The permanent tissue which are homogenous and is composed of structurally and functionally similar type of cells. The main simple permanent tissues of the plants are;
1. Parenchyma 2. Collenchyma 3. Sclerenchyma
Parenchyma: It is the most common type of tissue which simple and unspecialized. It is distributed all over the different parts of the plant mainly in the softer portions of the parts of the plant body. it is usually isodiametric and vary in shape.They are closely packed with small inter cellular space.
Collenchyma: It is a living tissue with elongated cells which is thick walled.The cell wall of collenchyma is unevenly thickened; it is composed of cellulose, hemicellulose, and pectic materials. It is found in the hypodermis of certain plants and also on both sides of the veins in the leaves.
Sclerenchyma: Sclerenchyma are simple tissue meant for the mechanical function. It is thick walled and lignified and is characterized by the absence of living protoplasm. The sclerencyma gives mechanical strength to the plant organ, firmness and stiffness to the part of the plant where it is present.