In the process of forming the plant body, branching formed, i.e., a certain system of branched axes arose. Thanks to him, the living body significantly increases the total area of contact with the earth, water and air. In lower plants, as a result of this process, a system of thalli or thalli is formed. The higher ones have roots and shoots. The branching mechanisms of each group of plants differ significantly from each other.
general information
The main stem is the stem (axis) of the upper order, the axis of the second are the lateral stems formed from the lateral buds. They also continue to branch and form rods of the third, fourth order and so on. If the vertex of the main axis branches in a fork-like manner and gives rise to two or more axes of the next order, then this is a dichotomous branch, or apical. This type is inherent in multicellular plants that live in water and some telome plant organisms. For others, lateral branching is more characteristic, with the so-called lateral outgrowths forming on the main rod giving rise to the lateral rods. As a result, a system of roots, shoots or thalli appears.
Branching varieties
Living plant organisms have the following branching types that determine their appearance:
- Sympodial - in this case, the main core stops growing or dies.The plant continues to grow due to the lateral axes, one or two. With this type of branching, they do not grow very high. However, many side shoots provoke a huge seed formation. This branching of linden and birch is pronounced.
- False dichotomous - the development of the main axis stops. The two axes formed below become the main and develop approximately the same. Then they stop growing and are replaced by others, i.e., axes of the next order. Such branching is present in horse chestnut, lilac and in the inflorescences of some flowering plants.
- The forked (dichotomous) branching is considered the most primitive or initial. The process is as follows: the apical (apical) meristem bifurcates, forming two lateral branches, also giving two of the same, and so on. Such branching is characteristic for mosses, plunds, algae, some ferns and gymnosperms.
- Monopodial - the shoot grows in height due to the main rod, called monopodia. Side shoots, which are also able to branch, depart from it. However, they do not exceed the main axis in height ever. Such branching occurs in conifers, as well as in horsetails.
- Tillering - in this case, branching is carried out at the tillering node, i.e., at one node at the surface of the earth. You can observe it in cereals. Dense perennial bushes are called turf.
Comparative characteristics of branch types
Consider a brief description of the different types of branching:
- Dichotomous - two branches grow from the apex of the cone, and then two again grow from the apical cone of the growth of each formed branch. It is observed in algae, bryophytes and grouse.
- Monopodial - growth and increase in the volume of the main stem lasts throughout life due to the apical kidney. Lateral branches are less developed. Such branching is typical for beech, spruce, pine.
- Sympodial - the top of the main stem has no development. But the side kidney closest to it forms an escape, and already it continues to grow the stem. As an example - walnut, apple tree, linden.
Branching in higher plants
In telome plants, these types of branching are distinguished:
- Sympodial - in a certain period, the apical bud of the shoot dies (disappears) and lateral development occurs, which can be one or more. From them sprouts grow, replacing those that have stopped growing. The resulting sympathies in the outcome of this process are the axial organ of the plant. The possibility of escaping to sympodial growth is very important, since with various damage to the upper kidney, the axis is built up by lateral shoots. Thanks to this branching, it is quite easy to form foliage in shrubs and trees.
- Monopodial is the result of the work of one apical meristem (educational tissue), i.e., when each axis in the branching system is monopod. This branching occurs in both gymnosperms and angiosperms.
Monopodial branching
In this type of branching, there is a main axis that goes up from the base of the plant body to its apex, forming axes of the second order due to axillary buds. Then the latter in their development also repeat the main axis, that is, on the axes of the second order the axes of the third are formed, and this continues further.
Moreover, throughout the life of the plant, the main stem grows in size and grows due to the apical bud. You can see such branching in land plants - fir, spruce, ash, oak, dandelion, clover.
Branching shoots
A shoot is a vegetative organ of a plant equipped with a stem, buds and leaves.
Branching is an action that results in the formation of new (other) shoots. This is an axial organ, therefore it has a group of educational cells (apical meristem), due to which it grows in length. Due to the growth of its constant branching. In higher plants, as a result, root and shoot systems appear, and in lower ones, a branched thallus. Branching shoots makes it possible to better supply the plant with nutrients of an organic nature and significantly increase the photosynthetic surface.
Forked branch
Branching determines the structure of the aerial parts of the plant. The forked is a special branching order in which at the peak the main axis is divided into two. The latter develop almost identically, and the main one stops its growth. A variant of dichotomous branching occurs at the root, shoot or venation of the leaf. In the latter case, the veins in the leaf plate branch forked. For example, in ferns or ginkgo bilobate. Apical branching is inherent in fungi, many algae, the plaiform and fern-shaped and other living forms that do not have shoots.
As a result of the branching process, the appearance of the same type of plant elements occurs, which to one degree or another recreate each other and are interconnected. In higher plants, forked branching is extremely rare.