What is mycorrhiza in biology?

In nature, there are many very interesting adaptations that help living beings. They are both in animals, and in plants, fungi, bacteria and others. It's amazing how creative and unique the natural environment is! It is only necessary to recall the diversity of species of different living beings, as this uniqueness becomes apparent.

One of such wonders of wildlife is an interesting symbiosis between representatives of different kingdoms - mushroom root - a phenomenon that helps to survive in the conditions of fierce competition for nutrients. What is mushroom root, or mycorrhiza? We will open this concept in the course of the article.

Kingdom Mushrooms: a general characteristic

To begin with, you should generally remember who are the mushrooms and what are they? In biology there is a special section, a separate discipline, the purpose of which is to study these organisms. It is called mycology. According to the latest data, today there are over one hundred thousand different types of mushrooms, both unicellular and multicellular.

The figure is considerable, especially since this realm of living nature is intensively developing and numerically progressing. Parasitic and saprophytic forms reach a special variety.

Mushrooms occupy a special position in the system of the organic world due to the presence of a number of characteristic features in the structure and way of life. Therefore, they are all united into a separate kingdom.

Distinctive features of mushrooms

What are these features? It's all about the similarity of representatives with both plants and animals. For a long time this put scientists at a dead end. After all, creatures turn out to be unique and incomprehensible, since they combine the signs of completely opposite organisms.

Thus, the common features that unite mushrooms with plants include:

• Phytohormones and vitamins;
• Unlimited apical growth throughout life;
• Attached lifestyle (lack of ability to move);
• The presence of a strong cell wall;
• Nutrition by absorption of substances.

However, there are signs that are related to the organisms under consideration and to animals:

• Heterotrophic method of nutrition (ie consumption of ready-made organic compounds, impossibility of their independent synthesis inside the body);
• The presence in the cell wall of a complex carbohydrate chitin, from which the shells of crustaceans, insects and other animal creatures are composed.

The combination of such features allows us to consider fungi as unique creatures worthy of uniting into a separate realm of living nature.

General outline of the structure of the fungus

The main feature in the structure of the organisms under consideration are the hyphae, which form the mycelium and in the higher basidiomycetes the fruiting bodies. They are thin threads, white or translucent, which consist of cells separated by partitions. Hyphae strongly branch, intertwine, fuse and form a large underground network - mycelium. Outside, they also form a fruiting body in higher mushrooms - a leg and a hat.

All other representatives of hyphae serve only to form a mycelium. The latter is needed for absorption of nutrients, vegetative reproduction, spore formation and sexual process.

It is the mycelium of the fungus that takes part in the formation of the mushroom root. Therefore, what is mycorrhiza, it becomes clear if you know what is represented by the body itself. This is a combination of the underground part of fungi with the roots of higher plants. A kind of mutually beneficial cooperation, helping to survive both creatures.

Thus, the hyphae of the fungus form a mycelium, it is intertwined with roots and mycorrhizas or mushrooms are formed. This is the main feature in the structure and way of life of a significant part of the representatives of the kingdom in question.

What is mycorrhiza in biology?

If we consider this unique phenomenon from a scientific point of view, we can only once again be surprised at the skill of living beings in fitness for survival. To give a more precise concept of what mycorrhiza is in biology, one can use a definition. This symbiotic relationship between fungi and plants, which are carried out due to the close interlacing of mycelium and roots in the underground environment.

The term "mycorrhiza" was proposed as far back as 1885 by the scientist Frank. The existence of this phenomenon became known four years earlier. What is mycorrhiza of the fungus, explained in 1881, the Russian scientist F.I. Kamensky. It was he who first studied and described mushroom.

Almost all higher plants enter into similar relationships with mushrooms, not only with those that we are accustomed to seeing and collecting in the forest, but also with smaller, even underground ones. Such a symbiosis turned out to be so successful and beneficial for both sides that the absence of mycorrhizas in the plant is considered an exception in nature.

Which classes of fungi are capable of the phenomenon under consideration?

1. Bazidiomycetes (hymenomycetes, hysteromycetes).
2. Ascomycetes (most species).
3. Zygomycetes (some species).

Which plants are capable of symbiosis with the mycelium of the fungus?

1. Almost all of the perennial representatives, belonging to a variety of life forms (grass, shrubs, trees).
2. Very rarely annual plants.

In general, those representatives that live on the surface of water and in its thickness do not form mushroom root.

Classification

We found out what is mycorrhiza, the definition was given to it. Now we will consider what types of mushroom are, after all it turns out that not everything is so simple. There is a classification reflecting variants of this symbiosis.

There are three main types of mycorrhizas:

• Endotrophic ("endo" - inside);
• Ectotrophic ("ecto" - outside);
• Mixed, or endoectotrophic.

Let us consider in detail each type mentioned.

Endotrophic mycorrhiza

What is mycorrhiza of the endotrophic type? This is the interaction between the fungus and the root of the plant, in which the mycelium is not at all outside, but completely absorbed inside. The hyphae penetrate the integumentary cells and develop within the roots themselves, sucking out the plant juices. In this case, some of the mycelium dissolves and goes to food.

An interesting feature is that endophytic fungi are transmitted in the form of a spore by inheritance in the same plant species. That is, spores penetrate into the pollen, from there they enter the seed, and the new plant organism from birth has its own endogenous fungus.

The presence of a mycelium inside the root does not affect its normal development, branching, and so on. The fungus remains unnoticed from the outside at all.

Exotrophic mycorrhiza

On the question of what is mycorrhiza of exotrophic type, the answer is obvious. It is logical to conclude that this is an outwardly visible formation. This is really so. Fungi-ectophytes have a well-developed, powerful, branching mycelium. Hyphae cover the roots of the plant so tightly that a peculiar cover is obtained. In this case, the root hairs die off as unnecessary.

Individual strands of hyphae can penetrate under the coverslips of the plant, but do not enter the cells themselves. A similar type of mushroom root is most often formed between trees and agaric fungi. That is why many edible species people find whole families in the shadow of the crown of a tree.

Mixed mycorrhiza

What is mycorrhizas of mixed type? This is a kind of symbiosis of endo- and ectogribes with plant roots at the same time. The most common type of mushroom. Another name is endoectomycorrhiza.

Obviously, the essence of this phenomenon lies in the simultaneous penetration of hyphae into the root cells and at the same time forming a dense cover from them outside. Most often this symbiosis is observed between hat agaric mushrooms and various trees. Example: boletus, birch, amanita, white fungus and others.

Many species can not exist at all without mycorrhizas, so no methods of their artificial cultivation have been found so far.

The importance of mycorrhizas in the life of the fungus

Now we know what mycorrhiza is. And its meaning should also not remain a secret. Obviously, the main role is the exchange of nutrients between two different organisms.

What do plants get as a result of this symbiosis?

1. The area of the suction surface is increased due to multiple branches of the hyphae.
2. The mushroom provides water and minerals.
3. The plant receives hormones, vitamins.
4. The fungus translates many compounds into a form that can be assimilated by plants (for example, potassium, calcium, sodium, phosphorus, etc.).

What does the fungus get from the plant?

1. Organic compounds, mainly carbohydrate.
2. Amino acids.
3. Some phytohormones and growth substances.

Thus, mycorrhiza is a completely mutually beneficial cooperation, often vital for both parties.