Tissues are structures consisting of many similar cells that are united by common functions. All multicellular animals and plants (with the exception of algae) are made up of different types of tissues.
What are fabrics?
Animal tissues are divided into four types:
- epithelial;
- muscular;
- connecting;
- nervous tissue.
All of them, with the exception of the nervous one, are subdivided, in turn, into types. So, the epithelium can be cubic, flat, cylindrical, ciliated and sensitive. Muscle tissues are divided into striated, smooth and cardiac. The connective group combines fat, dense fibrous, loose fibrous, reticular, bone and cartilage, blood and lymph.
Plant tissues are of the following types:
- educational;
- conductive;
- covers;
- mechanical cloth;
- excretory (secretory);
- basic tissue (parenchyma).
All of them are divided into subgroups. So, educational tissues include apical, intercalary, lateral and wound tissues. Conductors are divided into xylem and phloem. Integumentary tissues combine three types: epidermis, cork and crust. Mechanical is dividedon collenchyma and sclerenchyma. Secretory tissue is not divided into types. And the main tissue of plants, like all others, is of several types. Let's take a closer look at them.
What is the main tissue of plants?
There are four types of it. So, the main fabric happens:
- aquifer;
- airy;
- Assimilation;
- reserve.
They have a similar structure, but they also have some differences from each other. The functions of the main tissues of these four types are also somewhat different.
The structure of the main fabric: general characteristics
The main tissue of all four species consists of living cells with thin walls. Tissues of this type are so called because they form the basis of all the vital organs of the plant. Now let's look at the functions and structure of the main tissues of each type separately in more detail.
Water-bearing tissue: structure and functions
The main tissue of this species is built from large cells with thin walls. The vacuoles of the cells of this tissue contain a special mucous substance that is designed to retain moisture.
The function of an aquifer is to store moisture.
Aquiferous parenchyma is found in the stems and leaves of plants such as cacti, agave, aloe and others growing in arid climates. Due to the large amount of such tissue, the plant can stock up on water in case it does not rain for a long time.
Features of the air parenchyma
The cells of the main tissue of this species are at a distance from each other. Between them are intercellular spaces in which air is stored.
The function of this parenchyma is that it supplies the cells of other plant tissues with carbon dioxide and oxygen.
This tissue is present mainly in the body of marsh and aquatic plants. It is rare in land animals.
Assimilation parenchyma: structure and functions
It consists of medium-sized cells with thin walls.
Inside the cells of the assimilation tissue, there are a large number of chloroplasts - organelles responsible for photosynthesis.
These organelles have two membranes. Inside the chloroplasts are thylakoids - disc-shaped sacs with the enzymes they contain. They are collected in piles - grains. The latter are interconnected with the help of lamellae - elongated structures similar to thylakoids. In addition, chloroplasts contain starch inclusions, ribosomes necessary for protein synthesis, their own RNA and DNA.
The process of photosynthesis - the production of organic substances from inorganic substances under the action of enzymes and solar energy - occurs precisely in thylakoids. The main enzyme that provides these chemical reactions is called chlorophyll. This is a green substance (it is thanks to it that the leaves and stems of plants have such a color).
So, the functions of the main tissues of this species are the photosynthesis mentioned above, as well as gas exchange.
Assimilation tissue is most developed in the leaves and upper layers of stems of herbaceous plants. It is also present in green fruits. Assimilation tissue is not located on the very surface of the leaves and stems, but under the transparent protective skin.
Features of the storage parenchyma
The cells of this tissue are characterized as medium in size. Their walls are usually thin, but can be thickened.
The function of the storage parenchyma is the storage of nutrients. As such, in most cases, starch, inulin, and other carbohydrates serve, and sometimes proteins, amino acids and fats.
This type of tissue is found in the embryos of the seeds of annual plants, as well as in the endosperm. In perennial grasses, bushes, flowers and trees, storage tissue can be found in bulbs, tubers, root crops, and also in the core of the stem.
Conclusion
Basic tissue is the most important in the plant body, as it is the basis of all organs. Tissues of this type provide all vital processes, including photosynthesis and gas exchange. Also, the main tissues are responsible for creating stocks of organic substances (starch in the largest amount) in the plants themselves, as well as in their seeds. In addition to nutrient organic compounds, air and water can be stored in the parenchyma. Not all plants possess air and water-bearing tissues. The former are present only in desert varieties, and the latter in swamp varieties.
