Plant Strengthening Tissues: Definition, Collenchyma, Sclerenchyma, Characteristics, Types and Structures

Plant Strengthening Tissues: Definition, Collenchyma, Sclerenchyma, Characteristics, Types and Structures – What are the plant reinforcement tissues and their differences?, On this occasion About the knowledge.co.id will discuss it and of course about other things that also cover it. Let's look at the discussion together in the article below to better understand it.

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Plant Strengthening Tissues: Definition, Collenchyma, Sclerenchyma, Characteristics, Types and Structures

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Reinforcing network or often referred to as supporting network is one of the constituent networks Plants that function to strengthen or support the plant body so that plants can stand upright.

Based on the shape and nature, there are 2 (two) plant supporting tissues, namely collenchyma tissue and sclerenchyma tissue.

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Collenchyma Network

The definition of collenchyma tissue is a network that functions as a strengthening or supporting tissue in plant organs that are still actively growing and developing.

Collenchyma tissue is composed of living cells, has an elongated shape and generally has walls with irregular thickening. The thickening of the walls mainly occurs at the corners and consists of a thick cellulose material.

Collenchyma tissue only has a primary wall which is soft, flexible and not lignified. The cell contents may contain tannins and chloroplasts. Collenchyma can be found on stems, leaves, flowers, and fruits and roots that are exposed to sunlight.

• Characteristics of Collenchyma Network

Characteristics or features of collenchyma tissue, namely:

• • Has an elongated shape parallel to the center of the organ where the collenchyma is located.
  • Collenchyma cell walls are not lignified, but contain cellulose, pectin and hemicellulose.
  • Some collenchyma cells have chloroplasts so they can function to support photosynthesis.
  • Usually collenchyma cells experience local thickening.

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  Kinds of Colenchyma Network

Based on the shape of the thickening and its location, the types of collenchyma tissue can be divided into:

• • Angular collenchyma
    Angular collenchyma (corner) is collenchyma tissue that is thickened at the corners. This collenchyma tissue can be found in leaves, for example the leaves of the celery plant.
  • Lamellar collenchyma
    Lamellar collenchyma (tangential) is collenchyma tissue that is thickened in the tangential or spreading part of the cell wall. This tissue supports the strength of the outer layers of plant structures, such as stems or leaves.
  • Annular collenchyma
    Annular collenchyma is collenchyma tissue whose cell walls are evenly thickened. This type of collenchyma is rarely found because it is only found in carrot leaves and some vines.
  • Lacunar collenchyma
    Lacunar collenchyma (lacunate) is collenchyma tissue that has thickened on the surface of the space between cells.

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  Location of collenchyma in plants

Collenchyma tissue can be found in stems, leaves, as well as in flower and fruit parts. In stems, collenchyma may form fully cylindrical or arranged into bundles that extend parallel to the axis of the stem. In leaves, collenchyma is found on both sides of the main leaf vein or on one side only, and is also present along the edge of the leaf.

Rarely found on the roots that are in the ground. Only occasionally are plants whose roots rise above the ground to find collenchyma tissue, because the formation of collenchyma tissue occurs when exposed to sunlight. And usually there is collenchyma directly under the epidermis.

• Collenchyma structure

Sizes and shapes vary. It can be short prisms or long elliptical like fibers with tapered ends and there is an intermediate form between the two forms.

According to Muller, there are three main forms due to thickening of the collenchyma cell walls:

• • Angle collenchyma or angular collenchyma. with longitudinal thickening at the corners of the cells. In cross sections, corner thickening is seen where three or more cells meet. For example on the stems of Solanum tuberosum and on Salvia.
  • Plate or plank collenchyma, with thickening especially on the tangential walls. For example, in the cortex of the trunk of Sambucus nigra
  • Lacunar collenchyma, which is similar to corner collenchyma, but contains many intercellular spaces around which wall thickening occurs. For example on Ambrosia stems.
  • Duchaigne (1955 in Fahn, 1982) provides an additional type of collenchyma, namely ring (annular) collenchyma.

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  Collenchyma cell arrangement

Can be found on stems, leaves and on the flowers, fruits and roots, especially if the roots are exposed to light. The collenchyma cell wall is an example of a primary wall that expands and thickens as the cell grows larger.

The collenchyma walls are mainly composed of cellulose and pectin compounds and contain a lot of water. The fresh material of the collenchyma walls contains about 67% water. Fahn (1982) stated that according to Roelofsen collenchyma cell walls contain 45% pectin, 35% hemicellulose and about 20% cellulose.

Collenchyma cells have active protoplasts which are capable of eliminating wall thickening when the cells are stimulated to divide as when the cells form cork cambium. Collenchyma such as parenchyma can contain chloroplasts so that it can carry out photosynthesis.

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Sclerenchyma Network

Sclerenchyma tissue is a network of reinforcement or supporting tissue with a thick secondary wall because it contains lignin. This sclerenchyma tissue is only found in plant organs that no longer carry out growth and development.

Sclerenchyma tissue consists of sclerenchyma fibers (sclerenchyma fibers) and sclereids (stone cells). Sclerenchyma fibers are long, slender, and are found in strands or circles. Sclerenchyma fibers can be found in flax, Agave, and Hibiscus sabdariffa fibers.

Meanwhile, sclereids are shorter in size and have an irregular shape. Actually sclereids can be found in all parts of the plant, especially the bark, sieve tubes and seeds. The coconut shell is almost entirely composed of sclereids.

Stone cells in fruit can provide characteristics, for example a sandy structure on the skin of the fruit and pear flesh or sandy grains on the flesh of a guava.

The function of the sclerenchyma tissue is to strengthen the parts of plants that are mature or not undergo growth and development as well as protect the parts or soft organs that are in inside. For example in coconut shells, castor seed shells and walnuts.

Sclerenchyma tissue is a supporting tissue found in plant organs that are no longer experiencing growth and development or in mature plants. Sclerenchyma tissue consists of fibers (sclerenchyma fibers) and sclereids (stone cells).

Sclerenchyma tissue is a mechanical tissue that is only found in plant organs that no longer carry out growth and development or fixed plant organs. Sclerenchyma functions to withstand all pressures so that it can protect weaker tissues.

Sclerenchyma does not contain protoplasts, so the cells are dead. The cell wall is thick due to the previous secondary thickening which consists of lignin.

• Characteristics of cells in sclerenchyma tissue

  • The cells are dead with thick cell walls
  • Thick secondary wall, generally composed of lignin
  • It is rubbery, generally no longer contains chloroplasts
  • The cells are more rigid than collenchyma, sclerechyma cells cannot elongate

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  Types of Sclerenchyma Tissue

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    Sclerenchyma Fibers (Fibers)

The sclerenchyma fibers consist of cells that are ± 2 mm in length and the sides are pointed at the ends. Sclerenchyma fibers are dead cells. The cell wall is thickened from wood and contains cellulose lamellae so that the cell lumen is narrow.

These fibers are in the form of polygons, namely pentagons or hexagons. The nooks are narrow which are shaped like narrow sloping channels. Sclerenchyma fibers in plants are formed at the same time when the growth of organs in plants stops.

Sclerenchyma fibers are found in separate strands or in whorls in the cortex and phloem, in scattered groups in the xylem and phloem. In Gramineae, the sclerenchyma fibers are arranged in a circular, squiggly system connected to the epidermis.

There are two types of sclerenchyma fibers, namely as follows.

• • • Fiber Outside the Xylem (Extraxilaris)

Some extraxilaris fibers are lignified and some are not. This fiber can be used to make rope, jute sacks, and textile base materials for clothing.

• • • Xylem Fiber (Xilari)

This type of fiber is the main component of wood because its walls contain lignin which makes the walls hard and stiff.

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    Stone Cells (Sclereids)

Sclereids are found in plant parts, including in the cortex, phloem, fruit, and seeds. The sclereid wall is composed of cellulose which contains a thick and hard lignin substance. In some plants, suberin and cutin are sometimes found.

The cells have narrow nodules and the slits are round, forming a canal called a nodal canal. The cell lumen is very narrow due to thickening of the cell wall.

Sclereids may be found singly or in small groups between cells, such as granules such as sand on the guava fruit flesh or a continuous mass such as on a coconut shell hard.

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