Among the existing five kingdoms of wildlife, mushrooms are in a special position. They have unusual features that characterize them as unique, peculiar, but very important and useful organisms for nature and humans. We will try to consider the features of the structure and life of mushrooms in the article in order to understand what is their uniqueness.
Characteristic
More than 100 species belong to the mushroom kingdom. Moreover, among them you can find a wide variety of forms according to the method of nutrition:
- saprophytes;
- parasites;
- symbionts.
Unicellular lower and multicellular higher structures of these organisms are widely distributed in nature and occupy a large place in the system of the organic world. Mushrooms and people do not ignore, being organisms that contact with them not only externally, but also at the cellular level, from the inside (parasitic fungi, candida).
A special class of basidiomycetes, or cap mushrooms, plays a big role in people's lives. After all, the vast majority of them are edible species used by humans as a valuable nutritious product throughoutmany millennia.
From a biological point of view, it is the structure of the fungus that deserves special attention, which has a number of related features with both plant and animal organisms. Although outwardly it is closer to the plant kingdom. In general terms, the structure of the fungus is quite simple: if the organism is unicellular, then it consists of non-cellular mycelium and hyphae with sporangia and spores. If we are talking about the highest representative, then the structural parts are:
- mycelium (mycelium) - underground part;
- hyphae intertwining in the aerial part in the form of a fruiting body;
- leg;
- hat.
There are also those that are a cross between lower and higher mushrooms in structure and lifestyle.
Classification
Modern systematics has 7 main classes, united in three departments. The structure and activity of mushrooms of each of them have their own characteristics and properties. Let's take a closer look at them.
Phicomycetes
The vast majority of these organisms are parasitic and saprophytic forms that use plants, animals, humans, food, household items for life. These include three classes:
- Chytridiomycetes - inhabitants of fresh and s alt waters. They parasitize on algae, they can also feed saprotrophically, decomposing the remains of plant and animal tissues. They are unicellular structures. The structural features of this type of fungus are that the cells have multiple outgrowths - rhizomycelia, which servefor attachment to the substrate, as well as for movement in the water column. Representatives: chytrid, monoblepharis, spizellomycete, rhizophid organisms.
- Oomycetes are very dangerous parasites of higher plants, as well as water mold forms. The structure of the fungus is represented by a multinuclear non-cellular mycelium, reproduction occurs due to mobile zoospores. The presence of cellulose in the cell wall indicates closeness with plants to a greater extent than other fungi. Representatives: phytophthora, peronospores and others. They cause not only rotting of parts of plants, but also diseases of marine life, sometimes destroying entire crops.
- Zygomycetes - inhabitants of soil and air, single-celled complicated forms. More will be considered on the example of the brightest representative - Mukora.
- Hyphochytridiomycetes are intermediate forms, in structure and lifestyle they are between oomycetes and chytridiomycetes.
Eumycetes
This category includes more developed perfect forms from three classes:
- Ascomycetes are valuable mushrooms in medical practice. The structure of the body implies the presence of mycelium, multicellular, septate and quite highly developed. Also, these mushrooms got their name (marsupials) for peculiar sacs, recesses or asci, in which sexual spores - ascospores - ripen. The structure contains hyphae, at the ends of which conidia are formed, which take part in reproduction. Representatives: yeast, penicillium, aspergillus and others. Valued for the fact that many speciescapable of producing antibiotics.
- Deuteromycetes, or imperfect fungi. Most of the representatives are of the genus Candida, which causes diseases of the same name in humans and animals. Damage to tissues and organs. They do not have real mycelium, only a pseudostructure. They reproduce by forming chlamydospores.
- Basidiomycetes, or cap forms. The structure of a mushroom of this class will be discussed in more detail below.
Similarities to other organisms
The structure of plant, animal, fungal cells has a number of common features. That is why it has not yet been finally decided whether to separate the organisms in question into a separate kingdom or still combine them with plants or animals.
The thing is that there are a number of signs in which mushrooms are similar to representatives of the flora:
- The capacity for unlimited growth throughout life.
- Fungi cells have dense cell walls, just like plants.
- The methods of reproduction are similar: with the help of spores and parts of the mycelium, that is, vegetatively.
- Inability to move in space.
- Absorption of nutrients by absorption method.
However, in contrast to those who, on these grounds, classify mushrooms as lower plants, a number of facts should be cited that testify to the no less similarity of these organisms with animals:
- The cell wall contains a polysaccharide - chitin. Although the same substance forms the outer skeleton of crustaceans and some insects.
- Traces ofuric acid.
- The reserve nutrient in these organisms is glycogen, just like in humans.
- By the way they absorb nutrients, these are heterotrophic organisms, since chlorophyll is not found in their cells.
Thus, it is obvious that mushrooms are still a separate kingdom, with their own specific features.
Structure of a fungus cell
The above similarities and differences with other living organisms are also reflected in the structure at a smaller, cellular level. Thus, a mushroom cell has a number of the following features:
- Outside, it is separated by a cell wall, like in plants. However, the substances that make up this structure show that there is more similarity with animals. Components: chitin (in some species, cellulose), glycan, polysaccharides, monosaccharides, heteropolymers. Over time, this structure can ossify, accumulating calcium oxalate s alts, then outwardly the mycelium and body will be solid, resembling a plant stem. In some cases, the cell wall is covered with mucus from the outside.
- Next is the standard structure of the plasma membrane - a fluid-mosaic formation, consisting of a bilipid layer with penetrating and embedded proteins for various purposes. The functions of the membrane are the same as in higher organisms - providing active and passive transport into and out of the cell.
- Under the plasmalemma is a protoplast, including a vacuole, a nucleus with nucleoli, a cytoplasm with hyaloplasm andorganelles.
- Vacuoles with cell sap are an absolute resemblance to a plant cell. During life, the number and size of these structures changes. In an adult cell, there is one large parietal vacuole filled with a solution containing polyphosphates, carbohydrates, nutritious organic molecules.
- The nucleus and nucleolus are most often found in single copies. They are located closer to the center of the cell and serve to store and transmit hereditary information in the form of nucleic acid molecules (DNA, RNA). The structure of the fungal cell is interesting in that the nuclei double during division by mitosis, but do not immediately divide into two cells by a transverse constriction. Therefore, for some time, two-core and three-core formations can be found in the structure of the fungus.
- Cytoplasm is a hyaloplasm and cell organelles. Carbohydrates are dissolved in the liquid medium, glycogen inclusions are located, microfilaments grow, and the cell cytoskeleton is formed. Organelles include mitochondria, ribosomes, and dictyosomes. Speaking about the structural features of the fungus, it is worth mentioning the lomosomes. These are translucent bodies, the role of which has not yet been clarified.
Thus, the cell of the fungus has common features with both the animal and the plant. However, it also includes highly specific components.
Single-celled fungi: mukor
Probably everyone has seen representatives of this kind. White fluffy mold that appears on food, vegetables and fruits, stale plant and animal tissues - these are fungi of the genus Mucor classZygomycetes.
Outwardly, when viewed with the naked eye, they look like a fluffy rug. Over time, it darkens and becomes bluish, gray. This happens when the spores in the sporangia mature, when the mold has become an adult and is preparing to reproduce.
The mold fungus mukor has a fairly simple structure. Firstly, all of it is one large cellular structure, and it is unicellular. It's just that the mycelium is multi-core, but without partitions, it branches strongly. It gives the impression of a multicellular organism, but it is not.
The hyphae of this fungus grow vertically upwards and form a sporangium at the end, more often a spherical shape, in which spores ripen. Another name for mukors is capitate molds. It was given to them precisely because of this structure and the location of spore-bearing structures.
After maturation, the smallest cells spill out of the bursting sporangium and begin their own germination into a new form. The sexual process is also available - it is also produced by the mold fungus mukor. The structure of the necessary organs is a translucent thread of one or different orders, which are connected to form a zygote. She subsequently gives a new hypha with sporangium, which is an independent organism.
This structure of the fungus does not in the least make it harmful to humans. Of course, some forms can cause mucormycosis in animals and humans, but the positive value of representatives of this class is also great. So, for example, they are producers of a valuable drug - ramycin. Also, having a high enzymaticactivity makes it possible to use them as yeast starters in the production of certain types of alcohols, cheeses, and so on.
Multicellular Fungi: Basidiomycetes
This class has over 31,500 different representatives. They include both parasites and symbionts. The most interesting group is edible mushrooms, called hat mushrooms. Such representatives of the kingdom enter into mutually beneficial cooperation with the roots of trees, forming the so-called mycorrhiza - a dense interlacing of fungal hyphae and plant roots. Of course, not all representatives do this, but those that are edible fall into this category.
The structural features of the hat fungus are that it is multicellular, perfect, having certain parts of the body that are its hallmarks. So, each such representative has an aboveground and an underground part.
Appearance
The external structure of the fungus consists of the formation of a hat of various shapes, a fruit stalk of unequal massiveness and length, and an underground part - mycorrhiza, consisting of mycelium and hyphae, together with tree roots.
Probably, everyone who has ever walked through the forest could see multi-colored delicate mushroom caps peeking out from the interweaving of foliage and forest floor. White, red, orange, yellow, brown, small and large, fragrant and fleshy, tasty and very nutritious - these organisms have firmly entered the life of people and form a certain part of the diet of most ofthem.
On the outside you can see only the fruiting body itself, but the structural features of the cap fungus can only be understood with a more subtle analysis, incision and microscopy.
Body structure
Stump, hat, mycelium (mycelium) - these are the main structural parts of such representatives. The structure of the fruiting body of the fungus is different. Rather, their sizes and colors differ, as well as some features of the hat. Inside, both the leg and the hat are a dense interweaving of mushroom hyphae in various combinations.
So, the leg contains several hundred thousand of the thinnest threads, closely woven into a common structure. In the lower part, it smoothly passes into the mycelium, hidden underground. If you cut the mushroom very carefully, you can see these thin white thread-like outgrowths stretching from the ground and growing into the stump.
In the upper part, just under the hat, the stem of the mushroom has a veil or its remains during reduction in some species. This feature allows you to distinguish between poisonous and edible species, as well as systematize and classify them.
The upper part of the leg is crowned with a hat. Therein lies the feature. The structure of the cap mushroom makes it possible to distinguish edible forms from poisonous ones. So, there are two types of hat:
- Lamellar - is a small plate on the inside, in which spores are located and ripen. Examples of organisms: volushki, russula, mushrooms.
- Tubular - formed by tubes visible to the naked eye. On these structuresspores also develop to reproduce. Examples: oil mushrooms, porcini mushrooms, aspen mushrooms, chanterelles.
This structure of the cap and sporangia is called the hymenophore. Outside, the hat is covered with a thin and delicate layer of skin, which is also hyphae from the inside. It just has a different color, by which you can judge the type of mushroom.
Mycelium structure
Mycelium is a very important part that mushrooms form. The structure of the body is hyphae, as we have already mentioned. But the mycelium is elongated multinucleated cells, devoid of any pigments.
It is the mycelium that enters into symbiosis with the roots of trees and conducts minerals and water through mycelial outgrowths to the tree. In return, the fungus receives organic substances from the plant, which makes it a heterotroph in terms of nutrition.
The structure of the hat fungus involves reproduction by spores. However, mycelium, when exposed to normal conditions (good humidity, temperature), can itself give rise to new fruiting bodies. Therefore, the mycelium is boldly called the organ of vegetative reproduction.
Disputes
These tiny structures, which in a large mass are powder of different colors, are the main source of continuation of the genus of mushrooms. Spilling out of the sporangia on the hat, they are picked up by the wind and carried over long distances. Many animals that eat mushrooms cannot digest their spores, so they are excreted along with excrement into the environment. Here, future hat species get a chance at life in caserooting and germination of spores. By the shape, size and color of these cells, most types of fungi are identified, correlating them with one class or another.
In conclusion, I would like to say that representatives of the kingdom of fungi are very important organisms that affect entire ecosystems that are part of the food chain, causing irreparable harm to living beings, but also giving us an antidote for many diseases.
