What is mechanical organization Where is mechanical organization distributed?

Mechanical tissues are a group of cells with a significantly thickened cell wall, which has the effect of supporting the plant body or increasing its consolidation to withstand mechanical stress. According to whether it is cellulose thickening or intrinsic thickening, as well as the location and degree of thickening, it can be divided into two categories: thick-angled tissue and thick-walled tissue.

1) Thick horn tissue: The cells of thick horn tissue are living cells, often containing chloroplasts, and the cell wall is composed of cellulose and pectin, which is not lignified and unevenly thickened, generally thickening at the corner of the corner. Pachycarpus is the supporting tissue of the young organs (stems, petioles, peduncles) of the aboveground parts of dicots.

It is mainly distributed in rings or bundles under the epidermis of these organs, and in many young stems with edges and corners, thick-horned tissues are often concentrated in the edges and corners, such as motherwort stems.

2) Firmicute: Firmicute: Firmiform tissue is characterized by its cells having thick secondary walls, often with laminar lines and pores, and small cell cavities after mature cells, which become dead cells. According to its cell morphology, it can be divided into fiber and stone cells.

Fibers: are elongated cells with cellulose or lignified thickened cell walls. Usually dead cells, usually in bundles.

The tips of each fibroblast are tightly intercalated with each other for reinforcement. The fibers distributed in the skin are called baloem fibers or cortical fibers, and these fibers are generally more prominent in the pores and cell cavities, such as cinnamon. The fibers distributed in the essence are called wood fibers, and wood fibers tend to be extremely lignified and thickened, and the cell cavity is usually small, such as Kawaki-dori.

There is also a type of fiber that has a thin diaphragm in the cell cavity, and this fiber is called a separating fiber. In addition, there is also a kind of "crystal sheath fiber" is a general term for a complex composed of many parenchyma cells containing calcium oxalate square crystals surrounded by a bundle of fibers, such as licorice, cork, etc.

Stone cells: These are cells with significantly thickened and lignified cell walls and gradual death. The unthickened part of the cell wall is thin tubular and sometimes branched, projecting out in all directions.

As a result, tiny pores can be seen in the cell wall, called pores or striae, and the texture formed by the gradual thickening of the cell wall is called laminar striae. The shape of the stone cells is mostly spherical or polyhedral shaped, but there are also short rods or branched, and the size is also variable. Stone cells are often distributed in single or group parts of plants, such as Codonopsis, Phellodendron chinensis, star anise, and almonds. The leaves or flowers of some plants are also distributed, and these stone cells are usually branched, so they are also called teratomorphic stone cells or pillar cells.

Mechanical organization is the smallest component of mechanical equipment, the basic object of mechanical design, and the cause of mechanical failure is also the main replacement object of mechanical maintenance. The main mechanical parts are screws, nuts, cams, gears, pulleys, sliders, bearings, shafts, etc.

The mechanical tissues are distributed around the various organs that are still growing, and in the mature organs of herbaceous plants with little or no secondary growth. Thickhorn tissues are composed of living cells, and the cell wall of thickhorn tissues is more plasticity than phloem fibers and has considerable tensile stress.

Mechanical tissue is the tissue that plays the main role of supporting and protecting plants. It has a strong ability to resist compression, tensile and flexure, the plant can have a certain hardness, the branches can stand upright, the leaves can be flattened, and can withstand the invasion of storms and other external forces, all of which are related to the existence of this tissue.

According to the different cell structures, mechanical tissues can be divided into two types: collenchyma and sclerenchyma.

Distribution of thick-horned tissues:

Thick horn tissue is distributed in stems, petioles, leaves, flower stalks and other parts, and is generally absent in roots. The distribution of thick-horned tissues has a distinct characteristic, that is, it is generally always distributed in the periphery of the organ, either directly under the epidermis, or separated from the epidermis by only a few layers of parenchyma cells.

In stems and petioles, the thick-horned tissues tend to form continuous cylinders or separate bundles, and are often particularly developed in the ridged parts of stems and petioles with ridged protrusions, such as in the square stems of mint, and in the ridged stems and petioles of pumpkin and celery. In the leaves, the thickhorned tissues are located in bundles on one or both sides of the larger veins.

It is found in herbaceous plant stems, woody stems that have not yet undergone secondary growth, petioles, main veins of leaves, peduncles, etc. It is often located under the epidermis and is distributed in rings or bundles. In ridged stems, the ridge is particularly well developed to enhance the support of the stem.

The function of mechanical tissue is the tissue that plays the main supporting and protective role of plants.

It has a strong ability to resist compression, tensile and flexure, the limbs can have a certain hardness, the branches can stand upright, the leaves of the tree can be flattened, and can withstand the invasion of storms and other external forces, all of which are related to the existence of this tissue. According to the cell structure.

The mechanical tissues can be divided into collenchyma and sclerenchyma.

Related Introductions

Mechanical tissues are found around various organs that are still growing, and herbaceous plants with little or no secondary growth.

of mature organs. Thickhorn tissues are all composed of living cells, and thickhorn tissues have a cell wall.

is more plasticity than phloem fibers and has considerable tensile stresses, such as the strength of thick-horned tissue bundles in celery petioles than vascular bundles in the same petiole.

Big. The most obvious feature of the mechanical tissue thickhorn histiocytes is that the cell wall has an uneven thickening, and this thickening is of a primary wall nature. The thickening of the wall is usually particularly noticeable at the angular septum at the adjacency of several cells, so it is called pachyangular tissue.

a. The epidermis of onion scale leaves has the function of protecting the mesophyll and belongs to the protective tissue, so it is incorrect;

b. The cambium layer of the stem of dicot plants, which has meristemic ability and belongs to meristem, is incorrect;

5. D wood fiber and bast fiber have a strong supporting role and belong to the mechanical organization, so they are correct;

Therefore, 5d is chosen

Mechanical tissues can be divided into two categories: collenchyma and sclerenchyma. Mechanical tissue is the tissue that plays the main role in supporting and protecting the source of plant grinding. It has a strong ability to resist compression, tensile and flexure, the plant can have a certain hardness to match, the branches can stand upright, the leaves can be flattened, and can withstand the invasion of storms and other external forces, all of which are related to the existence of this tissue.

Thickhorn collenchyma is a type of plant mechanical tissue, the most obvious feature of its cells is that the cell wall has an uneven thickening, and this thickening is of a primary wall nature. They are mainly distributed in the inner epidermis of the stem and petiole of the angiosperm primary plant body, which not only harmonizes with the growth of stems and leaves, but also plays a mechanical supporting role in these blind organs, especially when the xylem is not fully developed, this effect is more significant.