Ground tissues:Parenchyma, Collenchyma, Sclerenchyma

hardness:
P < C < S PCS

Parenchyma
Place: Found in cortex and pith of stem and cortex of root and mesophyll of leaves.

features:made up of thin-walled living cell, metabolically active and capable of division, capable of elongation, potentially meristemic(modified to form epidermal cell)

functions:
1.mechanical support of non-woody plant,
2. facilitate gas exchange,
3. contains chloroplast for photosynthesis

Collenchyma
place: under the epidermis of stems and around the midrib of leaves.

features: similar to parenchyma, with additional deposits of cellulose at the coners of the cell walls .

functions:
1. mechanical support to young, actively glowing stems and leaves.

Sclerenchyma
features: dead cells with cell contents lost----thickened and impermeable to water, evenly thickened cell wall

secondary thickening: laying down of secondary cell wall which is highly lignified on the primary cell wall except at the pit. It formed when the cell growth is stopped.

functions:
1. high mechanical strength provided by high tensile strength and compressional strength of lignin.

Fibres:
elongated and tapering cells
found in vascular tissues(phloem...), behind epidermas

Sclereids:
shorty and relatively spherical
behind epidermas, cortex, fruits, seeds