No one knows exactly when mushrooms and plants entered into a mutually beneficial alliance called mycorrhiza. It's about about the close symbiosis of the root system higher plants and mushroom mycelium. For some representatives of the flora, this alliance turned out to be vital. However, mushrooms do not go unnoticed either. What is mycorrhiza and how is it useful for trees?

Mushroom root

Traces of symbiotic associations of fungi with plant roots have been found in fossil remains of Carboniferous and Devonian deposits. Currently, mycorrhiza formation is characteristic of all gymnosperms, most terrestrial angiosperms (more than 70% monocots and 80% dicots) and higher spores - ferns, mosses, mosses.

Without mycorrhiza, the vast majority of aquatic animals, as well as representatives of some terrestrial families, are able to develop normally. herbaceous plants, for example, sedge, rush, clove, goosefoot, cruciferous. Mycorrhiza occurs more often in perennial plants than in annual plants.

Mycorrhiza occurs more often in perennial plants than in annual plants.

Benefiting from it

Mycorrhizal associations play important role in plant life. Thanks to symbiosis with fungal mycelium, the absorbing surface of the root system increases many times and the supply of nutrients and water from the soil improves, which in turn leads to optimization water regime plant symbionts, intensifying their physiological processes, increasing resistance to stress factors. This is especially important for young tree seedlings with a poorly developed root system. The ability to form mycorrhizae also saves trees from nutritional deficiency in conditions of insufficient moisture, dryness or salinity of soils (in cold taiga regions, desert and semi-desert areas). Due to symbiosis with fungal mycelium, heathers survive on nutrient-poor acidic soils.

Mycorrhiza-forming fungi are capable of biologically synthesizing active substances such as vitamins (mainly group B) and growth regulators, decompose various soil compounds, converting them into a form accessible to plants. Direct transmission through fungal hyphae to trees of such essential elements, such as phosphorus, nitrogen, potassium, sodium, magnesium, calcium, etc. With a good supply of these essential elements, many plants can develop normally without mycorrhiza, but on a depleted substrate without it they grow poorly or die. With the help of the branched and extended mycelium of symbiotrophic fungi, redistribution and exchange of nutritional components also occurs between various organisms in the plant community.

In soils, mycorrhiza improves the cohesion of soil particles, reduces erosion, and increases the soil's ability to retain water. Together with saprophytes, mycorrhiza-forming fungi help accelerate the decomposition of forest litter. Due to its ability to destroy minerals rocks organic acids (glycolic, oxalic, etc.) they play an important role in soil transformation processes.

The “cover” of hyphae of fungal mycelium that forms around the roots of trees and shrubs is also a natural mechanical barrier that protects plants from exposure to pathogenic microorganisms and various pollutants. Some mycorrhizal fungi are capable of releasing substances similar to antibiotics, which increases resistance and prolongs the life of the entire mycorrhizal association as a whole.

The symbiont fungus also has a positive effect on seeds various plants. Often, seed germination and seedling development are possible only in the presence of fungal mycelium. This is especially true for heathers and orchids.

In turn, mycorrhizal fungi receive carbohydrates, amino acids, and phytohormones from plants, which they are not able to synthesize on their own. Many tubular, russula, and arachnoid plants do not form fruiting bodies in the absence of symbiont plants, although their mycelium may well exist saprophytically. In general, it should be noted that a certain part of such mushrooms (in particular, pig mushrooms) are quite mobile in relation to the type of food, depending on living conditions.

Entering into symbiosis with forest plants, cap mushrooms can form peculiar “witch’s rings” on the soil surface, which arise due to the circular growth of mycelium in the soil, on the periphery of which mushroom fruiting bodies are formed annually.

The beneficial properties of mycorrhiza are widely used in forestry and agriculture. The standard technique is mycorrhization of substrates, seed and planting material. Thus, in coniferous nurseries, soil mycorrhization is specially carried out in order to protect seedlings from root fungus pathogens. In those climatic zones Where the natural development of mycorrhiza occurs relatively slowly (for example, in the southern regions), artificial infection of forest shelterbelts is carried out to accelerate the establishment of seedlings.

The addition of forest soil with mushroom mycelium has a particularly beneficial effect on the survival of oak when grown in steppe regions. In young oak trees, in the presence of mycorrhiza, an increase in the concentration of chlorophyll in the leaves and more active photosynthesis were noted. Similar results were obtained for spruce seedlings. The possibility of stimulating mycorrhiza formation in local fungi found in soils by selecting agrotechnical techniques (loosening, tillage) has been identified. When using such methods to achieve best results it is necessary to take into account the specific effects of mycorrhiza-forming fungi and select the most favorable combinations.

The addition of forest soil with mushroom mycelium has a particularly beneficial effect on the survival of oak when grown in steppe regions.

Symbiont mushrooms

On the part of fungi, representatives of basidiomycetes (hymenomycetes, gasteromycetes), less often ascomycetes and zygomycetes, can participate in the formation of mycorrhiza. Thus, mycorrhiza-formers are the majority of tubular ones, many of which are edible and widely known: fly mushrooms, boletus, boletus, and white. Mycorrhizae can form lamellar (milk mushrooms, umbrellas, rows), some marsupials (for example, related to truffles). Specific feature mycorrhiza-forming fungi - a limited set or absence of hydrolytic enzymes that decompose lignin and cellulose (for example, laccase), and, accordingly, the energy dependence on plant symbionts due to this factor.

During the formation of mycorrhiza, the hyphae of the fungus located in the soil are closely intertwined, fused with the roots and root hairs of plants, often forming a kind of cover. In this case, the roots can undergo significant anatomical and morphological changes, but this does not harm the owner. It is interesting that several types of fungi can simultaneously form mycorrhizae with the same “host”; in addition, symbionts have different degrees of selectivity when choosing partners. For example, the red fly agaric and White mushroom can enter into a symbiotic relationship with representatives of more than 20 species woody plants, including fir, spruce, pine, beech, poplar, oak. At the same time, different types of butterfly are capable of forming mycorrhiza only with certain coniferous species, and boletus and boletus - most often with birch and aspen.

Nature of the relationship

Based on the nature of the relationship between the mycelium and roots, three main types of mycorrhiza are distinguished: external ectotrophic (lat. ektos– “outside”), internal endotrophic (lat. endon- “inside”), transitional or mixed ectoendotrophic (combines features of both ecto- and endomycorrhizae).

With the development of external, or ectotrophic, mycorrhiza, the hyphae of the fungus tightly entwine the surface of the root or rhizome, disperse widely in the surrounding soil, and can also penetrate to a shallow depth into the intercellular space of the root cortex. Root hairs usually die off, partial destruction of the surface tissues of the root may occur, the root cap is partially reduced, young roots remain shortened, begin to branch and thicken, and apical growth may stop. Usually these are annual associations that die off by the winter cold. Ectotrophic mycorrhiza is characteristic mainly of forest trees - most conifers (spruce, larch), many deciduous (beech, birch, oak), found in some shrubs and herbaceous ones.

If, when interacting with mushroom mycelium appearance plant roots practically does not change, and the hyphae of the fungus are not only localized in the intercellular space of the peripheral tissues of the root, but also penetrate into the cells - this indicates the formation of internal or endotrophic mycorrhiza. Moreover, there is no “mushroom” cover on the surface of the root, the root hairs are preserved, and the shape of the roots, as a rule, remains constant. Inside the root cells, hyphae can sometimes form tree-like growths (arbuscules), tangles (peletons), swellings or bubbles (vesicles), but the cells themselves remain viable and can partially digest the mycelium embedded in them. Endotrophic mycorrhiza is widespread mainly in various types herbaceous (primarily in orchids, for which such symbiosis is obligatory), is also observed in some tree (juniper, poplar, apple, pear) and shrub species.

Mycorrhiza is also often found in woody plants. transitional type– ectoendotrophic, which combines the characteristics of ecto- and endomycorrhiza. In this case, the fungal mycelium entwines the root ends of the plant, forming a dense fungal sheath, and the fungal hyphae penetrate both the root cells and the intercellular spaces, where they grow, forming a dense network (Hartig’s network).

It is interesting that in all cases of mycorrhiza development on the root system of a plant, the hyphae of the symbiont fungus do not penetrate into the central cylinder and endoderm, as well as into the meristem of the root apex.

The intensity of mycorrhiza formation is directly dependent on the conditions environment. So, for example, with a low content of available mineral compounds (especially nitrogen and phosphorus) in the soil, mycotrophic plants may tend to form the most developed mycorrhiza, since the symbionts are forced to build an extensive network to search for nutritional components. Optimal soil acidity values ​​usually vary between pH=3.5–5.5; when pH values ​​shift to a more alkaline region (6.5–7.0), mycorrhiza formation is inhibited.

No less important factor– content of a sufficient amount of water in the soil. During warm periods, with uniform precipitation penetrating the soil to the optimal depth for mycelial growth (up to 1.5 m), many mycorrhiza-forming fungi can experience increased productivity with active education fruiting bodies, in particular in boletus, boletus, boletus, moss fly, russula, etc. During drought with a lack of moisture, the development of mycorrhiza can slow down and stop, and the formation of fruiting bodies does not occur. On the contrary, excess moisture prevents the saturation of the nutrient substrate with oxygen, the content of which determines the respiratory processes of the symbionts.

Temperature and light conditions have a certain significance. The most favorable temperatures are considered to be 15–20 °C; at temperatures below 7–8 °C, the growth of mushroom mycelium gradually stops. In trees growing in strong shade, a relatively weak intensity of mycorrhiza formation is noted, which is apparently due to the low rate of accumulation of carbohydrates necessary for the normal functioning of the fungal component.

Optimal soil acidity values ​​usually vary between pH = 3.5–5.5.

Symbiote– the organism is a participant in symbiosis.

Soprofit- a plant lacking chlorophyll and feeding on decaying organic substances from the remains or waste of animals and plants.

Mycelium– the vegetative body of fungi, consisting of thin branched threads (hyphae).

Hyphae- a filamentous formation in fungi, consisting of many cells or containing many nuclei.

Basidiomycetes- a division of the fungal kingdom that includes species that produce spores in club-shaped structures called basidia.

Ascomycetes(marsupial fungi) - a department in the kingdom of fungi, including species with septate (divided into parts) mycelium and specific organs of sexual sporulation - bags (asci).

Zygomycetes- a department of fungi, including species with developed coenocytic mycelium of variable thickness, in which septa are formed only for the separation of reproductive organs.

In Russia they love mushrooms. Due to their high content of beneficial nutrients, their nutritional value is sometimes equated to meat. True, they are considered heavy food: chitin, which is part of their cell walls, is very poorly digested, so children and people with weak digestion should not eat them. And mushroom poisoning is much more common than meat poisoning. And it’s not just that inexperienced mushroom pickers confuse edible and inedible mushrooms.
The hotter and drier the summer, the more rumors and reports of poisoning by edible mutant mushrooms arise. Last year even
Rospotrebnadzor warned residents Saratov region, that “due to the abnormally hot summer, mushrooms can mutate, acquiring uncharacteristic properties, including edible mushrooms - causing severe poisoning.”

A good environmental situation does not guarantee anything

Intensity of mushroom accumulation harmful substances increases with ambient temperature. “In hot and dry weather, fewer fruiting bodies are formed, and accordingly, the concentration of harmful substances in them increases,” explains Belyakova. In addition, in hot, dry weather, harmful substances that get into the soil are not washed out by rain, so the first mushrooms that appear after a drought are especially dangerous.
Mushrooms absorb the greatest amount of harmful substances in cities, industrial zones, and along the sides of highways and roads. But mushrooms stuffed with pesticides, herbicides and fertilizers can be found anywhere: large enterprises released into the atmosphere toxic substances, which are carried by the wind and fall with precipitation in the most harmless places. So you can be poisoned by edible mushrooms in forests remote from industrial centers. For example, cadmium was found in mushrooms collected in the forest near the village of Vasyutino in the Sergiev Posad district of the Moscow region at a concentration of 8 mg/kg. For acute poisoning, 15-30 mg of cadmium is sufficient, and the lethal single dose for cadmium, according to WHO estimates, ranges from 350 mg. Last year in mushrooms Voronezh region, which was heavily damaged by fires, a high content of cadmium was also found - almost twice the norm: a huge mass of ash that formed on the site of the ashes collected a large number of harmful substances, including cadmium.
In some types edible mushrooms, growing in relatively clean forests, the content of lead and arsenic exceeds the permissible levels several times. Thus, researchers from Moscow State University calculated that it is enough to eat about three hundred grams of environmentally friendly rowing or raincoat within a week to exceed permissible norm consumption of arsenic (and taking into account the amount of arsenic entering the human body with food and drinking water, - 100 grams of these mushrooms is enough).
“The concentration of harmful substances in mushrooms can be higher than normal even on uncontaminated soils,” says Belyakova, “imagine, the mycelium absorbs substances from an area of ​​several hundred square meters- this is a huge coverage! - and all of them are concentrated in the fruiting bodies. That is, the accumulation of harmful substances by mushrooms is not necessarily associated with a poor environmental situation. Mushrooms are able to perceive these elements from the soil, where they are contained only in the form of traces, absorb them and store them in the fruiting body. But when there are emissions or some kind of environmental disaster, the situation, of course, sharply and significantly worsens: mushrooms collect all the harmful substances that enter the soil."
At the same time, it is almost impossible to predict how long the soil will store poisons: “The accumulation of heavy metals in the soil is a complex process,” Belyakova continues. “It depends on many things, in particular on whether there was rain, how abundant it was, how in this place pass groundwater— and from a host of other factors. But if there is a release, the mushrooms will absorb and accumulate hazardous substances as long as they remain in the soil. Because, although the fruiting body does not live long, the mycelium can exist for tens and hundreds of years."

You don’t have to travel far to find radioactive mushrooms

A quarter of a century after the Chernobyl accident, in many affected regions (not only in Russia, but also in Europe), mushrooms still remain contaminated with radiation. Every now and then news appears that Belarus exports radioactive mushrooms to Europe, and in 2009 the German government paid hunters 425 thousand euros as compensation for boar meat that was contaminated with radiation (boars are big fans of mushrooms, so they are especially sensitive to radiation pollution ). German experts believe that in the next 50 years the situation in better side will not change - contamination of some types of mushrooms will most likely remain at the same level, and maybe even increase slightly. However, you don’t have to travel that far to get radioactive mushrooms - in some areas Leningrad region The permissible content of radioactive cesium in mushrooms has been exceeded by more than twice. Olga Tsvetnova and Alexey Shcheglov, who participated in the liquidation environmental consequences Chernobyl accident, explain this by the fact that mushrooms are “champions in the accumulation of radioactive cesium. On average, in mushrooms its concentration is more than 20 times higher than in the most contaminated layer of forest litter, and two to three orders of magnitude higher than in the least contaminated wood ".
The main mineral element included in the fruiting bodies of mushrooms is potassium, a chemical analogue of cesium-137, so mushrooms absorb radioactive cesium especially actively. At the same time, strontium-90, another common radioactive element, is absorbed by mushrooms much less well.
As in the case of heavy metals, the content of radionuclides in mushrooms depends on their species, soil properties and characteristics of the water regime. Mushrooms accumulate more radiation in highly humidified areas. forest soils, and mycorrhiza-forming fungi do this best (for example, Polish mushroom, svinushka, butterdish, boletus, boletus), since their mycelium is located in the upper layer of soil, where the concentration of radionuclides is maximum. Soil saprophytes (umbrella mushroom, puffball) accumulate less radionuclides, and the purest of all are mushrooms growing on trees, such as honey mushrooms. "When consuming mushrooms collected in forests contaminated with radionuclides and heavy metals, there is a high probability of not only internal exposure, but also the increased impact of these elements on the human body,” explain Tsvetnova and Shcheglov.
However, although Rospotrebnadzor calls wild mushrooms " mortal danger"Don't despair.

What to do if you still want mushrooms?

When picking mushrooms, you need to follow simple precautions. “We must remember that you should not collect mushrooms along roads, near landfills and factories,” reminds Belyakova. “There are especially many harmful substances in the soil, and no matter how good and edible you may think the mushroom collected in these places is, it may turn out to be cause of severe poisoning and serious problems with health. Each person has their own dose. You can eat from the same plate with someone: one will feel bad, the other will not - this is all very individual. The standard “exclusion zone” is 30-50 km around large industrial centers.”
In any case, the risk of getting serious poisoning from one plate of edible mushrooms is not very high, but it is still better to control yourself and not overuse mushrooms. In addition, you should not rush for the first harvest of mushrooms after the drought.
The collected mushrooms need to be boiled, ideally draining the broth 2-3 times - this is what collects significant amount salts of heavy metals and even radioactive cesium. " Cooking significantly reduces the content of radionuclides, console Tsvetnova and Shcheglov. “Successive cooking for 15-45 minutes with at least two changes of water reduces the concentration of 137Cs in mushrooms to acceptable values.”

Cheers! ;-)

Fungi - saprotrophs feed on the decomposition of dead plant debris (fallen leaves, pine needles, branches, wood).

Mushroom symbionts receive nutrients not only from the forest floor, but also from the roots of tree species. They enter into a peculiar form of cohabitation with trees (symbiosis), forming the so-called mycorrhiza, or fungal root, on the roots of trees. Symbionts cohabit with certain tree species. Thus, aspen boletuses grow, as a rule, under aspens, boletus under birch trees, oak boletus next to oak trees, etc. However, a large number of mycorrhizal fungi can live with not just one, but many tree species. For example, boletus forms mycorrhiza not only with aspen, but also with birch, and the porcini mushroom cohabits with almost fifty trees.

Mushroom lovers want to know under which trees which mushrooms are especially common, and in which forests to look for which mushrooms. Every tree has its own helper green living. A mushroom without a tree and a tree without a mushroom are no residents.

And so under what tree?

Under the birch: white truffle, porcini mushroom, dubovik (white double), real mushroom(mokhnach), boletus, black boletus, russula (including green), purple row, thin pig, deer mushroom, valui and of course the red fly agaric.

Under the oak: porcini mushroom, speckled oakberry, oak saffron milk cap, milkweed, (pepper, blue) milk mushroom, russula (pink), smooth spurge, white trumpet mushroom, svinushka, deer mushroom, violin mushroom, satanic mushroom(looks like white), valui, red fly agaric.

Under the aspen: (red and simple) boletus, milk mushroom (aspen, dog), russula, valui.

Under the spruce: porcini mushroom (a real white spruce boletus), truffle (white), (red) camelina, boletus, boletus (black), real raw milk mushroom, (black, yellow) milk mushroom, russula (red), valui, svinushka , chanterelle, red fly agaric.

Under the pine tree: boletus (strong blackhead), camelina (orange), oiler (real), flywheel (green, yellow-brown, chestnut), russula (dark red, brittle), blackberry, purple row, pigwort, red fly agaric.

Under the poplar: boletus (gray), milk mushroom (aspen, blue).

Under the centuries-old linden tree: oakberry, pigweed, satanic mushroom.

Under the alder: truffle, porcini mushroom, spurge.

Under the hazel tree: truffle, porcini mushroom, spurge, milk mushroom (pepper), valui.

Under the juniper: (white) truffle.

Articles about Hunting

07/26/2011 | Mushrooms: you can, but it’s better - you can’t

The hotter and drier the summer, the more rumors and reports of poisoning by edible mutant mushrooms arise. Last year, even Rospotrebnadzor warned residents of the Saratov region that “due to the abnormally hot summer, mushrooms can mutate, acquiring uncharacteristic properties, including edible mushrooms - causing severe poisoning.”

Boletus mushrooms accumulate both radiation and cadmium, but if you cook the soup longer and drain the water twice, you can take a risk. Photo: PhotoXpress

They simply absorb nutrients from the environment

“These, of course, are not mutants, there were simply emissions, and the mushrooms accumulated harmful substances,” says mycologist Galina Belyakova, deputy dean of the Faculty of Biology of Moscow State University. “Mushrooms are a special kingdom of living organisms; in addition to their own characteristics, they combine characteristics of animals and plants. In their lifestyle, they resemble plants, but fungi are heterotrophs, that is, they feed on ready-made organic substances and, unlike plants, are not able to produce them themselves, but actively absorb nutrients from the environment."

Arbuscular mycorrhiza is the oldest, primary form of symbiosis between plants and soil fungi. The fungi involved in it penetrate inside plant cells, forming special intracellular structures there - arbuscules

According to the method of nutrition, there are three main environmental groups mushrooms:

1. saprotrophic fungi that feed on dead organic matter. Such fungi can live, for example, on soil or on dead wood;

3. symbiont mushrooms that form a mutually beneficial alliance with green plants (plants feed the mushrooms with organic matter, and the mushrooms help the plants absorb minerals from the soil). The third group includes lichens (a union of a fungus and an algae) and mycorrhiza (a symbiosis of a fungus and the root of a higher plant).

The mushrooms that we collect are only a small part of the fungal organism, its fruiting body. Fruiting bodies grow on mycelium (mycelium), which is a network of thin branched threads. “The area occupied by the mycelium is huge—hundreds of square meters—and the fungus feeds on this entire area,” says Belyakova. “Mushrooms growing on the soil—soil saprotrophs—release enzymes into the soil and then absorb ready-made nutrients through the entire surface of the mycelium. And everything that was in the soil is then concentrated in the fruiting bodies of these mushrooms. But not all mushrooms feed on what is in the soil, for example, honey mushrooms grow on trees and feed by decomposing wood - therefore, their content of harmful substances is always much lower" .

Along with nutrients, mushrooms also absorb heavy metals (cadmium, mercury, lead, copper, manganese, zinc and others), radionuclides, pesticides and other harmful substances. The content of heavy metals in mushrooms is several times higher than in the soil in which they grow. "At these concentrations, metals are not harmless, and although they may not be enough to cause severe poisoning immediately, but if you eat mushrooms regularly, the consequences can be very serious,” says toxicologist Nikolai Garpenko from the University of Nottingham.

Heavy metals accumulate in the body and are very poorly excreted from it. Acute poisonings proceed rapidly, while chronic poisonings (caused, as a rule, by prolonged exposure and accumulation of harmful substances) are more blurred. Symptoms of heavy metal poisoning can be general (nausea and vomiting, abnormal heartbeat and blood pressure, constriction or dilation of the pupils, lethargy, drowsiness or, conversely, excitability) or specific to each substance. But, whatever the symptoms, first aid for all poisonings is standard (then you must call a doctor).

On the shores of the Kandalaksha Bay, russula grow in lichen. Photo: PhotoXpress

Alexey Shcheglov and Olga Tsvetnova, employees of the Department of Radioecology and Ecotoxicology of the Faculty of Soil Science at Moscow State University, have been studying the ability of fungi to accumulate harmful substances for many years. In their opinion, mushrooms not only intensively accumulate heavy metals, but have a specific affinity for some of them. Thus, some mushrooms may contain 550 times more mercury than the substrate on which they grow. Different types mushrooms prefer to accumulate various heavy metals: the umbrella mushroom absorbs cadmium well, pig mushroom, black milk mushroom and raincoat absorb copper; champignon and porcini mushroom - mercury, russula accumulates zinc and copper, boletus - cadmium. Shcheglov and Tsvetnova explain that the accumulation of heavy metals and radionuclides depends on many factors - from chemical properties the element itself, biological features the type of mushroom, the age of the mycelium and, of course, the conditions in which the mushroom grows: climate, water and soil composition.

Toxic substances accumulate first in the spore-bearing layer of the mushroom, then in the rest of the cap, then in the stem: “metabolic processes are most intense in the caps, therefore the concentration of macro- and microelements there is higher than in the stems. As the fruiting bodies develop, the intensity also changes accumulation of elements. In young fruiting bodies, as a rule, there are more of them than in old ones,” they say.

A good environmental situation does not guarantee anything

Champignons can be grown anywhere. The best soil for them is horse manure, but they are not demanding of light. Photo: RIA NOVOSTI

The intensity of accumulation of harmful substances by fungi increases with ambient temperature. “In hot and dry weather, fewer fruiting bodies are formed, and accordingly, the concentration of harmful substances in them increases,” explains Belyakova. In addition, in hot, dry weather, harmful substances that get into the soil are not washed out by rain, so the first mushrooms that appear after a drought are especially dangerous.

Mushrooms absorb the greatest amount of harmful substances in cities, industrial zones, and along the sides of highways and roads. But mushrooms stuffed with pesticides, herbicides and fertilizers can be found anywhere: large enterprises emit toxic substances into the atmosphere, which are carried by the wind and fall with precipitation in the most harmless places. So you can be poisoned by edible mushrooms in forests remote from industrial centers. For example, cadmium was found in mushrooms collected in the forest near the village of Vasyutino in the Sergiev Posad district of the Moscow region at a concentration of 8 mg/kg. For acute poisoning, 15-30 mg of cadmium is sufficient, and the lethal single dose for cadmium, according to WHO estimates, ranges from 350 mg. Last year, mushrooms in the Voronezh region, which were heavily damaged by fires, also contained a high content of cadmium - almost twice the norm: a huge mass of ash that formed at the site of the ashes collected a large amount of harmful substances, including cadmium.

In some types of edible mushrooms growing in relatively clean forests, the content of lead and arsenic exceeds the permissible levels several times. Thus, researchers from Moscow State University calculated that it is enough to eat about three hundred grams of environmentally friendly rowing or raincoat within a week to exceed the permissible intake of arsenic (and taking into account the amount of arsenic entering the human body with food and drinking water, 100 grams is enough these mushrooms).

“The concentration of harmful substances in mushrooms can be higher than normal even on uncontaminated soils,” says Belyakova. “Imagine, the mycelium absorbs substances from an area of ​​​​several hundred square meters - this is a huge coverage! - and all of them are concentrated in the fruiting bodies. Then there is an accumulation of harmful substances by mushrooms is not necessarily associated with a bad environmental situation. Mushrooms are able to perceive these elements from the soil, where they are contained only in the form of traces, absorb them and store them in the fruiting body. But, when there are emissions or some kind of environmental disaster, the situation ", of course, sharply and significantly worsens: the mushrooms collect all the harmful substances that enter the soil."

At the same time, it is almost impossible to predict how long the soil will store poisons: “The accumulation of heavy metals in the soil is a complex process,” Belyakova continues. “It depends on many things, in particular on whether there was rain, how abundant it was, how groundwater flows in a given place - and from a host of other factors. But if there is a release, the mushrooms will absorb and accumulate dangerous substances as long as they remain in the soil. Because, although the fruiting body does not live long, the mycelium can exist for dozens and hundreds of years."

You don’t have to travel far to find radioactive mushrooms

A quarter of a century after the Chernobyl accident, in many affected regions (not only in Russia, but also in Europe), mushrooms still remain contaminated with radiation. Every now and then news appears that Belarus exports radioactive mushrooms to Europe, and in 2009 the German government paid hunters 425 thousand euros as compensation for boar meat that was contaminated with radiation (boars are big fans of mushrooms, so they are especially sensitive to radiation pollution ). German experts believe that in the next 50 years the situation will not change for the better - contamination of some types of mushrooms will most likely remain at the same level, and maybe even increase slightly. However, you don’t have to travel that far to buy radioactive mushrooms—in some areas of the Leningrad region, the permissible content of radioactive cesium in mushrooms is more than twice as high. Olga Tsvetnova and Alexey Shcheglov, who participated in the elimination of the environmental consequences of the Chernobyl accident, explain this by the fact that mushrooms are “champions in the accumulation of radioactive cesium. On average, its concentration in mushrooms is more than 20 times higher than in the most contaminated layer of forest litter, and on two to three orders of magnitude more than in the least contaminated wood."

The main mineral element included in the fruiting bodies of mushrooms is potassium, a chemical analogue of cesium-137, so mushrooms absorb radioactive cesium especially actively. At the same time, strontium-90, another common radioactive element, is absorbed by mushrooms much less well.

As in the case of heavy metals, the content of radionuclides in mushrooms depends on their species, soil properties and characteristics of the water regime. Fungi accumulate more radiation on heavily moistened forest soils, and mycorrhiza-forming mushrooms do this best (for example, Polish mushroom, pigwort, butterfly, boletus, boletus), since their mycelium is located in the upper layer of soil, where the concentration of radionuclides is maximum. Soil saprophytes (umbrella mushroom, puffball) accumulate less radionuclides, and the purest of all are mushrooms growing on trees, such as honey mushrooms. “When consuming mushrooms collected in forests contaminated with radionuclides and heavy metals, there is a high probability of not only internal radiation, but also increased exposure to these elements on the human body,” explain Tsvetnova and Shcheglov.

However, although Rospotrebnadzor calls wild mushrooms a “mortal danger,” do not despair.

What to do if you still want mushrooms?

When picking mushrooms, you need to follow simple precautions. “We must remember that you should not collect mushrooms along roads, near landfills and factories,” reminds Belyakova. “There are especially many harmful substances in the soil, and no matter how good and edible you may think the mushroom collected in these places is, it may turn out to be cause of severe poisoning and serious health problems. Each person has their own dose. You can eat from the same plate with someone: one will feel bad, the other will not - it’s all very individual. The standard “exclusion zone” is 30-50 km around large industrial centers."

In any case, the risk of getting serious poisoning from one plate of edible mushrooms is not very high, but it is still better to control yourself and not overuse mushrooms. In addition, you should not rush for the first harvest of mushrooms after the drought.

The collected mushrooms need to be boiled, ideally draining the broth 2-3 times - it is this that collects a significant amount of heavy metal salts and even radioactive cesium. “Culinary processing significantly reduces the content of radionuclides,” console Tsvetnova and Shcheglov. “Successive cooking for 15-45 minutes with at least two changes of water reduces the concentration of 137Cs in mushrooms to acceptable values.”

Tatiana Vayntrob

In Russia they love mushrooms. Due to their high content of beneficial nutrients, their nutritional value is sometimes equated to meat. True, they are considered heavy food: chitin, which is part of their cell walls, is very poorly digested, so children and people with weak digestion should not eat them. And mushroom poisoning is much more common than meat poisoning. And it’s not just that inexperienced mushroom pickers confuse edible and inedible mushrooms.

The hotter and drier the summer, the more rumors and reports of poisoning by edible mutant mushrooms arise. Last year, even Rospotrebnadzor warned residents of the Saratov region that “due to the abnormally hot summer, mushrooms can mutate, acquiring uncharacteristic properties, including edible mushrooms - causing severe poisoning.”

They simply absorb nutrients from the environment

Arbuscular mycorrhiza is the oldest, primary form of symbiosis between plants and soil fungi. The fungi participating in it penetrate inside plant cells, forming special intracellular structures there - arbuscules.

“These, of course, are not mutants, there were simply emissions, and the mushrooms accumulated harmful substances,” says mycologist Galina Belyakova, deputy dean of the Faculty of Biology of Moscow State University. “Mushrooms are a special kingdom of living organisms; in addition to their own characteristics, they combine characteristics of animals and plants. In their lifestyle, they resemble plants, but fungi are heterotrophs, that is, they feed on ready-made organic substances and, unlike plants, are not able to produce them themselves, but actively absorb nutrients from the environment."

Based on their feeding method, there are three main ecological groups of mushrooms:

1. saprotrophic fungi that feed on dead organic matter. Such fungi can live, for example, on soil or on dead wood;

3. symbiont mushrooms that form a mutually beneficial alliance with green plants (plants feed the mushrooms with organic matter, and the mushrooms help the plants absorb minerals from the soil). The third group includes lichens (a union of a fungus and an algae) and mycorrhiza (a symbiosis of a fungus and the root of a higher plant).

The mushrooms that we collect are only a small part of the fungal organism, its fruiting body. Fruiting bodies grow on mycelium (mycelium), which is a network of thin branched threads. “The area occupied by the mycelium is huge—hundreds of square meters—and the fungus feeds on this entire area,” says Belyakova. “Mushrooms growing on the soil—soil saprotrophs—release enzymes into the soil and then absorb ready-made nutrients through the entire surface of the mycelium. And everything that was in the soil is then concentrated in the fruiting bodies of these mushrooms. But not all mushrooms feed on what is in the soil, for example, honey mushrooms grow on trees and feed by decomposing wood - therefore, their content of harmful substances is always much lower" .

Along with nutrients, mushrooms also absorb heavy metals (cadmium, mercury, lead, copper, manganese, zinc and others), radionuclides, pesticides and other harmful substances. The content of heavy metals in mushrooms is several times higher than in the soil on which they grow. “At such concentrations, metals are not harmless, and although they may not be enough to cause severe poisoning immediately, if you eat mushrooms regularly, the consequences can be quite serious,” says toxicologist Nikolai Garpenko from the University of Nottingham.

Heavy metals accumulate in the body and are very poorly excreted from it. Acute poisonings proceed rapidly, while chronic poisonings (caused, as a rule, by prolonged exposure and accumulation of harmful substances) are more blurred. Symptoms of heavy metal poisoning can be general (nausea and vomiting, abnormal heartbeat and blood pressure, constriction or dilation of the pupils, lethargy, drowsiness or, conversely, excitability) or specific to each substance. But, whatever the symptoms, first aid for all poisonings is standard (then you must call a doctor).

Alexey Shcheglov and Olga Tsvetnova, employees of the Department of Radioecology and Ecotoxicology of the Faculty of Soil Science at Moscow State University, have been studying the ability of fungi to accumulate harmful substances for many years. In their opinion, mushrooms not only intensively accumulate heavy metals, but have a specific affinity for some of them. Thus, some mushrooms may contain 550 times more mercury than the substrate on which they grow. Different types of mushrooms prefer to accumulate different heavy metals: the umbrella mushroom absorbs cadmium well, pig mushroom, black milk mushroom and raincoat absorb copper; champignon and porcini mushroom - mercury, russula accumulates zinc and copper, boletus - cadmium. Shcheglov and Tsvetnova explain that the accumulation of heavy metals and radionuclides depends on many factors - on the chemical properties of the element itself, the biological characteristics of the mushroom species, the age of the mycelium and, of course, on the conditions in which the mushroom grows: climate, water and soil composition.

Toxic substances accumulate first in the spore-bearing layer of the mushroom, then in the rest of the cap, then in the stem: “metabolic processes are most intense in the caps, therefore the concentration of macro- and microelements there is higher than in the stems. As the fruiting bodies develop, the intensity also changes accumulation of elements. In young fruiting bodies, as a rule, there are more of them than in old ones,” they say.

A good environmental situation does not guarantee anything

The intensity of accumulation of harmful substances by fungi increases with ambient temperature. “In hot and dry weather, fewer fruiting bodies are formed, and accordingly, the concentration of harmful substances in them increases,” explains Belyakova. In addition, in hot, dry weather, harmful substances that get into the soil are not washed out by rain, so the first mushrooms that appear after a drought are especially dangerous.

Mushrooms absorb the greatest amount of harmful substances in cities, industrial zones, and along the sides of highways and roads. But mushrooms stuffed with pesticides, herbicides and fertilizers can be found anywhere: large enterprises emit toxic substances into the atmosphere, which are carried by the wind and fall with precipitation in the most harmless places. So you can be poisoned by edible mushrooms in forests remote from industrial centers. For example, cadmium was found in mushrooms collected in the forest near the village of Vasyutino in the Sergiev Posad district of the Moscow region at a concentration of 8 mg/kg. For acute poisoning, 15-30 mg of cadmium is sufficient, and the lethal single dose for cadmium, according to WHO estimates, ranges from 350 mg. Last year, mushrooms in the Voronezh region, which were heavily damaged by fires, also contained a high content of cadmium - almost twice the norm: a huge mass of ash that formed at the site of the ashes collected a large amount of harmful substances, including cadmium.

In some types of edible mushrooms growing in relatively clean forests, the content of lead and arsenic exceeds the permissible levels several times. Thus, researchers from Moscow State University calculated that it is enough to eat about three hundred grams of environmentally friendly rowing or raincoat within a week to exceed the permissible intake of arsenic (and taking into account the amount of arsenic entering the human body with food and drinking water, 100 grams is enough these mushrooms).

“The concentration of harmful substances in mushrooms can be higher than normal even on uncontaminated soils,” says Belyakova. “Imagine, the mycelium absorbs substances from an area of ​​​​several hundred square meters - this is a huge coverage! - and all of them are concentrated in the fruiting bodies. Then there is an accumulation of harmful substances by mushrooms is not necessarily associated with a bad environmental situation. Mushrooms are able to perceive these elements from the soil, where they are contained only in the form of traces, absorb them and store them in the fruiting body. But, when there are emissions or some kind of environmental disaster, the situation ", of course, sharply and significantly worsens: the mushrooms collect all the harmful substances that enter the soil."

At the same time, it is almost impossible to predict how long the soil will store poisons: “The accumulation of heavy metals in the soil is a complex process,” Belyakova continues. “It depends on many things, in particular on whether there was rain, how abundant it was, how groundwater flows in a given place - and from a host of other factors. But if there is a release, the mushrooms will absorb and accumulate dangerous substances as long as they remain in the soil. Because, although the fruiting body does not live long, the mycelium can exist for dozens and hundreds of years."

You don’t have to travel far to find radioactive mushrooms

A quarter of a century after the Chernobyl accident, in many affected regions (not only in Russia, but also in Europe), mushrooms still remain contaminated with radiation. Every now and then news appears that Belarus exports radioactive mushrooms to Europe, and in 2009 the German government paid hunters 425 thousand euros as compensation for boar meat that was contaminated with radiation (boars are big fans of mushrooms, so they are especially sensitive to radiation pollution ). German experts believe that in the next 50 years the situation will not change for the better - contamination of some types of mushrooms will most likely remain at the same level, and maybe even increase slightly. However, you don’t have to travel that far to buy radioactive mushrooms—in some areas of the Leningrad region, the permissible content of radioactive cesium in mushrooms is more than twice as high. Olga Tsvetnova and Alexey Shcheglov, who participated in the elimination of the environmental consequences of the Chernobyl accident, explain this by the fact that mushrooms are “champions in the accumulation of radioactive cesium. On average, its concentration in mushrooms is more than 20 times higher than in the most contaminated layer of forest litter, and on two to three orders of magnitude more than in the least contaminated wood."

The main mineral element included in the fruiting bodies of mushrooms is potassium, a chemical analogue of cesium-137, so mushrooms absorb radioactive cesium especially actively. At the same time, strontium-90, another common radioactive element, is absorbed by mushrooms much less well.

As in the case of heavy metals, the content of radionuclides in mushrooms depends on their species, soil properties and characteristics of the water regime. Fungi accumulate more radiation on heavily moistened forest soils, and mycorrhiza-forming mushrooms do this best (for example, Polish mushroom, pigwort, butterfly, boletus, boletus), since their mycelium is located in the upper layer of soil, where the concentration of radionuclides is maximum. Soil saprophytes (umbrella mushroom, puffball) accumulate less radionuclides, and the purest of all are mushrooms growing on trees, such as honey mushrooms. “When consuming mushrooms collected in forests contaminated with radionuclides and heavy metals, there is a high probability of not only internal radiation, but also increased exposure to these elements on the human body,” explain Tsvetnova and Shcheglov.

However, although Rospotrebnadzor calls wild mushrooms a “mortal danger,” do not despair.

What to do if you still want mushrooms?

When picking mushrooms, you need to follow simple precautions. “We must remember that you should not collect mushrooms along roads, near landfills and factories,” reminds Belyakova. “There are especially many harmful substances in the soil, and no matter how good and edible you may think the mushroom collected in these places is, it may turn out to be cause of severe poisoning and serious health problems. Each person has their own dose. You can eat from the same plate with someone: one will feel bad, the other will not - it’s all very individual. The standard “exclusion zone” is 30-50 km around large industrial centers."

In any case, the risk of getting serious poisoning from one plate of edible mushrooms is not very high, but it is still better to control yourself and not overuse mushrooms. In addition, you should not rush for the first harvest of mushrooms after the drought.

The collected mushrooms need to be boiled, ideally draining the broth 2-3 times - it is this that collects a significant amount of heavy metal salts and even radioactive cesium. “Culinary processing significantly reduces the content of radionuclides,” console Tsvetnova and Shcheglov. “Successive cooking for 15-45 minutes with at least two changes of water reduces the concentration of 137Cs in mushrooms to acceptable values.”