XYLEM ppt.pptx

7/27/2019 XYLEM ppt.pptx

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XYLEM

BY:

NUR LIYANA BT

ZAINOODIN

6BSN


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A complex tissue contain more than one type of cell

Xylem Vascular tissue A tissue that function as a tube/vessel enabling water and

other substances(in solution) to move from one part toanother part of plant

FUNCTION OF XYLEM:

Transport water and dissolved minerals from the rootsto the stems and leaves


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XYLEM COMPRISES 4 TYPES OF CELL

TRACHEIDSVESSEL

ELEMENTSXYLEM FIBRES(SCLERENCHYMA)

XYLEMPARENCHYMA


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TRANCHEIDS AND

XYLEM VESSEL ELEMENT Trancheids and xylem vessel elements die on maturity

Their wall have been thickened with lignin deposits

Prevents entry of food substances

No organelles to block water flow

Provide mechanical support keep the plant upright

Have pits on their wall

Allow the lateral movement of water between trancheids andvessels

The end of vessel end is open end


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Pits membrane are permeable to water

The end walls of tracheid have many bordered pits allow

water pass through

The end of tracheid overlap with each other, forming a longtube which can facilitate the movement of water.

Tracheid is longer but have smaller diameter than vesselelements

Tracheid differ from vessel elements in shape


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PICTURE OF

TRACEIDS


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PIT PAIRS AND PIT

MEMBRANE PIT PAIRS pits in the wall of cell oppose the pits inthe adjacent cell wall

Pit pairs are separated by PIT MEMBRANE Made up of primary cell wall and middle lamella

Permeable to water


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PIT PAIRS AND PIT

MEMBRANE


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XYLEM VESSEL Long tube made up of many vessel elements joined

together end-to-end

The end of each vessel are open the cavity form achannel

Vessels are more efficient in water transport comparedto tracheid

Water flowing from one tracheid to another has topass through bordered pits-resistance to flow water.

Flowering plants have both vessel and tracheids.

Other plants only have tracheids to transport water.


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Parenchyma cell- the only living cells in the xylemtissue Store various type of food

Form pith rays that connect the primary xylem to secondaryxylem


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TWO TYPE OF XYLEM TISSUE

Primary xylem

Formed firstduring thegrowth of a

plant

Comprisesprotoxylem and

metaxylem

Secondary xylem

Formed whensecondary

thickening occuras a result of

vascular cambiumdivision

Only occur inwoody plants


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SECONDARY XYLEM

Stiff and cannot be flexed

When the rate of elongation is high, the plant stem is

most flexible and spiral or annular thickening occur

If there is not much elongation, scalariform, reticulate

and pitted thickening occur.

(refer page 92-Oxford Fajar)

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XYLEM ppt.pptx