Page 60 - PG 101-Course notes مذكرة النظري 24-25 with spec

Medicinal plants (PG 101) Level 1 Clinical Pharmacy-PharmD

3- Sclerenchyma

➢ They are non-living cells with thick often lignified secondary wall.

➢ Made up of a primary wall (cellulose) and a secondary wall (lignin).

• Function? support

They are divided into:
a- Fibers : b- Sclerides:

• Shape: Long, narrow, spindle- • Shape: Isodiametric, Elongated,
shaped, pitted. With lignified Bone-shaped, Stellate, filamentous
with lignified walls.
walls.

• The cells are strongly thickened
leaving only a small, narrow
lumen. The thickening is lignin.

• Location: Xylary and • Distribution: Cortex, phloem, fruit,
extraxylary seed outer coat Isolated or in
• Xylary fibers occur in xylem groups
tissue, whereas extra-xylary
fibers occur in tissues other than
xylem as the phloem, sheath of
vascular bundles of Monocots
and in cortex of plant organs.

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