What are tissues?
The group of cells performing similar tasks collectively is called tissue. Tissues organize the body of an organism. Many types of tissues are associated with each other to perform efficiently and from the tissue system.
Collenchymaare the supporting tissues in plants. This article will discuss the definition, origin, shape, structure, and functions of collenchyma tissues.
Definition of Collenchyma
The word collenchyma is derived from the Greek word “kolla” meaning “glue” and énkhuma means “infusion”.
The parenchyma cells with uneven angular thickening which support the young growing part of the plant are called collenchyma. These forms separate continuous strands or cylindrical surfaces near the surface of the stem cortex, in petioles, and along the veins of leaves.
Collenchyma tissues are absent in roots. These tissues are absent in stem and leaves of many monocot plants.
Origin
Collenchyma establishes from the ground meristem or from procambium (e.g., Apium graveolens). They might likewise originate from extended cells, which look like procambium.
Structure of collenchyma
The walls are enlarged by high amounts of pectin as well as hemicellulose. Protein and cellulose are also present. Main pit areas can be differentiated in the wall surfaces. The cellulose microfibrils are either oriented transversely or at the same time transverse as well as longitudinal.
The longitudinal microfibrils may also alternate with no cellulosic materials, as is showed by electron microscopic research with the petiole of Apium graveolens.
The collenchyma tissues consist of chloroplasts in green organs. They form a complete cylinder in the stem as well as are present in the margin of leaves.
Characteristic of Collenchyma
These are long-living cells with differing cell wall thickness. The collenchyma includes cellulose, hemicelluloses, and pectic materials. Collenchyma gives flexibility to petiole, stems of young plants, leave vessels, support framework, and mechanism.
These are primarily found in young stems, under the epidermis, leaf capillaries, and also petiole.
It is likewise observed in avocado fruit hypodermis. Some collenchymas might perform photosynthesis and also store food.
Size and Shape
Different collenchyma tissues have different sizes and shapes. Mostly these cells are elongated with tapering ends. The longest collenchyma tissues are present in the central position. The shorter collenchyma tissues are present in the periphery.
Types of Collenchyma
Following are the types of collenchyma:
- Angular Collenchyma
The thickenings in the wall of these cells are present in the angles of the cells. They are found in the petioles of some plants.
- Lamellar Collenchyma
The thickenings in these tissues are present on the tangential walls of the cell. These are present in the stem, cortex of some plants.
- Lacunar Collenchyma
In these tissues, thickenings are present in the wall which faces intercellular spaces. Lacunar collenchymas are present in the petiole of composite species.
Functions of Collenchyma
- Collenchyma has considerable elasticity. Therefore, they provide mechanical support to plants.
- These are present in herbaceous stems. In this case, they provide support and strength to such weak stems.
- In some tissues, collenchyma contains chloroplast. Such collenchyma takes part in photosynthesis.
- Collenchymas are present around the vascular bundle in leaves and provide support to leaf tissues.
- The collenchymas form bundle sheaths and bundle caps in leaves.