How plants "gnaw" stones

To grow a plant, it needs to be given all the nutrients in solutions; they easily penetrate the cell walls to the roots. However, it is wrong to think that a plant can only feed on solutions. Many nutrients in the soil are found in the form of sparingly soluble compounds and minerals, which undoubtedly serve as a food source for plants. And even if the plant food consisted only of soluble substances, they could very soon be washed out of the soil, and the soil would become barren.

Many nutrients in the soil are found in the form of sparingly soluble compounds and minerals, which undoubtedly serve as a food source for plants

All insoluble components of the soil - minerals and rocks - are gradually destroyed and give up the nutrients in the solution, thereby maintaining soil fertility. This occurs under the influence of temperature changes, from the destructive action of water, the work of microorganisms, etc. But the plants themselves take a serious part in this. Due to the fact that plant sap is usually acidic and roots emit carbonic acid when breathing (which dissolves some rocks), plant roots corrode minerals and rocks, "bite" into them, thereby extracting the food they need.

This can be detected by giving a plant a stone, a mineral, containing this element, as a kind of nutritional element, especially if the plant is deprived of any other source of this element. The plant, in search of the food it needs, finding no other source, will braid this stone with its roots and begin to extract food from it, destroying it with its roots and literally biting into it. Traces of how the plant gnawed a stone, it is easy to see on it.

To do this, you need to take possibly poor soil or better completely barren sand, add all the nutrients necessary for the plant into it (as we did when growing plants in water), with the exception of one that we give it in the form of a stone. For example, take a piece of marble from which plants can take lime, but at the same time, the nutrient mixture must be prepared without lime, that is, in our recipe, replace the first salt - calcium nitrate with the same amount of ammonium nitrate. A solution of the powder, made according to the specified recipe, moisten the sand, poured into an ordinary flower pot and plant some plant in it. The bottom of the pot is pre-laid with a piece of marble plate. To better print on it the traces of the roots that destroy the marble, you need to take a polished plate of marble (a broken piece of a table, a washstand, etc.).

In 2-3 months, when the plant has developed well, you can take out this marble plate and you will see a grid corroded by the roots on it - the imprints of the roots. To make the root imprint clearly visible, it is enough to wipe the plate with charcoal, graphite, etc. Neither charcoal nor graphite will adhere to the polished part of the plate, and all the gnawed spots will turn black (of course, white marble is wiped with charcoal, and black marble must be wipe with chalk).

Instead of marble, you can take phosphorite, or feldspar, or a piece of mica, but you should always deprive the plant of the element that it will take from these stones (that is, from phosphorite phosphorus, from feldspar and potassium mica); in addition, you need to choose stones with a very smooth, as if polished surface or polish them with fine sand or emery dust.

This ability of plants to destroy minerals and rocks plays a huge role in soil formation.

The soil consists of destroyed rocks and organic matter (decayed plants). But the first plants on earth were to begin their development on rocks destroyed by water and air. They had to settle on rocks, minerals, destroying them with their roots. After the death of these plants, destruction continued with humus, which is formed from their residues. Thus, the soil was created.

Such pioneers of plant life and the entire organic world can now often be seen on stones and rocks in the form of thickets of lichens and various plants gnawing stones.