Living organisms consisting of algae and fungus. Lichens
Kira Stoletova
The most mysterious symbiosis of fungus and algae is the Lichens department. An organism consisting of two components is studied by a science called lichenology. Until now, scientists have not been able to establish the nature of their occurrence, and they are obtained in laboratory conditions with great difficulty.
Body composition
Previously it was thought that the symbiosis of fungi and algae in lichen is represented by a mutually beneficial way of coexistence of two organisms, in which:
- mushrooms receive carbohydrates produced by the second component during photosynthesis;
- algae need minerals and cover to protect them from drought.
Irina Selyutina (Biologist):
Nowadays the union is represented differently: the spores of the fungus choose a “nurse” for themselves, but the latter can resist the union. The main rule in symbiosis is mutually beneficial coexistence. A lichen will turn out if both components experience difficulties in living alone: they lack nutrition, light, and temperature. Favorable factors do not force them to unite.
Fungi that interact behave differently with algae. Forms hyphae with all available species, but some of them are simply eaten. Synthesis only appears with similar classes. In coexistence, both organisms change their structure and appearance.
Body structure
Structurally, lichen consists of two components: fungal hyphae with algae woven into them.
The algal component is a phycobiont, which can be represented by cyanobacteria (blue-green algae), green or yellow-green algae. Fungal component, or mycobiont - marsupial or basidiomycetes.
If the arrangement of algae is uniform throughout the entire thallus, it is called homeomeric, and if only in the upper layer, it is called heteromeric. This is the so-called thallus, or thallus, or body of the lichen.
The internal structure of the lichen thallus includes the following components:
- Upper crust (cortical layer): formed by tightly intertwined hyphae. It is colored in different colors due to the presence of pigments. This crust is thicker and provides protection and absorption of water from the air.
- Core layer: formed by the internal hyphae of the fungus and the green cells of algae, with which photosynthesis, transformation and storage of substances are associated.
- Lower skin (cortical layer): thin, equipped with rhizoids, thanks to which the body of the lichen is attached to the substrate. In addition, the hyphae secrete acids that can dissolve the substrate and absorb minerals.
Based on their appearance, the following types of thallus are distinguished:
- scale;
- leafy;
- bushy.
The first ones look like a thin crust, firmly fused with the surface. Leafy ones are supported by bundles of hyphae - rhizoids. Bushy ones look like a hanging bush or beard.
The color can be gray, brown, greenish, yellow or black. The concentration is regulated by specific dyes, iron content, and acids in the environment.
Reproduction methods and life cycle
In lichen, both components are endowed with the ability to reproduce. The fungus reproduces vegetatively - by parts of the thallus or with the help of spores. The body appendages are torn off from the thallus and moved by animals, people or the wind. Controversy also spreads.
The second component is divided vegetatively. The symbiotic complex improves the ability to reproduce. And some species practically do not exist outside the lichen.
Irina Selyutina (Biologist):
Lichens reproduce either by spores, which are formed by the mycobiont sexually or asexually, or vegetatively.
During sexual reproduction On the thalli of lichens, as a result of the sexual process, sexual sporulation is formed in the form of fruiting bodies (apothecia; perithecia and gasterothecium are known in lichens).
In addition to the spores formed during the sexual process, lichens also have asexual sporulation– conidia, pycnoconidia and stylospores that arise exogenously on the surface of conidiophores.
During vegetative propagation usually there is a separation of pieces of the thallus, which can be torn off by gusts of wind or soredia (microscopically small glomeruli consisting of one or more algae cells surrounded by fungal hyphae) or isidia (small outgrowths on the upper surface of the thallus).
Organisms grow slowly. Forms an increase per year from 0.25 to 10 mm. But they are undemanding to environmental conditions:
- grow on rocks, soil, tree trunks and branches, on inorganics: glass, metal;
- withstand dehydration.
Tolerant to temperatures from -47 to 80℃, 200 species live in Antarctica. They were able to live outside the earth's atmosphere for about two weeks. Lichens are indicators of the cleanliness of the environment - they are not found in places with heavy pollution.
The role of lichens
There are about 20 thousand species. The symbiont forms a distribution network throughout the world. Organisms of particular importance in tundra and forest areas:
- Serve as food for reindeer.
- They take part in the weathering of rocks and soil formation.
- They become a place for the reproduction and residence of a number of invertebrate animals.
A person uses them:
- To determine the age of the rocks, because the lichens themselves live up to 4500 thousand years.
- To obtain antibiotics, you need the species of Cetraria, Cladonia, Parmelia, and Usnea.
Symbiosis. Popular science with Anna Urmantseva.
Conclusion
The symbiotic union of two organisms is still being studied. If previously it was possible to obtain only 1 organism in 800 attempts in the laboratory, now, thanks to discoveries, the study is moving faster. When successful, both organisms benefit from coexistence.
The structure and activity of lichens
Lichens are a group of very peculiar organisms, the body of which consists of two components - a fungus (mycobiont) and an algae (phycobiont).
Note 1
The science that studies lichens is called lichenology.
The vegetative body of the lichen - the thallus, or thallus - is formed by the interweaving of fungal hyphae, and among them are cells or threads of algae - evenly (thallus of the homeomeric type), or only in the upper layer (thallus of the heteromeric type).
In most lichens, the phycobiont is the unicellular green alga Trebuxia, but 28 more algae genera can be part of lichens. Among them there are blue-green, green, yellow-green and brown.
For a long time, the relationship between a fungus and an algae in the lichen organism was considered as a mutually beneficial existence for both organisms (symbiosis), since as a result, its heterotrophic organism of the fungus received organic substances from the autotrophic algae, and the organism of the algae from the fungus received mineral compounds dissolved in water, as well as protection from drying out.
The algae included in the body of lichens are extremely resilient. They can withstand prolonged drying and significant temperature changes.
A characteristic feature of lichens is the absence of green color and leaves. Thallus lichens are mostly grayish, brown, yellow or almost black in color. Color depends on specific pigments, iron salts, content and concentration of various acids.
Lichens grow very slowly; the annual growth of the thallus in various species ranges from 0.25 - 1 to 36 mm per year.
One of the most characteristic biological features of lichens is their unpretentiousness to living conditions. They can exist on rocks, soil, tree trunks and branches, fences, and even metal and glass.
Reproduction of lichens
Lichens reproduce by vegetative, sexual and asexual methods.
Vegetatively: parts of the thallus or specially adapted formations - isidia and soredia.
Isidia are outgrowths of different shapes and sizes on the surface of the thallus, containing both components of the lichen. They can break off from the lichen and spread by wind, water or animals.
Soredia are small dust particles that consist of one, two or several unicellular algae entwined with fungal hyphae. They are formed in the middle of the thallus. They are released after it ruptures and are carried by the wind. Each component of the lichen is capable of reproducing individually: algae - by division, fungi - by spores.
Classification of lichens
Based on the appearance of the thallus, three types of lichens are distinguished:
cumulative, or cortical, - in the form of a crust that is tightly fused with the substrate (lecanora, aspicillium). It can reach a thickness of 0.5 cm, and in diameter it ranges from a few millimeters to 20 - 30 cm. Sometimes several lichens grow together and form large spots.
Note 2
There are so-called nomadic lichens that have a spherical thallus. They are not attached to the substrate and can be carried by the wind.
leafy - have the appearance of a flattened leaf-shaped plate, horizontally attached to the substrate by bundles of hyphae (rhizoids, rhizines, or gomphs). Usually the shape of the thallus is round, with a diameter of 10 - 20 cm. Representatives are parmelia, xanthoria. In the mountains of Siberia and Chukotka, nomadic foliose lichens are found - one of the most beautiful lichens.
bushy - look like a bush or hanging beard (cladonia, usnea). They are attached to the substrate by a small lower part of the thallus or thin filamentous rhizoids. The largest fruticose lichens reach a height of 50 cm.
In the very first classifications, scientists divided all living beings into only two kingdoms - animals and plants. Now many organisms previously classified as plants are classified into separate kingdoms. Some of them are familiar to us. These are, for example, mushrooms - the familiar cap mushrooms, as well as molds, powdery mildews, rusts, etc. Lichens growing on rocks and on tree trunks consist of two organisms living together - a fungus and an algae.
IMPORTANT DIFFERENCES
It was previously believed that mushrooms were primitive plants that did not have leaves. We now know that mushrooms differ from real plants in many ways. The substances that make up fungi are not like those we find in even the simplest real plants. But the main difference is that mushrooms are not capable of producing food for themselves, that is, they are not capable of photosynthesis. Fungi extract nutrients from other - living or dead - organisms. Many cap mushrooms feed on the substrate on which they grow - rotting wood or manure.
MUTUAL AID
Lichens can survive in the harshest conditions. They grow in poor soils, on rocks, in the coldest regions of the Arctic. Many develop extremely slowly. This ability to survive in difficult conditions is due to the fact that two organisms are present in the body of the lichen - a fungus and an algae. None of them could survive on their own under these conditions. The algae is usually located in the middle of such a “sandwich”, between two layers of the mushroom. The layers of the fungus protect the algae and supply it with water, and the algae produces food for both itself and the fungus through the process of photosynthesis.
- Diatoms are single-celled plant-like organisms that live in the sea. They are usually included in the kingdom of protists (single-celled).
- Cap mushrooms reproduce by dispersing millions of tiny spores. At the first stage, a mycelium (fungal mycelium) grows from the spore. Later, fruiting bodies appear on the mycelium, capable of forming new spores.
- Many mushrooms grow in dark, damp places, such as forest soil. They feed on rotting wood and other plant material.
- Most algae live in the sea or off the coast.
- A lichen consists of two organisms - an algae that produces food through photosynthesis, and a fungus that absorbs water.
- Laminaria seaweed reaches a length of 65 m.
All living organisms on the planet are divided into kingdoms. The classification was based on the presence of a nucleus. There is a kingdom of prokaryotes that do not have a nucleus. These include bacteria and blue-green algae (cyanea). The kingdom of eukaryotes includes those organisms that have a nucleus: fungi, plants and animals. Despite the fact that bacteria, fungi, plants (algae and higher), animals constitute separate kingdoms, there are also common features between them.
Bacteria and cyanides are classified as prokaryotes. Their main differences are:
- lack of a clearly defined core;
- absence of membrane organelles;
- the presence of mesosomes (a kind of protrusion of the membrane into the middle of the cell);
- small ribosomes compared to eukaryotes;
- Bacteria have one chromosome, cyanobacteria have several chromosomes that are located in the cytoplasm;
- absence of nucleoli;
- no mitochondria;
- the cell wall of bacteria consists of murein, and that of cyanides consists of cellulose;
- flagella are distinguished by their simple structure and small diameter;
- There is no sexual process; reproduction occurs through division.
Under unfavorable conditions, many microorganisms form spores, which can lie for years waiting for suitable conditions for life and development. Plants and fungi also produce spores, but they need them to reproduce. There are microbes that feed like plants and are autotrophs, and some feed like animals and are heterotrophs. Unlike other living organisms, whose life is impossible without the presence of oxygen, there are microorganisms that are able to live in an anaerobic environment, and oxygen, on the contrary, is destructive for them.
Bacteria are the most numerous creatures on the planet, and most of them are still unexplored.
plant kingdom
The classification is based on their main difference - autotrophic nutrition. They are capable of converting inorganic substances into organic ones. To do this they need solar energy. This is also characteristic of cyanobacteria. Thanks to plants and cyanobacteria, the air on the planet is enriched with oxygen, which is so necessary for other living organisms. Plants are a source of food for many other organisms. They are divided into two subkingdoms: algae and higher ones. Algae do not have roots, stems and leaves, unlike higher forms.
A special place is occupied by primitive algae (pyrrophytes), whose cells lack histones in their chromosomes; their structure is close to the nucleoid of bacteria. The cell wall of some algae is made of chitin, like those of animals and fungi. Red algae differ from other species in that their cells do not have flagella. There are differences in structural features and biochemical processes.
kingdom of mushrooms
For a long time, scientists argued about whether to classify mushrooms into a separate kingdom or not. As a result of long debates, they were nevertheless identified separately, since they have much in common with both plants and animals.
Their method of nutrition is the same as that of animals - heterotrophic. Just like animals, they lack plastids and have chitin in their cell walls. As a result of metabolic processes, urea is formed. Fungi, like plants, absorb nutrients through absorption. They are immobile and have a growth pattern similar to that of plants.
Some fungi reproduce like bacteria ─ asexually, some like plants ─ vegetatively, some like animals ─ sexually. Many of them, like microbes, process dead living organisms, thereby playing the role of “orderlies”. Many of them are beneficial and are used in the production of antibiotics, hormones, and vitamins.
Depending on how they consume organic substances, they are divided into three types:
Lichens
Many scientists insist on classifying lichens as a separate kingdom. There are several reasons for this. They can be symbionts:
- mushroom and algae;
- bacteria fungi and algae.
Based on their appearance, they are divided into three groups:
- cortical (which grow on stones and firmly grow together with the surface);
- leafy (attached to the surface with a stalk);
- bushy (attached to the soil, trees, shrubs in the form of bushes).
The body of the lichen is called the thallus, which differs in size, color, shape and structure among different species. The thallus can be from several centimeters to a meter.
Lichens grow very slowly, but their lifespan can be from hundreds to thousands of years.
As a result of symbiosis, a single organism is obtained. Moreover, the hyphae of the fungus are closely intertwined with algae cells. Thus, the lichen combines two completely different organisms in structure and method of nutrition. Fungi that form a symbiosis with algae are not found separately in nature, but the species of algae participating in the symbiosis can also be found as a separate living organism.
Lichens have a unique way of feeding: fungi absorb dissolved minerals, and cyanobacteria form organic matter and participate in the process of photosynthesis. Lichens can reproduce either by spores or by dividing the thallus.
The sensitivity of lichens to polluted environments makes them indicators of cleanliness. Many species are used for animal nutrition and for medicinal purposes.
animal kingdom
The animal kingdom is divided into two subkingdoms: protozoa and multicellular. Even though protozoa are made up of a single cell, just like bacteria, they have all the characteristics of animals. There are species of protozoa that feed autotrophically in the light, and in its absence switch to heterotrophy. Protozoa can reproduce both asexually (cell division) and sexually (conjugation).
What animals and plants have in common is metabolism and cell structure. The main difference is the way of eating. Animals are heterotrophs, that is, they feed on ready-made organic compounds and are not able to synthesize inorganic substances. For the most part they are mobile.
The more complex structure of the eukaryotic cell suggests that they received these improvements as a result of evolution. And the simultaneous existence on earth of both prokaryotes and eukaryotes suggests that biological processes are characteristic of all forms of life. All living organisms live in complete interaction with each other, and the disappearance of at least one of the species would lead to irreversible consequences. There is a place on the planet for all types of ecological chain.
Plan:
1. General characteristics of mushrooms and their significance in nature.
2. General characteristics of algae and their importance in nature.
3. Lichens as symbiotic organisms.
1. General characteristics of mushrooms and their significance in nature
By your organization mushrooms differ from both plants and animals. Currently, they are recognized as an independent kingdom of eukaryotic organisms.
Fungi are heterotrophic (osmotrophic) eukaryotic organisms, usually of a mycelial structure.
Origin. Mushrooms(Fungi) is an ancient group of organisms. In the fossil state, remains of fungi are first observed from the Silurian and Devonian of the Paleozoic era (~450 million years ago), and all known fossil fungi are very similar to modern ones. However, it is assumed that they occurred much earlier (~1 billion years ago).
Some modern mycologists believe that the bulk of fungi originated from colorless flagellated protozoans, even before the division of living organisms into plants and animals.
Currently, from 70 to 100 thousand species of fungi along with lichens (~13.5 thousand species) have been described (it is assumed that there are 1.5 - 1.6 million of them).
~2.2 thousand species of mushrooms have been discovered in the Republic of Belarus.
Science deals with the study of mushrooms - mycology(from Greek mykes- mushroom).
Taxonomy. Fungi, apparently, are a collective group that unites taxa of different origins. Main divisions of mushrooms:
|
Divisions (number of species) |
Mycelium |
Reproduction |
|
Zygomycotes (~400) |
Mostly unseptate |
Sporangiospores, less often conidia; zygogamy (sporangium) |
|
Ascomycots(~ 30000) |
Septate or single budding cells; there are fruiting bodies |
Conidia; gametangiogamy (with the formation of asci) |
|
Basidiomycota(>30000) |
Septated; there are fruiting bodies |
Conidia; somatogamy (with the formation of basidium) |
|
Deuteromycota(>30000) |
Septated |
Conidia; sexual intercourse is not observed |
Cell structure. The fungal cell, as a rule, has a well-defined hard cell shell 80 - 90% consisting of nitrogen-containing polysaccharides (mainly chitin, as in insects) associated with proteins and lipids. It also includes pigments(carotenoids) and other substances.
In the protoplast, surrounded plasmalemma, clearly visible ribosomes, mitochondria, endoplasmic reticulum, lysosomes, vacuoles. Golgi apparatus usually poorly developed. Between the cell membrane and the plasmalemma are located losomesomes – membrane structures that look like numerous vesicles (their function has not yet been fully established). Fungal cells can contain from 1 to 20 – 30 cores, which have a typical structure, but are very small (1 - 3 microns). Fungal cells also contain numerous inclusions: granules glycogen(the most important reserve substance of mushrooms, as well as animals), drops lipids, volutin, organic acids.
Unlike plants, fungal cells do not plastid And photosynthetic pigments are never formed starch.
Body structure. The size of mushrooms varies widely: from microscopic to half a meter or more.
The basis of the vegetative body of most mushrooms is mycelium, or mycelium, which is a system of microscopic thin threads - gif with apical (apical) growth and lateral branching (Fig. 4.1.).
The part of the fungal mycelium that penetrates the substrate is called substrate mycelium, and the part located on the surface is by air mycelium.
Substrate mycelium serves to attach to the substrate, absorb and transport water and minerals dissolved in it. Reproductive organs are usually formed on aerial mycelium.
Some fungi (oo- and chytridiomycotes (mushroom-like protists), zygomycotes) are characterized by "non-cellular" mycelial hyphae, devoid of partitions and representing, as it were, one giant cell, often highly branched with a large number of nuclei, i.e. they do not have partitions (septa) inside – unseptate (unseptated) hyphae. Such mushrooms are conventionally classified as inferior.
In most fungi (asco-, basidio- and deuteromycetes) mycelium divided by partitions (septa) into separate parts - compartments ( compartments), externally similar to cells containing one or more haploid nuclei. In the center of the septum there remains a pore through which the cytoplasm passes. Such hyphae are called articulated or septate. Fungi whose mycelium consists of such hyphae are conventionally classified as highest.
In a number of mushrooms (asco- and basidiomycota) the so-called fruiting body– a structure consisting of plectenchyma – false tissue formed as a result of the interweaving and fusion of mycelium threads, each of which is divided in only one transverse direction.
IN fruiting bodies the reproductive organs are located - aski And basidia.
TO
M
Rice. 4.2.
Modifications of mycelium. 1 – pseudomycelium of yeast; 2 – rhizomorphs of honey agaric on a stump; 3 – fruiting bodies of honey agaric on rhizomorphs; 4 – ergot sclerotia.
Rhizomorphs- These are well-developed and differentiated mycelial strands. Their outer hyphae have thick, dark-colored walls and perform a protective function, while the inner (thin-walled, light-colored) have a conductive function. They can reach several meters in length (for example, brownie mushroom, honey agaric). So, for example, using rhizomorphs honey fungus easily moves from tree to tree and causes infection. In addition, it is capable of forming fruiting bodies on trees at a height of 2–3 m or more above the ground.
Sclerotia– dense interlacing of mycelium hyphae. Serve to withstand unfavorable conditions in winter, during drought, etc. Dimensions from 1 mm to 20 – 30 cm in diameter, weight up to 20 kg. Rich in reserve nutrients (glycogen, other fats). From them mycelium or sporulation organs develop.
Reproduction. Characteristic of mushrooms asexual And sexual reproduction (Fig. 4.3.).
Asexual reproduction can be vegetative or spore-based.
Vegetative reproduction is carried out by pieces (scraps) of mycelium or as a result of the disintegration of hyphae into individual cells, each of which gives rise to a new organism. Yeast and some others are able to reproduce budding.
Cells with thin membranes are called arthrospores (oidia), and with thick dark-colored shells - chlamydospores(designed to withstand adverse conditions).
|
Mushroom propagation |
||||
|
asexual |
sexual |
|||
|
vegetative |
spore |
gametogamy |
somatogamy |
gametangiogamy |
|
mycelium pieces dept. cells budding |
sporangiospores zoospores |
isogamy heterogamy |
are formed |
are formed sporangia |
|
Rice. 4.3. Mushroom propagation diagram. |
||||
Asexual spore reproduction is carried out sporangiospores, conidiospores or conidia, zoospores(Fig. 4.4.) .
WITH
Rice. 4.4.
Sporulation in fungi. Asexual: 1 – zoospores; 2 – sporangiospores; 3 – conidiospores. Sexual: 4 – formation of ascospores; 5 – formation of basidiospores.
Sexual reproduction was observed in all groups of fungi, except deuteromycota(that's why they are called imperfect fungi).
The forms of the sexual process in fungi can be divided into three main groups: gametogamy, gametangiogamy And somatogamy(Fig. 4.5.).
Gametogamy – merger gametes(sex cells with an n set of chromosomes) formed in the organs of sexual reproduction – gametangia. Often observed in lower fungi. Gametogamy May be isogamous(fusion of morphologically indistinguishable motile gametes), heterogamous(fusion of motile gametes differing in size) and oogamous(fusion of large immobile eggs formed in oogonia(female genital organs) with small motile spermatozoa formed in antheridia(male genital organs)).
WITH
Rice. 4.5.
Forms of the sexual process in mushrooms. 
Gametangiogamy – fusion of the contents of two specialized reproductive structures ( gametangium) not differentiated into gametes. Characteristic for zygomycot (zygogamy; at the same time they form sporangium) and ascomycot(ascogamy; is formed ask- a bag in which 8 haploid cells are formed ascospore).
A characteristic feature of the sexual process in lower fungi is that the zygote, after an obligatory period of rest, divides reductionally (meiosis) and germinates to form organs of asexual reproduction (sporangia), in which spores are formed that germinate into haploid hyphae. Consequently, in most primitive fungi, the entire life is spent in the haploid stage (the diploid stage - the zygote - is short-lived).
In higher fungi, during the sexual process (gametangiogamy, somatogamy), the cytoplasms first merge - plasmogamy, and male and female nuclei are located near each other, forming dikaryons. U ascomycot The dikaryonic stage is represented by ascogenic hyphae (hyphae on which organs of sexual sporulation are formed - aski) and short-term. U basidiomycot it takes up most of the life cycle. Subsequently, nuclear fusion occurs - karyogamy. The resulting diploid nucleus (zygote), without a resting period, undergoes reduction division to form haploid spores.
Thus, in the development cycle of higher fungi, there is an alternation of haploid (haploid hyphae predominate in ascomycot), dikaryontic (dicaryonic hyphae predominate in basidiomycot) and diploid (short-term, in the form of a zygote) phases.
Saprotrophic fungi extract nutrients from dead, decaying organic material (such as mold - Penicillum, Mucor).
Enzymes are secreted (released) into organic matter, so that digestion occurs outside the fungus. The resulting soluble products are absorbed by the fungus.
Symbiotic fungi enter into a close, mutually beneficial relationship with other organisms (with the roots of higher plants or with algae).
Mycorrhiza – mutualistic association of the fungus with plant roots; lichen– association of fungus and algae.
Thus,mushrooms is a separate group of heterotrophic organisms that combine the characteristics of plants and animals.
WITH plants Fungi are united by the presence of a well-defined cell wall, immobility in a vegetative state, reproduction by spores, unlimited growth, and absorption of food by osmosis.
WITH animals fungi are united by heterotrophy, the presence of chitin in the cell wall, the absence of plastids and photosynthetic pigments, the accumulation of glycogen as a reserve substance, the formation and release of a waste product - urea.
Environmental groups. Among ground mushrooms (~70,000) are distinguished:
– coprophiles – live on manure heaps, places where animal droppings accumulate, etc. ( dung beetles, pilobus and etc.);
– keratinophils – live on the horns, hooves and hair of animals (representatives of the family Gymnoaskovic);
–
– predatory – living as saprotrophs, but can feed nematodes, rotifers, protozoa, small insects;
Most carnivorous mushrooms are hyphomycetes(one of the department orders deuteromycota). However, this also includes some representatives of other divisions (zygomycots, oomycots, chytridiomycots and basidiomycots).
The mycelium of predatory fungi develops in the soil, on plant debris and other substrates, but they receive part of their nutrition from the tissues of the prey they have caught. The prey is captured using various trapping devices Fig. 4.6.):
–
Rice. 4.6.Types of traps for predatory mushrooms. 1
– adhesive three-dimensional networks; 2, 6
– adhesive heads; 3
– shrinking rings; 4
– sticky outgrowths of hyphae; 5
– non-compressible rings.
– mechanical traps in the form non-adhesive non-compressible rings (Dactylaria snow-white);
– shrinking rings(representatives of genera dactylaria, monacrosporium, arthrobotrys).
– soil – live in the soil, participate in the decomposition of organic matter, in the formation of humus (for example, Mucoraceae);
– bedding– mushrooms that destroy forest litter (fallen leaves, pine needles).
Meaning.
1. In nature they participate in the biological cycle of substances - decomposers.
Saprotrophic fungi decompose organic matter of dead animals and plants into mineral substances, making them available to autotrophs; participate in the formation of humus; together with bacteria, they are the main suppliers of CO 2.
2. Man uses it in industry.
Yeast(single-celled fungi) are used in the baking, brewing, wine, and alcohol industries - they ferment sugar with the release of CO 2 and alcohol.
Biologically active substances, organic acids of mushrooms are used in the microbiological industry.
Enzymes are obtained:
– pectinases– used to clarify fruit juices;
– cellulases– for processing raw materials, roughage, destruction of paper waste residues;
– proteases– for protein hydrolysis;
– amylase– for hydrolysis of starch, etc.
Used to obtain vitamins (group B), plant growth regulators ( gibberellin; it is obtained using mushrooms from the genus Fusarium), protein, antibiotics (penicillin, fumagillin, griseofulvin), citric acid (using Aspergillus niger), as medicinal raw materials ( ergot) to obtain medications, etc.
3. Widely eaten.
In terms of nutritional value, mushrooms are approximately at the same level as vegetables. Adding mushrooms to food improves the taste of dishes.
The dry matter of the fruiting body of cap mushrooms contains on average 20 - 40% protein, 17 - 60% carbohydrates, 1.5 - 10% lipids and 6 - 25% mineral elements, organic acids, vitamins (A, B 1, B 2, PP), resins and essential oils that give mushrooms their unique smell and taste.
Only grinding dried mushrooms into flour releases the proteins!!!
4. Preparations based on certain fungi are used as a biological method of controlling weeds and pests.
Boverin– a preparation for the destruction of harmful insects; trichodermin– to combat soil pathogens of plants; verticillin– to combat whiteflies in greenhouses.
5. Great and negative value of mushrooms:
Olpidium brassicae(chytridiomycetes) – causes “black leg” of cabbage seedlings.
Synchytrium endobioticum(chytridiomycetes) – causes potato cancer.
Phytophthora infestans(oomycetes) – causes rot of potatoes (tubers and tops).
– develop saprotrophically on food products, industrial materials and products (wood, sleepers, wooden bridges and buildings, rubber, books, newspapers, fuel), cause their damage and cause great economic damage (accelerate the corrosion of metals, damage optics, etc. );
The harmful activity of fungi in book depositories and museums is very dangerous (there are up to 200 species of such fungi). They are capable of destroying from 10 to 60% of paper fibers within 3 months.
– phytopathogenic fungi cause great harm to agriculture and forestry;
– pathogens of human diseases (mycoses, candidiasis, dermatomycosis) and domestic animals (they cause especially great damage to beekeeping);
Mycotoxicoses – diseases of humans and animals associated with poisoning of food and feed with toxins (poisons) of fungi.
The phenomenon of “drunk bread” has long been known - infection of grain with fungi of the genus fusarium. Flaxseed oil obtained using mushrooms of the same genus is “drunken oil.”
– some waste products of fungi are poisons and affect the human body at very low concentrations (0.000001 percent).
In fact, all mushrooms are poisonous to a certain extent. However, their toxicity often depends on the formation of intermediate decomposition products formed when eating stale mushrooms. Therefore, before eating, it is necessary to boil them in one or more waters - in this case, the poisonous principles are dissolved and removed along with the water.
Among yeast there are no species that form substances toxic to humans (they change the taste, color, appearance of food products, but do not release toxins)!!!
6. Some mushrooms are used in religious events.
For example, cult of sacred Mexican mushrooms. Mushrooms of the genus psilocybe eaten raw by a person causes hallucinations, accompanied by gaiety, excitement, and fantastic visions. Substance psilocybin now synthesized and used in psychotherapy.
Hallucinogens are also found in other mushrooms ( red fly agaric, horns-sclerotia ergot purple and etc.).
Living organisms consisting of algae and fungus
Artistic features of A's works
Analysis of the educational program of the elementary school of the Taurida Gymnasium