Among the existing five kingdoms of wildlife, mushrooms are in a special position. They have unusual signs that characterize them as unique, peculiar, but very important and useful for nature and human organisms. We will try to consider structural features and vital functions of fungi in the article in order to understand what makes them unique.
Characteristic
The kingdom of mushrooms includes more than 100 species. Moreover, among them you can find the most diverse forms of nutrition:
- saprophytes;
- parasites;
- symbionts.
Unicellular lower and multicellular higher structures of these organisms are widespread 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 large class in the life of people is played by a special class of basidiomycetes, or hat mushrooms. Indeed, the vast majority of them are edible species used by humans as a valuable nutritious product for many 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 kingdom of plants. In general, the structure of the fungus is quite simple: if the body 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 as follows:
- mycelium (mycelium) - underground part;
- GIFs intertwined in the aerial part in the form of a fruiting body;
- leg;
- a hat.
There are also those that are a cross between the lower and higher mushrooms in structure and lifestyle.
Classification
Modern systematics has 7 main classes, combined in three departments. The structure and vital functions of the fungi of each of them have their own characteristics and properties. Let's consider them in more detail.
Ficomycetes
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:
- Chitridiomycetes are inhabitants of fresh and salt waters. They parasitize on algae and can also eat 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 serve for attachment to the substrate, as well as for movement in the water column. Representatives: chytrid, monoblepharic, spizellomycete, rhizophidia organisms.
- Oomycetes are very dangerous parasites of higher plants, as well as water molds. The structure of the fungus is represented by multinuclear non-cellular mycelium, reproduction occurs due to motile 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 parts of plants, but also diseases of marine inhabitants, sometimes they destroy whole crops.
- Zygomycetes are inhabitants of soil and air, unicellular complicated forms. More will be considered on the example of the most prominent representative - mukor.
- Hypochitridiomycetes - intermediate forms, in structure and lifestyle are between oomycetes and chitridiomycetes.
Eumitsets
This category includes more developed perfect forms of three classes:
- Ascomycetes are valuable mushrooms in medical practice. The structure of the body implies the presence of mycelium, multicellular, septic and quite highly developed. Also, these mushrooms received their name (marsupials) for peculiar sacs, indentations or asks in which sexual spores ripen - ascospores. Hyphae are present in the structure, at the ends of which conidia are formed that take part in reproduction. Representatives: yeast, penicillus, aspergillus and others. They are appreciated by the fact that many species are capable of producing antibiotics.
- Deuteromycetes, or imperfect mushrooms. Most representatives are of the genus Candida, which causes diseases of the same name in humans and animals. Affect tissues and organs. They do not have a real mycelium, only a pseudostructure. Propagate, forming chlamydospores.
- Basidiomycetes, or cap forms. The structure of the fungus of this class will be discussed in more detail below.
Similarity with other organisms
The structure of plant cells, animals, fungi has a number of common features. That is why it has not yet been finally decided whether it is worth isolating the organisms in question into a separate kingdom or still combining them with plants or animals.
The thing is that there are a number of signs by which mushrooms are similar to representatives of the flora:
- Ability for unlimited growth throughout life.
- Mushroom cells have dense cell walls, like plants.
- Reproduction methods are similar: using spores and parts of the mycelium, that is, vegetatively.
- Inability to move in space.
- Absorption of nutrients by absorption.
However, in contrast to those who, according to these characteristics, classify fungi as lower plants, a number of facts should be cited indicating that these organisms are no less similar to animals:
- The cell wall contains a polysaccharide - chitin. Although the same substance forms the outer skeleton of crustaceans and some insects.
- Traces of uric acid were found in the waste products of the fungi.
- The reserve nutrient in these organisms is glycogen, as in humans.
- By the method of absorption of nutrients, these are heterotrophic organisms, since chlorophyll is not found in their cells.
Thus, it is obvious that all the same mushrooms are a separate kingdom, with its own specific features.
The structure of the fungus cell
The above similarities and differences with other living organisms are also reflected in the structure at a smaller, cellular level. So, a fungal 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 are more similarities with animals. Components: chitin (in some types of cellulose), glycan, polysaccharides, monosaccharides, heteropolymers. Over time, this structure can become stiff, accumulating salts of calcium oxolate, then outwardly the mycelium and the 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 liquid-mosaic formation, consisting of a bilipid layer with piercing and built-in proteins for various purposes. The functions of the membrane are the same as those of higher organisms - providing active and passive transport to and from the cell.
- Under the plasmalemma is a protoplast including a vacuole, a nucleus with nucleoli, a cytoplasm with hyaloplasm and organoids.
- Vacuoles with cell juice are an absolute resemblance to a plant cell. Throughout life, the number and size of these structures change. In an adult cell, there is one large parietal vacuole filled with a solution containing polyphosphates, carbohydrates, and nutritious organic molecules.
- The nucleus and nucleolus are most often present 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 fungal cell structure is interesting in that the nuclei double during mitosis, but do not immediately divide into two cells by transverse constriction. Therefore, for some time in the structure of the fungus, binuclear and trinuclear formations can be detected.
- The 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, dictiosomes. Speaking about the structural features of the fungus, it is worth mentioning the lomasomas. These are translucent bodies, the role of which has not yet been clarified.
Thus, the fungal cell has common features with both animal and plant. However, it also includes highly specific components.
Unicellular Mushrooms: Mucor
Representatives of this kind were probably seen by everyone. White fluffy mold that appears on food, vegetables and fruits, stale plant and animal tissues - these are mushrooms of the genus Mucor of the class Zygomycetes.
Externally, when viewed with the naked eye, they look like a fluffy rug. Over time, it darkens and becomes gray, gray. This occurs when spores mature in sporangia, when the mold has matured and is preparing for reproduction.
The fungus mold mucor structure is quite simple. First, all of it is one large cell structure, and it is one-celled one. Just the mycelium is multi-core, but without partitions, it branches strongly. It seems that there is a multicellular organism, but this is not so.
The hyphae of this fungus grow vertically upward and form sporangia at the end, most often spherical in which spores mature. Another name for mucors is capitate molds. It was given to them precisely because of such a structure and location of spore-bearing structures.
After maturation, the smallest cells spill out of a bursting sporangium and begin independent germination in a new form. Also the sexual process is available - it is also produced by the mold fungus mucor. The structure of the desired organs is a translucent filament of one or different orders, which combine to form a zygote. She subsequently gives a new hypha with sporangia, which is an independent organism.
This structure of the fungus does not make it harmful to humans. Of course, some forms can cause mucoromycosis of animals and humans, however, the positive value of representatives of this class is also great. So, for example, they are producers of a valuable drug - ramicin. Also, the possession of high enzymatic activity makes it possible to use them as yeast starter cultures in the production of certain types of alcohols, cheeses, and so on.
Multicellular Mushrooms: Basidiomycetes
This class has over 31,500 thousand different representatives. Among them there are both parasites and symbionts. The most interesting group are edible mushrooms, called cap mushrooms. Such representatives of the kingdom enter into mutually beneficial cooperation with the roots of the trees, forming the so-called mycorrhiza - a dense interweaving of hyphae of the fungus and the roots of the plant. Of course, not all representatives do this, but those that are edible fall into this category.
The structural features of the cap fungus are that it is multicellular, perfect, having certain parts of the body, which are its hallmarks. So, each such representative has an aboveground and underground part.
Appearance
The external structure of the fungus consists of the formation of a hat of various shapes, fruit stalks of unequal massiveness and length and the underground part - mycorrhiza, consisting of mycelium and hyphae in combination with tree roots.
Probably everyone who had walked through the woods at least once could see the multi-colored tender hats of mushrooms peering from the interweaving of foliage and forest litter. White, red, orange, yellow, brown, small and large, aromatic and fleshy, tasty and very nutritious - these organisms have firmly entered the life of people and make up a certain part of the diet of most of them.
Outside, you can see only the fruiting body itself, but the structural features of the cap mushroom can be understood only with more subtle analysis, incision and microscopy.
Body structure
A stump, a hat, a mycelium (mycelium) are the main structural parts of such representatives. The structure of the fruit body of the fungus is different. Rather, they differ in size and color, as well as some features of the cap. Inside, it’s like a leg, that a hat is a dense interweaving of mushroom hyphae in different combinations.
So, the leg contains several hundred thousand of the thinnest strings, 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 filiform outgrowths stretching from the ground and growing into a stump.
In the upper part, immediately under the hat, the fungus leg has a coverlet or its remains during reduction in some species. This feature allows you to distinguish between poisonous species and edible, as well as systematize and classify them.
The upper part of the leg is crowned with a hat. It is a feature. The structure of the cap mushroom makes it possible to distinguish edible forms from poisonous ones. So, a hat is of two types:
- Lamellar - represents on the inside small plates in which spores are located and mature. Examples of organisms: traps, russula, mushrooms.
- Tubular - formed by tubules visible to the naked eye. On these structures, spores for reproduction also develop. Examples: butterfish, porcini mushrooms, boletus, chanterelles.
This structure of the cap and sporangia is called a hymenophore. Outside, the hat is covered with a thin and delicate layer of peel, which also represents hyphae from the inside. It just has a different color, according to which you can judge the type of mushroom.
The structure of the mycelium
Mushroom picker is a very important part that mushrooms form. The body structure 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 the trees and conducts mineral substances and water along the mycelial outgrowths to the tree. Instead, the fungus receives organic matter from the plant, which makes it a heterotroph by the method of nutrition.
The structure of the cap mushroom implies spore reproduction. However, the 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 propagation.
Disputes
These smallest structures, which in large mass are powder of different colors, are the main source of the continuation of the genus of fungi. Having got enough sleep from a sporangia on a hat, they are caught by a wind and are carried on long distances. Many animals that eat mushrooms cannot digest their spores, therefore they are excreted into the environment. Here, future hat species get a chance at life in case of rooting and spore germination. The shape, size and color of these cells identify most types of fungi, correlating them with one class or another.
In conclusion, I want to say that representatives of the mushroom kingdom are very important organisms that affect entire ecosystems that are part of the food chain, cause irreparable harm to living creatures, but also give us an antidote to many diseases.