Contents
The section of biology that studies the structure, nutrition and development of fungi is called mycology. This science has a long history and is conditionally divided into three periods (old, new and latest). The earliest scientific works on the structure and activity of fungi that have survived to this day date back to the middle of 150 BC. e. For obvious reasons, these data were revised many times in the course of further study, and a lot of information was disputed.
A description of the structure of fungi, as well as the main features of their development and nutrition, are presented in detail in this article.
General characteristics of the structure of the mycelium of the fungus
All mushrooms have a vegetative body called mycelium, that is, mycelium. The external structure of the mycelium of mushrooms resembles a bundle of thin twisting threads, called “hyphae”. As a rule, the mycelium of ordinary edible fungi develops in the soil or on decaying wood, and the parasitic mycelium grows in the tissues of the host plant. Mushroom fruiting bodies grow on the mycelium with spores with which the fungi reproduce. However, there are a large number of fungi, in particular parasitic ones, without fruiting bodies. The peculiarity of the structure of such fungi lies in the fact that their spores grow directly on the mycelium, on special spore bearers.
The young mycelium of oyster mushroom, champignon and other grown mushrooms is thin white threads that look like a white, gray-white or white-blue coating on the substrate, resembling a cobweb.
The structure of the mycelium of the fungus is shown in this diagram:
In the process of maturation, the shade of the mycelium becomes creamy and small strands of intertwined threads appear on it. If during the development of the acquired mycelium of fungi (in a glass jar or bag) on the surface of the substrate (grain or compost can act as its role), the strands are approximately 25-30% (installed by eye), then this means that the planting material was of high quality. The fewer strands and the lighter the mycelium, the younger and usually more productive it is. Such a mycelium will take root without any problems and will develop in the substrate in greenhouses and greenhouses.
Speaking about the structure of the fungus, it is important to note that the rate of growth and development of oyster mushroom mycelium is much greater than that of champignon mycelium. In oyster mushrooms, the planting material becomes yellowish after a short time and with a large number of strands.
This figure shows the structure of the oyster mushroom:
The creamy shade of oyster mushroom mycelium does not at all indicate low quality. However, if the threads and strands are brown with brown drops of liquid on their surface or on a container with a mycelium, then this is a sign that the mycelium has overgrown, grown old or has been exposed to adverse factors (for example, it has been frozen or overheated). In this case, you should not count on a good survival of the planting material and on the harvest.
These signs will help determine how mycelium grows in the substrate. The formation of strands in the general structure of the fungus indicates the readiness of the mycelium for fruiting.
If there are spots or plaques of pink, yellow, green, black colors in a container with mycelium or in a sown substrate (on a garden bed, in a box, in a plastic bag), it can be said with certainty that the substrate is moldy, in other words, covered with microscopic fungi, a kind of ” competitors” of cultivated champignons and oyster mushrooms.
If the mycelium is infected, then it is not suitable for planting. When the substrate is infected after the mycelium is planted in it, the infected areas are carefully removed and replaced with a fresh substrate.
Next, you will learn what are the structural features of the spores of the fungus.
The structure of the fruiting body of the fungus: the shape and features of the spores
Although the most famous is the shape of the fruiting body of the fungus in the form of a hat on a stalk, it is far from the only one and is only one of the many examples of natural diversity.
In nature, you can often see fruiting bodies that look like a hoof. Such are, for example, tinder fungi that grow on trees. The coral-like form is characteristic of horned mushrooms. In marsupials, the shape of the fruiting body is similar to a bowl or glass. The forms of fruiting bodies are very diverse and unusual, and the color is so rich that it is sometimes quite difficult to describe mushrooms.
To better imagine the structure of the fungus, look at these drawings and diagrams:
Fruiting bodies contain spores, with the help of which fungi multiply inside and on the surface of these bodies, on plates, tubes, spines (cap mushrooms) or in special chambers (raincoats).
The shape of the spores in the structure of the fungus is oval or spherical. Their sizes vary from 0,003 mm to 0,02 mm. If we examine the structure of the spores of the fungus under a microscope, we will see droplets of oil, which are a reserve nutrient designed to facilitate the spores to germinate in the mycelium.
Here you can see a photo of the structure of the fruiting body of the fungus:
The color of the spores varies, ranging from white and ocher-brown to purple and black. The color is set according to the plates of an adult fungus. Russula is characterized by white plates and spores, in champignons they are brown-violet, and in the process of maturation and an increase in the number of plates, their color changes from pale pink to dark purple.
Thanks to such a fairly effective method of reproduction as scattering billions of spores, mushrooms have been successfully solving the issue of procreation for more than one million years. As the well-known biologist and geneticist, Professor A. S. Serebrovsky figuratively put it in his “Biological Walks”: “After all, every autumn, the scarlet heads of fly agaric appear here and there from under the ground and, shouting with their scarlet color: “Hey, come in, don’t touch me, I am poisonous! ”, Millions of their insignificant spores scatter in the quiet autumn air. And who knows how many millennia these mushrooms have been preserving their fly agaric genus with the help of spores since they so radically solved the greatest of life’s problems … “
In fact, the number of spores released into the air by the fungus is simply enormous. For example, a small dung beetle, whose cap is only 2-6 cm in diameter, produces 100-106 spores, and a sufficiently large mushroom with a cap 6-15 cm in diameter produces 5200-106 spores. If we imagine that all this volume of spores germinated and fertile bodies appeared, then a colony of new fungi would occupy an area of 124 km2.
Compared with the number of spores produced by a flat tinder fungus with a diameter of 25-30 cm, these figures fade, since it reaches 30 billion, and in fungi of the puffball family the number of spores is unimaginable and it is not for nothing that these fungi are among the most prolific organisms on earth.
A mushroom called giant langermannia often approaches the size of a watermelon and produces up to 7,5 trillion spores. Even in a nightmare, you can’t imagine what would happen if they all sprouted. The mushrooms that emerged would cover an area larger than that of Japan. Let’s let our imagination run wild and imagine what would happen if the spores of this second generation of fungi germinated. Fruiting bodies in volume would be 300 times the volume of the Earth.
Fortunately, nature made sure that there was no mushroom overpopulation. This fungus is extremely rare and therefore a small number of its spores find the conditions in which they could survive and germinate.
Spores fly in the air anywhere in the world. In some places there are fewer of them, for example, in the region of the poles or over the ocean, but there is no corner where they would not be at all. This factor should be taken into account and the structural features of the body of the fungus should be taken into account, especially when breeding oyster mushrooms indoors. When the mushrooms begin to bear fruit, their collection and care (watering, cleaning the room) must be done in a respirator or at least in a gauze bandage covering the mouth and nose, as its spores can cause allergies in sensitive people.
You can not be afraid of such a threat if you grow champignons, ringworms, winter mushrooms, summer mushrooms, since their plates are covered with a thin film, which is called a private cover, until the fruiting body is fully ripe. When the mushroom ripens, the cover breaks, and only a ring-shaped footprint remains from it, and the spores are thrown into the air. However, with this development of events, there are still fewer disputes, and they are not so dangerous in terms of causing an allergic reaction. In addition, the harvest of such mushrooms is harvested before the film is completely broken (at the same time, the commercial quality of the product is significantly higher).
As shown in the picture of the structure of oyster mushrooms, they do not have a private bedspread:
Because of this, spores in oyster mushrooms are formed immediately after the formation of plates and are released into the air throughout the entire growth of the fruiting body, starting from the appearance of plates and ending with full ripening and harvesting (this usually occurs 5-6 days after the rudiment of the fruiting body will form).
It turns out that the spores of this fungus are constantly present in the air. In this regard, advice: 15-30 minutes before harvesting, you should slightly moisten the air in the room with a spray bottle (water should not get on the mushrooms). Together with droplets of liquid, spores will also settle on the ground.
Now that you have familiarized yourself with the characteristics of the structure of fungi, it’s time to learn about the basic conditions for their development.
Basic conditions for the development of fungi
From the moment of formation of the rudiments and until full ripening, the growth of the fruiting body most often takes no more than 10-14 days, of course, under favorable conditions: normal temperature and humidity of the soil and air.
If we recall other types of crops grown in the country, then for strawberries from the moment of flowering to full ripening in central Our Country it takes about 1,5 months, for early varieties of apples – about 2 months, for winter this time reaches 4 months.
In two weeks, cap mushrooms are fully developed, while puffballs can grow up to 50 cm in diameter or more. There are several reasons for such a rapid development cycle of fungi.
On the one hand, in favorable weather, it can be explained by the fact that on the mycelium underground there are already mostly formed fruiting bodies, the so-called primordia, which contain full-fledged parts of the future fruiting body: stem, cap, plates.
At this point in its life, the fungus intensively absorbs soil moisture to such an extent that the water content in the fruiting body reaches 90-95%. As a result, the pressure of the contents of the cells on their membrane (turgor) increases, causing an increase in the elasticity of the fungal tissues. Under the influence of this pressure, all parts of the fruiting body of the fungus begin to stretch.
It can be said that humidity and temperature give impetus to the beginning of the growth of primordia. Having received data that the humidity has reached a sufficient level, and the temperature meets the conditions of life, the mushrooms quickly stretch in length and open their caps. Further, at a fast pace, the appearance and maturation of spores.
However, the presence of sufficient humidity, for example, after rain, does not guarantee that many mushrooms will grow. As it turned out, in warm, humid weather, intensive growth is observed only in the mycelium (it is he who produces the pleasant mushroom smell so familiar to many).
The development of fruiting bodies in a significant number of fungi occurs at a much lower temperature. This is due to the fact that mushrooms need a temperature difference in addition to humidity to grow. For example, the most favorable conditions for the development of champignon mushrooms are a temperature of +24-25°C, while the development of the fruiting body begins at +15-18°C.
At the beginning of autumn, autumn honey agaric reigns supreme in the forests, which loves the cold and reacts very noticeably to any temperature fluctuations. Its temperature “corridor” is +8-13°С. If this temperature is in August, then the honey agaric begins to bear fruit in the summer. As soon as the temperature rises to + 15 ° C or more, the mushrooms cease to bear fruit and disappear.
The mycelium of flammulina velvet-legged begins to germinate at a temperature of 20 ° C, while the fungus itself appears on average at a temperature of 5-10 ° C, however, a lower temperature down to minus is also suitable for it.
Similar features of the growth and development of fungi should be taken into account when they are bred in open ground.
Mushrooms have the feature of rhythmic fruiting throughout the growing season. This is most clearly manifested in cap mushrooms, which bear fruit in layers or waves. In this regard, there is an expression among mushroom pickers: “The first layer of mushrooms went” or “The first layer of mushrooms came down.” This wave is not too abundant, for example, in white boletus, it falls at the end of July. At the same time, the mowing of bread takes place, which is why mushrooms are also called “spikelets”.
During this period, mushrooms are found on elevated places, where oaks and birches grow. In August, the second layer ripens, late summer, and in late summer – early autumn, the time of the autumn layer comes. Mushrooms that grow in autumn are called deciduous mushrooms. If we consider the north of Our Country, the tundra and forest-tundra, then there is only an autumn layer – the rest merge into one, August. A similar phenomenon is typical for high mountain forests.
The richest harvests under favorable weather conditions fall on the second or third layers (end of August – September).
The fact that mushrooms appear in waves is explained by the specifics of mycelium development, when cap mushrooms begin to bear fruit throughout the season instead of the period of vegetative growth. This time for different types of mushrooms varies greatly and is determined by weather conditions.
Thus, in champignon grown in a greenhouse, where an optimally favorable environment is formed, the growth of the mycelium lasts 10-12 days, after which active fruiting continues for 5-7 days, followed by the growth of mycelium for 10 days. Then the cycle repeats again.
A similar rhythm is found in other cultivated mushrooms: winter fungus, oyster mushroom, ringworm, and this cannot but affect the technology of their cultivation and the specifics of their care.
The most obvious cyclicity is observed when growing mushrooms indoors under controlled conditions. In open ground, weather conditions have a decisive influence, due to which the layers of fruiting can move.
Next, you will learn what type of nutrition mushrooms have and how this process occurs.
How does the process of feeding mushrooms: characteristic types and methods
The role of fungi in the general food chain of the plant world can hardly be overestimated, since they decompose plant residues and thus actively participate in the unchanging cycle of substances in nature.
The processes of decomposition of complex organic substances, such as cellulose and lignin, are the most important problems in biology and soil science. These substances are the main components of plant litter and wood. By their decay, they determine the cycle of carbon compounds.
It has been established that 50-100 billion tons of organic substances are formed on our planet every year, most of which are plant compounds. Every year in the taiga region, the level of litter varies from 2 to 7 tons per 1 ha, in deciduous forests this number reaches 5-13 tons per 1 ha, and in meadows – 5-9,5 tons per 1 ha.
The main work on the decomposition of dead plants is carried out by fungi, which nature endowed with the ability to actively destroy cellulose. This feature can be explained by the fact that fungi have an unusual way of feeding, referring to heterotrophic organisms, in other words, to organisms that lack the independent ability to convert inorganic substances into organic ones.
In the process of nutrition, fungi have to absorb ready-made organic elements produced by other organisms. This is precisely the main and most important difference between fungi and green plants, which are called autotrophs, i.e. self-forming organic substances with the help of solar energy.
According to the type of nutrition, fungi can be divided into saprotrophs, which live by feeding on dead organic matter, and parasites, which use living organisms to obtain organic matter.
The first type of fungi is quite diverse and very widespread. They include both very large fungi – macromycetes, and microscopic – micromycetes. The main habitat of these fungi is the soil, which contains almost countless spores and mycelium. No less common are saprotrophic fungi growing in forest turf.
Many species of fungi, called xylotrophs, have chosen wood as their habitat. These can be parasites (autumn honey agaric) and saprotrophs (common tinder fungus, summer honey agaric, etc.). From this, by the way, we can conclude why it is not worth planting winter honey agarics in the garden, in the open field. Despite its weakness, it does not cease to be a parasite capable of infecting trees on the site in a short time, especially if they are weakened, for example, by unfavorable wintering. Summer honey agaric, like oyster mushroom, is completely saprotrophic, therefore it cannot harm living trees, growing only on dead wood, so you can safely transfer the substrate with mycelium from indoors to the garden under trees and shrubs.
Popular among mushroom pickers, autumn honey agaric is a real parasite that seriously damages the root system of trees and shrubs, causing root rot. If no preventive measures are taken, then the honey agaric that ends up in the garden can ruin the garden for just a few years.
Water after washing the mushrooms should absolutely not be poured into the garden, unless in a compost heap. The fact is that it contains many spores of the parasite and, having penetrated into the soil, they are able to get from its surface to the vulnerable places of trees, thereby causing their disease. An additional danger of autumn honey agaric is that the fungus, under certain conditions, can be a saprotroph and live on dead wood until there is an opportunity to get on a living tree.
Autumn honey agaric can also be found on the soil next to the trees. The threads of the mycelium of this parasite are closely intertwined into the so-called rhizomorphs (thick black-brown strands), which are able to spread underground from tree to tree, braiding their roots. As a result, honey agaric infects them in a large area of the forest. At the same time, fruiting bodies of the parasite are formed on strands developing underground. Due to the fact that it is located at a distance from the trees, it seems that the honey agaric grows on the soil, however, its strands in any case have a connection with the root system or tree trunk.
When breeding autumn mushrooms, it is necessary to take into account how these mushrooms are fed: in the process of life, spores and parts of mycelium accumulate, and if they exceed a certain threshold, they can cause infection of trees, and no precautions will help here.
As for mushrooms such as champignon, oyster mushroom, ringworm, they are saprotrophs and do not pose a threat when grown outdoors.
The foregoing also explains why it is extremely difficult to breed valuable forest mushrooms under artificial conditions (porcini mushroom, boletus, camelina, butterdish, etc.). The mycelium of most cap mushrooms binds to the root system of plants, in particular trees, resulting in the formation of a fungus root, i.e. mycorrhiza. Therefore, such fungi are called “mycorrhizal”.
Mycorrhiza is one of the types of symbiosis, often found in many fungi and until recently remained a mystery to scientists. Symbiosis with fungi can create most woody and herbaceous plants, and the mycelium located in the ground is responsible for such a connection. It grows together with the roots and forms the conditions necessary for the growth of green plants, while at the same time receiving ready-made nutrition for itself and the fruiting body.
Mycelium envelops the root of a tree or shrub with a dense cover, mainly from the outside, but partially penetrates inside. Free branches of the mycelium (hyphae) branch off from the cover and, diverging in different directions in the ground, replace the root hairs.
Due to the special nature of nutrition, with the help of hyphae, the fungus sucks water, mineral salts and other soluble organic substances, mostly nitrogenous, from the soil. A certain amount of such substances enters the root, and the rest goes to the fungus itself for the development of mycelium and fruiting bodies. In addition, the root provides the fungus with carbohydrate nutrition.
For a long time, scientists could not explain the reason why the mycelium of most cap forest mushrooms does not develop if there are no trees nearby. Only in the 70s. XNUMXth century it turned out that mushrooms do not just tend to settle near trees, for them this neighborhood is extremely important. A scientifically confirmed fact is reflected in the names of many mushrooms – boletus, boletus, cherry, boletus, etc.
The mycelium of mycotic fungi penetrates the forest soil in the root zone of trees. For such fungi, symbiosis is vital, because if the mycelium can still develop without it, but the fruiting body is unlikely.
Previously, the characteristic way of feeding mushrooms and mycorrhiza was not given much importance, because of which there were numerous unsuccessful attempts to grow edible forest fruit bodies in artificial conditions, mainly boletus, which is the most valuable of this variety. White fungus can enter into a symbiotic relationship with almost 50 tree species. Most often in forests there is a symbiosis with pine, spruce, birch, beech, oak, hornbeam. At the same time, the type of tree species with which the fungus forms mycorrhiza affects its shape and color of the cap and legs. In total, approximately 18 forms of white fungus are isolated. The color of the hats ranges from dark bronze to almost black in oak and beech forests.
The boletus forms mycorrhiza with certain types of birches, including the dwarf birch, which is found in the tundra. There you can even find boletus trees, which are much larger than the birches themselves.
There are mushrooms that come into contact only with a certain tree species. In particular, larch butterdish creates a symbiosis exclusively with larch, which is reflected in its name.
For the trees themselves, such a connection with fungi is of considerable importance. Judging by the practice of planting forest strips, it can be said that without mycorrhiza, trees grow poorly, become weak and are subject to various diseases.
Mycorrhizal symbiosis is a highly complex process. Such ratios of fungi and green plants are usually determined by environmental conditions. When plants lack nutrition, they “eat” partially processed branches of the mycelium, the fungus, in turn, experiencing “hunger”, begins to eat the contents of the root cells, in other words, resorts to parasitism.
The mechanism of symbiotic relationships is quite subtle and very sensitive to external conditions. It is probably based on the parasitism common to fungi on the roots of green plants, which, in the course of long evolution, turned into a mutually beneficial symbiosis. The earliest known cases of mycorrhiza of tree species with fungi were found in Upper Carboniferous deposits approximately 300 million years old.
Despite the difficulties of growing forest mycorrhizal mushrooms, it still makes sense to try to breed them in summer cottages. Whether you succeed or not depends on various factors, so success cannot be guaranteed here.