Parenchyma
– occur in roots and shoots
– relatively unspecialized/and dominant
– retain ability to undergo meristematic/actively dividing activity
– have thin primary walls
– no secondary walls
– have large vacuoles surrounded by peripheral cytoplasm
– mainly functions in storage of nutrients and water
– but when turgid, parenchyma tissue is important in giving support and shape to the plant
Collenchyma
– Relatively simple tissue
– cells remain alive/may become meristematic
– more elongated than parenchyma cells
– walls are irregularly thickened
– thickening of walls usually around the corners
– occur in stems and leaves
– functions as important supporting tissues to young plants
– also in older non-woody plant stems and in leaves
Schlerenchyma
– specialized supportive cells
– dead at maturity
– have thick hardened secondary walls
– very small/narrow lumen
– made up of fibres and sclereids
– fibres are elongated with tapered ends
– fibres are tough, strong but flexible
– sclereids are often irregularly shaped
– unbranched sclereids are called stone cell
– common in hard part of seeds, etc.