Permanent Tissue

The tissues that are completely grown and has lost the ability of division are known as permanent tissues. The meristematic tissues divide and differentiate to form the permanent tissues.

permanent tissue

Types of Permanent Tissue

Simple Permanent Tissue

These are also known as homogenous tissues. They are made up of a single cell type, usually with the same origin, structure, and function.

Simple permanent tissue is further classified into three types:

Parenchyma

  • The cells have an oval or round shape.
  • The cell wall is made up of hemicellulose or cellulose.
  • The cell is thin-walled.
  • The cells have vacuoles and very small nucleus.
  • It is found in all parts of the plant.
  • The protoplasm is living and dense.

Collenchyma

  • Cells are long and thick walled.
  • The cell wall is made up of cellulose and pectin.
  • It is the only tissue with the highest refractive index due to the presence of pectin.
  • It is found in hypodermis of dicot stem and the vascular bundle of dicot leaf.
  • The amount of chloroplast is less in the cells.
  • The cells have no intercellular spaces.

Sclerenchyma

  • These are dead tissues, very hard and rigid in texture.
  • Cells are thick walled with various size and shapes.
  • These provide mechanical support and rigidity to the plant.

Complex permanent Tissue

The complex tissues are made up of different types of cells performing diverse functions. These are of two types:

Xylem

  • It transports water and nutrients from the roots to the leaves of the plant.
  • It provides support to the plants.
  • It is divided into-tracheids, vessels, xylem fiber, and xylem parenchyma.

Phloem

  • It translocates the prepared organic food from the leaves to different parts of the plant.
  • It is also known as bast.
  • It is composed of sieve tubes, companion cells, phloem parenchyma, and phloem fibers.

Special Tissues

The special tissues are structurally modified to perform secretory functions. These are of two types:

Laticiferous Tissues

  • These plant tissues contain latex.
  • They originate from the meristematic tissues and mature with other tissues.
  • The cells are elongated, thin-walled and multinucleated.
  • These are found in a large number of families such as Apocynaceae, Euphorbiaceae, Compositate, etc.

Glandular Tissues

  • These consists of different glands which secrete resins, oil, mucilage, tannin, etc.
  • These glands are located on the epidermis.

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