In nature, there are several groups of amazing organisms that do not belong to any of the known kingdoms of wildlife. And all because they are a combination of several of them. One of the most striking such examples are lichens. They are even being studied by a separate science called lichenology. What are the features of the structure of lichens, their habitats and vital processes? All this will be discussed in detail in our article.
Amazing symbiosis
These organisms not like anyone else are the result of cohabitation of fungi and algae. But not all representatives of these groups are able to form this mutually beneficial cohabitation. What are the structural features of lichens? The body of the fungi, or mycelium, consists of many thin threads called hyphae. Between them are cells of cyanobacteria - blue-green algae. As a result, a single organism is formed. It is able to function only in the presence of viable fungi and algae.
What are the structural features of lichens
The constituent parts of this natural symbiosis are not at all randomly located. The structure of the lichen (the diagram illustrates the location of the individual elements) has a clear structure. Is the body of these organisms a thallus? or tall. Its basis is the hyphae of the fungus, which are condensed above and below, forming the so-called crust. Its functions are similar to those of the integumentary tissue of plants. This is protection against adverse conditions and the relationship of the body with the environment.
Mushroom threads are also located inside the lichen, but are more loose and spacious. This is a prerequisite, because between them are cells of cyanobacteria. Like mushrooms, lichens have rhizoids. These formations in terms of their functions and location in the body resemble the roots of higher plants. And their main difference is the lack of all types of tissue. Thus, the rhizoid cells are not specialized and unite only anatomically.
Classification of Lichens
The structural features of lichens determine their association into groups according to the shape of the body - the thallus. Depending on this, several groups are distinguished:
- Scum - in appearance resemble powder. They cover the stones or bark of trees with a thin crust, sometimes visually merging with the surface.
- Leafy - have a clearer structure. Their thallus is small flakes that can easily be separated from the substrate.
- Bushy - most in appearance resemble lower plants. As a rule, they have a wide and flat base, the shape of a small bush or a hairy structure.
The main processes of life
The internal structure of the lichen also determines the physiological characteristics of these organisms. Since they are formed by fungi and algae, all life processes are similar to these groups of wildlife.
Food
Mushrooms and green algae feed on fundamentally different ways: hetero- and autotrophic. Therefore, lichens are characterized by the first and second. This is of great importance for the process of adaptation of these organisms to different living conditions. After all, if there are no conditions for the independent formation of carbohydrates, the body absorbs the nutrient particles necessary for life from the soil or other substrate. Algae carry out the process of photosynthesis, providing lichens with the necessary organic substances and enriching the air with oxygen. And mushrooms absorb water with dissolved minerals from the substrate. They are used by cyanobacteria for the process of photosynthesis. This way of eating is called mixotrophic.
Breeding
To determine the type of reproduction of these organisms, it is necessary to once again recall what are the structural features of lichens. And since they consist of mushrooms and algae, the process of reproducing their own kind is able to carry out both the first and second. This fact is also important for their adaptation and dissemination.
Like fungi, lichens form spores - asexual reproduction cells. They are carried by wind and water over long distances and are very viable. In favorable conditions, they begin to develop, forming an adult organism. As lower plants, lichens reproduce asexually vegetatively, namely, by parts of the thallus. These can be quite large bushes or very small fragments containing only a few hyphae of fungi and cyanobacterial cells. This is enough for the rapid development of the whole organism. The vegetative method of reproduction is predominant in comparison with spore formation.
The value of lichens in nature and human life
What is the structure of lichen, we found out. Now let's look at the main aspects of its significance in wildlife. It is no coincidence that lichens are called "pioneers" of the plant world. After all, it is they who are capable of developing in places where other organisms cannot live. For example, settling on solid rocks, they gradually destroy them. As a result, there is a basis for the formation of soil cover - the necessary living conditions for plants.
Lichens are absolutely unpretentious to the living conditions, but prefer high humidity. When drought or freezing occurs, they suspend the intensity of vital processes and resume them after. Lichens are food for some northern animals. In medicine, they are used as bactericidal agents.
Lichens are a special group of organisms, which is a mutually beneficial cohabitation of mushrooms and algae. They combine the properties of these kingdoms of nature, being indicators of the cleanliness of the environment and the basis of the vegetation cover of the tundra.