Permanent tissue is that tissue in which cells are unable to divide and gain shape, size, and function due to differentiation. Depending upon the composition, permanent tissues can be two types: (a) Simple permanent tissue- These tissues are made up of a similar type of cells which perform the same function or similar set of function. These tissues are of three types- parenchyma, collenchyma, and sclerenchyma. Parenchyma is living tissue with a thin cellulosic cell wall. They have intercellular spaces in them. Vacuoles are also present in them. The main function of parenchyma is the storage of food. Collenchyma is also living cell but with pectocellulose thickening in the corner of the cells. Intercellular space is absent. Their main function to provide strength along with flexibility. Sclerenchyma is dead tissue. Their cell wall has a deposition of lignin. Their main function is to provide strength to the plant. (b) Complex permanent tissue- They are made up of different type of cells. E.g. phloem and xylem.
