Lab 2

Plant Tissues

Plant tissues1 -meristematic tissues.

a.Apical meristematic of root.b.Apical meristematic of stem.

2-permanent tissues:a.Ground tissue.:

1-parenchyma.2-collenchyma.

3-schlerenchyma.b.Dermal tissue.c.vascular:

1-xylem. 2-phloem.

a.Apical meristematic of root (L.S)

L.S ----Longitudinal section. T.S ------ Transverse section.

2-permanent tissues:Parenchyma: – thin walled & alive at maturity.

Function: 1-the most important function of the parenchyma cells of roots and stem is the storage of food (e.g. starch) and water

2-the intercellular air spaces permit gaseous exchange.

Parenchyma

Collenchyma – thick walled & alive at maturity.Function:

*the collenchyma serve as supporting and strengthening tissue,

*in collenchyma with chloroplasts ,photosynthesis takes place.

Collenchyma

Sclerenchyma – thick walled and dead at maturity.Function:

1-sclerenchyma is an important supporting tissue in plants,

Sclerenchyma

b.Dermal tissue.

Thin straight

wall

Stomata

alive at maturity

*the stomata of leaves and stems allow gaseous exchange to take place which is necessary for photosynthesis and respiration,

*water vapour may be given off through the stomata during transpiration.

Complex Tissue

Xylem –transport water and mineral salts.

Phloem – transport food from the leaf to all parts of plant.

*sieve tubes transport organic compounds,*companion cells helps to regulate the metabolic activities of the

sieve tube elements,

sieve-tube members (no nucleus at maturity, cytoplasm present), companion cells, fibers, parenchyma, and ray cells .

c.vascular:1-xylem.(L.S)

B.annular. –C.spiral.-D. helical - E.reticular. F. Scalari form .G-pitted.

B.Annular .

2-phloem.

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Thank you for listening

T :Aldanah Alqahtani