Permanent tissue is those tissue that becomes mature and also has loosened the power of further division. Permanent tissues are composed of cells that do not go further cell division. All cells in permanent tissue are mature and fully functionalized. Cells of permanent tissue have a permanent s shape, size, and function due to morphological and biochemical differentiation. These cells have a low metabolic rate. Permanent tissue is also called mature tissue. Permanent tissue is a derived form of meristematic tissue. There are two types of permanent tissue in plants on the basis of the composition.
On the basis of composition, permanent tissue can be simple permanent tissue, complex permanent tissue, and special types of tissue or secretary tissue.
1. Simple Permanent Tissue
Simple permanent tissue is homogenous tissue that is made up of a similar group of non-dividing cells that performs a similar set of functions as well as similar origins. It is of three types: parenchyma, collenchyma, and sclerenchyma.
Parenchyma is a simple permanent tissue that is made up of thin-walled living similar oval, rounded or polygonal isodiametric cells with or without intercellular spaces. The cell wall is made up of cellulose. Internally each cell has a large central vacuole and has a peripheral cytoplasm and nucleus. Parenchyma is found in the non-woody or soft area of stems, leaves, roots, flowers, fruits, etc. It is classified into the following types to perform special functions:
- Simple parenchyma
- Pholem Parechyma
- Xylem Parenchyma
Collenchyma is a simple living permanent tissue with the deposition of cellulose and pectin in specific areas of their walls. It has a high refractive index. Cells of collenchyma are generally elongated, circular, oval, or angular in the transverse sections. Internally each cell possesses a large central vacuole and has a peripheral cytoplasm along with the nucleus. Few chloroplasts may be present. Depending upon the wall thickenings, collenchyma is three types: angular, lamellate, and lacunae collenchyma.
- Angular Collenchyma
- Lamellate collenchyma
- Lacunate collenchyma
Sclerenchyma is a simple highly thick-walled dead tissue. The cell wall is made up of cellulose or lignin or both. It s found in hard parts of plants and helps in mechanical supports and also helps in stiffness to the plant’s parts. Sclerenchyma is two types: Fibres and sclereids.
2. Complex permanent Tissue
Complex permanent tissue is heterogeneous tissue that is made up of different groups of cells to perform a common function. It is also called conducting tissue, vascular tissue, or physio-mechanical tissue. It consists of phloem and xylem.
Phloem is a complex permanent tissue that transports food in plants. It is also called bast. It consists of four types of cells: sieve elements, companion cells/ albuminous cells, phloem parenchyma, and phloem fibers.
Xylem is a complex permanent tissue that helps in the transport of water and minerals and also helps in mechanical strength. It has four components: tracheids, vessels, xylem or wood parenchyma, and xylem or wood fibers.
Hence, these are the types of permanent tissue in plants. Hope you understand this section very clearly. If you have any comments and queries then please comment down.
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