In nature, there are many very interesting devices that help creatures live. They are found in both animals and plants, fungi, bacteria and others. It's amazing how inventive and unique the natural environment is! One has only to remember the diversity of species of various living beings, as this uniqueness becomes apparent.
One of these miracles of wildlife is an interesting symbiosis between representatives of different kingdoms - mushroom root - a phenomenon that helps to survive in conditions of fierce competition for nutrients. What is a mushroom root, or mycorrhiza? We will reveal this concept in the course of the article.
Kingdom Mushrooms: general characteristics
To begin with, 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's called mycology. According to the latest data, today more than one hundred thousand different types of fungi are known, both unicellular andmulticellular.
The figure is considerable, especially since this kingdom of wildlife is intensively developing and numerically progressing. Parasitic and saprophytic forms reach a special diversity.
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, 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 baffled scientists. After all, the creatures are unique and incomprehensible, since they combine the signs of completely opposite organisms.
So, the common features that unite mushrooms with plants include:
- the ability to synthesize phytohormones and vitamins inside the body;
- lifelong apical growth;
- attached lifestyle (lack of mobility);
- presence of a strong cell wall;
- nutrition by absorption of substances.
However, there are signs that make the considered organisms related to animals:
- heterotrophic way of eating (that is, the consumption of ready-made organic compounds, the impossibility of their independent synthesis inside the body);
- presence in the composition of the cell wall of the complex carbohydrate chitin, which consists of covers of crustaceans, insects and other animal creatures.
The combination of these traits allowsconsider mushrooms as unique creatures worthy of being united in a separate kingdom of wildlife.
General plan of the structure of the fungus
The main feature in the structure of the organisms under consideration is the hyphae that form the mycelium and fruiting bodies in higher basidiomycetes. They are thin threads, white or translucent, which consist of cells separated by septa. The hyphae strongly branch, intertwine, coalesce and form a large underground network - the mycelium. Outside, they also form a fruiting body in higher mushrooms - a stem and a hat.
In all other representatives, hyphae serve only to form mycelium. The latter is needed for nutrient absorption, vegetative reproduction, spore formation and the sexual process.
It is the mycelium of the fungus that takes part in the formation of the mushroom root. Therefore, what mycorrhiza is, it becomes clear if you know how the organism itself is represented. 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, the hyphae of the fungus form a mycelium, it intertwines with the 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 marvel once again at the ingenuityliving beings in adaptation to survival. To give a more accurate concept of what mycorrhiza is in biology, you can use the definition. This is a symbiotic relationship between fungi and plants, which is carried out through the close interweaving of mycelium and roots in the underground environment.
The term "mycorrhiza" was proposed back in 1885 by the scientist Frank. The existence of this phenomenon became known four years earlier. What is fungal mycorrhiza, explained in 1881 by the Russian scientist F. I. Kamensky. It was he who first studied and described the mushroom root.
Practically all higher plants enter into a similar relationship with mushrooms, and not only with those that we are used to seeing and collecting in the forest, but also with smaller ones, even underground ones. Such a symbiosis turned out to be so successful and beneficial for both parties that the absence of mycorrhiza in the plant is considered an exception in nature.
What classes of fungi are capable of the phenomenon under consideration?
- Basidiomycetes (Hymenomycetes, Gasteromycetes).
- Ascomycetes (most species).
- Zygomycetes (some species).
What plants are able to enter into symbiosis with the mycelium of the fungus?
- Practically all perennial representatives belonging to a variety of life forms (grasses, shrubs, trees).
- Very rare annuals.
In general, those representatives that live on the surface of the water and in its thickness do not form a mushroom root at all.
Classification
We figured out whatmycorrhiza, the definition was given to her. Now let's look at what types of mushroom root are, because it turns out that not everything is so simple. There is a classification that reflects the variants of such a symbiosis.
There are three main types of mycorrhiza:
- endotrophic ("endo" - inside);
- ectotrophic ("ecto" - outside);
- mixed or endectotrophic.
Let's take a closer look at each specified type.
Endotrophic mycorrhiza
What is endotrophic mycorrhiza? This is such an interaction between the fungus and the root of the plant, in which the mycelium is not outside at all, but is completely absorbed inside. Hyphae penetrate under the integumentary cells and develop inside the roots themselves, sucking out the juices of the plant. At the same time, some of the mycelium dissolves and goes to food.
An interesting feature is that endophytic fungi are inherited as spores in the same plant species. That is, the spores penetrate the pollen, from there they enter the seed, and the 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 fungus goes unnoticed from the outside at all.
Exotrophic mycorrhiza
To the question of what exotrophic mycorrhiza is, the answer is obvious. It is logical to conclude that this is a visible formation from the outside. It really is. Mushrooms-ectophytes have a well-developed, powerful, branching mycelium. gifsso densely envelop the roots of the plant that a kind of cover is obtained. At the same time, the root hairs die off as unnecessary.
Individual strings of hyphae can penetrate under the integumentary tissues of the plant, but they do not get inside the cells themselves. This type of fungus root is most often formed between trees and agaric fungi. That is why people find many edible species in whole families in the shade of the crown of a tree.
Mixed mycorrhiza
What is mixed mycorrhiza? This is a kind of symbiosis of endo- and ecto-fungi with plant roots at the same time. The most common type of fungus. 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, the formation of a dense sheath from them outside. Most often, such a symbiosis is observed between cap agaric mushrooms and various trees. Example: boletus, boletus, fly agaric, white mushroom and others.
Many species cannot exist without mycorrhiza at all, therefore, methods for their artificial cultivation have not yet been found.
The importance of mycorrhiza in the life of a fungus
Now we know what mycorrhiza is. And its meaning should not remain a secret either. Obviously, the main role is the exchange of nutrients between two different organisms.
What do plants get as a result of this symbiosis?
- The area of the suction surface increases due to multiple branches of the hyphae.
- 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, s alts of potassium, calcium, sodium, phosphorus, and so on).
What does a mushroom get from a plant?
- Organic compounds, mainly of carbohydrate nature.
- Amino acids.
- Some phytohormones and growth substances.
Thus, mycorrhiza is a completely mutually beneficial cooperation, often vital for both parties.
