1) cells containing chloroplasts,

2) mycorrhiza,

3) fruiting body,

4) fungal organism.

A24. To produce the drug penicillin using biotechnology, the following are grown under special conditions:

1) bacteria,

2) algae,

3) viruses,

4) mold fungi.

A25. Mushrooms and plants are brought together:

1) autotrophic method of nutrition,

2) heterotrophic mode of nutrition,

3) the presence of organs and tissues,

4) the presence of a cell wall and reproduction by spores.

Tasks with multiple choice of correct answers.

IN 1. By what characteristics can mushrooms be distinguished from animals?

A) feed on ready-made organic substances,

B) have a cellular structure,

C) grow throughout life,

D) have a body consisting of hyphae,

D) absorb nutrients from the surface of the body,

E) have limited growth.

AT 2. Mushrooms, like plants:

A) grow throughout life,

B) have limited growth,

C) absorb nutrients from the surface of the body,

D) feed on ready-made organic substances,

E) have a cellular structure.

Compliance tasks.

AT 3. Match the groups of mushrooms according to their feeding method and their examples.

GROUPS OF MUSHROOMS EXAMPLES OF MUSHROOMS

A) saprotrophs, 1. fly agaric,

3. late blight,

4. smut,

5. yeast,

6. ergot.

AT 4. Establish a correspondence between the groups of fungi based on the structure of the fruiting body and their examples.

GROUPS OF MUSHROOMS EXAMPLES OF MUSHROOMS

A) Tubular mushrooms, 1. porcini mushroom,

B) Lamellar mushrooms. 2. wave,

3. boletus,

4. boletus,

5. champignon,

6. Russula.

AT 5. Establish a correspondence between the characteristics of organisms and the group for which it is characteristic.

GROUPS OF ORGANISMS SIGNS OF ORGANISMS

A) Mushrooms, 1. are classified into a special kingdom,

B) lichens. 2. the body is a thallus,

3. have a fruiting body,

4. according to the method of nutrition - auto-heterotrophs,

5. enter into symbiosis with plant roots,

6. represent a symbiosis of fungi and algae.

Tasks to establish the correct sequence.

AT 6. Establish the sequence of phases of development of the cap mushroom, starting with the entry of spores into the soil.

A) Germination of spores and formation of mycelium,

B) maturation of the fruiting body and formation of spores,

B) formation of the fruiting body,

D) spread of spores.

Free-response tasks (C1-2 – short, C4-5 – extended)

C1. What basic rule must be followed when collecting mushrooms to maintain their numbers?

C2. Why is the soil in forest plantations populated with mycorrhizal fungi?

The cap is the main part of the fruiting body. The lower part of the cap is covered with a hymenophore (spore-bearing layer of the cap). Spores are formed on the hymenophore in the hymenium, with the help of which fungi reproduce.

When identifying individual types of mushrooms, we pay special attention to the shape of the cap, the nature of its surface, color and size.

Cap shape can be: spherical, hemispherical, oval, cushion-shaped, bell-shaped, tuberculate, flat, funnel-shaped and cone-shaped.

The surface of the cap can be: smooth, pitted, folded, furrowed, bare, velvety, slimy, felted, hairy, fibrous, flaked, scaly, matte, shiny, sticky or dry.

The edge of the cap can be straight, wavy-curved, curled down and up, sharp or rounded with or without remnants of the cover.

Cap color: can be a variety of different tones and shades.

Cap sizes vary.

If the diameter of the cap of many types of honey mushrooms or collibias is only 15-20 mm, then in some types of mushrooms it reaches 200-350 mm. The cap of the large variegated umbrella mushroom (Macrolepiota procera) reaches 500 mm.

In addition to the above-mentioned signs, when determining, it is necessary to pay attention to the nature of the surface of the cap, its hygrophanicity, the nature of the relationship of the skin with the pulp (it is separated or not separated from the pulp at all).

The hymenophore of the capped fruiting bodies of mushrooms is: veined, lamellar, spinous, tubular, smooth.

The veins can be thick or thin, frequent or sparse, simple or branched, often connected to each other by septa, anastomoses (anastomosis) of different colors.

The spines can be short or long, thick or thin, pointed or blunt; frequent or rare, fragile or elastic, different tones and shades.

The plates can be wide or narrow, dense or sparse, thin or thick, differently attached to the stem.

The main feature is the nature of the edge of the plates, but you should also pay attention to their shape - what they are: whole-cut, eaten, finely grooved, jagged, saw-toothed or covered with flakes. To the touch, the plates can be: hard, soft, elastic or brittle. A very important feature is the color of the plates, which can be white, cream, ocher, pink, blood red, yellow, blue, violet, green, light brown, dark brown or black.

In species of some genera of agaric fungi, the initial color of the plates changes as the fruiting bodies mature, depending on how the ripening and ripe spores are colored.

This phenomenon, for example, is observed in species of the genera Volvariella, Entoloma, champignon Agaricus, Cortinarius, Hypholoma, etc.

n. In young fruiting bodies of some species of spider webs, the plates are blue, green, purple, yellow, cream or reddish in color. And in old fruiting bodies, mature spores change the color of the plates to brown or rusty brown.

The tubes can be short or long, easily separated from the pulp or not separated at all, attached to the stem, notched, free, separated or descending.

The tubes are most often white, yellow, reddish, yellow-green, olive, yellow-brown or gray-pink. As the fruiting body matures, the color of the tubes usually changes. The color of the tubes in many species changes upon contact with air.

Edible and poisonous cap mushrooms

The mouth of the tubes is usually called pores.

First of all, you should pay attention to their shape, size and color. The color of the pores can change at different stages of development and does not always coincide with the color of the tubes. In some species, when light pressure is applied to the pores, brown or brownish-pink spots remain on them.

The structure of the leg. The leg can be solid or hollow. Its pulp can be hard, soft, brittle, watery, leathery, elastic, gristly, etc.

n. During the growth period of the fruiting body, the stem lifts and supports the cap. Depending on how the leg is attached to the cap, there are central, eccentric and lateral legs. First of all, we pay attention to the shape, size, surface and color.

The shape of the leg can be barrel-shaped, cushion-shaped, club-shaped, cylindrical and fusiform.

A very important feature is the end of the basal part of the stalk, which can be blunt, rounded, conically narrowed, tuberous or with a root-like outgrowth.

The surface of the leg can be smooth, longitudinally fibrous, wrinkled, ribbed, mesh, bare, velvety, flaky, scaly, mucous, sticky or dry, shiny or matte.

The color of the leg is also important. It can be single-colored or multi-colored, or have a rich range of colors.

The most famous are cap mushrooms, such as porcini mushrooms, boletus and aspen mushrooms, chanterelles, milk mushrooms, saffron milk caps and many others.

The structure of a cap mushroom. Most edible mushrooms (except truffles, strings and morels) have a fruiting body, which is formed by a stalk and a cap.

What we call mushrooms in everyday life are essentially their fruiting bodies. The mycelium itself (the main part of each mushroom) is located in the soil. It consists of thin branching white threads. Each cell of the mycelium in cap mushrooms in most cases contains two nuclei. There are no plastids in fungal cells.

The fruiting bodies of cap mushrooms serve to produce spores, which in turn serve for reproduction.

Tubes and plates make it possible to increase the surface on which spores form many times over. Even a small fruiting body produces millions of spores, and often there are tens or even hundreds of millions of them. The spores of cap mushrooms are very small and light and are carried by air currents. In addition, squirrels and other small animals, storing mushrooms, contribute to the spread of spores.

Once in favorable conditions, that is, warm and humid, the spore germinates into a hypha. Hyphae grow, branch, and the number of cells in them increases.

Gradually, mycelium is formed, consisting of many hyphae. Mycelium, or mycelium, is the vegetative part of the mushroom. This is that white “web”, well known to mushroom pickers, which can often be seen in the forest on fallen branches and leaves, on bare soil. But the main part of the mycelium is hidden under the surface of the soil.

Mycelium is the main state of the fungus. The fungus can remain in this form for a long time, but for reproduction the spores must mature.

Where there are too many mushroom pickers and the fruiting bodies do not have time to produce spores, the mushrooms thin out and even disappear altogether, as, for example, near nearby cities.

Most mushrooms form fruiting bodies in late summer and early autumn.

But there are also very early mushrooms. Already at the end of April, morels are collected in the middle zone. Their quarrels form not on the bottom, but on the top side of their wrinkled hats.

Both the cap and the stem of the fruiting body consist of mycelium threads tightly adjacent to each other.

However, if all the threads in the stem are the same, then in the cap they form two layers - the upper one, covered with skin, often colored with different pigments, and the lower one.

In some mushrooms, for example, in the porcini mushroom, boletus, and oiler, the lower layer is penetrated by numerous tubes. Tubular mushrooms have this structure of the lower part of the fruiting body. In lamellar mushrooms, the lower layer of the fruiting bodies has numerous plates (saffron milk caps, russula, volnushki).

Education dispute.

Spores (special cells with the help of which mushrooms reproduce) are formed in tubes or on the plates of the cap. The spores are very small and light. After ripening, they spill out, are easily picked up and carried by the wind.

In addition, they can be spread by insects and slugs, as well as squirrels and hares that eat mushrooms. In the digestive organs of these animals, the spores are not digested and are thrown out along with the droppings.

Once in moist, humus-rich soil, fungal spores germinate and mycelium threads develop from them.

Only occasionally can a mycelium grown from one spore form new fruiting bodies. In most species of fungi, fruiting bodies develop on myceliums formed by fused cells of filaments grown from different spores. A feature of this fusion of two cells is the process of interaction of their nuclei. They do not merge, but only connect in pairs. Therefore, the cells of such a mycelium remain binuclear for a long time and only then merge.

The mycelium grows slowly, and only after accumulating sufficient reserves of nutrients does it form fruiting bodies.

Symbiosis of fungi and plants

Cap mushrooms absorb water, mineral salts from the soil, as well as organic substances formed in the soil as a result of the decomposition of plant residues.

Many cap mushrooms obtain organic matter from tree roots.

Mushroom pickers are well aware that boletus grows under birch trees, aspen boletus grows in aspen forests, and boletus grows under pine and larch trees. This connection between mushrooms and trees is explained by the fact that the mycelium of certain types of mushrooms comes into close contact with the roots of certain tree species.

In this case, the mycelial hyphae entwine the root and even penetrate into its cells. The relationship between a mushroom and a tree is “beneficial” for both parties. The roots of the tree receive water and mineral salts from the fungus, and the mushroom from the roots of the tree receive organic substances necessary for nutrition and the formation of fruiting bodies. Such connections between different organisms are called symbiosis.

The symbiosis of fungal mycelium with roots is called mycorrhiza.

Many cap mushrooms form mycorrhizae, but not all. This is how one of the most valuable edible mushrooms, champignon, does not form mycorrhiza.

Among the cap mushrooms there are both edible and poisonous. Of the edibles, the most valuable are champignons, white mushrooms, boletus mushrooms, boletus mushrooms, boletus mushrooms, and milk mushrooms. Fruiting bodies of different types of mushrooms are formed at different times.

At the end of April - beginning of May, morels and lines appear. A little later - champignons. In mid-June, when the rye is heading, boletus mushrooms appear.

Following them are boletus, boletus, and russula. From the second half of summer until frost, mushrooms of all types form fruiting bodies.

When collecting, it is advisable to handle the mycelium as carefully as possible. There is no need to dig mushrooms out of the soil, as this will damage the mycelium. You should use light, careful movements to twist the fruit tepa out of the soil.

In this case, the mycelium threads are almost not damaged.

If the weather is dry, the fruiting bodies of the mushrooms begin to grow only at the end of summer. As soon as the air temperature drops steadily, their growth stops.

When collecting mushrooms, you must use the main rule - if you are not completely sure that the mushroom is edible, it is better not to take it. The fly agaric and toadstool have a high content of toxic substances. Double mushrooms are especially dangerous: false chanterelles and false honey mushrooms and others, since they are very similar to edible ones.

Pale toadstool mushrooms are very similar in appearance. However, the underside of the cap of the toadstool is greenish-white, while that of the champignon is pink.

The fly agaric has a distinctive bright red cap with white spots, although fly agarics are sometimes found with gray caps.

The porcini mushroom has its own counterpart - the gall mushroom.

However, the upper part of the gall mushroom stump is covered with a pattern in the form of a black or dark gray mesh, and its flesh, unlike the pulp of the porcini mushroom, turns red at the break. False chanterelles are also similar to edible chanterelles, but their caps are smooth, reddish-orange, rather than light yellow like the edible ones. In addition, white juice is released from the broken cap of the false chanterelle.

Edible honey mushrooms have a ring of film on the stump.

False honey mushrooms do not have such a film and their plates under the cap are greenish.

In some years, in some areas, edible mushrooms may contain toxic substances. In addition, old fruiting bodies of edible mushrooms can also become poisonous. It is dangerous to eat mushrooms grown near highways, chemical and other industrial enterprises that pollute the environment with harmful substances. Mushrooms grown in areas contaminated with radionuclides pose a great danger.

The fruiting bodies of fungi are capable of intensively accumulating these substances.

Materials: http://biofile.ru/bio/1103.html

The fruiting body consists of a cap and a stalk (the stalk is also called a stump). The hat can be painted in different colors (brown, bluish, red, etc.). There are cap mushrooms that do not have legs (truffles, morels).

In addition to the fruiting body, cap mushrooms have mycelium (mycelia), which are characteristic of all species belonging to the kingdom Mushrooms.

Cap mushrooms

Mycelium hyphae

Each cell can have several nuclei. Fruiting bodies grow on the mycelium; they consist of the same hyphae, but tightly adjacent to each other. In the mushroom cap, the hyphae form two layers. The top layer is covered with skin, the color of which is given by various pigments.

The bottom layer of the cap may contain either tubes or plates. In the first case, these are tubular mushrooms (boletus, boletus), in the second - lamellar ones (russula, saffron milk caps).

Tubular mushroom (oil can)
Lamellar mushroom (russula)

Cap mushrooms feed by absorbing organic substances from the soil along with water and inorganic substances by the mycelium.

Therefore, mushrooms grow in places where there is a lot of humus, the partial decomposition of which enriches the soil with organic matter.

Another way of feeding mushrooms is through symbiosis with trees. Many cap mushrooms penetrate the roots of trees with their hyphae. The so-called mycorrhiza is formed.

Through it, the fungus receives organic substances from plants. The tree receives water and minerals from the fungus, which are absorbed by the branched mycelium from a large area of ​​soil.

Each type of mushroom is able to enter into symbiosis only with certain trees. So saffron milk caps form mycorrhizae with pines and spruces, boletus mushrooms with birch trees, etc. Accordingly, these mushrooms can only be found near “their” trees.

The fruiting bodies of many mushrooms are edible (boletus, porcini mushroom, boletus, champignons, russula, etc.). However, there are also many poisonous mushrooms (white toadstool, fly agaric, false mushrooms, etc.).

In addition, old fruiting bodies also become poisonous. Mushrooms accumulate heavy metals, so they should not be collected near roads or in industrial areas.

Materials: http://biology.su/fungus/blewits

In everyday life, mushrooms are the fruiting bodies of cap mushrooms. Fruiting body consists of a cap and a stem (the stem is also called a stump). The hat can be painted in different colors (brown, bluish, red, etc.). There are cap mushrooms that do not have legs (truffles, morels).

In addition to the fruiting body, cap mushrooms have mycelium (mycelium), characteristic of all species belonging to the kingdom Mushrooms.

You can see the mycelium of the cap mushroom in the soil near the surface. Usually it is a plexus of thin branching threads of a whitish color. It is the mycelium that is the main body of the fungus, while the fruiting bodies serve for reproduction.

The thread (hyphae) of the mycelium consists of one row of long cells.

Each cell can have several nuclei. Fruiting bodies grow on the mycelium; they consist of the same hyphae, but tightly adjacent to each other. In the mushroom cap, the hyphae form two layers. The top layer is covered with skin, the color of which is given by various pigments. The bottom layer of the cap may contain either tubes or plates. In the first case, these are tubular mushrooms (boletus, boletus), in the second - lamellar (russula, saffron milk caps).

Cap mushrooms, like all fungi, do not have chloroplasts (like other plastids), and therefore are not plants and cannot eat through photosynthesis.

Cap mushrooms feed by absorbing organic substances from the soil along with water and inorganic substances by the mycelium. Therefore, mushrooms grow in places where there is a lot of humus, the partial decomposition of which enriches the soil with organic matter.

Another way of feeding mushrooms is through symbiosis with trees. Many cap mushrooms penetrate the roots of trees with their hyphae.

The so-called mycorrhiza. Through it, the fungus receives organic substances from plants. The tree receives water and minerals from the fungus, which are absorbed by the branched mycelium from a large area of ​​soil. Each type of mushroom is able to enter into symbiosis only with certain trees.

So saffron milk caps form mycorrhizae with pines and spruces, boletus mushrooms with birch trees, etc. Accordingly, these mushrooms can only be found near “their” trees.

Mushroom reproduction is carried out by spores that are formed in the tubes or plates of the lower layer of the cap. Fungal spores are small and light enough to be spread by wind. In addition, they are often spread by invertebrates on their bodies, or by vertebrates that eat the fungi.

Mushroom fruiting body

In the digestive tract of animals, the spores are not digested and are excreted along with the droppings. Once in favorable conditions, the fungal spore germinates, gradually forming a large mycelium. After some time, fruiting bodies begin to grow on the mycelium.

The fruiting bodies of many mushrooms are edible (boletus, porcini mushroom, boletus, champignons, russula, etc.).

However, there are also many poisonous mushrooms (white toadstool, fly agaric, false mushrooms, etc.). In addition, old fruiting bodies also become poisonous. Mushrooms accumulate heavy metals, so they should not be collected near roads or in industrial areas.

The body of the mushroom is mycelium, consisting of thin threads - gif. The mycelium has a close connection with the substrate, which is due to the osmotic absorption of nutrients. U higher The mycelium of mushrooms is divided into individual cells by partitions - septa, i.e. they have a septate (cellular) mycelium. Inferior mushrooms have noncellular structure mycelium, since its hyphae are not divided into partitions, but are like one branched cell with many nuclei.

Fungi are isolated in their morphophysiological organization from the rest of the world of living beings. They cannot be classified as either plants or animals. There are two theories of the origin of fungi: animal and plant, since fungal cells have characteristics of both animal and plant cells (Table 5.2).

Plant theory fungi suggests their origin from green algae, from which it follows that fungi are primarily a clearly regressive group of plants that have lost chloroplasts.

Animal theory is based on the fact that fungi are initially chlorophyll-free organisms, i.e. come from simple heterotrophic organisms, and not from algae. This theory is preferable, since achlorophyll-free algae, classified as green, accumulate starch as a reserve product, while fungi do not have starch.

Table 5.2. Features of the structure of a mushroom cell

Fungi are heterotrophs. Like bacteria, they are characterized by extracellular digestion, carried out by releasing enzymes into the external environment. Absorption of broken down nutrients occurs osmotically across the entire surface of the body. Mycelium cells deposit carbohydrates in the form of glycogen, fats in the form of lipid droplets, and proteins in vacuoles as reserve nutrients.

Mushrooms are capable enter into symbiosis with higher plants, forming mycorrhiza(mushroom root). Fungi use carbohydrates synthesized by the plant and obtain for it (due to the mineralization of organic compounds) various compounds with nitrogen, phosphorus, and produce growth activators and vitamin-like substances.

Multiply Fungi can be vegetative, asexual and sexual.

Vegetative reproduction can occur by parts of the mycelium (in almost all mushrooms), by budding (yeast). Asexual reproduction occurs due to the formation of zoospores, sporangiospores and conidia.

Zoospores are formed in fungi leading an aquatic lifestyle (chytridiomycetes, oomycetes). Their mobility is ensured by flagella (1 or 2 of them). They are formed inside single-celled zoosporangia and, when ripe, enter the water. They become covered with a shell and grow into a new individual.

Sporangiespores are formed endogenously - inside unicellular sporangia that arise on sporangiospheric hyphae. One sporangium can contain up to 10 thousand spores, which, when ripe, emerge from the sporangium and are distributed by the wind over considerable distances. Once in favorable conditions, the spore grows into a new mycelium (for example, in mucor).

Conidia are formed exogenously on special hyphae - conidiophores. Conidia form chains, detach and, in a favorable environment, germinate into new mycelium (for example, in penicillium).

Sexual reproduction in lower fungi happens:

During the fusion of gametes - gametogamy(isogamy, heterogamy and oogamy);

With the fusion of two multinucleated specialized reproductive organs (gametangia) - zygogamy.

Sexual reproduction in higher fungi:

gametangiogamy; archicarp - female gametangium, antheridium - male (in marsupial fungi);

somatogamy- fusion of haploid somatic cells of heterothallic hyphae (+ and - physiologically different hyphae), for example in higher basidiomycetes.

The sexual process always ends with the formation of a diploid zygote, its meiotic division and sporulation.

The lower fungi include the zygomycota division, the higher ones include the divisions: marsupials, basidiomycota, imperfect.

DEPARTMENT OF ZYGOMYCOTA(ZYGOMYCOTA)

Mucor is widely distributed in nature as white mold (Fig. 5.15). Saprophyte by way of nutrition; develops on soil and food products. Mycelium hyphae are an elongated, overgrown giant cell with many nuclei (non-cellular structure). Nuclei - with a haploid set of chromosomes (n). Numerous vertical sporangiophores with brown-black sporangia develop on the mycelium. As a result of mitosis, the contents of the sporangium break up into many spores (up to 10 thousand). After maturation, the sporangium shell bursts and the spores disperse, germinating into new individuals. Reproduction can be asexual (spores), vegetative (parts of mycelium), and rarely sexual (zygogamy).

With zygogamy (Fig. 5.16), physiologically different hyphae - heterothallic, conventionally designated as + and -, begin to grow towards each other. At the ends of the hyphae, gametangia are formed, separated by septa from the rest of the hyphae. Next, gametangiogamy occurs, consisting in the fusion of 2 specialized reproductive structures (gametangia), not differentiated into gametes, and a zygote with many diploid nuclei is formed. The zygote is covered with a thick brown membrane. After a period of rest, the nuclei undergo meiosis, and the zygote grows into an embryonic sporangium. The haploid nuclei + and - formed after meiosis pass into it. Spores are formed in the sporangium; after they mature, the sporangium is opened, the spores disperse and grow into new mycelia (+ and -).

Rice. 5.15. The structure of mucor (Mucor mucedo): 1 - hypha; 2 - mycelium; 3 - sporangiophore; 4 - sporangium with spores

Some mucor fungi cause mycosis (mucoromycosis) of the lungs (false tuberculosis), brain and other human organs, as well as agricultural plants. Many species of the genus have high enzymatic activity, which is used in the production of “soy cheese” from soybean seeds, alcohol from potato tubers, etc.

Rice. 5.16. Life cycle of mucor (Mucor): A - haploid phase; B - diploid phase: 1 - two heterothallic (opposite in physiological sign) mycelium; 2 - sporangiophore; 3 - sporangium; 4 - disputes; 5 - spore germination; 6 - gametangium; 7 - pendants; 8 - zygospore; 9 - germinating zygospore; 10 - germinating mycelium

DEPARTMENT MARSPIAL FUNGI, OR ASCOMYCOTS(ASCOMYCOTA)

This is one of the most extensive classes of fungi, including more than 30 thousand species. This class includes yeasts, represented by single budding cells, and mushrooms with large fruiting bodies, such as morels and strings. Ascomycots are widespread in nature in all natural zones. According to their feeding method, they are saprophytes. The mycelium of marsupial fungi is septate, i.e. divided into cells (with a haploid set of chromosomes). A characteristic feature of ascomycots is the presence of bags (asks) formed as a result of the sexual process. Bags are closed structures containing a certain number of ascospores (spores of sexual reproduction) and formed as a result of meiosis.

In many ascomycotas, pouches are formed in the fruiting bodies (subclass Fruit marsupials). There are 3 types of fruiting bodies: cleistothecia, perithecia And apothecium. In other representatives, the bags lie open on the mycelium (subclass Holosumchatae).

Asexual reproduction also plays a large role in the development cycle. Asexual reproduction spores - conidia- are formed as a result of mitosis on mycelium with haploid nuclei (n) or conidiophores of various structures.

The most common and most practical is genus Yeast (Saccharomyces). Yeast is represented by single, oval cells (Fig. 5.17). Yeasts are characterized by vegetative reproduction, carried out by budding; To do this, they need a nutrient medium, the presence of sugar in it and a certain temperature. Under unfavorable conditions it occurs sexual process; When 2 haploid daughter cells fuse (chologamy), a zygote is formed, which turns into a bursa. As a result of meiosis, four spores (ascospores) are formed in the bag, which germinate into new yeast cells.

Baker's yeast (Saccharomyces cerevisiae) combines many cultivated yeasts: alcohol, beer, wine, bakery. All these yeasts decompose sugar into ethyl alcohol and CO 2. So, when yeast is added to the dough, it begins to decompose the glucose present there, formed from starch. In this case, CO 2 is released, which provides the dough with porosity and an increase in volume. When baking, ethanol and CO 2 evaporate.

Rice. 5.17. Brewer's yeast (Saccharomyces cerevisiae): A - unicellular thallus; B - bag with ascospores; B – budding

Yeast is a valuable food and feed product. Contain up to 50% protein, as well as fats and carbohydrates. They synthesize vitamins in large quantities, especially B2. They are used in the treatment of anemia, and also as a source of protein when added to feed products in livestock and poultry farming.

Subclass Fruit marsupials(Carpoascomycetidae)

Representatives of this subclass are characterized by the presence of fruiting bodies containing bags. Fruiting bodies are formed due to a dense plexus of haploid and dikaryon (binucleate) hyphae, also called ascogenous. Fruiting bodies (ascocarps) are of 3 types: closed (closed) - cleistothecia, semi-closed - perithecia, unclosed (open) - apothecia.

The development cycle of ergot proceeds with a change of nuclear phases (Fig. 5.18). Thus, in the fall, cereal plants form sclerotia- dark purple outside and white inside horns, representing the mycelium of the fungus (dehydrated hyphae) in the dormant stage. In winter, sclerotia fall from the cereals onto the soil and overwinter in it. In spring, sclerotia germinate on the soil, forming thread-like outgrowths crowned with heads - stroma. In these stroma, as a result of the sexual process, they are formed fruiting bodies - perithecia, filled with long cylindrical bags (asci) containing filamentous ascospores - spores of sexual reproduction (Fig. 5.19). Spores mature as a result of meiosis during flowering of the cereal. Spores are actively released by the wind, land on the stigma of a flowering cereal and germinate. The resulting mycelium penetrates the ovary of the pistil and destroys it. At the ends of the mycelial hyphae, as a result of mitosis, conidia are released - spores of asexual reproduction, i.e. conidial sporulation occurs. At the same time, the hyphae of the fungus secrete droplets of sweet liquid - “honeydew”. Insects transfer conidia to the flowers of neighboring plants and infect them.

Rice. 5.18. Purple ergot (Claviceps purpurea): A - rye ear with sclerotia (1); B - stroma (2), grown on overwintered sclerotia; B - longitudinal section through the stroma with perithecia; G - longitudinal section through perithecia (3) with bags; D - bag with filamentous ascospores (4); E - conidial sporulation

Rice. 5.19. Development of a bag with ascospores: A, B - formation of a zygote at the apex of the ascogenous hypha; B-E - meiosis and development of the bag with ascospores

Unclosed fruiting bodies - apothecia- found in such representatives as morels (Morchella), stitches (Gyromitra). This open fruiting body is usually saucer-shaped, goblet-shaped, measuring from 0.1 to 10 cm, of various colors - from bright orange or red to brown and black. Upper layer (hymenium) contains many bags. The fruiting bodies of fungi from this group consist of a sterile stalk and a folded or lobed cap (Fig. 5.20).

Morels and strings are edible mushrooms, but when eating the strings, you must first boil them and drain the water.

Rice. 5.20. Ascomycota - appearance and fruiting bodies of morels and strings:

A - conical morel (Morchella coinca); B - common stitch (Gyromitra exculenta); 1 - sections of fruiting bodies

DEPARTMENT OF BASIDIOMYCOTA(BASIDIMYCOTA)

This class unites almost all groups of cap mushrooms, numbering about 30 thousand species. The vegetative body is represented by segmented mycelium, consisting of segmented hyphae.

Reproduction:vegetative(carried out by parts of the mycelium), asexual(conidia) and sexual.

During the sexual process, no special organs of sexual reproduction are formed. The sexual process takes place in the form somatogamy(Fig. 5.21). From the germinating haploid basidiospore, the primary mycelium develops, which then turns into segmented. Each segment is uninucleate. Soon it happens hologamy- fusion of terminal hyphal cells. However, the fusion of the contents of the segments is not accompanied by the fusion of the nuclei. Dikaryons are formed, which then divide synchronously. This is how it is formed secondary dikaryonic mycelium.

Rice. 5.21. Development of basidiomycete fungus. Diagram of the development cycle: A - diagram of the development cycle: 1 - basidium; 2 - basidiospore; 3 - primary mycelium; 4 - dikaryonic mycelium; 5 - fruiting body from dikaryon mycelium; B - development of basidium with basidial spores

A fruiting body is formed on the dikaryon mycelium, which consists of a stump and a cap. Hymenial layer caps can be lamellar or tubular. In the hymenial layer, at the ends of dikaryonic hyphae from 2 nuclear cells, basidia. In terms of their development, basidia are homologous to bursae. The sexual process is completed in the basidium, i.e. The dikaryon nuclei fuse and a diploid nucleus is formed. This single-celled basidia is called Holobasidia. The resulting diploid nucleus is divided by meiosis to form 4 haploid nuclei (see Fig. 5.19, A). By this time, four tubular outgrowths are formed in the upper part of the basidium - sterigma. The resulting nuclei flow into the sterigmata and 4 basidiospores are formed: 2 conventionally with the sign - and 2 with the sign +. Therefore, the primary mycelia growing from them will be heterothallic. Basidia are formed directly on hyphae or in fruiting bodies of various shapes, but most often consisting of a cap and a stalk. The development cycle alternates between 3 phases: haploid(short) - these are basidiospores, dikaryonny(lasts the main part of life) - dikaryonic mycelium and diploid(short-term) - young basidium before the formation of basidiospores.

DEPARTMENT OF DEUTEROMYCOTA(DEUTEROMYCOTA),OR IMPERFECT MUSHROOMS(FUNGI IMPERFECT!)

Deuteromycota, along with bisidiomycota and ascomycota, are the largest group of fungi, uniting 25-30 thousand species. These fungi are asexual forms (anamorphs) that reproduce asexually - by conidia. Their life cycle takes place in the haploid stage without sexual process. It is quite possible that deuteromycotes are the most specialized lineages of fungal evolution.

Has great medical importance genus Penicillium. Penicillium has a segmented greenish mycelium consisting of mononuclear segments. The hyphaconidiophores extending upward branch at the upper end onto sterigma. The latter in appearance resemble a brush or hand and end in a chain of external spores - conidia (Fig. 5.22). Conidia- These are spores of asexual reproduction, formed through mitosis.

A sexual process is also observed, as a result of which closed spherical fruiting bodies of bright yellow color are formed directly on the mycelium - Cleistothecia. Bags with 8 ascospores are formed inside the cleistothecia. Mature ascospores emerge from the bags after rupture of the cleistothecium.

Penicillium (Penicillium), A saprophyte, based on its feeding method, settles on food products and products (fabrics, leather), causing them to spoil. Penicillium is used not only in medical practice, but also in the food industry for the preparation of special types of cheese (“Roquefort”).

Rice. 5.22. Deuteromycota penicillium: 1 - mycelium; 2 - conidiophore; 3 - conidia; 4 – sterigmata

The importance of mushrooms in human activity is great. They participate in the cycle of substances in nature. Fungi, like bacteria, mineralize organic matter and take part in the formation of humus. They are used in the food industry for the production of alcohol, wine, beer, kvass, in baking, for the production of proteins and vitamins. Fungi produce organically active substances - antibiotics, enzymes, organic acids, etc.

Fungi can cause corrosion of metals and destroy leather, paper, and fabrics. Many fungi cause significant harm to humans, animals and plants, causing a number of diseases (mycoses, ringworm, scab), and also lead to food spoilage and thereby cause various poisonings.

LICHEN DEPARTMENT(LICHENES)

This is a group of symbiotropic plants consisting of 2 components - autotrophic algae And heterotrophic fungi. The fungal base of lichens is formed mainly marsupial mushrooms. The algal component consists of species, classified in most cases as representatives of the departments green And blue-green algae. Algae isolated from lichen do not differ from free-living forms. Physiologically, this type of symbiosis is based on intercellular exchange between algae and fungi. The fungus feeds on the carbohydrates of the algae, and the algae receive minerals from the fungi. However, symbiosis with fungi leads to the emergence of a new biological quality, which is expressed in the lichen in its ability to reproduce as a single organism.

The vegetative body of lichens is represented by a thallus that has different colors (gray, greenish, brown-brown, yellow or almost black). Morphologically, there are 3 main types of lichen thallus: scale (crust), leafy And bushy(Fig. 5.23), however, there are also transitional forms. The most poorly organized are scale, or cortical, thalli; they have the appearance of powdery, granular, lumpy deposits that grow tightly together with the substrate and do not separate from it without significant damage.

Rice. 5.23. Different types of lichen thalli: A - cortical (graphis - Graphis scripta); B - leafy (xanthoria - Xanthoria); B - bushy (cladonia - Cladonia)

More highly organized lichens have a leafy thallus in the form of plates, scales or rosettes, adhered to the soil or trees with the help of rhizines - analogues of rhizoids, consisting of bundles of fungal hyphae.

The highest organization in their structure is achieved by lichens with a bushy type of thallus, having the appearance of a branched bush (12-15 cm in height) and merging with the substrate only at the base.

According to the anatomical structure, lichens are homeomeric and heteromeric (Fig. 5.24). In the more primitive ones - homeomeric- fungal hyphae and algae are evenly distributed throughout the thickness of the thallus. At heteromeric structure on the cross section of the lichen from above you can see the so-called upper bark. It is formed by intertwining and closely interlocking fungal hyphae. Under the bark, the fungal hyphae lie more loosely, and between them there are algae cells (gonidial layer). Inside the thallus, a core can be distinguished, consisting of loose fungal hyphae and large voids filled with air. Below it is the lower crust, which is similar in structure to the upper crust. Individual hyphae (rhizins) pass through it from the core, securing the lichen in the substrate.

Most lichens tolerate drying out easily. Photosynthesis and nutrition stop at this time, which explains their insignificant annual growth.

Reproduction lichens mainly vegetative, based on the ability of lichens to regenerate from individual areas. It is carried out by fragmentation (separation of sections of the thallus) or with the help of separate groups of algal cells surrounded by fungal hyphae and different in shape - soredia, isidia and lobula (Fig. 5.25). Soredia- the smallest formations of a round shape, including one or several algae cells and surrounded by fungal hyphae. Isidia- tuberculate rod-shaped outgrowths on the upper surface of the thallus.

Rice. 5.24. Anatomical structure of lichen thallus: A - section of the homeomeric lichen thallus: 1 - fungal hyphae; 2 - algal component;

B - section of heteromeric lichen: 1 - upper cortical layer; 2 - gonidial layer; 3 - middle layer with fungal hyphae; 4 - lower cortical layer; 5 - rubbers

Rice. 5.25. Reproduction of lichens: A - soredia; B - isidium

Lobula They look like small scales located vertically on the surface of the thallus or along its edges. In addition, asexual reproduction is observed with the help of spores that are independently formed in both algae and fungi.

Sexual reproduction has not been sufficiently studied, but in general terms it proceeds in the same way as in free-living fungi.

Meaning there are a lot of lichens. They decompose and mineralize soil organic matter. They are pioneers - one of the first to populate rocks, they destroy their surface layer and, dying, form humus on which other plants settle. Lichens are indicators of air purity, as they cannot tolerate even the slightest impurities of sulfur dioxide gases. From some of their types, paint and a special substance - litmus (for the chemical industry) are obtained. In the tundra and forest-tundra, lichens (moss moss) are the main food for deer. Edible lichens are also found in semi-desert and desert regions of Kyrgyzstan and Turkmenistan.

The mushroom kingdom includes many species. Lower fungi belong to microorganisms. A person can only see them through a microscope or on spoiled food. Higher mushrooms have a complex structure and large sizes. They can grow on the ground and on tree trunks and are found where there is access to organic matter. The bodies of fungi are formed by thin, tightly adjacent hyphae. These are exactly the species that we are used to collecting in baskets while walking through the forest.

Higher mushrooms - agaricaceae

Perhaps every person has an exact idea of ​​what an ordinary mushroom looks like. Everyone knows where they can grow and when they can be found. But in reality, the representatives of the mushroom kingdom are not so simple. They differ from each other in shape and structure. The bodies of fungi are formed by a plexus of hyphae. Most of the species known to us have a stem and a cap, which can be painted in different colors. Almost all mushrooms that humans eat are classified as agaricaceae. This group includes species such as champignons, valui, saffron milk caps, chanterelles, honey mushrooms, porcini mushrooms, trumpet mushrooms, etc. So it is worth studying the structure of these mushrooms in more detail.

General structure of higher fungi

The bodies of fungi are formed by intertwined giant multinucleated cells - hyphae, which make up the plectenchyma. In most capped representatives of the order Agaricaceae, it is clearly divided into a rounded cap and a stalk. Some species belonging to the aphyllophoraceae and morels also have such an external structure. However, even among the agaricaceae there are exceptions. In some species, the leg may be lateral or completely absent. And in Gasteromycetes, the bodies of the fungi are formed in such a way that no such division is detected, and they do not have caps. They have a tuberous, club-shaped, spherical or star shape.

The cap is protected by a skin, under which there is a layer of pulp. It may have a bright color and smell. The stem or stump is attached to the substrate. This could be soil, a living tree, or the corpse of an animal. The stump is usually dense, its surface varies depending on the species. It can be smooth, scaly, velvety.

Higher fungi reproduce sexually and asexually. The vast majority form spores. The vegetative body of the fungus is called mycelium. It consists of thin branching hyphae. The hypha is an elongated thread that has apical growth. They may not have partitions, in which case the mycelium consists of one giant multinucleate, highly branched cell. The vegetative body of fungi can develop not only in soil rich in organic matter, but also in the wood of living and dead trunks, on stumps, roots, and much less often on shrubs.

The structure of the fruiting body of a cap mushroom

The fruiting bodies of most agaricaceae are soft, fleshy and juicy. When they die, they usually rot. Their life span is very short. For some mushrooms, only a few hours may pass from the moment they appear above the ground to the final stage of development; less often, it lasts a couple of days.

The fruiting body of mushrooms consists of a cap and a centrally located stalk. Sometimes, as mentioned above, the leg may be missing. Hats come in various sizes, from a few millimeters to tens of centimeters. Walking through the forest, you can see how small mushrooms with a cap the size of a little finger pad have grown out of the ground on thin, delicate legs. And a heavy giant mushroom may sit next to them. Its cap grows up to 30 cm, and the leg is heavy and thick. Porcini mushrooms and milk mushrooms can boast such impressive sizes.

The shape of the cap is also different. There are cushion-shaped, hemispherical, flattened, bell-shaped, funnel-shaped, with an edge curved down or up. Often, over the course of a short life, the shape of a mushroom’s cap changes several times.

The structure of the cap of mushrooms of the order agaricaceae

The caps, like the bodies of mushrooms, are formed by hyphae. They are covered with a thick skin on top. It also consists of covering hyphae. Their function is to protect internal tissues from loss of vital moisture. This prevents the skin from drying out. It can be painted in different colors depending on the type of mushroom and its age. Some have white skin, others have bright skin: orange, red or brown. It can be dry or, on the contrary, covered with thick mucus. Its surface can be smooth and scaly, velvety or warty. In some species, for example, butterfish, the skin is easily removed completely. But in russula and russula it lags behind only at the very edge. In many species, it is not removed at all and is firmly connected to the pulp that is located under it.

Under the skin, therefore, the fruiting body of the mushroom is formed by pulp - sterile tissue built from a plexus of hyphae. It varies in density. The flesh of some species is loose, while others are elastic. It can be brittle. This part of the mushroom has a specific species-specific odor. It can be sweet or nutty. The aroma of the pulp of some species is acrid or peppery-bitter; it can have a rare and even garlicky tint.

As a rule, in most species the flesh under the skin on the cap is light in color: white, milky, brownish or greenish. What are the structural features of the mushroom body in this part? In some varieties, the color at the break site remains the same over time, while in others the color changes dramatically. Such changes are explained by the oxidative processes of dyes. A striking example of this phenomenon is the boletus. If you make a cut on its fruiting body, this place will quickly darken. The same processes are observed in moss and bruise.

In the pulp of such species as volnushka, milk mushroom and saffron milk cap, there are special hyphae. Their walls are thickened. They are called milky passages and are filled with a colorless or colored liquid - juice.

Hymenium - fruiting layer

The fruiting body of the mushroom is formed by pulp, under which, directly under the cap, there is a fruiting layer - the hymenium. This is a series of microscopic spore-bearing cells - basidium. In the overwhelming majority of agaric hymeniums, they are located openly on the hymenophore. These are special protrusions located on the underside of the cap.

The hymenophore has a different structure in different species of higher fungi. For example, in chanterelles it is presented in the form of thick branched folds that descend onto their stem. But in blackberries, the hymenophores are in the form of brittle spines that are easily separated. The tubes are formed, and the lamellar ones, accordingly, have plates. The hymenophore can be free (if it does not reach the stalk) or adherent (if it grows tightly with it). The hymenium is necessary for reproduction. From the spores that spread around, a new vegetative body of the fungus is formed.

Fungal spores

The structure of the fruiting body of the cap mushroom is not complex. Its spores develop on fertile cells. All agaric fungi are unicellular. As in any eukaryotic cell, a spore is divided into a membrane, cytoplasm, nucleus and other cellular organelles. They also contain a large number of inclusions. Spore size is from 10 to 25 microns. Therefore, they can only be viewed through a microscope at good magnification. In shape they are round, oval, spindle-shaped, granular and even star-shaped. Their shell also varies depending on the species. In some spores it is smooth, in others it is spiny, bristly or warty.

When released into the environment, spores often resemble powder. But the cells themselves can be either colorless or colored. Often among mushrooms there are spores that are yellow, brown, pink, red-brown, olive, purple, orange and even black. Mycologists pay great attention to the color and size of spores. These signs are stable, and they often help in identifying the types of mushrooms.

Structure of the fruiting body: mushroom stalk

The fruiting body of the mushroom is familiar to almost everyone. The stem, like the cap, is formed from tightly intertwined threads of hyphae. But these giant cells are distinguished by the fact that their shell is thick and has good strength. The mushroom needs the stem for support. She lifts it above the substrate. The hyphae in the stalk are connected into bundles that are adjacent to each other in parallel and go from bottom to top. This is how water and mineral compounds flow from the mycelium to the cap. The legs are distinguished into two types: solid (the hyphae are pressed closely) and hollow (when a cavity is noticeable between the hyphae - lactifers). But in nature there are also intermediate types. These are the legs of the bruise and the chestnut tree. These species have a dense outer part. And in the middle the leg is filled with spongy pulp.

Anyone who has an idea of ​​the appearance of the fruiting body of a mushroom knows that the legs differ not only in structure. They have different shapes and thickness. For example, russula and boletus have a smooth and cylindrical stem. But in the well-known boletus and aspen boletuses, it evenly expands towards its base. There is also an obverse club-shaped hemp. It is very common among agaric mushrooms. Such a leg has a noticeable expansion at the base, which sometimes turns into a bulbous swelling. This form of hemp is most often found in large species of mushrooms. It is typical for fly agarics, cobwebs, and umbrellas. Mushrooms in which mycelium develops on wood often have a stem narrowed towards the base. It can be elongated and turn into a rhizomorph, stretching under the roots of a tree or stump.

So, what does the body of an agaricaceae mushroom consist of? This is a stalk, which lifts it above the substrate, and a cap, in the lower part of which spores develop. Some types of mushrooms, for example, fly agaric mushrooms, after the formation of the ground part, are covered with a whitish shell for some time. It is called the “common veil”. As the fruiting body of the mushroom grows, pieces of it remain on the round cap, and at the base of the stump a bag-like formation is noticeable - a volva. In some mushrooms it is free, while in others it is attached and looks like a thickening or ridges. Also, remnants of the “common blanket” are the bands on the stem of the mushroom. They are noticeable in many species, especially early in development. As a rule, in young mushrooms the belts cover the developing hymenophore.

Differences in the structure of cap mushrooms

Fungi differ from species to species. The fruiting bodies of some are not similar to the structure described above. There are exceptions among agaric mushrooms. And there are quite a few such species. But the lines and morels only superficially resemble agaric mushrooms. Their fruiting bodies also have a clear division into a cap and a stalk. Their cap is fleshy and hollow. Its shape is most often conical. The surface is not smooth, but rather ribbed. The stitches have an irregularly shaped head. It is covered with easily perceptible winding folds. Unlike agaric mushrooms, in morels the spore-bearing layer is located on the surface of the cap. It is represented by "bags" or asci. These are containers in which spores are formed and accumulated. The presence of such a part of the mushroom body as asca is common to all. The stem of morels and pods is hollow, its surface is smooth and even, and there is a noticeable tuberous thickening at the base.

Representatives of another order - aphyllophorous mushrooms, also have capped fruiting bodies with a pronounced stalk. This group includes chanterelles and blackberries. Their cap has a rubbery or slightly woody structure. A striking example of this is tinder fungi, which are also included in this order. As a rule, aphyllophoran mushrooms do not rot, as happens with agaric mushrooms with their fleshy body. When they die, they dry out.

Also slightly different in structure from most cap species are mushrooms of the order of horned mushrooms. Their fruiting body is club-shaped or coral-shaped. It is completely covered with hymenium. An important feature of this order is the absence of a hymenophore.

The order Gasteromycetes also has an unusual structure. In this group, the body of the fungus is often called a tuber. In species included in this order, the shape can be very diverse: spherical, star-shaped, ovoid, pear-shaped and nest-shaped. Their size is quite large. Some mushrooms of this order reach a diameter of 30 cm. The most striking example of gasteromycetes is the giant puffball.

Vegetative body of a mushroom

The vegetative body of mushrooms is called their mycelium (or mycelium), which is located in the soil or, for example, in wood. It consists of very thin threads - hyphae, the thickness of which varies from 1.5 to 10 mm. The hyphae are highly branched. The mycelium develops both in the substrate and on its surface. The length of the mycelium in such nutritious soil, such as forest litter, can reach 30 km per 1 gram.

So, the vegetative body of fungi consists of long hyphae. They grow only at the top, that is, apically. The structure of the mycelium is very interesting. The mycelium in most species is noncellular. It is devoid of intercellular partitions and is one giant cell. It has not one, but a large number of cores. But mycelium can also be cellular. In this case, under a microscope, the partitions separating one cell from another are clearly visible.

Development of the vegetative body of the fungus

So, the vegetative body of the fungus is called mycelium. Once in a moist substrate, the rich spores of cap mushrooms germinate. It is from them that the long filaments of the mycelium develop. They grow slowly. Only after accumulating a sufficient amount of nutritious organic and mineral substances does the mycelium form fruiting bodies on the surface, which we call mushrooms. Their rudiments themselves appear in the first month of summer. But they finally develop only with the onset of favorable weather conditions. As a rule, there are a lot of mushrooms in the last month of summer and in autumn, when the rains come.

The feeding of cap species is not at all similar to the processes occurring in algae or green plants. They cannot synthesize the organic substances they need on their own. There is no chlorophyll in their cells. They need ready-made nutrients. Since the vegetative body of the fungus is represented by hyphae, it is they that contribute to the absorption of water with mineral compounds dissolved in it from the substrate. Therefore, they prefer forest soils rich in humus. They grow less frequently in meadows and steppes. Mushrooms take most of the organic substances they need from tree roots. Therefore, most often they grow in close proximity to them.

For example, all lovers of quiet hunting know that porcini mushrooms can always be found near birch, oak and spruce trees. But you need to look for delicious saffron milk caps in pine forests. Boletus grows in birch groves, and boletus grows in aspen groves. This can easily be explained by the fact that mushrooms establish a close relationship with trees. As a rule, it is useful for both types. When a densely branched mycelium entwines the roots of a plant, it tries to penetrate them. But this does not harm the tree at all. The thing is that, located inside the cells, the mycelium sucks water from the soil and, of course, mineral compounds dissolved in it. At the same time, they also enter the root cells, which means they serve as food for the tree. Thus, the overgrown mycelium performs a function that is especially beneficial for old roots. After all, they no longer have hairs. How is this symbiosis useful for mushrooms? They receive from the plant useful organic compounds that they need for nutrition. Only if there are enough of them, the fruiting bodies of cap mushrooms develop on the surface of the substrate.

Mycota, Fungi

Fungi are one of the largest kingdoms of organisms. The first representatives appeared 450 - 500 million years ago. Their groups originated independently from different flagellates. Some are thought to have evolved from algae or amoeboid ancestors. There are approximately 120,000 species of mushrooms, varying in appearance and distribution.

In terms of the presence of urea in the metabolism, chitin in the cell wall, and a reserve product - glycogen, fungi are close to animals. And in their method of feeding by absorption (absorptive nutrition), rather than swallowing food, and in their unlimited growth, they resemble plants.

General characteristics, structural features, nutrition, reproduction:

Cells have cell wall And protoplast. The cell wall of lower fungi consists of pectin substances, and of higher ones - of carbohydrates close to cellulose, with a significant admixture chitin(close to insect chitin). The protoplast contains cytoplasm (homogeneous in young cells), in which the plasmalemma and tonoplast, ribosomes, mitochondria, Golgi apparatus, endoplasmic reticulum, 1-2 or many small nuclei are clearly distinguishable. There are no plastids. Spare substances – glycogen, fats, volutin (located in the cytoplasm), protein granules (in vacuoles). There is no starch.

Fungi reproduce vegetatively, asexually and sexually.

Vegetative propagation mushrooms occurs: 1) parts of mycelium ; 2) oidia (arthrospores) - formed as a result of the disintegration of hyphae into individual cells, giving rise to new mycelium; 3) chlamydospores ( formed as oidia) - have a harder, often dark-colored shell (smut fungi) and are designed to withstand unfavorable conditions; 4) budding - lateral outgrowths are formed on the mycelium, which are separated from it.

Asexual reproduction in fungi occurs in three ways: zoospores, sporangiospores and conidia. Zoospores(mainly in aquatic fungi) have flagella, are motile and are formed in zoosporangia. Sporangiospores- These are immobile spores that develop in sporangia. Conidia characteristic of higher fungi (ascomycota, basidiomycota, deuteromycota) and are formed on special hyphae - conidiophores. In this case, the tip of the conidiophore is separated by a septum, becomes rounded and falls off in the form of a conidia. Under the first conidia, before it separates, the next one is formed in the same way, etc., as a result, a whole chain is formed.

Sexual reproduction in fungi it is very diverse and noted in all taxa except Deuteromycota. Moreover, the sexual process consists of two stages: 1 - fusion of the cytoplasm of two cells ( plasmogamy); 2 - nuclear fusion ( karyogamy), and these stages are separated in time.

There are several types of sexual process (Fig. 9.1).

Rice. 9.1. Some types of sexual process in fungi.

gametogamy– fusion of gametes formed in gametangia;

gametangiogamy - fusion of the contents of two multinucleate specialized reproductive organs (male and female gametangia), which are not differentiated into gametes; here we can consider the nuclei freely located in the gametangia as gametes; characteristic of zygomycots and ascomycots;

somatogamy- genital organs are not formed, but haploid somatic cells of physiologically different hyphae merge; characteristic of basidiomycotes;

hologamy(in mushrooms with unicellular mycelium) - a fusion of two individuals is observed.

The sexual process in the so-called higher fungi ends with the formation of a zygote, its meiotic division and the formation of sexual sporulation.

There is still a lot of controversy in the taxonomy of fungi. Until recently, there was a division of fungi into lower (chytridiomycetes, oomycetes and zygomycetes) and higher (ascomycetes, basidiomycetes and deuteromycetes). Currently, true fungi include four taxa that have a common origin - zygomycotes, ascomycotes, basidiomycotes, deuteromycotes(imperfect fungi) and lichens, the thalli of which are formed by fungal mycelium. Oomycota and Chytridiomycota are classified as mushroom-like protoctists. The listed taxa are usually considered classes (they have the endings - mycete, - mycetes) or departments (have the ending - mikota, - mycota).

Division Zygomycota (Zygomycota)

One of the representatives of this department Mukor, or capitate mold ( Mucor mucedo) – saprotroph. It develops on moistened bread, fruits, vegetables, and manure in the form of white fluffy mold. Vertical sporangiophores with sporangia (initially club-shaped and then spherical) rise from the mycelium, within which spores are formed. The totality of sporangiophores usually forms a gray or white fluff with brown or black heads at the ends. The spores are carried through the air and, under favorable conditions, form new mycelium.

The sexual process is observed only when two hyphae of different sexes meet and touch. At the ends of such hyphae a large multinucleate cell is formed, bounded by a septum. At the point of contact of heterosexual hyphae, as a result of the deslidging of the cell walls, the cytoplasm and nuclei of both cells merge. The resulting zygote with numerous diploid nuclei is covered with a thick brown spiny shell. After a long period of dormancy, the nuclei undergo meiosis, and the zygote grows into an embryonic sporangium, within which spores are formed that produce hyphae of different quality (Figure 9.2).

Rice. 9. 2. Mukor ( Mucor mucedo): A– mycelium with sporangia; B– formation of sporangium; IN– germination of the zygote; G– gametangiogamy .

Division Ascomycota, or marsupial fungi (Ascomycota )

Marsupial fungi reproduce by spores that form in asci (bags). The formation of spores is preceded by the sexual process, which occurs in a latent form. On the hyphae of the mycelium, organs of sexual reproduction are formed (archicarps - female, antheridia - male), containing cytoplasm and several nuclei. The archicarp consists of a filamentous trichogyne and an expanded base - ascogon; the antheridium is a single-celled oval-shaped formation. When these organs come into contact, the trichogyne grows with its end into the cavity of the antheridium and the contents of the antheridium move into the ascogon, then both cytoplasms merge (plasmogamy), and the nuclei are arranged in pairs, forming dikaryons. The fertilized ascogon germinates with ascogenous hyphae. The terminal cells of the latter grow, and fusion of dikaryon nuclei (karyogamy) occurs in them to form one diploid nucleus. This nucleus divides first by meiosis, then mitosis, and 8 haploid nuclei of future spores are formed. As a result, bags containing ascospores develop at the end of ascogenous hyphae (Fig. 9. 3).

Rice. 9. 3. The sexual process in the marsupial fungus Pyronema: a – antheridium (1) and archicarp (2) with trichogyne (3); b – transition of the contents of the antheridium into the archicarp; c – formation of dikaryons in Askogon; d – formation of dikaryonic ascogenous hyphae (4); e, f – formation of a zygote at the apex of the ascogenous hypha; g, h, i, j – meiosis and development of the bag with ascospores.

In addition to the sexual process, ascomycotes have vegetative reproduction (parts of mycelium, oidia, budding) and asexual reproduction - with the help of conidia developing on conidiophores.

So the species of the genus Saccharomyces (yeast fungi) are single, mononuclear, spherical or oval cells that reproduce vegetatively by budding. The latter is facilitated by a sufficient amount of sugar, a temperature of 25-30°C and aeration. Only as a result of intensive reproduction do chains of cells (pseudomycelium) appear, which subsequently disintegrate (Fig. 9. 4).

Rice. 9.4. bread yeast ( Saccharomyces cerevisiae): 1 – yeast cell, 2 – beginning of budding, 3 – budding (formation of pseudomycelium), 4 – sac with spores.

When the nutrient medium is depleted, the sexual process can be observed in yeast. It consists of the fusion (copulation) of two haploid cells. Subsequently, a bag with 4-8 ascospores is formed from the zygote. The genus under consideration unites both natural and “cultivated” (production) species, the existence of which is closely connected with the entire history of the fermentation industry. Brewer's or bread yeast is of great practical importance ( Saccharomycescerevisiae), which exist only in the form of cultivated races and wine yeast ( S. vini, S. ellipsoideus), which live on the surface and in the juice of various fruits.

Yeast colonies look like this: (Fig. 9. 5).

Rice. 9.5. Yeast colonies .

Other representatives of this class (for example, species of the genus Taphrina – tafrin), cause damage to stems, leaves, flowers, fruits of plants, promote their growth and deformation.

Class Fruit marsupial mushrooms (Carpoascomycetes). In representatives of this class, bags develop in special containers - fruiting bodies, varying in shape and size. There are several types of fruiting bodies: cleistothecia (closed, spherical fruiting body), perithecia (semi-closed, pitcher-shaped fruiting body with an opening at the top) and apothecium (open, cup-shaped fruiting body).

Ergot development cycle

Includes three stages: sclerotial, marsupial and conidial.

Stage I- formation of sclerotium (resting stage of the fungus). With severe damage to rye, individual ears may have up to 3-4 sclerotia. Then, when harvesting bread, sclerotia can spontaneously fall to the ground (they tolerate frost well and begin to germinate the next year after the rye sprouts), or during threshing they can fall into marketable or seed grain.

Stage II- red or dark pink club-shaped fruiting bodies appear on the germinating sclerotia, consisting of thin legs and spherical heads, seated with numerous small conical projections ("warts"). This stage is stroma. Warts on the head are the exits of perithecia - ovoid cavities formed in the peripheral part of the head. Numerous club-shaped bags grow in the perithecia, each of which develops 8 filamentous ascospores. By the time rye blooms, the fruiting bodies of the fungus are fully mature; at the same time, bags are squeezed out of the mucous-swelling perithecia and burst; at the same time, ascospores are ejected from them and are carried by air throughout the flowering rye.

Stage III begins with ascospores landing on the feathery stigmas of rye flowers and their germination. From the plexus of hyphae on the ovary of a flower, a mycelium is formed, as it develops, asexual reproduction of the fungus begins. It consists in the detachment of numerous small elliptical conidiospores from the ends of the hyphae. At the same time, the mycelium produces a sticky liquid containing sugary substances, called “honeydew.” Drops of the latter flow down the affected ear, taking with them conidiospores. The sweet liquid attracts insects, which, flying to other ears, spread conidiospores, thereby contributing to a new (repeated) infection of rye. Conidiospores, once on healthy rye flowers, also germinate, forming a mycelium on the ovary. Gradually, mycelium (formed from both ascospores and conidiospores), growing, destroys the ovary, and, ultimately, in place and instead of grain, a white oblong large mushroom body develops - a young sclerotium. By the time the rye ripens, the sclerotia also ripen; the hyphae become denser, the outer layer of the sclerotium becomes pigmented, turning dark purple (Fig. 9. 6 (a) - 9. 6 (b)).

Rice. 9.6(a). Ergot purpurea (Claviceps purpurea): 1 – ear of rye with sclerotia, 2 – sclerotium overgrown with capitate stroma, 3 – section of the stroma with perithecia, 4 – separate perithetium in the stroma with bursae, 5 – bursa with ascospores, 6 – conidial sporulation, sc – sclerotia, st – stroma, p – perithecia, s – bursae, sp – spores.

Rice. 9.6 (b). Ergot purpurea (Claviceps purpurea): an ear of rye with sclerotia, a sclerotium overgrown with capitate stroma.

Horns (sclerotia) of ergotamine (ergotoxin) strain ( CornuaSecalis cornuti stamm Ergotamini (Ergotoxini)) contain indole alkaloids, which have toxic properties and have a complex effect on the human body. A small amount of sclerotia ground into flour can cause a serious disease - ergotism, sometimes leading to death. In modern medicine, ergot alkaloids are widely used to treat cardiovascular and nervous diseases (adrenergic blocking activity), as well as in obstetric practice (cause uterine contractions).

The fruiting body - apothecium - has a locust ( Peziza), line ( Gyromitra), morel ( Morchella) (Fig. 9. 7).

Rice. 9. 7 (a). Apothecia poeciceae: 1 – petitsa, 2 – morel, 3 – line.

Rice. 9. 7 (b). The morel is real.

Petsitsa is found in forests, in places of fires, on the soil of vegetable gardens, and in cow dung. Its apothecia are more or less fleshy, and range in color from yellow to red and brown. String and morel are found in the forest in early spring. The fruiting body consists of a cap with a wrinkled surface, lined with a hymenium (a layer of asci separated by paraphyses (sterile hyphae)) and a stalk. The stitches contain poisonous helvelic acid (destroyed after prolonged boiling).

Division Basidiomycota, or basidiomycetes (Basidiomycota)

Conidial sporulation is rare in basidiomycota. The sexual process is carried out by the fusion of two vegetative cells of a haploid ( primary) mycelium.

Basidiomycotes do not have special reproductive organs. The organ of sexual sporulation is a special reproductive structure - basidia, on which are formed basidiospores. Hyphae growing from basidiospores heterothallic(origin from spores of opposite sexual signs: “+” and “-”), and when they come into contact, the sexual process occurs ( somatogamy). In this case, the contents of the cell of one hypha pass into the cell of another, where the cytoplasm merges ( plasmogamy). The nuclei do not merge, but form pairs - dikaryons, which subsequently simultaneously divide to form a dikaryonic (secondary) mycelium. Outgrowths are formed on the dikaryonic mycelium - basidia– where dikaryons and cytoplasm go. The sexual process is completed in the basidium: the nuclei of the dikaryon fuse ( karyogamy), The diploid nucleus divides through reduction (meiosis) and 4 haploid nuclei appear. In the upper part of the basidium, four tubular outgrowths are formed with an expansion at the end - sterigma. Nuclei with cytoplasm pass into them and four basidiospores appear: two with a “+” sign and two with a “-” sign, subsequently forming heterothallic haploid mycelia ( rice. 9.8).

Rice. 9. 8. Sexual process in basidiomycota (Basidiomycota ): A – basidiospores; B – haploid hyphae; B – somatogamy; D – formation of basidium: 1 – zygote, 2 – basidium, 3 – basidiospore.

There are three types of basidia: holobasidia ( unicellular, club-shaped or cylindrical), heterobasidia consist of two parts (hypobasidium and epibasidium), phragmobasidia(divided by septa into 4 cells, on the sides of which basidiospores are formed) ( rice. 9. 9).

Rice. 9. 9. Types of basidia: A – holobasidium; B – heterobasidium; B – phragmobasidium.

Basidia with basidiospores can arise directly on the mycelium, or on fruiting bodies(or inside them). Fruiting bodies vary in shape and consistency (loose, cobwebby, woody, etc.). On their upper or lower side there is a spore-bearing layer - hymenium. The surface of the fruiting body bearing the hymenium is called hymenophore. Based on the type of development and structure of the basidium, basidiomycota are divided into three classes: holobasidiomycetes (Holobasidiomycetes), phragmobasidiomycetes (Phragmobasidiomycetes), heterobasidiomycetes (Heterobasidiomycetes).

Class Holobasidiomycetes (Holobasidiomycetes). These are mainly saprophytes. The basidia are unicellular and, together with sterile hyphae, form the hymenial layer. The latter develops on the hymenophore (a dense base of the fruiting body of intertwined hyphae), which can be tubular or lamellar. Tubular hymenophore have representatives of the polypore and boletaceae families, lamellar– mushrooms from the families of lamellar and fly agaric.

In representatives of the families Boletaceae, Agaricaceae and Amanita, the hymenophore is located on the underside of soft, fleshy fruiting bodies that have a clearly visible central leg (“stump”) and cap.

Species of the Boletaceae family have fruiting bodies of different colors with tubular hymenophore. Almost all representatives of this family enter into symbiosis with the roots of higher plants, forming exotrophic mycorrhiza(the mushroom entwines the root, remaining on its surface). Most valuable White mushroom (Boletus edulis), it forms mycorrhizae with many deciduous and coniferous species. Sometimes they are confined to certain types of forests and types of woody plants: boletus(B. aurantiacus) - in aspen forests, boletus (B. scaber) - in birch trees. In addition, the listed representatives belong to edible mushrooms - their fruiting bodies are used as food ( rice. 9. 10).

Rice. 9. 10. White mushroom.

Rice. 9. 11. Fly agaric.

Rice. 9. 12. Champignon.

Division Deuteromycota, or imperfect fungi (Deuteromycota)

They unite about 30 thousand species. They have developed multicellular mycelium. They reproduce mainly asexually by conidium(rice. 9. 13), the sexual process is unknown (hence the name - imperfect).

Rice. 9. 13. Asexual reproduction in two typical representatives Deuteromycota: A - penicillium ( Penicillium), the conidiophore has the appearance of a microscopic brush; B– aspergillus ( Aspergillus), the conidiophore, spherically swollen at the apex, carries radially diverging chains of conidia.

In fact, imperfect fungi are considered a formal taxon, because they are asexual forms of representatives of the above-mentioned divisions (ascomycotes and basidiomycotes) and have much in common with them in morphology, biology and biochemistry.

Types of such genera as penicillium (Penicillium) And aspergillus (Aspergillus), serve as sources for the industrial production of a number of antibiotics, enzymes and organic acids. More and more new, more effective synthetic derivatives are constantly being introduced into medical practice, the starting material for which is still natural penicillin, obtained in large quantities from the industrial culture of this fungus.

Department of lichens – Phycomycota(Lichenes)

Representatives of the department are extremely widespread in nature. They live from deserts to the Arctic and Antarctic. There are about 25 thousand species of lichens.

Lichens are symbiotic complexes of organisms that are formed by a fungus (heterotrophic mycobiont) and algae or cyanobacteria (autotrophic phycobiont).

The fungus protects algae from drying out and extreme temperatures, and also supplies them with water and mineral salts. The algae supplies the fungus with the organic substances it creates.

Vegetative body of lichens - thallus, or thallus. The color of the thallus is due to various pigments and specific organic compounds (lichen acids). There are about 300 of the latter, and they are deposited on the surface of hyphae in the form of crystals, rods, grains and give the lichen thalli gray, bluish, greenish, yellow, orange, black and other colors.

The basis of the vegetative body of lichens (plectenchyma) form intertwined segmented hyphae of lichen fungi. Some hyphae have thick membranes that can swell when they absorb water. In addition, there are fatty hyphae containing droplets of fat. Lichens contain about 20 thousand fungi, mainly ascomycotes. Moreover, the fungal component (mycobiont) of each type of lichen is specific and differs from the mycobiont of other lichens.

Photosynthetic organisms in lichens are represented by unicellular and filamentous green algae (in the majority), as well as cyanobacteria. Unlike a mycobiont, the same type of algae can be a phycobiont of several species of lichens. In total, about 30 species of algae are found in lichens.

Based on the morphology of the thalli, three main groups of lichens are distinguished:

Scale, or cortical- a body in the form of crusts or scale, connected to the substrate over its entire surface and practically inseparable from it. Up to 80% of all lichens belong to this group ( rice. 9. 14).

Rice. 9.14. Scale lichens.

Leafy – body in the form of leaf-shaped plates, attached to the substrate by bundles of hyphae and easily separated from it. The upper and lower surfaces of the thallus can be distinguished ( rice. 9.15).

Rice. 9. 15. Foliaceous lichens.

Bushy- thallus in the form of a more or less branched bush rising from the ground or hanging from the branches ( rice. 9. 16).

Rice. 9. 16. Fruticose lichens.

According to the nature of the anatomical structure of the thallus, lichens are divided into: heteromeric And homeomeric (rice. 9. 17).

Rice. 9. 17. Structure of lichen thalli: A– heteromeric structure: 1 – upper crustal layer, 2 – gonidial (algal) layer, 3 – medullary layer, 4 – lower crustal layer; B– homeomeric structure.

U heteromeric The lichen thallus consists of several layers. In their thallus, the upper and lower bark are distinguished. The latter are formed by tightly interwoven hyphae of the mycobiont. They extend from the lower cortex rhizins(bundles of hyphae), and under the upper cortex is located gonidial(algal) layer consisting of a mass of algae located between the intertwining hyphae of fungi. Deeper is the “core”, which is formed by a loose plexus of fungal hyphae. Most lichens have this structure.

U homeomeric lichen algae are evenly distributed throughout the entire thickness among the intertwining hyphae of fungi. This structure is typical of crustose and a small part of foliose and bushy lichens.

Lichens reproduce mainly vegetatively - by fragments of the thallus or special organs - soredia And isidia. The separation of sections of the thallus occurs mechanically (especially in dry weather, when they become fragile). Soredia are formed inside the algal layer and consist of a small number of algae cells and the fungal hyphae entwining them. Through a gap in the upper bark of the thallus, the soredia fall out and are carried by the wind; under favorable conditions, they form a new thallus. Isidia also consist of algae cells and fungal hyphae entwining them, but are formed in the form of outgrowths on the surface of the thallus.

Each of the components of the lichen is capable of reproducing independently. The fungus can reproduce by spores that grow into mycelium. But a lichen is formed only if the hyphae of the fungus meet on their way the corresponding algae, which reproduces by cell division.

Lichens grow very slowly. Over the course of a year, their thallus grows in different species from 1 to 10 mm. The lifespan of the thallus in some species can reach 100 years or more.

Lichens are the first to settle in the most barren places on land. When they die, they form humus on which other plants can live. In relation to the substrate and environmental factors, lichens are divided into a number of ecological groups: epigeic- grow on soil epiphytic- on living plants, epixyl- on treated or rotting wood, epilithic- on the stones. The main condition for the settlement of lichens is long-term immobility of the substrate.

Polysaccharides accumulate in lichens, but there are few proteins and fats. Some lichen chemicals have antimicrobial properties. In addition, representatives of this department are used to obtain antibiotics (cladonia, parmelia, evernia, etc.), aromatic substances (some lichens synthesize valuable essential oil) and odor fixatives (lobaria, evernia), as well as wool dyes.

Lichens are sensitive to air pollution (they die at high concentrations of sulfur dioxide and other pollutants), therefore they are used as bioindicators of the degree of environmental pollution.

Fungi are ancient heterotrophic organisms that occupy a special place in the general system of living nature. They can be either microscopically small or reach several meters. They settle on plants, animals, humans or on dead organic matter, on the roots of trees and grasses. Their role in biocenoses is great and varied. In the food chain, they are decomposers - organisms that feed on dead organic remains, subjecting these remains to mineralization into simple organic compounds.

In nature, mushrooms play a positive role: they are food and medicine for animals; forming a fungal root, they help plants absorb water; Being a component of lichens, fungi create a habitat for algae.

Fungi are chlorophyll-free lower organisms that unite about 100,000 species, from small microscopic organisms to giants such as tinder fungi, giant raincoat and some others.

In the system of the organic world, mushrooms occupy a special position, representing a separate kingdom, along with the kingdoms of animals and plants. They lack chlorophyll and therefore require ready-made organic matter for nutrition (they belong to heterotrophic organisms). In terms of the presence of urea in the metabolism, chitin in the cell membrane, and a reserve product - glycogen, and not starch - they are close to animals. On the other hand, in their method of nutrition (by absorption, not ingestion of food), and unlimited growth, they resemble plants.

Mushrooms also have characteristics that are unique to them: in almost all mushrooms the vegetative body is a mycelium, or mycelium, consisting of threads - hyphae.

These are thin, thread-like tubes filled with cytoplasm. The threads that make up the mushroom can be tightly or loosely intertwined, branched, fused with each other, forming films like felt or strands visible to the naked eye.

In higher fungi, the hyphae are divided into cells.

Fungal cells can have from one to several nuclei. In addition to nuclei, cells also have other structural components (mitochondria, lysosomes, endoplasmic reticulum, etc.).

Structure

The body of the vast majority of fungi is built from thin filamentous formations - hyphae. Their combination forms the mycelium (or mycelium).

By branching, the mycelium forms a large surface, which ensures the absorption of water and nutrients. Conventionally, mushrooms are divided into lower and higher. In lower fungi, hyphae do not have transverse partitions and the mycelium is one highly branched cell. In higher fungi, the hyphae are divided into cells.

The cells of most fungi are covered with a hard shell; zoospores and the vegetative body of some protozoal fungi do not have it. The cytoplasm of the fungus contains structural proteins and enzymes, amino acids, carbohydrates, and lipids not associated with cell organelles. Organelles: mitochondria, lysosomes, vacuoles containing storage substances - volutin, lipids, glycogen, fats. There is no starch. A fungal cell has one or more nuclei.

Reproduction

In fungi, vegetative, asexual and sexual reproduction are distinguished.

Vegetative

Reproduction is carried out by parts of the mycelium, special formations - oidia (formed as a result of the disintegration of hyphae into separate short cells, each of which gives rise to a new organism), chlamydospores (formed in approximately the same way, but have a thicker dark-colored shell, tolerate unfavorable conditions well), by budding of mycelium or individual cells.

For asexual vegetative reproduction, no special devices are needed, but not many offspring appear, but few.

With asexual vegetative reproduction, the cells of the filament, no different from their neighbors, grow into a whole organism. Sometimes, animals or environmental movement tear the hypha apart.

It happens that when unfavorable conditions occur, the thread itself breaks up into individual cells, each of which can grow into a whole mushroom.

Sometimes growths form on the thread, which grow, fall off and give rise to a new organism.

Often, some cells grow a thick membrane. They can withstand drying out and remain viable for up to ten years or more, and germinate in favorable conditions.

During vegetative reproduction, the DNA of the offspring does not differ from the DNA of the parent. This type of reproduction does not require special devices, but the number of offspring is small.

Asexual

During asexual spore reproduction, the fungal filament forms special cells that create spores. These cells look like twigs that are unable to grow and separate spores from themselves, or like large bubbles within which spores form. Such formations are called sporangia.

In asexual reproduction, the DNA of the offspring is no different from the DNA of the parent. Less substances are spent on the formation of each spore than on one offspring during vegetative propagation. Asexually, one individual produces millions of spores, so the fungus has a greater chance of leaving offspring.

Sexual

During sexual reproduction, new combinations of characteristics appear. In this type of reproduction, the DNA of the offspring is formed from the DNA of both parents. In fungi, DNA combining occurs in different ways.

Different ways to ensure DNA unification during sexual reproduction of fungi:

At some point, the nuclei and then the DNA strands of the parents merge, exchange pieces of DNA and separate. The descendant's DNA contains sections received from both parents. Therefore, the descendant is in some ways similar to one parent, and in some ways - like the other. A new combination of traits can reduce or increase the viability of the offspring.

Reproduction consists of the fusion of male and female sex gametes, resulting in the formation of a zygote. Fungi are distinguished between iso-, hetero- and oogamy. The reproductive product of lower fungi (oospore) germinates into a sporangium in which spores develop. In ascomycetes (marsupial fungi), as a result of the sexual process, bags (asci) are formed - single-celled structures usually containing 8 ascospores. Bags formed directly from the zygote (in lower ascomycetes) or on ascogenous hyphae developing from the zygote. In the bag, fusion of the zygote nuclei occurs, then meiotic division of the diploid nucleus and the formation of haploid ascospores. The bursa is actively involved in the spread of ascospores.

Basidial fungi are characterized by a sexual process - somatogamy. It consists of the fusion of two cells of vegetative mycelium. The reproductive product is a basidium, on which 4 basidiospores are formed. Basidiospores are haploid; they give rise to haploid mycelium, which is short-lived. By fusion of haploid mycelium, dikaryotic mycelium is formed, on which basidia with basidiospores are formed.

In imperfect fungi, and in some cases in others, the sexual process is replaced by heterokaryosis (heterogeneity) and a parasexual process. Heterokaryosis consists of the transition of genetically heterogeneous nuclei from one segment of mycelium to another through the formation of anastomoses or fusion of hyphae. Nuclear fusion does not occur in this case. The fusion of nuclei after their transition to another cell is called the parasexual process.

The fungal filaments grow by transverse division (the filaments do not divide along the cell). The cytoplasm of neighboring fungal cells forms a single whole - there are holes in the partitions between the cells.

Nutrition

Most mushrooms look like long threads that absorb nutrients over their entire surface. Fungi absorb the necessary substances from living and dead organisms, from soil moisture and water from natural reservoirs.

Fungi release substances that break organic molecules into pieces that the fungus can absorb.

But under certain conditions, it is more beneficial for the body to be a thread (like a mushroom) rather than a lump (cyst) like a bacterium. Let's check if this is true.

Let's follow the bacteria and the growing thread of the fungus. A strong sugar solution is shown in brown, a weak solution is light brown, and sugar-free water is shown in white.

We can conclude: the filamentous organism, growing, may end up in places rich in food. The longer the thread, the greater the supply of substances that saturated cells can spend on the growth of the fungus. All hyphae behave as parts of one whole, and sections of the fungus, once in places rich in food, feed the entire fungus.

Molds

Molds settle on moist remains of plants and, less commonly, animals. One of the most common molds is mucor, or capitate mold. The mycelium of this fungus in the form of the finest white hyphae can be found on stale bread. Mucor hyphae are not separated by septa. Each hypha is one highly branched cell with several nuclei. Some branches of the cell penetrate into the substrate and absorb nutrients, while others rise upward. At the top of the latter, black round heads are formed - sporangia, in which spores are formed. Ripe spores are spread by air currents or by insects. Once in favorable conditions, the spore grows into a new mycelium (mycelium).

The second representative of mold fungi is penicillium, or blue mold. The mycelium penicillium consists of hyphae divided by transverse partitions into cells. Some hyphae rise upward, and branches resembling brushes are formed at their ends. At the end of these branches, spores are formed, with the help of which penicillium reproduces.

Yeast mushrooms

Yeasts are single-celled, immobile organisms of oval or elongated shape, 8-10 microns in size. True mycelium is not formed. The cell has a nucleus, mitochondria, many substances (organic and inorganic) accumulate in the vacuoles, and redox processes occur in them. Yeast accumulates volutin in cells. Vegetative propagation by budding or division. Sporulation occurs after repeated reproduction by budding or division. It occurs more easily when there is a sharp transition from abundant nutrition to insignificant nutrition, when oxygen is supplied. The number of spores in a cell is paired (usually 4-8). In yeast, the sexual process is also known.

Yeasts, or yeasts, are found on the surface of fruits and on carbohydrate-containing plant residues. Yeast differs from other fungi in that it does not have a mycelium and consists of single, usually oval, cells. In a sugary environment, yeast causes alcoholic fermentation, which results in the release of ethyl alcohol and carbon dioxide:

C 6 H 12 O 6 → 2C 2 H 5 OH + 2CO 2 + energy.

This process is enzymatic and occurs with the participation of a complex of enzymes. The released energy is used by yeast cells for vital processes.

Yeast reproduces by budding (some species by division). When budding occurs, a bulge resembling a kidney forms on the cell.

The nucleus of the mother cell divides, and one of the daughter nuclei becomes a bulge. The bulge grows quickly, turns into an independent cell and separates from the mother one. With very rapid budding, the cells do not have time to separate and the result is short, fragile chains.

At least ¾ of all mushrooms are saprophytes. The saprophytic method of nutrition is associated primarily with products of plant origin (the acidic reaction of the environment and the composition of organic substances of plant origin are more favorable for their life).

Symbiont fungi are associated primarily with higher plants, bryophytes, algae, and less often with animals. An example would be lichens and mycorrhiza. Mycorrhiza is the cohabitation of a fungus with the roots of a higher plant. The fungus helps the plant to absorb hard-to-reach humus substances, promotes the absorption of mineral nutrition elements, helps with carbohydrate metabolism with its enzymes, activates the enzymes of higher plants, and binds free nitrogen. From a higher plant, the fungus apparently receives nitrogen-free compounds, oxygen and root secretions, which promote the germination of spores. Mycorrhiza is very common among higher plants; it is not found only in sedges, cruciferous plants and aquatic plants.

Ecological groups of fungi

Soil mushrooms

Soil fungi are involved in the mineralization of organic matter, the formation of humus, etc. This group includes fungi that enter the soil only during certain periods of life, and fungi of the rhizosphere of plants that live in the zone of their root system.

Specialized soil fungi:

• coprophylls- mushrooms that live on soils rich in humus (dung heaps, places where animal droppings accumulate);
• keratinophylls- fungi that live on hair, horns, hooves;
• xylophytes- fungi that decompose wood, among them there are destroyers of living and dead wood.

House mushrooms

House mushrooms are destroyers of wooden parts of buildings.

Aquatic mushrooms

These include the group of mycorrhizal symbiont fungi.

Fungi growing on industrial materials (metal, paper and products made from them)

Cap mushrooms

Cap mushrooms settle on forest soil rich in humus and obtain water, mineral salts and some organic substances from it. They get some of their organic matter (carbohydrates) from trees.

The mycelium is the main part of every mushroom. Fruiting bodies develop on it. The cap and stem consist of mycelium threads tightly adjacent to each other. In the stem, all the threads are the same, and in the cap they form two layers - the upper one, covered with skin, colored with different pigments, and the lower one.

In some mushrooms, the bottom layer consists of numerous tubes. Such mushrooms are called tubular. In others, the lower layer of the cap consists of radially arranged plates. Such mushrooms are called lamellar. Spores form on the plates and on the walls of the tubes, with the help of which the fungi reproduce.

The hyphae of the mycelium entwine the roots of trees, penetrate them and spread between the cells. A cohabitation that is beneficial for both plants is established between the mycelium and plant roots. The fungus supplies plants with water and mineral salts; By replacing root hairs on the roots, the tree gives up some of its carbohydrates to it. Only with such a close connection of the mycelium with certain tree species is the formation of fruiting bodies in cap mushrooms possible.

Education dispute

Special cells called spores form in the tubes or on the plates of the cap. Ripe small and light spores spill out and are picked up and carried by the wind. They are spread by insects and slugs, as well as squirrels and hares that eat mushrooms. The spores are not digested in the digestive organs of these animals and are thrown out along with the droppings.

In moist, humus-rich soil, fungal spores germinate and mycelium threads develop from them. A mycelium arising from a single spore can form new fruiting bodies only in rare cases. In most species of fungi, fruiting bodies develop on myceliums formed by fused cells of filaments originating from different spores. Therefore, the cells of such a mycelium are binuclear. The mycelium grows slowly, and only after accumulating reserves of nutrients does it form fruiting bodies.

Most species of these fungi are saprophytes. They develop on humus soil, dead plant debris, and some on manure. The vegetative body consists of hyphae that form a mycelium located underground. During development, umbrella-like fruiting bodies grow on the mycelium. The stump and cap consist of dense bundles of mycelium threads.

In some mushrooms, on the underside of the cap, plates diverge radially from the center to the periphery, on which the basidia develop, and in them the spores are hymenophores. Such mushrooms are called lamellar. Some types of fungi have a veil (a film of infertile hyphae) that protects the hymenophores. When the fruiting body ripens, the covering breaks and remains in the form of a fringe along the edges of the cap or a ring on the stem.

In some mushrooms the hymenophore has a tubular shape. These are tubular mushrooms. Their fruiting bodies are fleshy, rot quickly, are easily damaged by insect larvae, and eaten by slugs. Cap mushrooms reproduce by spores and parts of mycelium (mycelium).

Chemical composition of mushrooms

In fresh mushrooms, water makes up 84-94% of the total mass.

Mushroom proteins are digested only 54-85% - worse than proteins of other plant products. Absorption is hampered by poor protein solubility. Fats and carbohydrates are absorbed very well. The chemical composition depends on the age of the mushroom, its condition, type, growing conditions, etc.

The role of mushrooms in nature

Many mushrooms grow together with the roots of trees and grasses. Their cooperation is mutually beneficial. Plants provide sugar and proteins to fungi, and fungi destroy dead plant remains in the soil and absorb water with minerals dissolved in it over the entire surface of the hyphae. Roots fused with fungi are called mycorrhiza. Most trees and grasses form mycorrhizae.

Fungi play the role of destroyers in ecosystems. They destroy dead wood and leaves, plant roots and animal carcasses. They convert all dead remains into carbon dioxide, water and mineral salts - something that plants can absorb. As they feed, the mushrooms gain weight and become food for animals and other mushrooms.