Lectures 8-9. Topic: Fungi and mushroom-like protoctists

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.

Yeasts and fungi are intracellular parasites and do not have mycelium.

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.

Why mushrooms are a separate kingdom

For a very long time, humanity has classified mushrooms as part of the plant kingdom, which is why there are still no mycology classes in schools: mushrooms are studied as part of the botanical section. But at the same time, the teacher always focuses the students’ attention on the fact that the mushroom kingdom is distinguished along with the rest.

The main reason for this approach is that mushrooms were named a separate kingdom only in the 70s. 20th century, although proposals for this were received back in 1831 from E. Fries. Also, C. Linnaeus wrote in his works about the need to separate the mushroom kingdom, who expressed deep doubt that the mushroom is a unique plant.

Thanks to the work of these and many other scientists, closer to the second half of the 20th century. the final understanding that fungi should be given a separate role in the systematization of biological species. This knowledge helped not only to assign the species its own kingdom, but also to advance in a number of studies that were carried out at the intersection of biology and other sciences (genetics, biochemistry, cytology, etc.). The consequence of these processes was the internal systematization of the newly introduced mushroom kingdom: towards the end of the 20th century . subspecies were identified and some forms were eliminated, which successfully “moved” into the plant kingdom.

Thus, the researchers managed to form the main unique feature of mushrooms, which is unique to them and is not represented in either plants or animals: the method of reproduction is vegetative, but it occurs in its own unique way. Mycelium (or more simply, mycelium) is thin branches of mushroom threads - hyphae, thanks to which “offspring” appears. Hyphae help consume water and other nutrients, thereby helping large individuals develop and new ones to appear.

Reproduction

Reproduction is necessary in order to maintain the population of the species, disperse and survive unfavorable conditions - heat, dryness or lack of food.

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 propagation, 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 sexual 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.

Diseases due to mushrooms

Unfortunately, scientists have discovered that mushrooms can not only be used in the medical field as medicine, but can also cause various types of diseases.

What are we talking about here?

In addition to standard champignons, chanterelles and others, mushrooms also include mold.

Fungal spores come into contact with us everywhere. And, unfortunately, if they get on the skin, especially in open wounds, they can quickly cause infections, which then, if undetected for a long time, spread to other organs.

Let's remember candida strains. They settle not only on surfaces and mucous membranes, but can also settle in the intestines. They cause local infections, which are most often grouped in the mouth and vagina, and sometimes can affect internal organs.

Patients with AIDS also experience the development of severe fungal infections, which further aggravates the condition. The same thing can happen in cancer patients.

If a person has a compromised immune system, he is susceptible to various infections, which are caused by fungi.

Such diseases are aspergillosis and mucormycosis. However, fortunately, such diseases are not very common in Russia. They are mainly found in North America and Africa.

The danger of fungal infections comes down to the fact that they develop very slowly, and people often cannot diagnose them in themselves in the early stages of development. And when he realizes that something wrong is happening to the body, it is already too late.

In addition to the diseases listed here, mushrooms provoke:

• leukemia;
• lung diseases;
• Hodgkin's disease;
• lymphoma;
• renal failure;
• diabetes.

Mushrooms surround us everywhere. They grow in forests, fields, sometimes we see them near our house, on football fields, in damp rooms, and so on. Some types of mushrooms are safe for humans, while others, on the contrary, are best avoided. But be that as it may, it is necessary to know all the nuances of the growth, development, danger and medicinal properties of mushrooms in order to use this knowledge to your advantage. No one knows in what situations you will encounter mushrooms and what information you will need about them. We have collected general information that will not only expand your horizons, but will also certainly be useful in your life.

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.

Based on their feeding method, there are three main groups of fungi: parasites, saprophytes and symbionts. These three groups cannot be sharply distinguished, because saprophytes, for example, often have the ability to feed on living substrate.

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 with the help of 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, mostly oval cells. In a sugary environment, yeast causes alcoholic fermentation, which results in the release of ethyl alcohol and carbon dioxide:

C6H12O6 → 2C2H5OH + 2CO2 + 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.

Parasitic fungi are very adapted to the host plant. In the first stages of life, they even stimulate its development; they do not kill cells or permeate them with mycelium, but feed with the help of outgrowths - haustoria.

There are exoparasites, which live on the surface of plants (powdery mildew), and endoparasites, which live on the body of the host. Among them there are intercellular (rust fungi) and intracellular (synchytria) parasites. These fungi parasitize plants, less often animals.

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 coexistence 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.

Great friendship

One of the remarkable abilities of mushrooms is the ability to enter into a special symbiosis with other plants, primarily with trees.

This phenomenon is called mycorrhiza, and there are several types:

• Ectotrophic mycorrhiza - when the hyphae of the fungus entwine the root of a tree, enclosing it in a kind of mycorrhizal tube. In this case, the hyphae penetrate the root rhizoderm and spread through the intercellular spaces, but do not penetrate the cells themselves.
• Endotrophic mycorrhiza - when hyphae climb directly into the cells of a tree root, without passing through the plasmalemma, but using pores for penetration. Inside the cell, hyphae can even branch, and such branching is called an arbuscule. At the same time, on the surface of the root, hyphae are generally not noticeable, but inside it they can form entire clusters.

Hyphae are the main material that makes up the body of the fungus, and it is from them that all the incredible variety of forms is formed, which the mushroom kingdom is rightfully proud of.

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

House mushrooms

House mushrooms are destroyers of wooden parts of buildings.

Aquatic mushrooms

Among them are saprophytes that live on plant debris, parasites of aquatic animals and plants, as well as fungi that cause fouling of wooden parts of ships, piers, etc.

Fungi parasites of plants and animals

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.

general characteristics

Mushrooms contain a combination of animal and plant characteristics. They are related to the plant world by the following features:

• the cell wall is clearly represented;
• attached way of life;
• unlimited growth;
• reproduce by spores;
• can synthesize vitamins;
• presence of vacuoles;
• absorptive way of eating.

The following signs are similar to animals:

• presence of chitin;
• absence of all types of plastids, including photosynthetic ones;
• heterotrophy;
• accumulate glycogen;
• metabolic product - urea.

Due to this specific structure and functioning, they are considered to be the oldest species of eukaryotes. But they have no evolutionary connection with plants. Today, more than 100,000 species of these representatives of the living nature of our planet have been studied. However, scientists believe that the real figure is much higher and can reach 250,000 or even 1.5 million.

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).

What are hyphas

A fungal hyphae is a typical morphological structural unit of a given organism.

This is a cylinder-shaped tube (5 to 10 µm in diameter). There are species in which hyphae grow up to 170 microns. Inside the shell of thin filaments there is multinucleated plasma, it forms new cells at the tip.

Irina Selyutina (Biologist):

Hyphae can unite into:

• rhizomorphs: more or less loose strands (several meters long and several millimeters thick);
• sclerotia: dense plexuses from which the fruiting organs are formed.

The entire collection of fungal hyphae makes up the mycelium (mycelium). That part of it that is located in the soil and, accordingly, hidden from human eyes is called the “vegetative body.” In cap mushrooms, the part located above the soil surface and intended for sporulation is called the “fruiting body.” Groups of hyphae that are tightly intertwined in the fruiting bodies form plectenchyma or false tissue, or pseudoparenchyma. In appearance, plectenchyma resembles the main tissue of plants - parenchyma, however, it is not formed by three-dimensionally dividing cells, but simply by closely spaced hyphae. The layer of hyphae covering the cap contains pigments that give it a specific color.

The mycelium constantly grows in length, at the end the threads begin to branch, and the protoplasm continuously moves towards the young part of the thread. Aged areas can be separated by a wall, which appears due to the ingrowth of the hyphal membrane.

Chemical composition of mushrooms

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

Mushroom proteins are absorbed only by 54-85% - worse than proteins from 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.

Conditionally edible mushrooms

The conditionally edible group includes mushrooms that become suitable for consumption only if properly prepared. Most often, they require pre-soaking in water for several hours, after which they are boiled, fried or stewed.

Real milk mushroom

Real breast milk The real
breast milk is distinguished by a flat-convex cap measuring 7-20 cm, which over time becomes funnel-shaped. The skin is yellowish or creamy white.

The stem of the mushroom is cylindrical, reaches 4-8 cm in length, yellowish or milky in color. The pulp has a dense and brittle texture. True milk mushrooms are found in mixed or deciduous plantings, most often growing in large groups. They ripen from late July to early October.

False chanterelle

False chanterelle
The false chanterelle has a fairly large cap, up to 4-6 cm, in some regions it can grow up to 8-10 cm. Its shape is convex, with curved edges, and becomes flat or slightly wavy with age. Its surface is velvety, yellowish-orange, sometimes with a brown tint. The leg is 0.5-1 cm wide and up to 5-7 cm long.

False chanterelles are found in forests, pine and deciduous plantations. The mushroom harvest can be harvested from the beginning of August until the last days of September.

Poplar row

Poplar row
The poplar row has a convex, hemispherical cap with curved edges, of a brownish-pinkish hue. Its size can reach 8-13 cm, the color of the flesh under the cap is slightly reddish. The mushroom stem is cylindrical, medium in size, strong and fleshy.

The poplar row ripens from the end of August to the second half of October. This mushroom can be found in deciduous plantings, parks, under poplar and aspen.

Winter honey fungus

Winter honey agaric
Winter honey agaric has a hemispherical cap of an ocher or brownish-yellowish hue, which becomes covered with dark spots with age. The mushroom stem is characterized by a cylindrical shape, its thickness is 1 cm, length up to 5-7 cm. The pulp is watery, milky in color.

Most often, winter honey mushrooms are collected at the end of November or the first half of December. Under suitable climatic conditions, fruiting continues throughout the winter. Mushrooms grow in deciduous plantings, on tree stumps and dead wood.

Champignon coppice

Copse champignon
Copse champignons can be recognized by their light cream or white color, spherical cap measuring 6-10 cm and the almost complete absence of scales. The pulp is thin, juicy and elastic.

The stem of the mushroom is cylindrical, hollow inside, up to 7-9 cm long. It has a pronounced white ring that can fall to the surface of the ground. Copper champignons are common in deciduous and coniferous forests. They can be collected from the second half of June to the beginning of September.

Interesting: Edible mushrooms - list, photo, name, description, video, when and where they grow

Wolf boletus

Wolf's boletus
The wolf's boletus is distinguished by a large semicircular, convex cap measuring 7-15 cm. Under favorable climatic conditions, its diameter can reach 20 cm. The color can be different - milky, beige, grayish, with pink-red or brown shades.

The leg is strong, cylindrical, up to 4-6 cm wide and up to 6-8 cm high. Its color is golden yellow or orange. Wolf's boletus grows in Israel, in oak forests. Ripens from November to the first half of February.

Valuy

Valuy
Valuy belongs to the mushrooms from the Russula family. It has a large cap of yellowish-brown or golden color, up to 10-15 cm in size. In young specimens it is spherical, but during the aging process it becomes almost flat.

The leg is barrel-shaped or cylindrical, with a diameter of 2-3 cm and a length of up to 7-13 cm. The pulp is snow-white and fragile, quickly darkens after cutting. Valuy can be harvested in deciduous and mixed plantings from July until the first frost.

Moss fly semi-golden

The semi-golden flywheel
The semi-golden flywheel has a yellowish-gray cap, hemispherical in shape, which becomes flat with age. Its diameter is usually 5-6 cm. This is a very rare mushroom that is found only in a few regions of Russia, Ukraine and Belarus.

The leg is cylindrical, straight and strong, 3-5 cm high. It can have a yellowish-orange, ocher-brown or reddish tint. Most often, moss fly grows in deciduous, mixed and coniferous forests, as well as among moss. Mushrooms can be collected from the second half of July to September.

Ramaria yellow

Ramaria yellow
Ramaria yellow has an unusual shape of the fruiting body, reminiscent of coral. It reaches 13-16 cm in diameter and 18-20 cm in height. The dense white stalk produces numerous cylindrical shoots. The mushroom can have various shades of yellowish-orange color.

Yellow ramaria can be seen in mixed deciduous and coniferous plantings. It grows both in groups and singly, most often appearing in August or September.

Speckled oakweed

Speckled Dubovik
Speckled Dubovik has a cushion-shaped, hemispherical cap, the diameter of which, depending on the growing conditions, reaches 8-16 cm. It has a velvety and matte surface of brown-chestnut, reddish-brown or black color.

The stem of the mushroom is barrel-shaped, its width is 3-4 cm, length 6-11 cm. With age, it thickens at the base and becomes covered with small dark red scales.

Speckled oak is found in coniferous and deciduous forests and appears from the first days of August until the end of September.

Pepper mushroom

Pepper Mushroom
Pepper mushroom can be recognized by its rich copper-brown, reddish-rust color. The diameter of the round-convex cap usually does not exceed 3-7 cm, the surface is velvety, the flesh is yellowish-gray, turning red at the cut site.

The mushroom has a cylindrical stalk up to 5-9 cm high, most often narrowed at the bottom and curved, without a ring. Its shade matches the color of the cap.

Pepper mushrooms are found in pine forests and forests, most often from the end of July to the first frost.

Gorkushka

Bittersweet
The main features of bittersweet are a flat-convex cap measuring up to 11-13 cm. With aging, it becomes fleshy, funnel-shaped and dry, with a rich brown-red color.

The stem of the mushroom has a cylindrical shape, with a edge at the base. Its height reaches 8-9 cm, diameter up to 0.5-2.5 cm. The color is whitish, pink or brown-red. Bitters can be collected in deciduous and mixed plantings from July to the end of October.

Yellow cobweb

Yellow webwort
Young yellow webworts have hemispherical caps, 3-8 cm in diameter. As they age, they become semi-prostrate.

The mushroom cap is yellowish-orange in color with a darker shade in the center. The leg is thickened at the base, large and massive, its height can reach 9-16 cm. The yellow spider web appears in the second half of August, grows until the end of September, and is most often found under deciduous trees.

Interesting fact : mushrooms and ferns are the oldest inhabitants of the planet, successfully surviving the era of dinosaurs.

Rhizopogon yellowish

Yellowish rhizopogon
Yellowish rhizopogon is not popular among mushroom pickers, since almost its entire fruiting body is located underground. It is tuberous, reminiscent of potatoes, the diameter reaches 4-6 cm. The color ranges from dark brown to brown-yellow.

The yellowish rhizopogon has dense and fleshy flesh of a snow-white hue with an olive tint and a garlicky aroma. Most often found in pine forests, ripens from mid-July to the first days of October.

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.

* * *

Total number of mushrooms on earth

At the very beginning of the article, we talked about how many mushrooms there are on the globe. However, this information should be specified in order to have a general idea of ​​the scale of growth.

Mushrooms are rightfully considered one of the largest groups of living organisms. Today they support all existing ecosystems; the disappearance of mushrooms will inevitably lead to tragedy.

According to modern scientists, today there are more than 250,000 officially registered species of mushrooms on earth. This also applies to the regions of the Far North, Russia, and other continents. Also, fungi also mean microorganisms, which are also named accordingly.

However, if each type of mushroom is divided into subspecies, for example, fly agaric can be red, variegated, gray, pink, and so on, then we will count more than one and a half million species. Agree, it’s big.

Scientists expect that new modified bred species will appear in the next century. They will appear both as a result of the developments of scientists, and may also become a direct consequence of changes in environmental conditions.

Due to severe air pollution, as well as a decrease in nutrients in the soil, the mushrooms will begin to change, resulting in their new manifestations.

What is the difference between plant nutrition and fungal nutrition?

The most important difference between cells and fungi is the way they absorb food. Plants are characterized by independent maintenance of their metabolism through photosynthesis (conversion of inorganic matter into organic compounds). But mushrooms cannot do this. They do not have chlorophyll (the green pigment in chloroplasts that is responsible for the process of photosynthesis). Therefore, the process is impossible for them. They are able to absorb finished substances through moisture. Some types of fungi are characterized by symbiotic coexistence with plants, thanks to which they can obtain the necessary nutrients.

A distinctive feature of mushrooms is also considered the fact that they can exist and develop without water, light and even without air.

Fungi are also capable of parasitizing on and inside living organisms.

Lecture 15. Fungi (Mycota), lichens (Lichenes)

Mushrooms (Mycota). An ancient group of organisms that appeared in the Proterozoic era (about 1 billion years ago) from ancient unicellular aerobic eukaryotes. Currently, the kingdom of Mushrooms has about 100 thousand species.

Structure . The body - the mycelium of most mushrooms consists of branched threads called hyphae; the mycelium of lower fungi is devoid of partitions and represents, as it were, one highly branched giant multinucleate cell (unsegmented, nonseptate mycelium). The mycelium of higher fungi is divided by transverse partitions (septa) into individual cells containing one or several nuclei (articulated, septate mycelium), and the septa have openings - pores, sometimes so large that nuclei pass through them along the entire hypha.

The cell membrane has a cell wall (like plants), but it consists not of cellulose, but of chitin fibers. Chitin is also characteristic of arthropods. Under the cell wall there is a plasmalemma that limits the internal space of the cell, filled with cytoplasm with organelles: nucleus (or nuclei), mitochondria, endoplasmic reticulum, Golgi apparatus, ribosomes; Fungi have large vacuoles. There are no plastids characteristic of plant cells. Many fungi form fruiting bodies, which are closely intertwined mycelial hyphae.

Metabolism. Fungi are heterotrophic organisms, not capable of photo- or chemosynthesis, the type of nutrition is heterotrophic: saprotrophic (non-living organic matter), parasitic and even predatory (roundworms - nematodes) fall into fungal traps. Symbioses with plants are characteristic. The mushrooms secrete enzymes that digest organic matter, and the absorption of nutrients occurs throughout the entire body surface osmotically. They grow throughout their lives, which is also typical for plants.

Most mushrooms are aerobic organisms; only a few are able to obtain energy through fermentation under anaerobic conditions. The main reserve substance, as in animals, is glycogen, one of the products of protein metabolism is urea (as in animals).

Reproduction. The division of fungal cells also occurs unusually - mitosis and meiosis are carried out without destruction of the nuclear membrane, the division spindle is formed under the nuclear membrane, after the distribution of chromosomes, the nucleus is separated by a constriction; centrioles, as in higher plants, are absent.

Asexual reproduction is carried out with the help of spores formed in special organs - sporangia (endogenous sporulation); in some, spores are formed directly on vertical hyphae - conidiophores (exogenous sporulation). Vegetative propagation occurs in parts of the mycelium or by budding;

Sexual reproduction occurs in almost all fungi; the forms of the sexual process are very diverse: due to the fusion of gametes formed in gametangia (isogamy, heterogamy, oogamy); somatogamy - fusion of two cells of vegetative mycelium; gametangiogamy - the fusion of two sexual structures that are not differentiated into gametes; hologamy - fusion of cells of unicellular fungi. In addition to asexual sporulation, fungi also undergo sexual sporulation - the formation of spores by meiosis after the fusion of the genetic material of gametes or nuclei.

In the life cycle of higher fungi, three phases alternate: haploid, dikaryonic and diploid. The diploid phase is usually short-lived, associated with the fusion of nuclei or gametes, but the haploid and dikaryonic phases make up the bulk of the life cycle. The different phases of the life cycle will be discussed below using specific examples.

Diversity . The kingdom Mushrooms is divided into two subkingdoms - the subkingdom Fungiformes and the subkingdom True Mushrooms. Only real mushrooms are studied in the school course. True fungi include 4 classes - zygomycetes (from lower fungi) and all higher fungi: ascomycetes, basidiomycetes and imperfect fungi or deuteromycetes. True fungi do not form motile cells at any stage of the life cycle.

Class Zygomycetes. There are about 400 species in the class; the mycelium of zygomycetes is nonseptate, branching, and multinucleate (the nuclei contain a haploid set of chromosomes). By type of nutrition - most are saprotrophs, there are insect parasites, some are symbionts, they form mycorrhizae on the roots of higher plants.

Mukor. The most famous representative of zygomycetes is mucor, which has the appearance of white mold. Usually the mycelium is immersed in the substrate on which it develops. On the surface of the substrate, the mycelium forms numerous vertical sporangiophores with sporangia. Up to 10 thousand multinucleated spores of asexual sporulation are endogenously formed in sporangia.

A widespread saprotrophic fungus that settles on food products (Fig. 82). By the time the spores mature, the sporangia turn black and the spores spill out. Once in suitable conditions, the spores germinate and give rise to a new mucor mycelium. This is how asexual reproduction of mucor occurs.

Reproduction. When the substrate is depleted, the mucor switches to sexual reproduction according to the gametaniogamy type. The hyphae of different mycelia (usually one thread is designated with a “-” sign, considering it male, and the other with a “+” sign, considering it female) are brought together by swollen ends - gametangia, which are separated from the mycelium by partitions, the membranes between them dissolve, and the fusion of cytoplasm and nuclei occurs different signs. A zygote is formed with numerous diploid nuclei, covered with a thick spinous membrane. After a period of rest, the nuclei undergo meiosis, the outer membrane of the zygote bursts, and it grows into a short hypha ending in a small sporangium. In it, as a result of meiotic division, “+” and “-” spores, spores of sexual sporulation, are formed. From these spores, vegetative “+” and “-” mycelia develop.

Meaning . Mucors take part in the cycle of organic (especially nitrogen-containing) substances in the soil. Often cause food spoilage. Some cause lung disease in birds, affect the hearing organs and central nervous system of humans, and cause dermatomycosis.

Class Ascomycetes. About 30,000 species of saprotrophic soil and mold fungi that settle on bread, vegetables and other products (Fig. 83). This class includes penicillium, yeast, morels, stitches, and ergot. The mycelium is haploid, septate, branching. Through the pores, the cytoplasm and nuclei can pass into neighboring cells. Asexual reproduction is carried out exogenously, with the help of conidia - spores (translated from Greek “conidia” - fine dust), which are detached from special cells of the conidiophore. During sexual reproduction, bags are formed - asci, in which haploid spores of sexual sporulation are formed. The class of ascomycetes is divided into two subclasses - gymnossumates and fruit marsupials. In gymnossumates, the asci are located openly, as in yeasts; in fruit marsupials, they are located in spherical fruiting bodies, closed ones - cleistothecia, flask-shaped with a hole at the top - perithecia, saucer-shaped - apothecia.

Penicillium (brush). Belongs to fruit marsupials. At first it looks like a white cobwebby coating, and then acquires a greenish or bluish tint. Conidiophores rise upward from the mycelium, the ends of which form a brush. At the tip of each branch, a chain of rounded spores - conidia - is formed exogenously. Due to the shape of the conidiophores, penicillium is sometimes called “watering can mold” - groups of conidia at the ends of the conidiophores resemble streams of water flowing from a watering can. They are carried by air currents and give rise to new mycelium. Sexual reproduction rarely occurs. In this case, the fusion of gametangia occurs and the formation of cleistothecia, fruiting bodies containing asci (bags), in which, after the fusion of nuclei, the formation of zygotes and meiosis, haploid ascospores develop. The formation of fruiting bodies can be detected by the appearance of a lemon-yellow color that appears where there is an accumulation of fruiting bodies.

Saprotrophic Penicillium species mineralize soil organic matter. Some species are used to prepare the antibiotic penicillin. In 1928, the English scientist and doctor Alexander Fleming noticed that around a penicillium colony grown on a Petri dish with a staphylococcus culture, all the staphylococcal cells around the penicillium died. Only in 1941-1942 did the industrial production of penicillin begin in England and the USA based on Penicillum notatum. In 1942, employees of the Institute of Epidemiology and Microbiology (IEM) named after. N.F. Gamaleya, headed by Z.V. Ermolyeva, established the production of domestic penicillin based on Penicillum chrysogenum. Also used in the food industry for the preparation of special types of cheese.

Yeast. They belong to the group of gymnasiums, the bags lie open on the mycelium. Unicellular fungi, the vegetative body of which consists of single oval cells with one nucleus. Yeasts are represented by a large number of species, widely distributed in nature. Baker's yeast exists only in culture, represented by hundreds of races: wine, bakery, beer. Wines occur naturally on the surface of fruits. Different species of yeast can exist in diploid or haploid phases.

Yeast is characterized by a highly pronounced aerobic metabolism. They use various sugars, simple and polyhydric alcohols, organic acids and other substances as a carbon source. The ability to ferment carbohydrates, breaking down glucose to form ethyl alcohol and carbon dioxide, served as the basis for the introduction of yeast into culture.

C6H12O6 → 2C2H5OH +2CO2

Under favorable conditions (the presence of carbohydrates in the environment and the desired temperature), yeast reproduces for a long time vegetatively - by budding. A bud appears at one end of the cell, begins to grow and separates from the mother cell. Often the daughter cell does not lose contact with the mother cell and begins to form buds itself. As a result, short chains of cells are formed. However, the connection between them is fragile, and when shaken, such chains break up into individual cells. With a lack of nutrition and excess oxygen, sexual reproduction occurs according to the hologamy type - two cells merge, after nuclear fusion, the diploid parent cell meiotically divides and a bag with 4 ascospores is formed. The spores fuse to form a new diploid yeast cell. Haploid yeasts have different life cycles, but during sexual reproduction, the formation of sexual spores always occurs.

Yeast is used in baking, brewing, and winemaking. Yeast contains up to 50% protein, fats, carbohydrates, and synthesizes vitamins (especially B2) in large quantities. Therefore, they have valuable food and feed properties. Brewer's yeast is used in the treatment of anemia. Feeder yeast is used to produce feed proteins.

Class Basidiomycetes. Cap mushrooms. There are about 30,000 higher fungi, the vegetative body of which is a branched mycelium consisting of segmented hyphae. This class includes almost all edible and poisonous mushrooms, polypores and two groups of parasitic fungi - smut and rust fungi.

A distinctive feature of basidiomycetes is the presence of two haploid nuclei in each mycelial cell. Such a cell is called dikaryonic, and the mycelium developing from it is called dikaryonic.

Most basidiomycetes are characterized by the formation of fruiting bodies. They have hoof-like projections, but most often consist of a cap and a stalk. In everyday life they are called mushrooms. As a rule, the cap is covered with colored hyphae that form a skin. The function of fruiting bodies is the formation of spores. On the underside of the cap there is a spore-forming layer, the hymenophore, on which special structures are formed - basidia. Mature basidia resemble an inflated glove with 4 fingers. In young basidia, haploid nuclei fuse and a diploid nucleus is formed, which soon divides by meiosis, resulting in the formation of 4 nuclei that migrate to the terminal processes of the basidia. When basidiospores mature, the pressure inside the basidium increases and the basidiospores are “shot” and spread with the help of air currents.

To increase the surface of sporulation (hymenophore), the lower part of the cap can be lamellar - has the form of plates radially diverging from the central lower surface of the cap in the form of rays (russula, chanterelle, milk mushroom, champignon) or tubular - has the form of tubes tightly adjacent to each other (boletus, aspen boletus, oiler, boletus).

Mushroom nutrition. The bulk of cap mushrooms are saprotrophs, but there are also parasites (for example, honey fungus). Cap mushrooms often enter into a symbiotic relationship with the roots of higher plants, especially woody ones, forming mycorrhiza - a fungal root. At the same time, the mycelium entwines the roots of trees, the mushrooms receive organic substances from the plants, and the plants receive water and mineral salts. For many mushrooms, such symbiosis is mandatory, since their mycelium can develop without the participation of tree roots, but fruiting bodies in this case are not formed.

Edible and poisonous mushrooms. About 200 forms of mushrooms are edible. The most famous are porcini mushroom, boletus, boletus, butter mushroom, champignon, oyster mushroom, saffron milk cap, milk mushroom and others. Among the inedible mushrooms there are also poisonous ones. The most dangerous are the pale toadstool, red fly agaric, and stinking fly agaric.

propagation . The edges of the plates or the inner surface of the tubes are represented by a layer of basidia. In the basidia, the dikaryonic phase of the development of basidiomycetes ends. The nuclei of the dikaryon fuse to form a diploid nucleus. It divides meiotically, and haploid nuclei pass into basidiospores that form on the surface of the basidium.

Basidiospores—spores of sexual reproduction—germinate into the primary mononuclear mycelium.

But for the formation of fruiting bodies, it is necessary that two primary mycelia meet (somatogamy) and cells with two nuclei are formed. Moreover, only cell protoplasts merge, and the nuclei form pairs - dikaryons, which begin to divide synchronously. As a result, secondary dikaryonic mycelium is formed (Fig. 85).

Fungi are parasites of plants. A large number of plant diseases arise as a result of their infection by various parasitic fungi. Fungal spores, produced in huge quantities, are spread by water and air currents and penetrate the plant body through damage to the integument. At the same time, many fungi are able to actively invade plants.

Smut fungi and rust fungi belong to the class Basidiomycetes. Smut fungi are malicious parasites of cereals (Fig. 86). Smut fungi attack flowers and inflorescences of cereals. When smut is infected, instead of grain, black dust is obtained, which is spores of the fungus. The ears become like charred firebrands. Infection by some species occurs during the flowering stage of cereals, when spores from the infected plant fall on the stigmas of the pistils of healthy plants. They germinate, the hyphae of the fungus penetrate the embryo of the seed, and a caryopsis is formed, which is apparently healthy. The next year, at the time of flowering, sporulation of the fungus begins, flowers are not formed, and the inflorescence takes on a charred appearance.

Ergot belongs to the class Ascomycetes. It is easily detected in the fall: on the ears, among the grains, black and purple horns are clearly visible - sclerotia, protruding from the ear.

They consist of tightly intertwined hyphae. This is the dormant stage of the fungus. During the rye ripening period, they fall to the ground and overwinter under the snow. In spring, they form reddish spherical heads on long stalks. Along the periphery of the head there are many fruiting bodies - perithecia, resembling pitchers, and here are the bags, asci with ascospores. Spores mature during the flowering of rye.

Ripe spores land on the stigma of the rye pistil and germinate, forming mycelium. The mycelial hyphae penetrate the ovary and destroy it. At the ends of the mushroom filaments, round conidiospores are formed in large numbers. At the same time, the threads of the fungus secrete a sweet liquid - honeydew, which attracts insects, primarily flies. Flying from one ear to another, insects spread fungal spores to uninfected ears. Conidia, once on the ovary, form a mycelium, which becomes denser by autumn, its outer layers are colored, and instead of caryopsis, horns are formed in the ear.

Ergot horns contain poisonous alkaloids, which, when entering the human body, cause poisoning (sometimes fatal), called ergotism. Ergot alkaloids cause severe convulsions, “evil writhing,” spasms of blood vessels so strong that tissues die, and gangrene begins—“Antonov fire.” One of the ergot alkaloids is a close chemical analogue of the drug LSD, a powerful hallucinogen. Some of the ergot alkaloids are used in medicine.

Tinder fungi. They belong to basidiomycetes. The hymenophore is tubular and grows annually from below. Polypores affect many deciduous trees. A tinder spore, once on a wound in a tree, grows into a mycelium and destroys the wood.

After a few years, perennial hoof-shaped fruiting bodies are formed. Polypores secrete enzymes that destroy wood and turn it into dust. Even after the death of a tree, the fungus continues to live on the dead substrate (as a saprotroph), annually producing large numbers of spores and infecting healthy trees. Therefore, it is recommended to remove dead trees and fruiting bodies of polypores from the forest.

The meaning of mushrooms. Mushrooms play an important role in the cycle of substances in nature, being decomposers of plant residues. Participate in soil formation processes. Fungi improve the nutritional conditions of plants (forming mycorrhiza with the roots of higher plants). The negative role of mushrooms is also great. They cause various diseases, parasitize plants, animals and humans, and spoil food. Wood-decaying fungi cause great damage to forestry, destroy large amounts of harvested wood, and destroy wooden buildings and wooden parts of buildings.

Their role in human economic activity is also important. They are used in the baking, brewing, dairy and wine industries for the production of wine, alcohol, beer, kvass, and kefir. Cap mushrooms have nutritional value, as they contain large quantities of proteins, fats, carbohydrates, vitamins, valuable salts and aromatic substances. They are used to produce antibiotics (penicillin), gibberellin - a growth substance, and drugs to kill harmful insects. Yeast is used as a medicinal product, as it is rich in vitamins.

Division Lichens (Lichenes). Includes about 20,000 species. Lichens are symbiotic organisms that include mycobionts - fungi (usually ascomycetes, less often - basidiomycetes) and phycobionts - photoautotrophic organisms: algae (green) or cyanobacteria. Mycobionts provide the phototrophic component with water and mineral salts, create a microclimate for normal existence, and the phycobiont synthesizes organic substances not only for itself, but also for the fungus. Such a close relationship arises between the symbionts that as a result a morphologically and physiologically integral organism is formed. This coexistence of fungus and algae is constant, but not entirely equal - the fungus plays the leading role in the symbiosis.

In low-organized lichens, some fungal hyphae penetrate into the algae and use their contents; in highly organized lichens, the hyphae form special structures that do not penetrate, but are tightly pressed against the algal cell membrane and, absorbing the necessary substances, do not interfere so much with the life of the phycobiont.

Structure. The body of the lichen is a thallus (thallus), not differentiated into organs. The basis of the thallus is made up of intertwined fungal hyphae, among which algae are located. There are two main types of structure of the lichen thallus - homeomeric and heteromeric thalluses. In a homeomeric lichen, algal cells are more or less evenly distributed throughout the entire thickness of the thallus; in a heteromeric lichen, the fungal hyphae on the upper and lower sides form a dense plexus - the upper and lower cortical layers, between which there is a core of loosely arranged hyphae and a layer of algae.

Based on their shape, crustose, foliose and fruticose lichens are distinguished. Scale lichens are located on the surface of the substrate in the form of scale and crust. The substrate for them is the bark of trees and shrubs, and various rocks. By releasing lichen acids, they destroy the surface of rocks, preparing the ground for the colonization of this surface by leafy and bushy lichens, mosses and then flowering plants. They are pioneers of plant communities.

Foliaceous lichens have a body in the form of leaf-shaped plates attached to the soil or trees with the help of bundles of hyphae (Parmelia, Xanthorium). Fruticose lichens look like more or less branched bushes, up to 12-15 cm high. The most famous of the fruticose lichens are moss, or reindeer moss and usnea. Resin moss is the name given to three species of the genus Cladonia – forest Cladonia, alpine Cladonia, and deer Cladonia. Usnea, a bearded lichen, has a beard-shaped thallus, thin threads of which hang from trees several tens of centimeters long.

Physiology of lichens . The fungus is a heterotrophic component, and the algae is autotrophic. Algae create organic matter that is used by both the algae and the fungus. Fungi protect algae from drying out and extreme temperatures and supply them with water and mineral salts. The relationship between fungus and algae is quite complex. The fungus can feed saprotrophically on dead algae and their metabolic products, or as a parasite, penetrating the cell and absorbing its contents. Therefore, the partnership in the lichen is not a symbiosis, but rather a controlled parasitism of the fungus on algae.

Lichens are able to absorb water both from the substrate and from the air with the entire thallus, they are light-loving, and undemanding to the substrate. Most lichens cannot withstand even the slightest air pollution; they can be used for a general assessment of the degree of environmental pollution. This is the basis of one of the areas of indicator ecology - lichen indication.

Lichens grow extremely slowly, especially crustose lichens - up to 1 mm per year. The growth per year for leafy ones is 1-8 mm, for bushy ones – 1-35 mm.

Reproduction of lichens is both sexual and asexual. Sexual reproduction is carried out due to the fungal component, which forms fruiting bodies (for example, apothecia, perithecia), in which bags with spores are formed. Germinating spores must meet the corresponding algae, only in this case a new lichen will form.

Algae cells can only reproduce vegetatively. Basically, lichens reproduce asexually, by parts of the thallus or by special formations - soredia or isidia.

Soredia are special formations consisting of fungal hyphae entwining algae cells (Fig. 90). They are formed inside the thallus and are released as a result of rupture of the cortical layer. Isidia are outgrowths of the thallus that form on the surface of the lichen and contain a group of algae under the cortical layer.

Lichens can exist in the most unfavorable conditions. They settle in the most barren places where other organisms are unable to exist.

Since lichens are very unpretentious, they are found on rocks among eternal ice and snow in the highlands, in the interior of Antarctica, on lifeless Arctic islands, in barren deserts, on completely bare volcanic formations. At the same time, they also feel good in tropical rainforests.

The meaning of lichens. Being the first settlers of uninhabited spaces, lichens play a significant role in the soil-forming process, gradually destroying rocks and preparing the conditions for the colonization of this territory by higher plants. In vast areas of the Arctic, lichens are the main food for reindeer (moss moss).

Lichens play a significant role in human life. Due to the presence of lichen acids, many of them have a pronounced bactericidal effect. In perfumery, lichens are used as scent fixatives for perfumes and to produce litmus. There are lichens (lichen manna) that can be used as food.

Lichens are not parasites, but their presence on tree trunks disrupts gas exchange and creates conditions for the proliferation of insect pests. Therefore, lichens should be cleaned from the branches and trunks of fruit trees.

Key terms and concepts

1. Mycelium. 2. Hyphae. 3. Septa. 4. Lower mushrooms. 5. Mukor. 6. Higher mushrooms. 7. Penicill. 8. Conidia. 9. Gametangia. 10. Aski. 11. Basidia. 12. Yeast. 13. Smut. 14. Ergot. 15. Mycobionts of lichens. 16. Phycobionts of lichens. 17. Soredia. 18. Isidia.

Basic review questions

1. Plant characteristics characteristic of fungi.
2. Animal characteristics characteristic of mushrooms.
3. What class does mucor belong to? Asexual and sexual reproduction of mucor.
4. What class does penicillium belong to? What spores form and where do they form?
5. What class does yeast belong to? What spores form and where do they form?
6. What mycelium is typical for cap mushrooms?
7. What parasitic fungi do you know?
8. What are the morphological types of thalli in lichens?
9. What are the four layers in heteromeric lichen?
10. Methods of asexual reproduction of lichens.

Author: Pimenov Anatoly Valentinovich. (Biology teacher, Municipal Educational Institution “Physical and Technical Lyceum No. 1”, Saratov)