**Ground Tissue Types:**
**Parenchyma:**
– Versatile ground tissue in plants.
– Constitutes filler tissue in soft parts.
– Forms cortex, pith, mesophyll, pulp, and endosperm.
– Often living cells capable of division.
– Large central vacuoles for storage and regulation.
– Simplest type of ground tissue.
– Functions in photosynthesis, storage, and secretion.
– Found in various plant organs.
– Cells have thin primary walls.
– Can differentiate into other types of cells.
**Collenchyma:**
– Composed of elongated cells with thickened walls.
– Provides structural support in growing shoots and leaves.
– Types include angular, tangential, annular, and lacunar.
– Living cells with primary cell wall of cellulose and pectin.
– Thicker walls under mechanical stress for support.
– Type of ground tissue.
– Provides support to plant organs.
– Alive at maturity.
– Found in stems, petioles, and leaves.
– Has unevenly thickened cell walls.
**Sclerenchyma:**
– Makes plants hard and stiff.
– Supporting tissue with fibers and sclereids.
– Cell walls consist of cellulose, hemicellulose, and lignin.
– Principal supporting cells in non-elongating tissues.
– Dead cells with thick secondary walls for strength.
**Fibers:**
– Long, slender prosenchymatous cells.
– Occur in strands or bundles, known as bast or fibers.
– Used for ropes, fabrics, and mattresses.
– Principal cell wall material is cellulose.
– Soft and elastic fibers like flax, hemp, jute, and ramie.
– Hard fibers found in monocots.
– Cell walls contain lignin besides cellulose.
– High load-bearing capacity.
– Originates from meristematic tissues.
– Associated with xylem and phloem in vascular bundles.
**Sclereids:**
– Reduced form of sclerenchyma cells.
– Have highly thickened, lignified walls.
– Form durable layers in plants.
– Variable in shape.
– Used to protect other cells.
The ground tissue of plants includes all tissues that are neither dermal nor vascular. It can be divided into three types based on the nature of the cell walls. This tissue system is present between the dermal tissue and forms the main bulk of the plant body.
- Parenchyma cells have thin primary walls and usually remain alive after they become mature. Parenchyma forms the "filler" tissue in the soft parts of plants, and is usually present in cortex, pericycle, pith, and medullary rays in primary stem and root.
- Collenchyma cells have thin primary walls with some areas of secondary thickening. Collenchyma provides extra mechanical and structural support, particularly in regions of new growth.
- Sclerenchyma cells have thick lignified secondary walls and often die when mature. Sclerenchyma provides the main structural support to the plant.
