In nature, there are many very interesting adaptations that help creatures live. Both animals and plants, fungi, bacteria, and others have them. It is simply amazing how inventive and unique the natural environment is! One has only to recall the diversity of species of various living beings, as this uniqueness becomes apparent.
One of these wonders of wildlife can be called an interesting symbiosis between representatives of different kingdoms - fungus root - a phenomenon that helps to survive in the conditions of fierce competition for nutrients. What is fungus root, or mycorrhiza? We will reveal this concept in the course of the article.
The Kingdom of Mushrooms: General Description
For starters, you should generally remember who mushrooms are and what they are? In biology there is a special section, a separate discipline, the purpose of which is the study of these organisms. It is called mycology. According to the latest data, today more than one hundred thousand different types of fungi are known, both unicellular and multicellular.
The figure is not small, especially since this realm of wildlife 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 lifestyle. Therefore, all of them are united in a separate kingdom.
Distinctive features of mushrooms
What are these features? The thing is the similarity of representatives with both plants and animals. For a long time, this confused scientists. After all, creatures are unique and incomprehensible, since they combine the signs of completely opposite organisms.
So, the common features that combine mushrooms with plants include:
- the ability to synthesize phytohormones and vitamins inside the body;
- unlimited apical growth throughout life;
- attached lifestyle (lack of mobility);
- the presence of a strong cell wall;
- nutrition by absorption of substances.
However, there are signs that are related to the organisms in question and with animals:
- heterotrophic method of nutrition (that is, the consumption of finished organic compounds, the impossibility of their independent synthesis within the body);
- the presence in the cell wall of the complex carbohydrate chitin, from which the covers of crustaceans, insects, and other animal creatures are composed.
The combination of such traits allows us to consider mushrooms as unique creatures worthy of uniting into a separate kingdom of wildlife.
The general plan of the structure of the mushroom
The main feature in the structure of the organisms under consideration is hyphae, which form the mycelium and fruit bodies in higher basidiomycetes. They are thin threads, white or translucent, which consist of cells separated by partitions. Hyphae strongly branch, intertwine, grow together and form a large underground network - mycelium. Outside, they also form the fruiting body of higher fungi - the leg and the hat.
In all other representatives, hyphae serve only for the formation of mycelium. The latter is needed for the absorption of nutrients, vegetative propagation, the formation of spores and the sexual process.
It is the mycelium of the fungus that takes part in the formation of the fungus root. Therefore, what is mycorrhiza, it becomes clear if you know what the body itself is. This is a combination of the underground part of mushrooms with the roots of higher plants. A kind of mutually beneficial cooperation that helps both creatures survive.
Thus, fungal hyphae form a mycelium, it is intertwined with roots and mycorrhiza, or fungus root, is formed. This is the main feature in the structure and lifestyle of a significant part of the representatives of the kingdom in question.
What is mycorrhiza in biology: definition
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 their adaptability to survival. It is possible to give a more precise concept of what mycorrhiza is in biology with the help of a definition. This is a symbiotic relationship between fungi and plants, which is carried out due to the close interweaving of mycelium and roots in the underground environment.
The term "mycorrhiza" was proposed as early as 1885 by the scientist Frank. The existence of this phenomenon became known four years earlier. What is fungal mycorrhiza, explained in 1881 by a Russian scientist F.I. Kamensky. It was he who first studied and described the fungus root.
Almost all higher plants enter into such relationships with fungi, not only with those that we are used to seeing and picking in the forest, but also with smaller ones, even underground ones. Such a symbiosis was so successful and beneficial for both sides that the absence of mycorrhiza in a plant is considered an exception in nature.
What classes of fungi are capable of this phenomenon?
- Basidiomycetes (Hymenomycetes, Gasteromycetes).
- Ascomycetes (most species).
- Zygomycetes (some species).
What plants are able to enter into symbiosis with mycelium of the fungus?
- Almost all perennial representatives related to a variety of life forms (grass, shrubs, trees).
- Very rarely annual plants.
At all, those representatives who live on the surface of the water and in its thickness do not form a fungus root.
Classification
We found out what mycorrhiza is, a definition was given to it. Now we will consider what types of fungal root are, because it turns out that not everything is so simple. There is a classification reflecting variants of such a symbiosis.
Three main types of mycorrhiza can be distinguished:
- endotrophic ("endo" - inside);
- ectotrophic ("ecto" - outside);
- mixed, or endoectotrophic.
Let us consider in more detail each specified type.
Endotrophic mycorrhiza
What is endotrophic mycorrhiza? This is an interaction between the fungus and the root of the plant, in which the mycelium is not located outside at all, but is completely absorbed inside. Gifs penetrate the integumentary cells and develop inside the roots themselves, sucking the plant sap. In this case, some of the mycelium dissolves and goes to food.
An interesting feature is that endophytic fungi are transmitted as spores by inheritance in the same plant species. That is, spores penetrate into pollen, from there they enter the seed, and a new plant organism from birth has its own endophyte fungus.
The presence of mycelium inside the root does not affect its normal development, branching, and so on. The mushroom goes unnoticed outside at all.
Exotrophic mycorrhiza
To the question of what is an exotrophic mycorrhiza, the answer is obvious. It is logical to conclude that this formation is noticeable from the outside. It really is. Ectophytes fungi have a well-developed, powerful, branching mycelium. Gifs so densely envelop the roots of the plant that they get a kind of cover. In this case, the root hairs die off as unnecessary.
Separate strings of hyphae can penetrate beneath the integumentary tissues of the plant, but do not enter the cells themselves. A similar type of fungus root is most often formed between trees and agaric mushrooms. That is why many edible species people find whole families in the shadow of the crown of a tree.
Mixed mycorrhiza
What is mixed mycorrhiza? This is a kind of symbiosis of endo- and ectogribs with plant roots at the same time. The most common type of fungus root. Another name is endoectomycorrhiza.
Obviously, the essence of this phenomenon is the simultaneous penetration of hyphae into the root cells and at the same time the formation of a dense sheath of them from the outside. Most often, such a symbiosis is observed between cap agaric mushrooms and various trees. Example: boletus, boletus, fly agaric, porcini mushroom and others.
Many species cannot exist without mycorrhiza at all, therefore, methods for their artificial cultivation have not yet been found.
The value of mycorrhiza in the life of the fungus
Now we know what mycorrhiza is. And its meaning also should not be kept secret. Obviously, the main role is the exchange of nutrients between two different organisms.
What do plants get as a result of such a symbiosis?
- The area of the suction surface increases due to multiple branches of hyphae.
- The mushroom provides water and minerals.
- The plant receives hormones, vitamins.
- The fungus converts many compounds into a form that can be absorbed by plants (for example, potassium, calcium, sodium, phosphorus, and so on).
What does the mushroom get from the plant?
- Organic compounds, mainly carbohydrate in nature.
- Amino acids.
- Some phytohormones and growth substances.
Thus, mycorrhiza is a completely mutually beneficial cooperation, often vital for both sides.