Lichens are a very peculiar group of living organisms that can live in conditions where no other plants take root. They withstand severe frosts and very high temperatures. They grow in the most unusual places: on stones and trees, sandy soils and fences, in the tundra and Antarctica. Having studied the features of these unusual organisms, one can answer the question of why lichens are called pioneers of vegetation cover. After all, it is they who appear first in such places where nothing can grow: on stones, in the desert or tundra. These amazing organisms, which are a symbiosis of fungus and algae, are still poorly understood. Scientists believe that they have existed on Earth for about 200 million years and play an important role in the development of the plant and animal world.
What are the features of lichens?
- This organism is a symbiosis of fungus and algae. They are completely dependent on each other. Initially, the fungus parasitized on the body of algae, but in the process of evolution a new organism was formed.
- Surprisingly, lichen nutrition. The strings of the fungus receive water and minerals from the environment, and organic matter from the body of the algae. In turn, the alga from the mushroom receives all the minerals it needs. In their diet, these organisms are almost independent of the soil. They settle in the most lifeless places, and then, dying, form a nutrient substrate for other plants. That is why lichens are called pioneers of vegetation cover.
- A feature of these organisms is their ability to live where no plant survives. With the help of special acids, they can dissolve rocky cover, magma or sand, creating soil over time.
- Lichens grow very slowly. Over the year, they increase by no more than 5 millimeters. But these organisms live a very long time. On average, their age is about 100 years, but there is information about lichens of two thousand years of age.
- These organisms are very unpretentious. It can withstand prolonged drought, frosts up to 60 degrees and fifty degrees of heat.
What are lichens?
The names of most of them do not say anything to an ordinary person. Many have seen these organisms, because they are so peculiar that they do not look like mushrooms or plants. What are lichens?
- Leafy can live on the bark of trees, cover the soil with a continuous carpet, or hang in the form of a beard from branches.
- Scale lichens look like thin crusts covering stones, tree bark, fences and walls. They resemble a gray scale.
- Bushy lichens live in coniferous forests, forming continuous carpets of beautiful branching bushes. Sometimes their height can reach half a meter.
Where do these organisms live?
Why are lichens called pioneers of vegetation? Yes, because they "pave" the road in the spread of other plants, mastering rocky and sandy soils. They are the first to appear in those places where nothing can grow. The main thing for their life is light and moisture in the air. Lichens are one of the most common organisms. You can meet him from the North to the South Pole. They love coniferous and mixed forests, tundra and taiga, rocky highlands and deserts. Some species can grow in water and on volcanic lava. They grow on iron, stones, porcelain, bricks, cardboard, fabric and glass.
It is this feature of them that is the answer to the question of why lichens are called pioneers of vegetation cover. They dissolve stones with the products of their vital functions, and when they die, they form a sub-extract, which subsequently is a breeding ground for the life of other plants.
The value of lichens
- Very sensitive to clean air, these organisms are an indicator of its pollution. They especially react to the content of sulfur dioxide in the atmosphere.
- Various acids secreted by lichens are used in the perfumery and cosmetics industries, from which paints and litmus are obtained. Some of their types secrete bactericidal substances, so they are used in traditional medicine.
- A cover of lichens in the tundra and coniferous forests protects the soil from erosion. They also protect trees from infection by fungi.
- The role of lichens is also that they are food for many animals, especially in the northern regions. Some of these organisms are edible for humans.