Plant tissue systems

This presentation explains about the organisation of different plant tissues

1. PLANT TISSUE SYSTEMS Mentor: Dr. T. Annie Sheron Assistant Professor of Botany Kakatiya Govt. College, Hanamkonda Ms. D. Shilpa II Yr. B. Sc. ( Bt.B.C .) Kakatiya Govt. College, Hanamkonda

2. A group of cells with common origin, structure and function is known as Tissue. The group of tissues which perform only one important function is known as Tissue system . The study of tissues is known as Histology. Depending upon their nature, structure and function tissues are divided into three categories. 1.Meristematic tissue 2.Mature or permanent tissue 3.Secretory tissue

3. MATURE TISSUES In this type of tissues growth is ceased either temporarily or permanently. They lost their divisional capacity temporarily or permanently and perform specialized functions These cells may be living or dead with thin or thick cell walls. Based on the number of kinds of cells involved in the composition of a tissue, permanent tissues are of 2 types. 1.Simple tissue 2.Complex tissue

4. SIMPLE TISSUES Homogeneous in nature and composed of structurally and functionally similar cells. The common simple tissues are Parenchyma Collenchyma Sclerenchyma

5. PARENCHYMA Repair the wounds ( Totipotency ) Buoyancy Photosynthesis Storage Transport Integral part of Vascular Tissue Most common tissue Simple and living with different shapes Perform many physiological functions

6. Types of Parenchyma 1.Chlorenchyma 2.Storage parenchyma 3.Aerenchyma 5.Idioblasts 6.Transfer cells

7. Chlorenchyma Storage Parenchyma Storage of Proteins, Fats, Oils & Water in Roots, Tubers ( eg . Potato), Seed Endosperm ( eg ; Cereals) & Cotyledons Aerenchyma

8. IDIOBLASTS An  idioblast  is an isolated plant cell that differs from neighboring tissues. Storage of reserves, excretory materials, pigments, minerals, secondary metabolites like tannins, mineral substances, myrosin , oil substance etc.

9. Transfer Cells Specialized parenchyma cells that have an increased surface area, due to infoldings of the plasma membrane. Short-distance high-volume transport of materials

10. COLLENCHYMA Living tissue but performs only one type of function . Location : Aerial parts of the plants -Below the epidermis Function : Provides strength & flexibility in herbs, young and mature parts of the plant body. Structure : Thick deposits of  Cellulose, Hemi cellulose & Pectin  in their cell walls

11. Angular: Only longitudinal walls have thickenings Annular : uniformly thickened cell walls Lamellar:  Primary cell thickenings in the internal and external tangential walls Lacunar :  Wall thickenings restricted around the intercellular spaces

12. SCLERENCHYMA Hard, rigid and dead tissues Location : Cortex of stems and in leaves Structure: T hick cell wall due to deposition of lignin. Have various sizes & shapes Function : Provides mechanical support as well as rigidity to plant body

13. Types of Sclerenchyma 1.Sclerides 2.Fibers

14. SCLERIDES: Occur in all plants of the plants especially in soft parts. Have extremely thick wall of lignin with narrow lumen Usually dead cells. But remain as living cells in the respective parts for a long time. Associated with phloem.

15. FIBERS Elongated cells with narrow lumen & tapering ends Thick secondary walls and oblique end walls Lignification of cell walls Present in pericycle of many dicots and secondary xylem and phloem tissue . According to position types of fibers are Xylary fibers Extra xylary fibers

16. XYLARY FIBERS/ WOOD FIBERS Integral part of the xylem. Develop from same meristematic mother cells along with the tracheary elements. Types of xylary fibers based on the cell wall thickenings and pits 1.Libriform fibres 2.Fibre tracheids

17. LIBRIFORM FIBERS longer than tracheids with thick walls and narrow lumen Presence of very short and slit like simple pits FIBRE TRACHEIDES Intermediate structures between fibres & tracheids . Secondary wall thickenings is less than libriform fibers but more than tracheids . These are living fibres and mucilagenous fibers .

18. EXTRA XYLARY FIBERS Found in various parts of the plant body other than xylem Based on their occurance these are classified into 3 groups . They are Phloem fibres or bast fibres Cortical fibers Perivascular fibers Ex: Commercial  fibers   like jute, flax , ramie etc.

19. Cannabis sativa (hemp) Gossyjpium sp. (cotton) Corchorus sp. (jute) Ramie Linum usitatissimum (flax)

20. COMPLEX TISSUES Made up of more than one type of cells Different cells perform different functions in only one system. Composed of only parenchyma and sclerenchyma 1.xylem 2.pholem They are both occur side by side in the plant and form conducting tissues and constitute a vascular bundle .

21. XYLEM: Appeared for the first time in the pteridophytes . Conducts water and minerals from the roots to the leaves and stem (One way transport) Xylem is a complex tissue. I t consists of 4 types of tissues. Dead tracheids Vessels Fibers Living parenchyma On the basis of components xylem can be classified into primary xylem and secondary xylem

22. TRACHEIDS Basic cell type in the xylem.  Main water conductive cells of Pteridiophytes , Gymnosperms primitive Angiosperms Elongated dead cells with tapering ends. Large & empty lumen Show longitudinal cell walls Walls show various types of thickenings (pits) due to deposition of lignin.

23. VESSELS/ TRACHEA Most active water conducting elements in all higher angiosperms Long cylindrical dead cells, characterised by a thick cell wall consisting of a primary (cellulose) and a secondary walls (Lignin) The character of the vessel element is the presence of pores in the end walls. The porous region is known as perforation plate .

24.  Xylem vessels exhibit different types of secondary thickenings. 1.Annular - in the form of rings  2.Spiral -  helix or coil 3.Scalariform - cross bands like steps of a ladder 4.Reticulate – network 5.Pitted - depressions on the primary wall  Helps in conduction of water, mechanical support & formation of wood (hard wood or porous wood)

25. XYLARY FIBRES: Dead sclerenchymatous cells Long, narrow with thick lignified wall and tapering ends. Helps in mechanical support Types : 1.Libriform fibres (with simple pit) 2. Fibre tracheids (with bordered pit)

26. XYLEM PARENCHYMA: This is only the living tissue in the xylem. Participate in conduction of mineral salts directly or indirectly. Meant for storage of reserve food.

27. PHLOEM/ BAST/ LEPTOME Permanent living complex tissue. Helps in translocation of organic food (sucrose ) from leaves to various parts of the plant. The primary phloem has its origin procambium & Secondary Phloem from vascular cambium. Consists of 4 types of elements Sieve elements Companion cells Phloem parenchyma Phloem fibers

28. SIEVE ELEMENTS First discovered by the forest botanist  Theodor Hartig  in 1837 Highly organized tissue that transports organic compounds made during photosynthesis. Types of Sieve elements Sieve cells - longer and narrower with smaller area for nutrient transport . Found in gymnosperms . Sieve tubes - shorter and wider with greater area for nutrient transport. Found in angiosperms. Between two sieve tubes there are present perforated sieve plates with many sieve pores

29. COMPANION CELLS Specialized cells, appear only in angiosperms . Sieve tube and companion cells are originated from the same mother cell. Associated with the sieve areas. Sieve tubes and companion cells are connected through pits. In Gymnosperm, albuminous cells are present in place of companion cells. Helps in transport of food along with sieve tubes.

30. PHLOEM PARENCHYMA Cells of the phloem parenchyma appear long and vertically oriented as in the primary phloem . Also called as Transfer cells or border parenchyma Involved in  the transport of foods. On the basis of arrangement they are classified 1. Axial parenchyma 2. Ray parenchyma

31. PHLOEM FIBRES Also called as Bast Fiber or Skin Fiber Fibres are more significant in primary as well as secondary phloem. Presence of only simple pits Support the conductive cells of the  phloem  and provide strength to the stem. commercially useful because of its great tensile strength and pliability Ex: Fibers of Flax , hemp ,  jute

32. SECRETORY SYSTEM Some of the cells in plants produce several by products. These by products not at all beneficial to the plants. These products are eliminated as excretory substances from the protoplasm of the cells. These substances which are formed in the elimination process are determined as secretions. Secretory structures are located in different parts of the plants.

33. Glandular Trichomes EXTERNAL SECRETORY STRUCTURES Hydathodes

34. INTERNAL SECRETORY STRUCTURES Lysigenous cavity is formed by the destruction or dissolution of cells. Schizogenous cavity is formed by the displacement of cells to the peripheral regions

35. Laticiferous tissue