Plants do not form mycorrhiza with any fungi. Mushrooms are mycorrhizal. Noticeable effect of mycorrhizae

Kira Stoletova

Everything on our planet is interconnected. A striking example of this is the concept of mushroom root. If this word is parsed, then it implies the life of a fungus on the root of plants. This is one of milestones symbiosis, which implies the life of a representative of one class at the expense of another and has the definition of mycorrhiza. But this is not always the case in nature. Some fungi do not form mycorrhiza and develop on their own.

What is fungus root

The concept itself is embedded in the word. This is one of the facts of the existence of a joint tandem between representatives of fungi and plants: the fungus develops on the roots of trees and shrubs, it forms a mycelium that penetrates into the thickness of the plant bark.

There are several types mycorrhizal fungi, which can develop both on the surface layers and penetrate directly into the thickness of the root, sometimes piercing it through. This is especially true for shrubs.

The fungus feeds on its "master" - and this is an indisputable fact. But if you conduct detailed studies, you can emphasize the benefits for each of the parties.

At the same time, the fungus itself also helps the plant to develop normally, providing it with the necessary nutritional components. It makes the roots of the plant looser, due to the fact that they are intertwined with mycelium. The porous structure allows more to absorb moisture to the plant and, accordingly, additional nutrients.

At the same time, there is an additional quality - the ability to extract nutrients from different types soils. As a result, when the tree is unable to obtain the required components from environment, mycorrhizal fungus comes to the rescue, delivering for itself and its owner an additional portion for life and development. That will not allow both representatives to dry out.

Varieties

The following fungi form mycorrhiza with roots:

1. Myccorisa ectotrophyca - spreads only in the upper layers;
2. Myccorisa endotrophyca - mycelium develops in the thickness of the root, sometimes piercing the body almost through;
3. Ectotrophyca, endotrophyca myccorisa (mixed type) - characterized by the peculiarity of each of the upper species, spreading its mycelium both on the surface and in the thickness of the root;
4. Peritrophyca myccorisa is a simplified form of symbiosis and at the same time a new stage in development. It is a placement near the root without penetration of processes.

What fungi form mycorrhiza with roots

The group of the above types includes many representatives of the edible and inedible classes:

• Gymnosperms;
• monocots;
• Dicotyledonous.

Their representatives are considered to be beloved by all porcini mushrooms, aspen mushrooms, honey mushrooms, chanterelles, boletus. Some types of mushrooms got their name precisely due to the distribution on a certain representative of plants. For example, aspen and boletus, birch and boletus, as well as others.

It is worth noting that the representative of the poisonous class, fly agaric, forms its own mycelium on the surface. coniferous trees. And although it is not edible, it provides its “master” with 100% nutritional components.

Fungi that do not form mycorrhiza

Conclusion

In the world there are fungi that do not form mycorrhiza, and those that form it. Among all the listed species, there are both edible and poisonous. But it is necessary to understand that each representative is very important, it performs certain functions in nature and without it, perhaps, some vital biological processes would not occur.

In order to visualize more clearly what the mycorrhiza of tree roots looks like, 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 sucking mycorrhizal endings differ from the growth, not mycorrhizal ones. Mycorrhizal sucking endings either swell club-shaped at the tip in oak, or form very characteristic "forks" and complex complexes of them, resembling corals, in pine, or have the shape of a brush in spruce. In all these cases, the surface of the sucking endings greatly increases under the action of the fungus. Having made a thin cut through the mycorrhizal end of the root, one can be convinced that the anatomical picture is even more diverse, i.e., the sheath of fungal hyphae braiding the root end can be of different thickness and color, be smooth or fluffy, consisting of such 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 from each other in color or structure. The so-called Hartig network can also be expressed to varying degrees, i.e., hyphae that go along the intercellular spaces and form together really something like a network. AT different occasions this network may extend to more or fewer layers of root parenchyma cells. The hyphae of the fungus partially penetrate into the cells of the cow parenchyma, which is especially pronounced in the case of aspen and birch mycorrhiza, and are partially digested there. But no matter how peculiar the picture internal structure mycorrhizal roots, in all cases it is clear that the hyphae of the fungus do not enter at all into the central cylinder of the root and into the meristem, i.e., into that zone of the root end, where the root grows due to increased cell division. All such mycorrhiza are called ectoendotrophic, since they have both a superficial sheath with hyphae extending from it, and hyphae passing inside the root tissue.

Not all tree species have mycorrhiza of the types described above. In maple, for example, mycorrhiza is different, that is, the fungus does not form an outer cover, but in the cells of the parenchyma one can see not separately running hyphae, but whole balls of hyphae, often filling the entire space of the cell. Such mycorrhiza is called endotrophic (from the Greek "endos" - inside, and "trophe" - nutrition) and is especially characteristic of orchids. Appearance mycorrhizal endings (shape, branching, penetration depth) are determined by the tree species, 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. At various times it was proposed for this different methods, up to careful tracing of the course of fungal hyphae in the soil from the base of the fruiting body to the root end. by the most effective method turned out to be sowing under sterile conditions of a certain type of fungus in the soil on which a seedling of a certain tree species was grown, that is, when mycorrhiza was synthesized 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 mycelium taken from a young fruiting body at the transition point of the cap to the stem, and in the other there was a liquid for the necessary soil moisture. Subsequently, scientists who continued to work on the synthesis of mycorrhiza made various improvements to the structure of such a device, which made it possible to conduct experiments under more controlled conditions and for a longer time.

When using the Melin method, by 1953, the relationship of tree species with 47 species of fungi from 12 genera was experimentally proven. To date, it is known that mycorrhiza with tree species can form more than 600 species of fungi from such genera as fly agaric, rowing, hygrophores, some lactic (for example, milk mushrooms), russula, etc., and it turned out that each can form mycorrhiza not with one, but with various breeds trees. In this regard, all records were broken by the marsupial fungus, which has sclerotia, granular coenococcus, which, under experimental conditions, formed mycorrhiza with 55 species of tree species. The greatest specialization is characterized by sublarch butterdish, which forms mycorrhiza with larch and with cedar pine.

Some genera of fungi are not able to form mycorrhiza - govorushki, kollybia, omfalia, etc.

And yet, despite such a wide specialization, the effect of different mycorrhiza-forming fungi on a higher plant is not the same. So, in the mycorrhiza of Scots pine, formed by the butter dish, 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, one should select such a fungus for a particular species that would have the most beneficial effect on it.

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

As regards tree species, high degree spruce, pine, larch, fir, and possibly most other conifers are considered mycotrophic, and oak, beech and hornbeam from deciduous species. Birch, elm, hazel, aspen, poplar, linden, willow, alder, mountain ash, bird cherry are weakly mycotrophic. These tree species have mycorrhiza in typical forest conditions, but in parks, gardens, and when growing as individual plants, they may not have it. In such fast-growing species as poplar and eucalyptus, the absence of mycorrhiza is often associated with their rapid consumption of carbohydrates formed during intensive growth, i.e., carbohydrates do not have time to accumulate in the roots, which is necessary condition for the settlement of the 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 was as follows: in the soil there is fierce competition between various organisms in the struggle for water and mineral salts. It is especially pronounced in the roots of higher plants and mycelium of fungi in humus soils, where there are usually a lot of fungi. Those plants that had a strong root system and good transpiration did not suffer much in the conditions of such competition, and those with a relatively weak root system and low transpiration, i.e., plants that were not able to successfully absorb soil solutions, left the predicament, forming 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 the absorption of water and the absorption of mineral salts. Thus, rapidly absorbing and rapidly evaporating water plants 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 the lignin-protein complexes of the soil, destroy them and make them available to higher plants. There were also suggestions, which were confirmed later, that the fungus and the plant can exchange growth substances, vitamins. Fungi, as heterotrophic organisms that need ready-made organic matter, receive primarily carbohydrates from a higher plant. This was confirmed not only by experiments, but also by direct observations. For example, if trees grow in heavily shaded places in the forest, the degree of mycorrhiza formation is greatly reduced, since carbohydrates do not have time to accumulate in the roots in the proper amount. The same applies to fast-growing tree species. Consequently, in sparse forest plantations, mycorrhiza forms better, faster and more abundantly, and therefore the process of mycorrhiza formation can improve during thinning.

Currently, about 300 thousand plant species grow on our land, of which 90% (according to other sources, even more) live in close cooperation with mushrooms, and these are not only trees and shrubs, but also herbs.

This relationship between plants and fungi scientific world received the name mycorrhiza (i.e. mushroom root; from the Greek. mykes- mushroom, rhiza- root). At present, only a small part of the plants (and this certain types from the family of amaranth, haze, cruciferous) can do without mycorrhiza, while most of them interact with fungi to one degree or another.

Some plants cannot do without mushrooms at all. For example, in the absence of symbiont fungi, orchid seeds do not germinate. Orchids throughout their lives are fed by mycorrhiza, although they have a photosynthetic apparatus and can independently synthesize organic substances.

The first who drew attention to the need for fungi for plants were foresters. After all, a good forest is always rich in mushrooms. The connection of mushrooms with certain trees is indicated by their names - boletus, boletus, etc. In practice, foresters encountered this only during artificial afforestation. At the beginning of the 20th century, attempts were made to plant a forest on the steppe lands, especially with respect to the planting of valuable species - oaks and conifers. In the steppes, mycorrhiza did not form on the roots of tree seedlings, and the plants died. Some immediately, others a few years later, others eked out a miserable existence. Then the scientists proposed, when planting, along with seedlings, to introduce forest soil from the areas where these plants grew. Plants in this case began to grow much better.

The same thing happened when trees were planted on waste heaps, dumps during the development of ore deposits, and during the reclamation of contaminated areas. It has now been proven that the introduction of forest soil (and with it fungal hyphae) has a positive effect on the survival rate of young trees and serves important condition their successful cultivation in treeless areas. The possibility of stimulating mycorrhiza formation due to local fungi present in soils, by selecting a number of agrotechnical methods (loosening, watering, etc.), was also revealed. A method has also been worked out for introducing pure cultures of mycorrhiza-forming fungi together with seedlings and seeds.

At first glance, it may seem that mushrooms live only in forests and soils rich in organic matter. However, this is not the case; they are found in all types of soils, including deserts. There are few of them only in soils where they are abused mineral fertilizers and herbicides, and is completely absent in soils devoid of fertility and treated with fungicides.

Mushroom spores are so small that they are carried by the wind over long distances. AT favorable conditions spores germinate and give rise to a new generation of fungi. Especially favorable for the development of fungi are moist soils rich in organic matter.

Can all fungi form mycorrhiza, i.e. live with plants? Among the huge variety of fungi (and according to various estimates there are 120-250 thousand species), about 10 thousand species are phytopathogens, the rest are saprophytic fungi and mycorrhiza-forming fungi.

Mushrooms - saprophytes live in the surface layer of the soil, among a large amount of dead organic matter. They have special enzymes that allow them to decompose plant litter (mainly cellulose and lignin), and, accordingly, provide themselves with food. The role of saprophyte fungi can hardly be overestimated. They process a huge mass of organic residues - leaves, needles, branches, stumps. They are active soil formers because they process great amount dead vegetation. Fungi free the surface of the soil and prepare it for the colonization of new generations of vegetation. The released minerals are re-consumed by the plants. Saprophytic fungi abound in forest litter, peat bogs, humus, and soils rich in organic matter. Forest soils are completely permeated with the mycelium of these fungi. So, in 1 gram of soil, the length of the hyphae of these fungi reaches a kilometer or more.

Mycorrhizal fungi do not have such enzymes, which is why they cannot compete with fungi that decompose dead vegetation. Therefore, they have adapted to coexistence with the roots of plants, where they receive the food they need.

What is mycorrhiza, and what fungi form it? The fungus with its threads (hyphae) braids the root, forming a kind of sheath up to 40 microns thick there. The thinnest threads stretch from it in all directions, penetrating the soil for tens of meters around the tree. Some types of fungi remain on the surface of the root, others grow inside it. Still others represent a transitional form intermediate between them.

Mycorrhiza, which braids the root, is characteristic of woody plants and perennial herbs. It is formed mainly by cap mushrooms: boletus, boletus, porcini mushrooms, russula, fly agaric, pale grebe, etc. That is, both edible and poisonous mushrooms for humans. For plants, all mushrooms are useful and necessary, regardless of their taste. Therefore, in no way should you destroy mushrooms, including poisonous ones.

Cap mushrooms, such as oyster mushrooms, mushrooms, champignons, umbrellas, dung beetles, are saprophytes (i.e., they feed on wood, manure or other organic matter), they do not form mycorrhiza.

The mushrooms that we collect in the forest are mycorrhiza fruiting bodies. Mushrooms are somewhat reminiscent of an iceberg, the apical part of which is represented by fruiting bodies (mushrooms in the everyday sense), necessary for the formation and spread of spores. The underwater part of the iceberg is mycorrhiza, which braids the roots of plants with its threads. It sometimes stretches for tens of meters. This can be judged at least by the size of the "witch rings".

In other fungi, the hyphae penetrate the tissues and cells of the root, receiving food for themselves from there. This is not carried out without the participation of the plant, because. in this case, the process of transferring nutrients is easier. In the presence of such fungi, plant roots undergo significant morphological changes, they branch intensively, forming special protrusions and outgrowths. This occurs under the action of growth substances secreted by fungi (auxins). This is the most common type of mycorrhiza in herbaceous plants and some trees (apple, maple, elm, alder, lingonberry, heather, orchids, etc.).

Some plants, such as orchids, heather, can develop normally only in the presence of mycorrhizal fungi. In others (oak, birch, conifers, hornbeam) - mycotrophy occurs almost always. There are plants (acacia, linden, birch, some fruit trees, many shrubs), which can develop normally both with and without fungi. This largely depends on the availability of nutrients in the soil; if there are a lot of them, then the need for mycorrhiza disappears.

A strong connection is established between the plant and fungi, and very often certain types of fungi are also characteristic of certain groups of plants. Most host plants do not have a strict specialization towards fungi. They can form mycorrhiza with several fungal species. For example, boletus, porcini mushroom, red mushroom, volnushka, milk mushrooms, russula, red fly agaric and others develop on a birch. On the aspen - boletus, russula, aspen breast. On different types of spruce - butterdish, white mushroom, camelina, yellow pickle, types of russula and cobwebs, different types of fly agaric. On the pine - white mushroom, Polish mushroom, real butter dish, granular butter dish, flywheel, russula, camelina, fly agaric. However, there are plants that are "served" by only one fungus. For example, larch butterdish creates mycorrhiza only with larch.

At the same time, there are also so-called universal mushrooms (among which, oddly enough, the red fly agaric), which are able to create mycorrhiza with many trees (both coniferous and deciduous), shrubs and herbs. The number of mushrooms that "serve" certain trees is different. So in pine there are 47 species, in birch - 26, in spruce - 21, in aspen - 8, and in linden - only 4.

Why is mycorrhiza useful for higher plants? The mycelium of the fungus replaces the root hairs of the plant. Mycorrhiza is, as it were, a continuation of the root itself. When mycorrhiza appears in many plants, due to the lack of need, root hairs do not form. The mycorrhizal cover with numerous fungal hyphae extending from it significantly increases the surface of absorption and supply of plants with water and minerals. For example, in 1 cm 3 of the soil surrounding the root, the total length of the mycorrhiza threads is 20-40 meters, and they sometimes go away from the plant for tens of meters. The absorbing surface of the branched filaments of the fungus in mycorrhiza is 1000 times larger than the surface of the root hairs, which sharply increases the extraction of nutrients, as well as water from the soil. In mycorrhizal plants, a more intensive exchange of nutrients with the soil is observed. In the mushroom cover accumulate in in large numbers phosphorus, nitrogen, calcium, magnesium, iron, potassium and other minerals.

Threads (hyphae) of fungi are much thinner than root hairs and are about 2-4 microns. Due to this, they can penetrate into the pores of soil minerals, where there are minute amounts of pore water. In the presence of fungi, plants tolerate drought much better, because fungi extract water from the smallest pores, from where plants cannot get it.

Fungal hyphae secrete various organic acids (malic, glycolic, oxalic) into the medium and are capable of destroying soil minerals, in particular limestone, marble. They are too tough for even such durable minerals as quartz and granite. By dissolving minerals, they extract from them the mineral elements of plant nutrition, including such as phosphorus, potassium, iron, manganese, cobalt, zinc, etc. Plants without fungi are unable to extract these elements from minerals on their own. These minerals are found in mycorrhiza in combination with organic substances. Due to this, their solubility is reduced, and they are not washed out of the soil. Thus, balanced plant nutrition, which is provided by the development of mycorrhiza, stimulates their harmonious development, which affects productivity and the ability to withstand adverse environmental factors.

In addition, fungal hyphae provide plants with vitamins, growth hormones, some enzymes and other substances useful for plants. This is especially important for some plants (for example, corn, onions) that lack root hairs. Many types of mycorrhizal fungi secrete antibiotics and thus protect plants from pathogens. With antibiotics, they protect their habitat, and with it the root of the plant. Many fungi form and release growth-stimulating substances into the environment, which activate the growth of roots and above-ground organs, accelerate the processes of metabolism, respiration, etc. In this way, they stimulate the release of the nutrients they need by the plant. Consequently, fungi with the products of their vital activity activate the activity of the root system of plants.

And what do mushrooms get in return? It turns out that plants donate up to 20-30% (according to some sources, up to 50%) of the organic matter synthesized by them to fungi, i.e. they feed mushrooms with easily digestible substances. Root secretions contain sugars, amino acids, vitamins and other substances.

Studies have shown that mycorrhizal fungi are completely dependent on the plants with which they form mycorrhiza. Indeed, it has long been noted that the appearance of fruiting bodies of fungi occurs only in the presence of plants - symbionts. This phenomenon has been noted for russula, cobwebs, and especially for tubular mushrooms - porcini, boletus, boletus, saffron mushrooms, fly agaric. Indeed, after cutting down the trees, the fruiting bodies of the accompanying mushrooms also disappear.

It has been established that there are complex relationships between fungi and plants. Mushrooms with their secretions stimulate the physiological activity of plants and the intensity of excretion of nutrients for fungi. On the other hand, the composition of the fungal community in the rhizosphere can be regulated due to substances secreted by plant roots. Thus, plants can stimulate the growth of fungi - antagonists of phytopathogens. Fungi that are dangerous to plants are inhibited not by the plants themselves, but by antagonist fungi.

However, in the plant community, as well as among people, conflicts are possible. If a new species is introduced into a stable plant community (whether on its own or planted there), the mycorrhiza prevailing in this community can get rid of this plant. It will not supply him with nutrients. A plant of this objectionable species will gradually weaken and eventually die.

You and I have planted some kind of tree and we are surprised that it grows poorly, not knowing about the “undercover” struggle. This has a certain ecological meaning. A new plant, having established itself in a new community for itself, sooner or later will “bring” along its own mycorrhiza, which will be an antagonist to the existing one. Isn't that what happens in human society? The new boss always brings his “team”, which most often comes into conflict with the established team.

Further research led to even more surprises, the role of mycorrhiza in the plant community. It turns out that the hyphae of fungi, intertwining with each other, are able to form the so-called "communication networks" and connect one plant with another. Plants with the help of fungi can exchange nutrients and various stimulants with each other. A kind of mutual aid was discovered, when stronger plants feed the weak ones. This allows plants, being at some distance, to interact with each other. Plants with very small seeds are especially in need of this. The microscopic seedling could not have survived if it had not been taken care of at first by the general nutrient network. The exchange of nutrients between plants has been proven by experiments with radioactive isotopes. Special experiments have shown that seedling plants grown by self-sowing near the parent plant develop better than isolated or transplanted ones. It is possible that seedlings are connected to the mother plant through a fungal "umbilical cord" through which mature plant fed a small sprout. However, this is possible only in natural biocenoses with established symbiotic relationships.

In such "communication networks" communication is not only trophic, but also informational. Turns out, remote friend from each other, plants with a certain impact on one of them - react to this impact instantly and in the same way. Information is transmitted through the transfer of specific chemical compounds. This is somewhat reminiscent of the transmission of information through our nervous system.

These experiments showed that the plants in the community are not just plants growing side by side, but a single organism, connected into a whole by an underground network of numerous very thin filaments of fungi. Plants are "interested" in a stable community, which allows them to resist the invasion of aliens.

After reading, a natural desire immediately arises to improve the life of their garden and horticultural crops through mycorrhiza. What needs to be done for this? There are many various ways, the essence of which is to introduce into root system cultivated plant a small amount of "forest" land where mycorrhizal fungi are presumably present. It is possible to introduce a pure culture of mycorrhizal fungi, which are commercially available, into the root system, which is quite expensive. However, in our opinion, the most in a simple way is next. They collect caps of well-ripened (old, wormy) mushrooms, preferably of different types, including inedible ones. They are placed in a bucket of water, stirred to wash off the spores on them, and garden and horticultural crops are watered with such water.

During the implementation of the project, state support funds were used, allocated as a grant in accordance with the order of the President Russian Federation dated March 29, 2013 No. 115-rp”) and on the basis of a competition held by the Knowledge Society of Russia.

A.P. Sadchikov,
Moscow Society of Naturalists
http://www.moip.msu.ru
[email protected]

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Photo of symbiosis of mushrooms with roots

A striking example of the symbiosis of fungi is mycorrhiza - the commonwealth of fungi and higher plants ( various trees). With such “cooperation”, both the tree and the mushroom win. Settling on the roots of the tree, the fungus will perform the function of absorbing root hairs, and helps the tree absorb nutrients from the soil. With such a symbiosis, the fungus receives ready-made organic substances (sugars) from the tree, which are synthesized in the leaves of the plant with the help of chlorophyll.

In addition, during the symbiosis of fungi and plants, the mycelium produces substances such as antibiotics that protect the tree from various pathogenic bacteria and pathogenic fungi, as well as growth stimulants such as gibberellins. It is noted that the trees under which hat mushrooms grow practically do not get sick. In addition, the tree and mushroom actively exchange vitamins (mainly B and PP groups).

Many cap mushrooms form a symbiosis with roots. various kinds plants. Moreover, it has been established that each type of tree is able to form mycorrhiza not with one type of fungus, but with dozens of different species.

In the photo Lichen

Another example of the symbiosis of lower fungi with organisms of other species are lichens, which are an alliance of fungi (mainly ascomycetes) with microscopic algae. What is the manifestation of the symbiosis of fungi and algae, and how does such “cooperation” take place?

Until the middle of the 19th century, it was believed that lichens are separate organisms, but in 1867, Russian botanists A. S. Famintsyn and O. V. Baranetsky established that lichens are not separate organisms, but a commonwealth of fungi and algae. Both symbiotes benefit from this union. With the help of chlorophyll, algae synthesize organic substances (sugars), which the mycelium feeds on, and the mycelium supplies the algae with water and minerals that it sucks out of the substrate, and also protects them from drying out.

Thanks to the symbiosis of the fungus and algae, lichens live in places where neither fungi nor algae can exist separately. They inhabit sultry deserts, highlands and harsh northern regions.

Lichens are even more mysterious creatures of nature than mushrooms. They change all the functions that are inherent in separately living fungi and algae. All vital processes in them proceed very slowly, they grow slowly (from 0.0004 to several mm per year), and age just as slowly. These unusual creatures are distinguished by a very long life span - scientists suggest that the age of one of the lichens in Antarctica exceeds 10 thousand years, and the age of the most common lichens that are found everywhere is at least 50-100 years.

Lichens, thanks to the community of fungi and algae, are much more hardy than mosses. They can live on substrates on which no other organism on our planet can exist. They are found on stone, metal, bones, glass and many other substrates.

Lichens still continue to amaze scientists. They found substances that no longer exist in nature and which became known to people only thanks to lichens (some organic acids and alcohols, carbohydrates, antibiotics, etc.). The composition of lichens, formed by the symbiosis of fungi and algae, also includes tannins, pectins, amino acids, enzymes, vitamins and many other compounds. They accumulate various metals. Of the more than 300 compounds contained in lichens, at least 80 of them are not found anywhere else in the living world of the Earth. Every year, scientists find new substances in them that are not found in any other living organisms. Currently, more than 20 thousand species of lichens are already known, and every year scientists discover several dozen new species of these organisms.

This example shows that symbiosis is not always a simple cohabitation, and sometimes gives rise to new properties that none of the symbionts had separately.

There are many such symbioses in nature. With such a commonwealth, both symbionts win.

It has been established that the desire for association is most developed in mushrooms.

Mushrooms enter into symbiosis with insects. An interesting commonwealth is the connection of some species mold fungi with leaf cutter ants. These ants specially breed mushrooms in their dwellings. In separate chambers of the anthill, these insects create entire plantations of these mushrooms. They specially prepare the soil on this plantation: they bring in pieces of leaves, grind them, “fertilize” with their feces and the feces of caterpillars, which they specially keep in the neighboring chambers of the anthill, and only then bring the smallest hyphae of fungi into this substrate. It has been established that ants breed only mushrooms of certain genera and species, which are not found anywhere in nature, except for anthills (mainly fungi of the genera Fusarium and Hypomyces), and each species of ants breeds certain types of mushrooms.

Ants not only create a mushroom plantation, but also actively care for it: they fertilize, cut and weed. They cut off the fruiting bodies that have appeared, preventing them from developing. In addition, ants bite off the ends of fungal hyphae, as a result of which proteins accumulate at the ends of the bitten hyphae, and swells are formed that resemble fruiting bodies, which the ants then feed on and feed their babies. In addition, when the hyphae are cut, the mycelium of the fungi begins to grow faster.

"Weeding" is as follows: if mushrooms of other species appear on the plantation, the ants immediately remove them.

Interestingly, when creating a new anthill, the future queen, after the mating flight, flies to a new place, begins to dig passages for the dwelling of her future family, and creates a mushroom plantation in one of the chambers. She takes mushroom hyphae from an old anthill before the flight, placing them in a special under-mouth bag.

Similar plantations are bred and termites. In addition to ants and termites, bark beetles, borer insects, some types of flies and wasps, and even mosquitoes are engaged in “mushroom growing”.

German scientist Fritz Schaudin discovered an interesting symbiosis of our common blood-sucking mosquitoes with the yeast actinomycetes, which help them in the process of sucking blood.

Oiler granular - forms mycorrhiza with Scots pine and other pines

Mycorrhiza formers (symbiotrophic macromycetes, mycorrhizal fungi, symbiotrophs) - mushrooms that form mycorrhiza on the roots of trees, shrubs and herbaceous plants. This is a specialized ecological group of fungi, isolated in the framework of modern mycology since the end of the 19th century. This group of fungi is specific in that its representatives enter into symbiosis with higher plants, do not have enzymes for the decomposition of cellulose and lignin and show energy dependence on the symbiont, which is the plant. The term mycorrhiza (“fungal root”) was introduced by the German fungi researcher A. V. Frank in 1885.

Mycorrhiza

Mycorrhiza - the formation of a symbiosis of a fungus and a plant. It manifests itself in the fact that the mycelium (mycelium), located 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 host. Mycorrhiza allows both the fungus and the plant to obtain the missing nutrients from the soil. In modern mycology, exotrophic and endotrophic mycorrhiza are distinguished. With exotrophic mycorrhiza (ectomycorrhiza), the hyphae of the mycelium braid the roots of plants from the outside, and with endotrophic mycorrhiza (endomycorrhiza), the hyphae penetrate into the intercellular space of the roots and inside the cells of the root parenchyma. Ectoendotrophic mycorrhiza (ectoendomycorrhiza) combines features of both ectomycorrhiza and endomycorrhiza. The phenomenon was described in 1879-1881. Russian scientist F. M. Kamensky and he also gave the first attempt to scientific explanation, the term was introduced by the German scientist A. V. Frank in 1885.

Differences between mycorrhiza-forming organisms and saprotrophs

Both mycorrhiza-forming organisms and saprotrophs use dead organic matter, in connection with which, within the framework of mycology, there is a problem of distinguishing between these groups.

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

L. A. Garibova in the book "The Mysterious World of Mushrooms" highlights the following differences, which indicate the difference in the biochemistry of these environmental groups mushrooms:

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

Symbiotrophs in the kingdom of fungi

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

Fly agaric red - forms mycorrhiza mainly with birch and spruce

Ascomycetes, basidiomycetes and zygomycetes act as mycorizoformers.

Thus, all tubular (bole fungi) are mycorrhizal fungi, many of which are edible and are collected by humans for human consumption: porcini mushrooms, boletus, aspen mushrooms, mossiness mushrooms, oak mushrooms.

Mycorrhiza is formed by some gasteromycetes, mainly of the genus False puffball, as well as some types of marsupial fungi related to truffles (species from the order of truffles ( Tuberales)).

In modern mycological literature, there are references that some fungi, for example, thin pig and lacquer, 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-forming organisms in the biocenosis

The functions of mycorrhiza-forming organisms in the biocenosis, as indicated in the book by L. G. Garibova "The Mysterious World of Mushrooms", are as follows:

1. Mycorrhiza formers transform nitrogen-containing compounds of the upper soil layer into a form that is assimilated by plants.
2. Mycorrhizal fungi contribute to the supply of plants with phosphorus, calcium and potassium.
3. Mycorrhiza-forming mycelium increases the area of ​​plant nutrition and water supply. AT arid conditions deserts and semi-deserts woody plants receive soil nutrition thanks to mycorrhiza-forming organisms.
4. Protection of plants from pathogenic microorganisms.

Literature

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