What is the root?It is a very important plant organ providing its growth and vital activity. The appearance of this organ scientists associated with the stage of development of the flora of the earth's surface.
The root is the underground part of the plant, which has apical growth and has a radial structure.
The main functions of the root are:
In addition, synthesized in the aerial partplants organic substances, as well as in the root of the hormones, amino acids, alkaloids, etc., accumulate in it and are a supply of nutrients. The root is also an organ of vegetative propagation of the plant.
Along with the definition of what is a root, the concept of the root system, which is formed by all the roots of the plant in the aggregate, always appears. Distinguish the main, accessory and lateral roots.
The main (or primary) root gets itsdevelopment still in the germinal root. In flowering and gymnosperms the main root is basic, has unlimited growth and positive geotropism (that is, it gives the right direction for plant growth).
The accessory roots are secondary and grow from stems, old roots or leaves.
Lateral roots grow from the main and accessory ones.
Root systems of their type arerod or fibrous. With the root system of the root, the primary root is strongly pronounced. This system is predominantly dicotyledonous plants (for example, carrots, dandelion, watermelon, sunflower). In the furry root system, the growth of the main root is not very pronounced, it is not distinguished among the accessory roots (for example, the root of valerian, plantain, rye). Such a root system is typical mainly for monocots.
The internal structure of the roots
What is a root from the point of view of its internalstructure? In its center there is a conducting root system, consisting of sieve tubes and vessels. Vessels provide transportation of water along with the useful substances dissolved in it to the aerial part of the plant from the root hairs. Sieve tubes, on the contrary, transport organic solutions from terrestrial organs to the cells of the root. Cells of the educational tissue of the root (cambium) are continuously divided and ensure that the growth of the roots in thickness.
What is the root, and all its main zones are clearly visible on the longitudinal section.
The root cover is formed by a cover cloth and covers the top of the root, protecting it like a cap from various damages. Its other function is to promote the progress of the root in the earth.
The fission zone is located immediately below the root cover and consists of small cells of the educational tissue, which by their constant division ensure the growth of the root.
The stretching zone is formed by still young, only growing cells stretching in the longitudinal direction and thereby carrying out root growth in length.
If the plant is carefully excavated, thenTo see how the roots bind the soil particles, this part is called the suction zone. It is covered with root hairs, the function of which is the absorption of water with nutrients. Hairs have a slimy surface.
Above the suction zone is the zone of conduct,It is formed by a conductive tissue and constitutes most of the length of the root. On the vessels of the root, upward along the stalk, water and mineral substances are advancing, which are directly dissolved therein.
In some plants, the roots can be modified in connection with the appearance of unfavorable conditions for plant growth and providing an adaptation to them.
