The root, being the most important organ, performs a number of irreplaceable functions and is quite diverse in terms of structural features. Without it, the life of plant organisms would be practically impossible. In our article, the fibrous root system will be considered in detail: in which plants it develops, what characteristic features it has, and how it helps organisms adapt to constantly changing environmental conditions.
What is a root
The root is the underground organ of the plant. Obviously, in plants it is not in the singular. Indeed, all the roots of one organism differ in appearance and developmental features. There are three types of underground parts of plants: main, lateral and adnexal. It won't be hard to tell them apart. The main root of a plant is always one. It stands out from the rest in size and length. It has lateral roots. They are enoughnumerous. And if the roots grow directly from the shoot, then they are adnexal.
Root functions
Without a root, the plant will die, because its functions are really vital. First of all, this is the fixation of organisms in the soil, the provision of mineral nutrition and the upward flow of water. When necessary, many plants form modifications of the root. For example, beets, carrots and radishes form root crops. These are thickenings of the main root. They accumulate water and a supply of necessary substances to survive adverse conditions.
Types of root systems
One type of root is not enough for a plant. After all, the life of the whole organism depends on the functioning of this organ. Therefore, the plant forms root systems, consisting of several types of underground organs. They are more efficient. The main types of root systems are tap and fibrous. Their main difference lies in the structural features. For example, a fibrous root system is distinguished by a small penetration depth, while a tap root system, on the contrary, allows plants to receive water from considerable depths.
Tap root system
The very name of this structure characterizes the features of its structure. She has a pronounced main root. This tap root system differs from fibrous. Due to this, plants with this structure are able to get water from a depth of sever altens of meters. Lateral roots extend from the main root, which increases the suction surface.
The structure of the fibrous root system
The fibrous root system consists of only one type of roots - adventitious. They grow directly from the above-ground part of the plant, so they form a bunch. Usually they are all the same length. Moreover, the main root at the beginning of development still grows. However, he subsequently dies. As a result, only those roots remain that grow from the shoot itself. Such a beam in most cases is quite powerful. Try to pull a wheat plant out of damp soil with your hands and you will see that it takes considerable force to do this. Sometimes lateral roots can also develop on adventitious roots, which further increases the diameter occupied by this system.
Which plants have a fibrous root system
In the process of evolution, this structure first appears in representatives of higher spore plants - ferns, club mosses and horsetails. Since in most of them the body is represented by an underground modification of the shoot, namely the rhizome, adventitious roots grow from it. This is a big step forward in the phylogeny of plant organisms, since algae and other spores had only rhizoids. These formations had no tissues and performed only the function of attachment to the substrate.
All plants that belong to the class Monocotyledons also have a fibrous root system. As well asthe absence of cambium, arcuate or parallel venation, and other features, this is their systematic feature. This class is represented by several families. For example, in Lileyny and Onion, a characteristic modification of the shoot is formed. This is a thickened underground stem in which water and all the necessary minerals are stored. It's called an onion. Bundles of adventitious roots grow from it. Rice, wheat, corn, rye, barley are members of the Cereal family. They also have a fibrous root system. Examples of this structure are also dahlia, asparagus, sweet potato, chistyak. Their adventitious roots are largely thickened and take on a tuberous shape. They also store nutrients. Such modifications are called root tubers. Support, respiratory, suckers and trailers also grow from the shoot. Therefore, they can also be considered a modification of the fibrous root system. For example, vines with trailer roots can grow even on a vertical surface. And orchids absorb moisture directly from the air. This is carried out by adventitious respiratory roots. A special modification is formed in corn. These are supporting roots. They surround the lower part of the stem and support a strong shoot with heavy cob fruits.
Advantages and disadvantages of fibrous root system
Plants that do not have to extract moisture from a considerable depth have a fibrous root system. This greatly distinguishes her from the othersimilar structure - rod. The main root is well developed in it, capable of penetrating tens of meters deep into the soil. This is a characteristic feature for all plants of the Dicotyledonous class. But the fibrous root system has its advantages. For example, it is able to occupy a significant area, which increases the suction surface. In wheat, the fibrous root system is up to 126 cm in diameter and up to 120 cm long. The degree of development of this structure depends entirely on environmental conditions. In loose soil, adventitious roots in corn can grow within a radius of 2 m, in an apple tree up to 15 or more. At the same time, the depth of penetration is quite significant. In some weeds, it reaches 6 m. Therefore, it is so difficult to get rid of them. If the soil is dense, and the oxygen content in it is not enough, then almost all adventitious roots are located in its surface layer.
So, the fibrous root system has a number of characteristic features. It is typical for plants of the monocotyledonous class: the cereal, onion and lily families. This structure consists of adventitious roots that grow from the shoot in a bunch, occupying a significant area.
