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 composed of various types of tissues.
What are the fabrics?
In animals, tissues are divided into four types:
- epithelial;
- muscle
- connecting;
- nerve tissue.
All of them, with the exception of the nervous one, are divided, in turn, into species. So, the epithelium can be cubic, flat, cylindrical, ciliated and sensitive. Muscle tissue is divided into striated, smooth and cardiac. The group of connectives combines fatty, dense fibrous, loose fibrous, reticular, bone and cartilage, blood and lymph.
Plant tissues are of the following types:
- educational;
- conductive;
- coverslips;
- mechanical fabric ;
- excretory (secretory);
- main tissue (parenchyma).
All of them are divided into subgroups. So, educational tissues include apical, intercalary, lateral and wound. Conducting are divided into xylem and phloem. The integumentary tissues combine three types: epidermis, cork and peel. Mechanical is divided into 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 consider them in more detail.
What is the main tissue of plants?
There are four types of it. So, the main fabric is:
- aquifer;
- airy;
- assimilation;
- storage.
They have a similar structure, but they also have some differences from each other. The functions of the main tissues of these four species are also somewhat different.
The structure of the main fabric: a general characteristic
The main tissue of all four species consists of living cells with thin walls. Tissues of this type are called so because they form the basis of all vital organs of the plant. Now let's look at the functions and structure of the main tissues of each species separately in more detail.
Aquifer tissue: structure and function
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 that it stores moisture.
The aquiferous parenchyma is found in the stems and leaves of plants such as cacti, agave, aloe and others growing in an arid climate. 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 airborne 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.
Such tissue is present mainly in the body of marsh and aquatic plants. In land, it is rare.
Assimilation parenchyma: structure and functions
It consists of medium-sized cells with thin walls.
Inside the cells of assimilation tissue in large numbers are chloroplasts - organoids responsible for photosynthesis.
These organoids have two membranes. Inside the chloroplasts are thylakoids - disk-shaped sacs with the enzymes contained in them. 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, intrinsic RNA and DNA.
The process of photosynthesis - the production of organic matter from inorganic substances by the action of enzymes and solar energy - occurs precisely in thylakoids. The main enzyme that provides these chemical reactions is called chlorophyll. This substance is green (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 the stems of herbaceous plants. It is also present in green fruits. Assimilation tissue is not located on the surface of the leaves and stems, but under a transparent protective skin.
Features of storage parenchyma
The cells of this tissue are characterized as medium in size. Their walls are usually thin, but can also be thickened.
The function of the storage parenchyma is the storage of nutrients. As such, in most cases, starch, inulin, as well as other carbohydrates, and sometimes proteins, amino acids and fats, are used.
This type of tissue is found in the seed embryos of annual plants, as well as in the endosperm. In perennial grasses, bushes, flowers, and trees, the storage tissue can be found in bulbs, tubers, root crops, and also in the core of the stem.
Conclusion
The main tissue is the most important in the body of the plant, as it is the basis of all organs. Tissues of this type provide all vital processes, including photosynthesis and gas exchange. The main tissues are also responsible for the creation of stocks of organic substances (the largest amount is starch) in the plants themselves, as well as in their seeds. In addition to nutritious organic compounds, air and water can be stored in the parenchyma. Not all plants possess airborne and aquiferous tissues. The former are present only in desert species, and the latter in marsh species.