Root: the structure of the root. Types of roots (biology)

One of the most important parts of the plant is the root. It is he who ensures the normal life of trees, herbs, shrubs and even water representatives of the flora. Often, the aerial part of the plant is just the tip of the iceberg. Most of it can be underground. It is no coincidence that the roots are so large, because they have very important functions. Let's get acquainted with the amazing features of the plant world.

Root functions

The roots of each plant carry out a whole range of tasks, which can vary from species to species, but in most cases these tasks are the same for both trees and smaller ones. The roots of trees and other aboveground plants allow them to be held in a vertical position, to resist the wind and animals. This is especially true for large trees because of their mass and height. The root system of aquatic plants helps them to attach to the bottom, and also prevents the overturning of some of them.

Another function of the roots is nutritious. They absorb water and minerals from the soil and deliver them to the right places. They also synthesize some amino acids, alkaloids and other elements that plants need. Some of the representatives of the flora generally store useful substances directly in the roots (mainly starch and other carbohydrates). Also do not forget about such a thing as mycorrhizas - a symbiosis of a plant with mushrooms. The key role in it is played by the root. The structure of the root is such that some plants multiply with it - root offspring.

Types of roots

Depending on the structure and function that is assigned to them, there are different types of roots. The first is the main one. It grows directly from the seed when it germinates, then to become the main axis of the entire root system. In addition to the main root there are also subordinate. They are formed from a variety of places - on stems, sometimes on leaves, and in some cases even on flowers. Another species is the lateral roots. They appear from the main or accessory roots and branch out, forming new and new processes.

Root Systems

All the roots that the plant possesses form the root system. Depending on the role of different roots in the life of their host, there are two types of systems - rod and barley. The first is the focus on the main root, which grows most intensively. In this type, the main rod develops much more efficiently than the lateral rod. However, this difference can be noticed mainly at the initial stage of growth. Over time, the lateral roots begin to inexorably catch up with their main colleague, and in older plants they are even larger than the main one. The core system is characteristic mainly for dicotyledons.

The second type is distinguished by the opposite features of the root characteristic of the root. Such a system is called friable. It is characteristic of monocotyledonous plants and is distinguished by its numerous accessory and lateral processes, which fill the space under the plant. In this case, the main root is usually poorly developed or practically undeveloped.

Root. The structure of the root

Each root is divided into several zones, each of which is responsible for its own unique functions. One of the most important places is the zone of division. It is at the tip of each root and is responsible for its growth in length. Here myriads of small cells multiply constantly. This process allows this part of the root to fulfill its difficult task. But the division zone is useless without the root cover, which is on the end of each spine. It is a layer of fused cells that protect dividing cells from mechanical damage. In addition, the root cover gives off a kind of mucus that promotes the movement of roots in the soil.

The next segment of the root is the extension zone. It is located just beyond the division area and is distinguished by the fact that its cells are constantly growing, although in them there is practically no division process. Then comes the suction zone - the place where water and minerals are drawn from the soil. This is due to the myriad of tiny hairs covering this site. They substantially increase the total absorption area. Each hair acts as a pump, sucking everything from the soil. Further there is a zone of carrying out, responsible for transportation of water with mineral substances upward. Also, the elements responsible for the vital activity of the root system descend from here. This part is very strong and it is from it that the lateral roots grow.

Cross section

If you cut the root, you can see the layers from which it is composed. First there is a peel width of only one cage. Under it you can see the root of the root - the parenchyma. It is through her friable tissue that water with mineral substances enters the axial cylinder. Forms its pericambium - the educational tissue of plants, which usually surrounds the conductive tissues. Around the conductive cylinder there are tightly closed cells of the endoderm. They are waterproof, which causes the life-giving moisture with the minerals to move upwards. But how then does the liquid get inside? This is due to special access cells located on the endoderm. In most cases, the roots of grass, trees, shrubs have such a structure, although sometimes there are differences.

Mycorrhiza

Often, the roots of trees are the place of their symbiosis with other forms of life. The most frequent partners of plants are mushrooms.

This phenomenon is called mycorrhiza, which stands for "mushroom root". This is hard to believe, but most trees depend on a fruitful alliance with the mycelium. Habitual birches, maples and oaks take a lot of advantage out of this symbiosis.

When the mycelium interacts with the roots, an exchange takes place, in which the mycelium gives the tree irreplaceable mineral substances, receiving in exchange carbohydrates. This evolutionary course allowed many plant species to live in conditions unsuitable for their species. Moreover, some representatives of the flora would not exist at all, if not for mycorrhiza. In addition to symbiosis with mushrooms, there is a profitable collaboration with bacteria, to which the root resorts. The structure of the root in this case will differ from what we are accustomed to. On it you can find nodules, which are inhabited by special bacteria that supply the tree with atmospheric nitrogen.

Conclusion

One of the most important parts of any plant is the root. The structure of the root is ideally suited to the tasks that it performs. The root system is an amazing mechanism that feeds plants. It is not in vain that various mystical currents consider that a tree unites the forces of heaven and earth. Its overhead part absorbs sunlight, and the roots are fed from the soil. The value of the root system is not obvious, since the overground part of the plant attracts the main attention: foliage, trunk, flower, stem. The root remains in the shadow, modestly fulfilling its honorable mission.