How do humans use mushrooms? Predators. Mushrooms are predatory examples of names. Carnivorous plants that prefer insects

Section contents: Mushrooms

We have already heard a lot about the different types of carnivorous plants. But few have heard that mushrooms can also be predators... But this is true! First the background...

Back in the second half of the 19th century, Russian researchers, first in 1869 by M. S. Voronin, and in 1881 by K. V. Sorokin, discovered and studied the fact that some soil fungi form closed rings of a certain diameter on their mycelium. Having carefully studied this phenomenon, the German scientist F.W. Zopf in 1888 came to the conclusion that these rings serve not just to passively catch nematodes, but also to actively kill them. Upon further investigation of this phenomenon, it turned out that mushrooms have a whole arsenal of means for catching prey: there are loops, heads, droplets of adhesive, and others.

Observations have shown that as soon as a nematode gets into a ring or loop, it immediately begins to resist, trying to free itself, but this is quite natural. But the more active its movements, the more trapping rings and loops the worm gets into. Two hours will pass, and then the movements of the captive nematode slow down and then stop completely. At this time, a sprout quickly grows from the fungus to the nematode, the expanded end of which is called the “infectious bulb.” First, it approaches the body of the victim, and then penetrates the worm and grows rapidly there. Soon the hyphae of the predator fungus fill the entire internal cavity of the animal’s body. Only about a day will pass - and all that remains of the nematode is the skin...

Interesting are representatives of predatory fungi from the genus Dactylaria, distributed throughout the world. The mycelium threads of this predatory fungus form outgrowths in the form of rings of three cells that respond to touch. When a nematode accidentally gets into such a loop, these cells swell in literally a tenth of a second, increasing three times in size, as a result of which they pull the victim so tightly that it soon dies. Then the mushroom can only grow inside the extracted victim and digest it.

There are species of fungi that hunt their prey in water. Thus, the species Zoopbagus tentaculum successfully hunts in ponds for various amoebas, collembolas, rotifers, nematodes and other microscopic animals. This fungus produces short shoots that serve as bait for prey. And as soon as the animal grabs it, it practically finds itself on a hook from which it can no longer free itself. And it grows, then quickly digests the victim and sucks it out from the inside.

Currently, mycologists know at least 200 species of modern predatory fungi, which belong to different systematic groups: zygomycetes, ascomycetes and basidiomycetes. All this indicates that predation occurred several times during the evolution of fungi, but almost nothing is still known about the chronology of these events, since fungi are rarely preserved in the fossil record. In this sense, German paleontologists were especially lucky when they discovered in a piece of amber 100 million years old single-celled trapping rings that belonged to an ancient predatory fungus. Fossil predatory mushrooms were also found in Mexican amber, whose age can reach 30 million years...

Thus, predator mushrooms are fungi that have acquired the ability to catch and kill microscopic animals using special trapping devices, and then use them for their food. Predatory mushrooms are specialized environmental group mushrooms, which is distinguished in modern mycology precisely by the way mushrooms feed, and their food is microscopic animals caught by mushrooms. These same types of fungi may also be classified as saprotrophic fungi, since in the absence of prey they feed on dead organic matter, like saprotrophs.

Continuing the mushroom theme of the previous post.

There are carnivorous animals, there are carnivorous plants, and there are also carnivorous mushrooms.

The predatory fungus Arthrobotrys anchonia caught the nematode ( roundworm) using two three-cell trapping rings. Photo by N.Allin and G.L.Barron (from www.uoguelph.ca)

When we talk about mushrooms, it never occurs to us that the term “predator” can be applied to them. After all, they are motionless, and they don’t even have a mouth. And yet, on earth there are not only insectivorous plants (for example, sundews), but also predatory fungi. This is not a figment of the imagination science fiction writers or Hollywood directors. Of course, their prey is even smaller in size than that of predator plants, but this is precisely the prey that they catch, kill and digest.

What kind of mushrooms are these and where do they grow? Predators include, for example, representatives of the genera Stylopagev\Arthrobotrys from the order Hyphomycetes. Fungi belong to the hyphomycetes, including life cycle which were not found to have sexual reproduction. All such mushrooms were called imperfect (fungi imperfect/). Later, however, it turned out that many of them are the asexual stage of other, already described species. In total, approximately 30 thousand species of imperfect fungi are known, of which more than 160 species feed on animals.

There are much more predatory mushrooms than carnivorous plants. They are almost ubiquitous: they are found in almost all types of soil, manure, and various organic residues. However, as a rule, we do not see them, and if we do, we do not know about their predation. You can only see how the mushroom kills its victim through a microscope.

Among the scientists who began to study them is I.I. Mechnikov. The first predatory mushroom described in the literature belongs to the genus Arthrobothrys. Its sexual stage is known asOrbilia from the group of ascomycetes, or marsupial fungi. Orbilia develops on rotting wood, where its small fruiting bodies, similar to reddish buttons, can be seen. However, some of its hyphae grow into the soil specifically for hunting.

We can say that predatory mushrooms spread their invisible networks right under our feet. And the nets do not remain without a catch. Fungi hunt small soil nematodes such as roundworms and their larvae. Some species living in water catch cyclops crustaceans and small roundworms - rotifers. The victims of predatory fungi can be amoebas and even small insects. However, their main prey is nematodes, which are barely visible to the naked eye. In the soil they are found in huge quantities - up to twenty million per square meter! And the mushrooms did not miss such an abundant food source.

How can mushrooms catch and eat a nematode? There are several types of traps for this. The predator's fishing system often resembles a fishing net with many hooks. Mushrooms Monacosporium cionopagum And Dactylella lobata form sticky, column-like branches. Some species from the genus Arthrobotrys They catch worms by spreading sticky nets or noose rings. Such a trap consists of three cells that form a ring with a diameter of about 30 microns. IN normal condition it is thin, but with a fairly wide opening. As soon as the crawling nematode inserts the front end of the body into the hole, a reaction is triggered and the cells of the ring sharply thicken, squeezing the prey as if in a vice. The animal tries to free itself, tugging at the mycelium threads, but all efforts are in vain. It happens that the victim gets entangled in two rings at once, although one is enough to catch him.

Dactylaria Candida has ring traps that do not squeeze the prey. Interestingly, hyphae with another type of traps - sticky buttons - grow from the eaten nematode. Buttons have a syncytial structure, that is, they are several cells fused with each other and contain several nuclei. Such traps release a special protein that interacts with carbohydrate molecules on the surface of nematodes. As a result, a glue is formed that tightly holds the prey.

In any case, the result of the hunt is the same: the hyphae of the fungus grow through the cuticle (the integumentary membrane of the worm) and secrete digestive enzymes. In many species, so-called assimilative, digestive hyphae penetrate the body of the victim. After a few hours, an empty shell remains from the nematode. The fungus uses the nutrients obtained in this way for the growth of mycelium or the formation of conidia (reproductive organs) and conidiospores.

Fungal traps do not wait for prey to be nearby and release specific substances that attract nematodes. After all, many nematodes feed on fungi and find them using chemical sense. They crawl towards the mycelium thickets in the hope of profiting, but they themselves end up for lunch. In experiments, mushrooms growing on one Petri dish caught more than five hundred worms per day!

It is interesting that some predatory fungi develop adaptations for hunting only in the presence of prey, while others always have them.

Some predatory fungi have come to live in aquatic environment. In a famous group Oomycetes Most representatives are saprophages, that is, they feed on organic debris. Some of them affect fish eggs and form mold on insects that fall into the water. Among them there is also a predator— Zoophagus, which catches rotifers. The name of the mushroom can be translated as “animal eater.”

In addition to inconspicuous mushrooms living in the soil, as it turns out, the well-known oyster mushroom can also be considered a predator! Yes, yes, this one edible mushroom also preys on nematodes. Only the mechanism of predation here is different: the mycelium of the fungus grows thin adventitious vegetative hyphae that secrete a toxin. This poison paralyzes nematodes, but does not kill. Hyphae of another type, directed, search for prey, grow inside, and then everything happens, as in other predatory fungi. The oyster mushroom toxin ostreatin acts not only on nematodes, but also on enchytraeids (large soil worms related to earthworms) and oribatid mites. However, it is not produced in the fruiting bodies, so we can safely eat oyster mushrooms. The original role of ostreatin is protection against mycelium eaters (mites, springtails, tardigrades). Another type of cap mushroom - Conocybe lactea - also produces a toxin that repels and kills nematodes, but this fungus, unlike predatory ones, does not eat dead worms.

In addition to nematodes, oyster mushrooms also consume bacteria. In soil, bacteria usually form microcolonies. Direct hyphae are sent to such microcolonies, grow inside and form special feeding cells that, with the help of enzymes, dissolve bacteria and assimilate their contents. After a fungal attack, only empty shells remain of bacterial cells. Several wood-eating mushrooms, and even some champignons, can hunt bacteria.

Why do mushrooms, and even wood-destroying ones, need predation? The answer is quite simple. Like insectivorous plants, fungi find an accessible source of nitrogen and phosphorus in animals, since these elements are contained in minute quantities in dead wood, and the nitrogen fixation mechanism characteristic of bacteria is absent in fungi. For example, in wood, the carbon to nitrogen ratio ranges from 300:1 to 1000:1, whereas normal growth requires 30:1. An important nutrient is clearly missing. So the mushrooms went on the hunting path.

Few people know that carnivorous plants exist, and perhaps very few have heard of carnivorous mushrooms.

These mushrooms are not quite ordinary: they live in the soil and are called soil fungi. They feed on organic substances formed during the decomposition of plants and animals. But among soil fungi there are species whose food is nematodes. Mushroom predators have their own tricks for catching delicious worms.

First of all, the filamentous mycelium spreads in such a way that rings form in the soil. From such rings a real fishing net. Nematodes will not slip through it, especially since the inside of the rings is very sticky. The nematode will try to escape in vain: the victim of the predatory fungus is doomed.

Among the mushrooms there are also “arcanists”. They form special catching loops at the ends of the hyphae. As soon as the nematode gets into it, the loop swells and contracts, squeezing the victim in an insidious embrace.

Predatory fungi even received the special name helminthophages - worm eaters. Could these predators be used to control nematodes?

At one of the coal mines in Kyrgyzstan, a disease caused by nematodes, hookworm, was widespread among miners. Professor F. Soprunov and his colleagues decided to use predatory mushrooms to combat them. In a mine where there were especially many nematodes, powder with fungal spores was sown. The conditions for mushrooms were excellent: there was moisture and warmth. The spores sprouted, and predators began to destroy the harmful worms. The disease was defeated.

Nematodes attack potatoes, sugar beets, and cereals. They do not disdain onions and garlic. It is difficult to name cultivated plants that would not be attacked by nematodes. That's why scientists are developing various ways to combat them, one of them is the use of mushrooms. And although there are still many unresolved questions facing scientists, this method is still promising.

Everyone knows citric acid, which is used both in the household and in Food Industry. Where do they get it from? From lemons, of course. But, firstly, lemons do not contain much acid (up to 9 percent), and secondly, lemons themselves are a valuable product. And now another source and method of obtaining citric acid was found. The mold fungus Aspergillus niger (black mold) copes with this task perfectly.

Russian scientists first developed methods technical use mushrooms to produce citric acid. Here's how it happens. First, a film of black mold is grown in a 20 percent sugar solution with the addition of mineral salts. This usually takes two days. Then the nutrient solution is drained, the lower part of the mushroom is washed with boiled water and a clean, sterilized twenty percent sugar solution is poured in. The mushroom quickly gets to work. Four days, and all the sugar has been converted into citric acid. Now it’s up to the person to isolate the acid and use it for its intended purpose.

This method is quite profitable. Judge for yourself: from lemons collected from one hectare, you can get about 400 kilograms of citric acid, and from sugar produced from sugar beets from the same area, mushrooms produce more than one and a half tons. Four times more!

... It was manufactured in 1943. The war was raging. And people had to wage another war... against mushrooms. Yes Yes. Against the most common mold fungi.

Unable to use the sun's energy to generate nutrients Just like green plants do, molds use organic matter, either living organisms or materials from organic matter. So the mushrooms attacked the leather cases of binoculars, cameras and other devices. What about the cases! Their secretions (various organic acids) corroded the glass, and it became cloudy. Hundreds of lenses and prisms failed.

But even this was not enough for the mushrooms. They began to inhabit motor fuel and brake fluids. When fuel containers are filled with kerosene, moisture always condenses on their cold inner walls. And even if it is not enough, it may be enough for mushrooms to begin to take root at the border of water and kerosene. The mold fungus, which extracts carbon from kerosene, is especially good here.

But it turned out to be even more suitable for mold fungi brake fluid containing glycerin or ethylene glycol. A film of mold also forms on the surface of such liquids. During operation of the mechanisms, its fragments are carried along with the fuel and cause clogging of the pipes and valves of the machine.

Many people know the house mushroom - a merciless destroyer of wood. When plastics were created, everyone breathed a sigh of relief: finally there was a material that was not afraid of mushrooms. But the joy was premature: mushrooms have also adapted to plastics.

Take, for example, polyvinyl chloride plastic used for insulation. Then the fungi attacked her, and very cleverly, with the help of tiny mites (up to 0.5 millimeters) that feed on mold fungi. In search of food, ticks crawl everywhere, including into electrical appliances. After they die, the fungal spores inside them germinate and begin to destroy the plastic. If this is insulation, then there may be a current leakage that occurs short circuit. Fungi and other plastics are affected.

True, now special additives are introduced into liquid or plastic that prevent the development of fungi. But for how long? After all, mushrooms are inventive organisms; they can adapt to this.

“...The patients were tormented by severe, unbearable pain, so that they complained loudly, gnashed their teeth and screamed... An invisible fire hidden under the skin separated the meat from the bones and devoured it,” - this is how the ancient chronicler described the still unknown disease, later called “evil writhing.” , "Anton's fire".

It was a serious illness. In France alone in 1129, more than 14 thousand people died from it. Other countries also suffered from it. The cause of the illness was unknown. It was believed that heavenly punishment falls on people for their sins. And no one could have thought that the cause of the terrible disease was bread, or rather, those black horns that were on the ears of grain. But here’s what’s strange: the monks ate this bread, but they didn’t get sick.

More than one century passed before the secret of black horns, ergot, was revealed.

But summer is coming to an end. The threads of the mycelium that come out intertwine, turn red, then become purple, even black purple, become denser and form a characteristic horn. All the troubles come from him. But only at the end of the 19th century it was discovered that horns contain toxic substances - alkaloids.

Why didn’t the monks get sick? The secret is simple. Turns out, poisonous properties alkaloids gradually decrease over time and completely disappear after two to three years. In monasteries, as a rule, there were huge reserves of bread. They lay there for years, and during this time the ergot lost its toxicity.

Now ergot has been eliminated from the fields. However, it is now specially grown. For what? They began to prepare medicines from ergot. They cause vasoconstriction.

Sometimes in the summer in the meadows there are grasses (fescue, hedgehog), which have many rusty-brown tubercles on their leaves and stems. These are sick plants. The disease is called rust. It is caused by special rust fungi. The most common fungus is Puccinia graminis - stem rust of cereals, related to higher mushrooms, although according to appearance it is unlike the honey mushrooms, boletuses and other similar mushrooms that we are familiar with.

Rust fungi are very small and have a rather complex development. At the end of June - beginning of July, the tubercles burst and spores fly out of them. This is a summer debate. They are yellowish in color, oblong or oval, and covered with many spines. The wind picks them up and carries them to new plants. They penetrate through the stomata into the leaf tissue, grow and form a fibniz. The mushroom grows quickly and can produce several generations in one summer. This is why the disease spreads quickly. The trouble is that rust affects not only wild cereals, but also cultivated ones (rye, wheat, oats, barley). Scientists began to study the development of puncture, but in the spring its trace was lost, and in the summer it reappeared on cereals. What's the matter? Where did the mushroom go? And how did it appear again on cereals?

Research continued. It turned out that when autumn comes and the grains ripen, puccinia begins to prepare for winter. Instead of rusty yellow tubercles, black ones appear, which contain special spores - winter ones. Each such spore consists of two cells with a rather thick shell, which protects the spores from unfavorable winter conditions. In winter they are at rest.

How did the fungus end up on cereals again? The way is this: after “sitting out” on the barberry leaves, the spores germinate, forming swellings on the underside of the leaf, filled with new “fresh” spores. And when they got on the grains, they caused rust on them. Needless to say, the device is quite ingenious, with the ability to confuse traces.

But not only puncture has intermediate host. This is typical for many other rust fungi. Thus, in oat rust, the intermediate plant is buckthorn. It was noticed: if there are no intermediate plants near the crops, rust does not develop on the main plants.

What prudence, ingenuity and perseverance these mushrooms demonstrate, winning their place in this world!

A predatory fungus that destroys nematodes is undoubtedly a friend of man, but there are mushrooms that are his enemies. For a long time, from about the 10th - 12th centuries, a human disease has been known in which general weakness, loss of appetite, vomiting, severe pain in the stomach and intestines.

IN severe cases Patients experienced curvature of their arms and legs or their necrosis, and in very severe cases, the soft tissues on the extremities turned black and separated from the bones.

When grinding grain affected by ergot, ergotine turns into flour. Bread and other products made from such flour retain their toxic properties and, when consumed, cause such a serious illness. It was later called ergotism.

Tinder fungi are also interesting. Some of their properties are used to produce so-called decorative wood. At the beginning of its development, the tinder fungus, without disturbing the strength of the wood, deposits various pigments in it, resulting in the appearance of colored spots, stripes, and stains.

After polishing, such wood becomes especially beautiful and is widely used in the manufacture of furniture, as well as in construction for various finishes and decorations. For example, walnut wood affected by tinder fungus from Kakheti and Guria is very highly valued. Under the influence of the fungus, black patterned stains appear in it. And maple wood in the initial stages of tinder fungus is used to make balalaikas and guitars.

In some northern regions, until recently, one of the species of polypores with a hoof-shaped perennial fruiting body was used as tinder when making fire. Abroad, very elegant things are made from its soft mass: handbags, gloves, frames, etc.

Some species of predatory fungi have adapted to living in an aquatic environment. In the Oomycetes group, most of the representatives are saprophages (feed on organic remains), but among them there is also a predator - Zoophagus, which preys on rotifers. The name of the mushroom translates as “animal eater.”

The most popular soil predator mushroom is oyster mushroom. As it turns out, this edible mushroom preys on nematodes. True, its mechanism of predation is different: thin adventitious vegetative hyphae sprout from the mycelium of the fungus, producing a poison - a toxin.

The toxin paralyzes nematodes, at the same time, directed hyphae search for prey and grow through it, digesting the nematode according to the principle of all other predatory species. Moreover, the toxin ostreatin produced by oyster mushrooms also affects oribatid mites and enchytraeid worms (relatives of earthworms).

The toxin is not produced in the fruit parts that humans eat. And the role of ostreatin, programmed by nature, is protection against pests (ticks, springtails, tardigrades).
In addition to the listed prey, bacteria also get into the “nets” of oyster mushrooms. Direct hyphae of oyster mushrooms grow through microcolonies of bacteria, form specific feeding cells in them, which, with the help of enzymes, dissolve bacteria and assimilate their contents. As a result, only empty shells remain of the bacterial cells.

Several other wood-eating fungi, and even some champignons, also prey on bacteria. Like insectivorous plants, carnivorous fungi take into animals nitrogen and phosphorus contained in dead wood in minute quantities (in wood the ratio of carbon to nitrogen ranges from 300:1 to 1000:1, and for normal growth 30:1 is required).

Stem nematode

Stem nematode- These are microscopic round worms, 0.3–0.4 mm long. The male and female differ little from each other. The larva is similar to the adult, but smaller in size.

The stem nematode develops intensively in rainy years. However, vegetative potato plants affected by this nematode do not differ in appearance from healthy ones, only sometimes thickening of the stem with cracks on it and shortened internodes are observed.

The first signs appear on the tubers during the harvesting period. Under the skin, where the nematode penetrates, small brown spots with powdery tissue are visible. As the disease progresses, lead-gray spots appear on the skin of the tubers, the skin peels off and brown destroyed tissue (rotten mass) is visible underneath.

The entire development cycle of this nematode takes place inside the tuber, so the main source of spread is seed potatoes. Several generations of the pest develop throughout the year. The female lays about 250 eggs or more. The larvae emerging from the eggs go through several stages of development and turn into adults. The high fertility of the stem nematode leads to its massive accumulation in tubers. When planting infected tubers, nematodes move from the mother tuber to the stem (no higher than 10 cm above the ground), then enter the stolons, from which they move to young tubers. Another source of infection is the soil, where nematodes enter during the decomposition of post-harvest residues and mother tubers. In the soil, the stem nematode can survive for several years, affecting other crops, weeds and falling into a state of suspended animation when unfavorable conditions. The stem nematode rarely moves from tuber to tuber during storage. Late-ripening varieties are less affected than early-ripening ones.

Control measures. Carefully sorting the potatoes and planting only healthy tubers. Alternation of crops and return to their original place no earlier than after 3–4 years. Systematic removal of weeds, plant residues and digging of the soil in the fall.