PERMANENT TISSUE.pptx

Permanent tissue

1. Permanent tissue Presented by :- GANAPATI PRADHAN +3 2 nd year

2. INTRODUCTION :- Tissue :- A group of cells having a common origin performing more or less a common or similar function . Type of Tissue :- (a) Meristematic tissue. (b) Permanent tissue.

3. Permanent tissue :- M eristematic tissue divide and differentiated to form permanent tissue. These are the matured meristematic tissue. They lost the ability to divide, may be permanent or temporarily.

4. Types of permanent tissue:- Simple tissue. Complex tissue . S ecretory/special tissue.

5. (a) Simple permanent tissue :- These are made up of only one type of cells i.e. all the cells are structurally as well as functionally similar. Generally it is divided into : (a) Parenchyma (b) Collenchyma (c) Sclerenchyma

6. (a) Parenchyma :- All the cells are living in nature. They are more or less isodiametric in nature. The cells are thin walled, vacuolated. Abundant intercellular space are found depending in their location. They are present in the cortex ,pith, ground tissues of petioles, endosperm of seeds . Parenchymatous tissue forms association with vascular tissue and known as vascular parenchyma. Cell wall is composed of cellulose & pectin i.e. pectocellulosic in nature.

7. Type of Parenchyma :- Chlorenchyma : - Any parenchymatous cells rich with chlroplasts are called chlorenchyma. It is found in leave. It’s main function is photosynthesis. Spongy tissue :- Spongy parenchyma are found below the palisade cells. -> They are loosely arranged isodiametric cells with lots of intercellular space. -> They are contains lesser number of chloroplast than palisade parenchyma.

8. Aerenchyma :- Parenchymatous tissues with big and large air space. These are mainly present in stem and petioles of hydrophytic plants. It‘s function is to provides buoyancy to the plant organ for floating.

9. Function of Parenchyma tissue Photosynthesis Parenchyma cells provide turgidity to plants. Provide mechanical strength. Act as storage tissue. Helps in conduction in association with vascular tissue. Serves as packing tissue.

10. (b) Collenchyma :- It is also a living simple tissue. Mainly found in peripheral regions of the stem & beneath the epidermis i.e. hypodermis. If the stem has ridges, collenchyma tissue is found below the ridges. The cell wall is unevenly thickened. It is not found in roots, due to thick wall. Based on the thickening pattern, collenchyma tissue can be of 4 types –

11. (a) Angular collenchyma :- Collenchyma tissue having wall thickening at the corners only. -> Thickening due to the deposition of pectin & hemicellulose along with cellulose. (b) Lamellar collenchyma :- Collenchyma tissue having wall thickening on their tangential walls. (c) Annular collenchyma :- In this all the cell have uniformly thickened cell walls. (d) Lacunar collenchyma :- Only collenchymatous tissue with intracellular spaces. Function :- Mechanical in function. - Gives supports to stems and pedicels. Provide rigidity & elasticity to the plant.

12. (C) Sclerenchyma :- These are dead tissue, due to loss of cytoplasm at maturity. Have thick cell wall. Thickness is due to the formation of secondary cell wall & deposition of lignin. Elongated cell with pits. Sclerenchyma cells divide into two types: (a) Fibres (b) Sclereids

13. (a) Fibres : Fibres are elongated and narrow cells with pointed ends. Cells are thick walled with narrow lumen. Contain pit in the cell wall and are slit type. Fibres are very long and overlap each other which increase their economical value. According to position fibres are two types: Fibres associate with xylem : wood fibre Fibres associate with phloem: bast fibre Bast fibre occur in phloem and due to their large length they are used in textile . Ex- hemp, jute (Corchorus capsularis)

14. (b) Sclereids :- Sclereids are known as stone cells or sclerotic cells. The cells are highly thickened, lignified with reduced lumen. Contains pits. Sclereids may be found in groups or isolated. The isolated sclereids are known as idioblast. The endocarp of stone fruit and pericarp of nuts and the seed coats are very hard due to presence of sclereids.

15. Sclereids may be of different shapes and grouped as : i) Brachysclereids – more or less isodiametric ii) Macrosclereids – rod shaped iii) Osteosclereids – columnar cells with enlarged ends iv ) Asterosclereids – star shaped v) Trichosclereids – when branched hair like vi) Filiform sclereids – elongated thread like

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