Simple tissues are of three types namely parenchyma, collenchyma and sclerenchyma.
Permanent tissues are tissues wherein the growth process has been ceased. These tissues originate from both the primary and the secondary meristematic tissues and possess a definite shape and organization, however, they lack the potential to divide.
On the basis of its constituent cell, Permanent tissues can be classified into two major types:
- Simple tissue – parenchyma, collenchyma and sclerenchyma
- Complex tissue – xylem and phloem
Parenchyma – they are living cells and walled, soft in nature due to the presence of thin-walled cells
Collenchyma – These are characterized by uneven thick-walled living cells. This unevenness in the thickening of the cell walls imparts partially hard giving mechanical support derived essentially from the elongated cells of the ground meristems, procambium sometimes.
Sclerenchyma – They have cells with thickened lignified walls, providing them strength and making them waterproof.