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PLANT TISSUES

Presented byNisha .W.J

Cells of common features join together toperform a special function.. These group of cellsare called tissues. Tissues seen in plants arecalled plant tissues.

Plant Tissues

Tissue formed of same kind of cells with thin cell wall. Itseen in soft parts of plants. Cell wall is made up of cellulose andcalcium pectate.

Paranchyma

Storage of reserve food materials.

Storage of water in succulent plants.

Helps in respiration and secretion.

Air storage, buoyancy and gas exchange in water plants.

Helps in regeneration and wound healing by meristamaticactivity.

Functions of parenchyma

Collenchyma tissue of similar cells with thickened cellwalls only at the corners. The corners of the cell walls becomethickened due to the deposition of substanes like suberin,pectin, cellulose etc.

Collenchyma

Serves an the chief supporting tissue.

Protect leaves from tearing.

Prevents the bending and breaking of stems.

Gives great flexibility to plant organs.

Some collenchymas possess chloroplast and carryout photosynthesis.

Occasionally it act as a meristemm during secondary thickening.

Functions of collenchyma

Tissue formed of thick walled cells, thickness is due to thedeposition of a substance called lignin. Hard plant parts aremade up of sclerenchyma cells. Sclerenchyma consist of twotypes namely, fibres and sclerids.

Sclerenchyma

Serve as a mechanical tissue.

Protect plant, body from damages, physical pressures etc.

Xylum fibres help the conduction of water

Fibrous sclerenchyma of fruits and seed help in dispersal of seeds.

Sclereids of some nuts from a hard protective cell.

Functions of Sclerenchyma

Xylum tissue is formed of elongated cells. These cellsunite together and are seen as pipes. Water and minerals absorbedby the roots reaches the leaves through these pipes. Due to thedeposition of lignin, the cells become hardened.

Xylum

Conducts water and solutes from roots to stem.

Serve as a supporting mechanical tissue.

Forms wood.

Xylem parenchyma stroes, water starch, fat etc.

Ray parenchyma brings about the radial conduction of water and solutes.

Functions of xylum

Phloem tissue formed of elongated cells.They areformed as pipe like structure.The food prepared in the leavesreaches the different parts through these pipes.

Phloem

Functions of phloem

Translocation of organic nutrients.

Phloem fiber s provide mechanical support and elasticity.

Storage of organic nutrients and other substances.

Reference

Angiosperm Antony Reproductive botany And palynologyIV th Semester Degree Programme – Kerala

VIII th Science text book IInd Part

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