The aerial part of plants is called the term"the escape". Its structure is due to the functions performed. Of course, each body is indispensable and determines the possibility of the existence of a biological species. Nutrition functions, growth processes, the possibility of adaptation are just some of the most important functions of the visible part of plant organisms.
In morphology, the axial and lateral partsof this organ: stalk and leaf. The structure of the shoot of the plant is striking in its variety: from the microscopic water duckweed to the giant forest sequoia. It is due to the different structure of the components of the above-ground part associated with the features of the habitat and climatic conditions. Here, too, are shortened rudimentary shoots - the kidneys.
The place where the sheet is attached to the axial partis called a node, and the angle that is formed between them is the sinus. Here are specialized kidneys that form leaves or flowers. The distance between the two places of attachment of the leaves is called the interstitial site.
The structure of the escape initially depends ondirection of growth and location in the space of the stem. Depending on these characteristics, erect erect, creeping, creeping, curling and clinging species are distinguished. Varied stems and the nature of the surface. It can be naked or with outgrowths, smooth or rough. If you cut the stem across, you can determine the shape: rounded, ribbed, with a certain number of faces or oblate.
The mustache of strawberries is also its escape, having shortened internodes.
Depending on the life formherbaceous and woody stems. The first do not have a cambium - a lateral educational tissue. In the first years of life, outwardly new shoots of trees and shrubs look like them. They are green and capable of photosynthesis. Over time, they become lighter, becoming more durable. They are able to hold large fruits and withstand strong wind gusts.
Depending on the features of the development cycleplants can be single, bi-annual and perennial. For example, asters fade in autumn, after which they die completely. Carrot and beet grow differently. In the first year of life, they form root crops, which are organs that store nutrients. In the autumn, their stem dies. But the plant exists in the form of a modified stem. With the advent of favorable conditions, the shoot again grows. At the same time for the second year of life on it as a result of flowering, seeds are formed, through which the plant multiplies.
The cycle of life of perennial plants,having studied the features of the structure of shoots of coniferous plants. These are shrubs or trees with a single powerful stem - the trunk. Its development begins with the germination of the seed. As a result of its growth, a seedling is formed, and then an adult plant. The life cycle of perennial plants ends with death. Conifers are considered to be real long-livers. So, the pine lives about 400 years, spruce - up to 500, and juniper - as many as 1000!
The lateral part of the shoot is no less functional andis diverse. It provides air supply, transpiration - evaporation of water from the surface, vegetative reproduction. Escape, the structure of which is determined by the functions performed, is characterized by a variety of leaves.
Cactus needles are needed to reduce the amount of moisture evaporated. A thumbnail wide at the horse chestnut, on the contrary, increases its number.
Leaves with a single plate are called simple, andwith several, located on one stalk, are complex. Considering them, you can see a certain pattern. It creates veins. These are vascular fibrous bundles of conductive tissue. By the nature of venation, the leaves are distinguished from mesh (maple, apple), parallel (corn, rye) and arched (plantain, lily of the valley) venation.
Escape, the structure of which depends on the quantityobtained by solar energy, is characterized by a different arrangement of leaves on the stem. In the case of their location, a regular spiral forms, and if the circle is opposite, or whorled.
In nature, there are no plants that do not renew foliage. She is thrown off both pine and spruce. Since not all the leaves fall off at once, no one notices this.
When there is a need to performadditional functions of shoots and their constituent parts are modified. Leaves can turn into spines or scales. In plant predators they are able to trap and digest small insects.
Features of the structure of escape can be considered andon an example of a bulb. Its flat modified stem is called the "bottom". There are several kinds of leaves on it: juicy - for storing water and nutrients, dry ones - for protection. In addition, from the kidneys, if there is a sufficient amount of water, young green leaves grow. The stalk root system also grows from the stem.
Jerusalem artichoke tubers, also calledearthen pear, also form a modification of the shoot - tuber. On the thickened fleshy stem are scarred kidneys, from which young shoots grow.
Underground stems with elongated intersticesare the rhizomes. They are similar to whips, they have well developed mechanical and conductive tissues. Of the kidneys located on the rhizome, leaves are formed. Those who are unfamiliar with the peculiarities of the structure of rhizomes, believe that if you get rid of the leaves, the whole plant will die. But this opinion is erroneous, because the main part of the plant is reliably protected and is underground.
The structure of the escape depends on the functions performed.This can be proved by considering the elements of the structure of its parts. The sheet is covered on the outside with a living tissue with a skin, in which are holes - stomata. They are necessary for protection and gas exchange. The internal content of the leaf is represented by the main storing and chlorophyll-bearing tissue, which is responsible for autotrophic nutrition of the whole plant. Elements of conductive and mechanical tissue, forming veins, are the basis for transporting the entire gamut of essential nutrients.
The vegetative organs of the plant are the root(its underground part) and escape. The structure of generative parts does not allow them to perform such functions. They carry out the process of sexual reproduction and spread of plants. But the flower develops on the stem, and for its development organic substances, formed in the leaves, are needed.
It can be concluded that the plant is a single organism, the functioning of parts of which is interrelated.
