These are composed of fully differentiated mature cells that have lost the power of division. They have attained their definite form and size.
Characteristic features of permanent tissues:
(i) Cells may be living or dead.
(ii) Cell walls may be thin or thick.
(iii) Cells may contain reserve, excretory or secretory substances.
(iv) Intercellular spaces may be present or absent.
(v) Metabolic activities are relatively slow.
(vi) Vacuoles prominent.
Classification of permanent tissues:
On the basis of origin, permanent tissues are of two types (a) Primary permanent tissues which develop from primary meristematic tissue, eg. Parenchyma, collenchymas etc. (b) Secondary permanent tissues which develop from secondary meristems. eg. Secondary xylem, secondary phloem, cork etc.
On the basis of function, permanent tissues are of the following types
(i) Photosynthetic or assimilatory tissue.
(ii) Food storing tissue.
(iii) Conducting or vascular tissue.
(iv) Secretory tissue
(v) Mechanical tissue
(vi) Protective tissue
Broadly permanent tissues are of the following three types:
(i) Simple tissues
(ii) Complex tissues
(iii) Special or Secretery tissues.
A simple tissue is made up of one type of cells forming a homogenous or uniform mass. These are of following three types: