: porcini mushrooms, boletus boletus, aspen mushrooms, mushrooms, oak trees.

Mycorrhiza is formed by some gasteromycetes, mainly of the genus Pseudo-raincoat, as well as some species of marsupial mushrooms belonging to truffles (species from the order of truffle ( Tuberales)).

In modern mycological literature, there are mentions that some fungi, for example, fine pig and varnish, can behave both as mycorrhiza formers and as saprotrophs, depending on the habitat conditions. They form mycorrhiza if conditions are unfavorable for trees (swamp, semi-desert, etc.)

The role of mycorrhiza formers in the biocenosis

The functions of mycorrhizal organisms in the biocenosis, as indicated in the book by L. G. Garibova "The Mysterious World of Fungi", are as follows:

Mycorrhizal formers convert nitrogen-containing compounds of the upper soil layer into a form that can be assimilated by plants.
Mycorrhizal fungi contribute to the supply of phosphorus, calcium and potassium to plants.
The mycorrhizal fungus increases the area of food and water supply to plants. In arid conditions of deserts and semi-deserts, woody plants receive soil nutrition due to mycorrhiza formers.
Protection of plants from pathogenic microorganisms.

Literature

Burova L.G. The mysterious world of mushrooms - Moscow: Nauka, 1991.

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21.03.2018

Every year the population of people on Earth is increasing. If the dynamics of growth does not undergo any changes, then the milestone of 8 billion people on the planet will be surpassed in 2024, and scientists from the UN claim that by 2100 the population of the planet will already be 11 billion (!) People. Therefore, the problem of food security is already facing humanity today is extremely acute.

Technologies used in agriculture at present, they mainly focus on the use of highly efficient varieties and the use of produced chemically fertilizers and growth stimulants. However, in the near future, as predicted by most scientists, the maximum limit of their effectiveness will be reached, so farmers around the world today are faced with the search for new and non-standard solutions Problems.

One of these solutions is based on the direct use of the capabilities of the earth's ecosystem, including living microorganisms, organic matter and minerals. Microscopic organisms and fungi, in the literal sense of the word, are right under our feet, while they have enormous potential to bring real benefits and economically justified benefits to agriculture.

The fact is that all higher plants and fungi are closely interconnected, being elements of one natural system, thus creating a kind of symbiosis that plays a significant role in the life of most cultures.

What is mycorrhiza?

Mycorrhiza or fungal root is a symbiotic association of the mycelium of the fungus with the roots of higher plants. This term was first introduced by Albert Bernhard Frank back in 1885.

As it turned out, about 90% of all plant varieties existing on earth contain mycorrhiza on their roots, which plays a significant role for their full growth and development.

Currently, scientists - agronomists put forward a scientifically based theory about the content of a special substance in the soil, glomalin, which is one of the varieties of vegetable protein. As it turned out, this substance accumulates in the soil precisely due to mycorrhizal fungi... Moreover, without this substance, the existence of plants is generally impossible.

Thanks to mycorrhiza, the absorbing root surface of most plants increases up to 1000 (!) Times. At the same time, these mushrooms contribute to a significant improvement in the soil, increase the porosity of the fertile soil layer and improve the process of its aeration.

The fact is that the root system of plants secretes glucose, which attracts symbionts or fungi that form mycorrhiza. Sensitively capturing sugar secretions, mushrooms begin to entangle the roots of plants with their hyphae, creating a mycelium, and even have the ability to penetrate deeply into the culture. The point of this penetration is to be able to transfer nutrients to each other.

Propagating on the roots of plants, fungi create a mass of thin absorbent threads, which have the ability to penetrate into the smallest pores of the minerals in the earth, thereby increasing the absorption of nutrients and moisture. Surprisingly, one cubic centimeter can contain mycorrhiza with a total length of threads up to 40 meters (!).

These threads, destroying minerals, extract from the soil the most valuable macro and microelements (for example, phosphorus), which are then supplied to plants.

At the same time, cultures infected with the fungus better resist various pathogenic infections, since mycorrhiza stimulate their protective functions.

Varieties of mycorrhiza

There are several varieties of mycorrhiza, but there are two main types:

Internal (endomycorrhiza). With internal mycorrhiza, fungi are formed directly in the root system of plants, therefore, the use of endomycorrhiza is more effective and is already used in agriculture.

Most often given view mycorrhiza is found on cultivated garden fruit trees (apple, pear, and so on), it can also be found on berry and grain crops, on some types of legumes and vegetables (in particular, tomatoes and eggplants). Endomycorrhiza is typical for most decorative crops and flowers.

· External or external (ectomycorrhiza). With external mycorrhiza, the fungus braids the root from the outside, not penetrating inside it, but forming around the roots some formations like a cover (hyphae mantle).

This type of symbiosis is less effective for use in agriculture, since the exchange nutrients is mainly one-sided, in which the mushroom consumes the sugar synthesized by the plant (glucose). Due to the action of special hormones secreted by the fungus, young plant roots begin to branch and thicken profusely.

Nevertheless, external ectomycorrhiza also provides plants with tangible benefits, helping them to survive the harsh winter time, because, together with sugars, the mushroom takes away excess moisture from the plant.

Most often, external ectomycorrhiza can be found in forests (in oak forests, birch groves, willows, poplars, maples, and so on, but it is especially characteristic of coniferous plant species), where fungi create a dense mycelium around the root system of trees.

Stages of germination of endomycorrhiza

Initially, fungal spores form special attachments to the root system of plants in the form of growths (suckers), which are called apressoria. Gradually, hyphae (a special process coming from the mycelium) begins to penetrate from these formations into the root. Hyphae is able to penetrate the outer epidermis, thus getting into the inner tissues of the root system, where it begins to branch out, forming a fungal mycelium. Then the hyphae penetrate into plant cells, where they create arbuscules in the form of complex branches, in which an intensive exchange of nutrients is carried out.

Arbuscules can exist for several days, and then dissolve, while instead of old hyphae, new arbuscules begin to form. This process programmed, controlled by a special set of genes, and is a hereditary systemic model responsible for the reconstruction of mycorrhiza.

Mycorrhiza in the service of man

Due to the fact that mycorrhiza have a positive effect on plants, contributing to their rapid growth and development, these mushrooms are increasingly used in agriculture, horticulture and forestry.

Alas, until scientists have learned how to control the process of mycorrhiza behavior, so they are not yet amenable to change and are poorly controlled. Nevertheless, even today mycorrhiza is actively used by some farms to support the growth and development of plants (especially young ones).

Mycorrhiza fungi are also used in highly depleted soils and in regions experiencing regular irrigation water problems. In addition, they are effectively used in regions in which man-made disasters have occurred, since mushrooms successfully resist various pollution, including extremely toxic (for example, mycorrhiza perfectly level negative impact heavy metals).

Among other things, this type of mushroom perfectly fixes nitrogen and solubilizes phosphorus, turning it into a more accessible and well-assimilated form by plants. Of course, this fact affects the yield of crops, moreover, without the use of expensive fertilizers.

It is noticed that plants treated with mycorrhiza give more friendly shoots, their root system develops better, and the consumer qualities and sizes of fruits improve. Moreover, all products are exclusively environmentally friendly, natural.

In addition, plants treated with mycorrhiza show resistance to pathogenic organisms.

Currently, there are a lot of drugs that are used to treat plant seeds that demonstrate a positive effect.

Endomycorrhizal mushrooms are great for improving the nutrition of vegetables, ornamental plants and fruit trees.

Especially valuable is the experience of gardeners from the United States, who chose a land completely devoid of fertility for planting fruit trees. The use of mycorrhizal preparations allowed scientists, even under such unfavorable conditions, after a while to create a blooming garden in this place.

Beneficial features mycorrhiza

Saves moisture (up to 50%)

Accumulates useful macro and microelements, thereby improving the growth and development of plants

Increases the resistance of plants to unfavorable climatic and weather conditions, and also resists salts and heavy metals, leveling the strong contamination of the soil with toxins

Increases productivity, improves the presentation and taste of fruits

· Helps to resist various pathogens and harmful organisms (for example, the fungus is effective against nematodes). Some varieties of fungi can suppress up to 60 varieties of pathogens that cause rot, scab, late blight, fusarium and other diseases

Increases plant immunity

Promotes the acceleration of the flowering process

Accelerates the process of survival of crops and has a positive effect on the growth of green mass

In fact, mycorrhiza has existed in nature for 450 million years and still works effectively, helping to diversify modern species cultures.

Mycorrhiza works on the principle of a pump, absorbing water from the soil and extracting useful substances from the soil, and in response, receiving vital carbohydrates for itself. Its spores can spread over tens of meters, covering a much larger area than conventional crops can afford. Therefore, thanks to such close cooperation, plants bear fruit better, show resistance to various diseases, tolerate adverse weather conditions and poor soils well.

Is mycorrhiza the future? Time will tell.

In order to more clearly imagine what the mycorrhiza of tree roots looks like externally, it is necessary to compare the appearance of root endings with mycorrhiza with the appearance of roots without it. The roots of the warty euonymus, for example, devoid of mycorrhiza, branch sparsely and are the same throughout, in contrast to the roots of rocks that form mycorrhiza, in which the mycorrhizal sucking ends differ from the growth ones, not mycorrhizal. The mycorrhizal sucking ends are either club-like swelling at the tip of an oak tree, or they form very characteristic "forks" and their complex complexes, resembling corals, in a pine, or have the shape of a brush in a spruce. In all these cases, the surface of the sucking ends under the influence of the fungus greatly increases. Having made a thin section through the mycorrhizal end of the root, one can make sure that the anatomical picture is even more varied, that is, the cover of mushroom hyphae that braids the root end can be of different thickness and color, be smooth or fluffy, consisting of so dense intertwined hyphae, which gives the impression of real tissue or, conversely, be loose.

It happens that the cover does not consist of one layer, but of two, differing in color or structure. The so-called Gartig network, that is, the hyphae that go through the intercellular spaces and together form a really something like a network, can also be expressed to varying degrees. V different cases this network can extend to more or less layers of cells of the root parenchyma. The hyphae of the fungus partially penetrate into the cells of the crustal parenchyma, which is especially pronounced in the case of mycorrhiza of aspen and birch, and are partially digested there. But no matter how peculiar the picture internal structure mycorrhizal roots, in all cases it is clear that the fungal hyphae do not at all enter the central cylinder of the root and the meristem, that is, into that zone of the root end, where due to increased cell division, the growth of the root occurs. All such mycorrhizae are called ectoendotrophic, since they have both a superficial sheath with hyphae extending from it, and hyphae passing through the root tissue.

Not all tree species have mycorrhiza types as described above. In maple, for example, mycorrhiza is different, that is, the fungus does not form an outer sheath, but in the cells of the parenchyma one can see not separate hyphae, but whole tangles of hyphae, often filling the entire space of the cell. Such mycorrhiza is called endotrophic (from the Greek "endos" - inside, and "trophy" - food) and is especially characteristic of orchids. The appearance of mycorrhizal endings (shape, branching, depth of penetration) is determined by the species of the tree, and the structure and surface of the cover depend on the type of fungus that forms mycorrhiza, and, as it turned out, not one, but two fungi can simultaneously form mycorrhiza.

What fungi form mycorrhiza and with what breed? It was not easy to resolve this issue. V different time proposed for this different methods, right up to careful tracing of the course of fungal hyphae in the soil from the base of the fruiting body to the root end. The most effective method it turned out that a certain type of fungus was sown under sterile conditions in the soil on which a seedling of a certain tree species was grown, that is, when the synthesis of mycorrhiza was carried out under experimental conditions. This method was proposed in 1936 by the Swedish scientist E. Melin, who used a simple chamber consisting of two flasks connected to each other. In one of them, a sterile pine seedling was grown and a fungus was introduced in the form of a mycelium taken from a young fruiting body at the place where the cap passes into the leg, and in the other there was liquid for the necessary soil moisture. Subsequently, scientists who continued to work on the synthesis of mycorrhiza made various improvements in the structure of such a device, which made it possible to conduct experiments under more controlled conditions and for a longer time.

By using Melin's method, by 1953, the connection was experimentally proved. tree species with 47 species of mushrooms from 12 genera. To date, it is known that mycorrhiza with woody species can form more than 600 species of fungi from such genera as fly agarics, ryadovki, hygrophors, some lactarius (for example, milk mushrooms), russula, etc., and it turned out that everyone can form mycorrhiza not with one, and with different breeds trees. In this respect, all records were broken by the marsupial fungus with sclerotia, the graniform cenococcus, which, under the experimental conditions, formed mycorrhiza with 55 species of tree species. The greatest specialization is characterized by sublarch butter dish, which forms mycorrhiza with larch and cedar pine.

Some genera of fungi are not capable of forming mycorrhiza - talkers, colibia, omphalia, etc.

And yet, despite such a wide specialization, the effect of different mycorrhizal fungi on the higher plant is not the same. So, in the mycorrhiza of Scots pine, formed by an oiler, the absorption of phosphorus from hard-to-reach compounds occurs better than when the fly agaric participates in the formation of mycorrhiza. There are other facts that confirm this. It is very important to take this into account in practice and when taking mycorrhization of tree species for their better development you should select such a mushroom for a particular breed, which would have the most beneficial effect on it.

It has now been established that mycorrhizal hymenomycetes do not form fruiting bodies in natural conditions without connection with tree roots, although their mycelium may exist saprotrophically. That is why until now it was impossible to grow milk mushrooms, camelina mushrooms, porcini mushrooms, aspen mushrooms and other valuable species of edible mushrooms on the beds. However, in principle it is possible. Someday, even in the not too distant future, people will learn to give the mycelium everything that it receives from cohabitation with the roots of trees, and will make it bear fruit. In any case, such experiments are carried out under laboratory conditions.

As for tree species, spruce, pine, larch, fir, perhaps most of other conifers, are considered mycotrophic to a high degree, and oak, beech and hornbeam as deciduous species. Birch, elm, hazel, aspen, poplar, linden, willow, alder, mountain ash, bird cherry are weakly mycotrophic. These species of trees have mycorrhiza in typical forest conditions, and in parks, gardens and when they grow as separate plants, they may not have it. In such fast-growing species as poplar and eucalyptus, the absence of mycorrhiza is often associated with the rapid consumption of the formed carbohydrates during intensive growth, i.e. carbohydrates do not have time to accumulate in the roots, which is necessary condition for the settlement of a fungus on them and the formation of mycorrhiza.

What are the relationships between the components in mycorrhiza? One of the first hypotheses about the nature of mycorrhiza formation was proposed in 1900 by the German biologist E. Stahl. It consisted in the following: in the soil, there is a fierce competition between various organisms in the struggle for water and mineral salts. It is especially pronounced in the roots of higher plants and the mycelium of fungi in humus soils, where there are usually a lot of fungi. Those plants that had a powerful root system and good transpiration did not suffer much under the conditions of such competition, while those in which the root system was relatively weak and transpiration was low, i.e., plants that were not able to successfully suck soil solutions, left predicament, forming a mycorrhiza with a powerfully developed system of hyphae, penetrating the soil and increasing the absorption capacity of the root. The most vulnerable point of this hypothesis is that there is no direct relationship between water absorption and absorption of mineral salts. Thus, plants that quickly absorb and quickly evaporate water are not the most armed in the competition for mineral salts.

Other hypotheses were based on the ability of fungi to act with their enzymes on lignin-protein complexes of the soil, destroy them and make them available to higher plants. Assumptions were also made, which were confirmed in the future, that the fungus and the plant can exchange growth substances, vitamins. Fungi as heterotrophic organisms requiring ready-made organic matter receive primarily carbohydrates from the higher plant. This was confirmed not only by experiments, but also by direct observations. For example, if trees grow in a forest in highly shaded places, the degree of mycorrhiza formation is greatly reduced, since carbohydrates do not have time to accumulate in the roots in the required amount. The same applies to fast-growing tree species. Consequently, in thinned forest stands, mycorrhiza forms better, faster and more abundantly, and therefore the process of mycorrhiza formation can improve during thinning.