There are more than four hundred species of different plants on our planet, and all of them perform a variety of functions. We, along with other animals, consume them for food, but with the difference that we subject plants to various types of processing - boil, fry, stew, preserve; we make clothes, medicines, furniture out of them; they supply all living things with oxygen. For many years, scientists have been studying different species, their properties, working on breeding new species that are more resistant to current environmental and climate conditions, and working on the preservation of endangered species, studying usefulness and other things that are important both for humans and for the environment as a whole. Specifically, now the topic will be touched upon, revealing such concepts as the structure of the root system, its types and functions.
What is a plant organ?
On the organs of a part of any plantdistributed according to function and structure. The principles of separation are the same as in animals, including humans. The ear and liver have different shapes and functions, and therefore are named differently. The same is true for leaves and roots. If we talk about higher plants, then the division of organs goes into two large groups, vegetative (those that serve for growth and nutrition) and reproductive (responsible for reproducing their own kind). Any type of root system refers to vegetative organs.
The concept of the root and its function
The root is the axial organ of the plant. First of all, it fixes the plants in the soil. It also performs the function of "nutrition", and now we are talking about such a part of the root as hairs. That is, the answer to the question of what function the root hairs perform is precisely the absorption from the soil of water and minerals necessary for the full life of the plant. Also, the root system is able to produce various substances, such as growth hormone, or various alkaloids, necessary for the whole plant. These substances can move up the stem of the plant, or they can accumulate in the root system itself. It can also work as a pantry - something like a cellar for useful nutrients. Plants with such a root are called root vegetables.
We are all familiar with carrots, beets, radishes, which are just these same root crops. What else the root system is capable of is interaction with “neighbors” in a certain place of growth. So, symbiosis is possible with other plants, with fungi, or even withmicroorganisms, and almost any type of root system is capable of this. In addition, the functions of the roots can also include vegetative reproduction. It has the advantage that a partner is not required for the emergence of a new plant, as in the case of sexual reproduction.
Vegetative propagation - what is the point
This reproduction of one's own kind can occur even with the help of an ordinary piece of paper. Once in favorable conditions, he can start an escape, and, for example, a new begonia will be born. A willow branch, breaking away from a tree, can also catch on in the ground and take root. Roots can do the same. In some plants, buds can form on the rhizome, from which new, full-fledged and identical individuals grow, or tubers are formed. The most striking example, which refers to the latter case, is a potato - a guest from America, which has taken root so well in our conditions. So, the tubers that form on the roots of this plant and are actively consumed by us for food are at the same time used for planting and growing new potato bushes, and, accordingly, new tubers. A sprouted potato, even a part of it that has at least one sprout, is able to give life to a new, full-fledged potato bush, no different from its “mother”. And good conditions can favor better bush development and even higher yields. All good farmers know what function the root hairs perform, and therefore they use such fertilizers and soil treatment methods, after which high yields of high-quality natural products are harvested. Of course, there's morea lot depends on the weather conditions for the period of growth, but that's another story. Back to vegetative propagation.
So, such reproduction is actively used in horticulture and agriculture. But along with the benefits, you can remember the harm. Yes, we are talking about weeds. For cultural economy there is such a problem as wheatgrass. The rhizomes of this plant are huge, and when damaged, they are easily restored, turning into a new plant. For example, if you crush one rhizome into four during shallow plowing, four new weeds will soon grow. This is bad for a person, namely for the owner of the plot, who wants to grow many different vegetables on it, but instead gets a crop of wheatgrass. But for the plant itself, this ability is a huge plus.
An interesting case where rhizomes have dormant buds. This often applies to trees. When the main plant is alive and thriving, these buds seem to be in a coma. They exist, they are alive, but there is no development. But if, say, a tree is cut down, then these buds are quickly activated and turn into young plants of the same species over time. Oak, linden, birch trees have such buds.
What are the main types of roots?
There are three types of roots. The main one develops from the germinal seed. Lateral roots depart from it, which are able to branch out. There are also adventitious roots. They can also appear on top of the plant, on stems or leaves. Together, the types of roots make up the whole root system. According to the characteristics of these types, the root system is distributed overspecies.
Types of root systems
If a plant has a well-defined main root, then such a root system is called tap root.
What does "well expressed" mean? This means that it is much thicker and longer than all the other roots that radiate from it. Such a root system is characteristic of dicotyledonous plants. If the main root of the plant is not expressed, then such a root system is called fibrous.
The main root may be absent or not different from the others.
Each root can be divided into several zones, which is responsible for a specific function.
Four distinct zones characteristic of a young root
The first zone is characterized by cells of the apical meristem. This is the division zone, or root cap. The length of the case reaches one millimeter.
The second zone is the zone of growth, or stretching. It is thanks to the growth of the cells of this part, only a few millimeters long, that the main elongation of the root occurs.
The third zone is the suction zone, or the zone of root hairs. There are a maximum of them here - the number is measured in hundreds of pieces per millimeter square, and they constantly absorb nutrients from the ground, which will go further, to the fourth root zone - to the conduction zone, where there are no longer any root hairs, but there is a formation of full-fledged powerful (on a scale individual plant) lateral roots.
Anyspecies of root systems have such zones on young roots. There are no clear divisions between the zones, they all smoothly transition into each other.
Interesting about young root zones
The root cap is also called calyptra. Its cells live no more than nine days, and then die off, exfoliating from the root. In this case, an abundant secretion of mucus occurs, which makes it easier for the root to grow further - deeper or wider, it doesn’t matter.
It is the stretch zone that pushes the root further into the ground. When the cells of this zone are filled with water, they stretch in length, and this happens until the cells finally harden and they enter the absorption zone. By the way, this area is actually transparent in appearance.
In the place where there was once a stretch zone, hairs begin to form. But above, in front of the conduction zone, at the same time they begin to die off. So the suction zone moves after pushing the root into the soil. The number of hairs per square millimeter is in the hundreds.
The suction zone is the most important part of the root for plant life
Root hairs of plants, as mentioned earlier, absorb water from the soil, minerals dissolved in water, which are necessary for proper growth. Therefore, let us dwell on this root zone and consider it in more detail.
What is a root hair?
What is the function of the root hairs, we have already roughly figured out. Now it's time to figure out how it happensdue to what features of the structure of these very hairs, the absorption of substances from the soil is possible. Any root hair, which, in principle, can take only three lines to describe, is actually very important.
The length of such a hair is quite small and lies in the range of 0.1-8 mm, according to other sources - 0.06-10 mm. The diameter of the hair can range from five to seventy micrometers. If we talk about the structure of root hairs, then these are, for the most part, elongated cells of the root skin. Almost all of this cell is a vacuole, around which there is a thin layer of cytoplasm, and which contains the cell nucleus. It is located in the cytoplasm so that it is located at the top of the hair.
Suction zone structure
If we make a cross section, we will see the presence of three main sections - this is the central cylinder, the bark and the outer coating in the form of a thin skin, on which root hairs are formed. The suction zone begins with the cells of the skin covered with mucus, to which the soil adheres. Thus, the absorption of vital substances from the soil is facilitated. Next comes the bark layer, which acts as a protector of the central cylinder, the creator of vitamin compounds and the custodian of reserve substances, most often starch. The central cylinder is a conductive tissue through which all the elements absorbed and created in the two previous sections move upwards into the plant.
Absorption and release
To understand how root hairs provide absorption of substances from the soil, it is worth mentioning two features. The first is hair cellsable to envelop a particle of the earth and literally grow together with it. The second - for better absorption, the hairs secrete various acids (oxalic, malic, carbonic). It is these two features that are key in the process of plant nutrition.
Dimensions of the root hair system
We figured out the function of root hairs. But here is the question: "How are such meager (recall, the size of one root hair is 0.1-8 mm) processes capable of feeding, for example, a huge birch?" The answer turns out to be simple. They take not by size, but by quantity. If we talk about the shoot of rye, which is four months old, then it has approximately … 14 billion root hairs. This is only ten thousand kilometers of a thread that absorbs everything and everything in its path, with an absorption area, by the way, in the region of four hundred square meters. What can we say about huge plants, the root system of which will spread for many meters around the trunk in the upper layers of the earth (for example, the roots of a walnut extend up to twenty meters around themselves), or those that take root deep into the ground (the same walnut a nut can penetrate to a depth of six to seven meters).
The walnut tree given as an example fixes the soil well and protects it from landslides precisely thanks to its root system. A person uses these features to save areas at risk of landslides, and also unwisely, the same person cuts down the forests that hold their roots.highlands.
Root hair lifespan
The formation of such root organs occurs relatively quickly. Sometimes something about a day is enough for this - the terms are different for each plant. But the hairs live for ten to twenty days. They are gradually replaced by new ones, growing after the advancement of the root in the soil at the place where the root growth zone has coarsened, moving further behind the root cap.
Thus, we learned what the function of root hairs is, without delving too deeply into the terminology of the biological sciences, which is difficult for simple ears, and, in addition, considering the individual features of the root system as a whole along the way.
