The living plant cell What is the main differences between plant cell and animal cell?? Cell wall: Formed of cellulose. Chloroplast: Responsible for photosynthesis. Vacuole: much larger in plant cells, store any nutrients and waste products .

1. PLANT TISSUES
Assoc. Prof. Dr. Mostafa Mahmoud Hegazy PH.D

2. Why we are studying botany?
Why we are studying plant tissues ?
1- Studying secrets of the drug factory ( plant cell ) to
obtain
A-the active constituents in maximum concentration
B- the drug in optimum quality to ensure the highest
activity.
Medicinal plants Dr. Mostafa Hegazy

3. 2- useful for other
pharmacognosy important
subjects as tissue culture and
biotechnology ex. Taxol gene
identification and transfer into
Saccharomyces cerevisiae.
3- Quality control (QC)
purposes to prevent adulteration
of valuable drugs with toxic or
less active plants.
Medicinal plants Dr. Mostafa Hegazy

4. The living plant cell
What is the main differences between plant
cell and animal cell??
Cell wall: Formed of cellulose.
Chloroplast: Responsible for photosynthesis.
Vacuole: much larger in plant cells, store any
nutrients and waste products .

5. Plant Tissues
Tissues are collections of cells (one or
more types) that work together.
There are several types of tissues in
plants, Cellular composition of each
tissue varies depending on its function .

6. Meristematic tissues (Growth Tissues)
Undifferentiated
•Have the ability to continue cell division
and differentiation for the life of the
plant.
• composed from small cells with dense
cytoplasm and proportionately large
nuclei.
Permanent
•Do not change into other kind of tissues.
•Retain their structure and functional
characteristics throughout life.

7. meristematic
tissues
Classification on basis of
position
Apical meristem
Located at tip of stems and
roots which responsible for
Elongation of roots and
shoots.
Intercalary meristem
in stem internodes
Lateral Meristem
Secondary growth in Most
trees, shrubs, and some
herbs
Cork cambium(Phellogen)
Produces cork cells and
cork parenchyma
Vascular cambium
Produces secondary
vascular tissue (xylem and
phloem)
Classification on basis of
function
Protoderm
forms epidermis
Procambium
forms primary vascular
tissue (xylem, phloem)
Ground Meristem
differentiates into ground
tissue (cortex, pith)

8. Permanent
Tissues
Simple
Epidermis (Normal
epidermis-
stomata – hairs)
Ground Tissues
Collenchyma
Parenchyma
Sclerenchyma
Fibers -
Sclereids
Secretory
Tissues
Complex
Xylem
Phloem
Periderm
Cork tissue (phellem) –
Cork cambium (phellogen) -
Parenchyma (phelloderm
Cork

9. 1- Epidermal tissue: (epi, upon;
derma, skin)
- Continuous layer of cells
covering surface of plant.
-coated by a waterproof, waxy [a
fatty substance] cutin (Cuticle) to
prevent dehydration.
- control gas movement through
epidermal pores called stomata.
- Some epidermal cells have
epidermal hairs (trichomes).

10. - Stomata
- The guard cells are movable
- Function of stomata: osmoregulation
and regulation of gas exchange.
Water pores:
Are open stomata with immovable guard
cells. They function to expel water
excreted into the intercellular spaces.

11. TYPES OF STOMATA
The surrounding cells are of varying number,
e.g. Digitalis leaves
1) Anomocytic stomata or Ranunculaceous
The stoma surrounded by usually 3 or more subsidiary
cells one of which smaller than the other, e.g.
Solanaceous leaves (Belladonna, Datura, Hyoscyamus)
2) Anisocytic stomata or Cruciferous
(unequal-celled type)
The stoma surrounded by 2 subsidiary cells
perpendicular to the osteole e.g. Mentha leaf.
3) Diacytic stomata or Caryophyllaceous
(Cross-celled type)
The stoma surrounded by 2 or more subsidiary cells, 2
of which are parallel to osteole. e.g. Senna leaf, Coca
leaf.
4) paracytic stomata or Rubiaceous

12. Trichomes or Hairs
Glandular Hairs
( Head and stalk)
NonGlandular Hairs or Covering
Trichomes
Trichomes or Hairs
Glandular Hairs
( Head and stalk)
NonGlandular Hairs or Covering
Trichomes
Head
Stalk

13. Glandular
hairs
Unicellular
Not common
multicellular
Multicellular
head
Multicellular
stalk
Unbranched
stalk
Uniseriate
stalk
1 row
Biseriate stalk 2 rows
Biseriate head e.g.
compositae hair
Pluriseriate stalk 3
or more rows e.g.
shaggy hair of
cannabis
Branched stalk e.g
branched hair in
Hyoscyamus muticus
Unicellular stalk
With
1- bicellular head
in digitalis
2- ovoid or club
shape multicellular
head ( clavate hair
) in Solanaceae
3- short stalk with
8 radiating cells
head ( labiaceous
hair ) in mentha
Unicellular
head
Unicellular
stalk e.g.
Digitalis
Multicellular
uniseriate
stalk e.g.
Lavender and
Belladona

14. Nonglandular hairs
Unicellular
Unbranche
d ex. senna
Branched
ex. cruciferae
multicellular
Unbranched
Uniseriate
1 row ex. Belladonna
and digitalis
Biseriate
2 rows ex. Twin hair
Arnica flower And
calendula
Pluriseriate
3 or more rows ex.
Shaggy hair cumin
Branched
Simple ex. Body
ending with 2
branches in tobacco
Other types
1-balanced hair or T-
shaped hair pyrethrum
2- stellate hair in Boldo
3-candelabra hair of
mullein
4- peltate hair of
cascarilla

15. Ground Tissues:
1-Parenchyma
Characters:
• Most common cell type.
• Shape: Spherical
• Thin cell wall, Has intercellular spaces and Living at maturity.
• Most parenchyma cells have the ability to differentiate
into other cell types under special conditions:
1- During repair and replacement of organs after injury.
2-Can resume meristematic activity to produce adventitious roots
and shoots.
Main functions :
- Photosynthesis - Storage.

16. 2- Collenchyma (Greek, (kolla-glue)
Characters:
• Thick walls (usually with uneven
thickness) with cellulose.
• No intercellular spaces
• Living at maturity.
• Function: flexible support.
• Occur in groups just beneath the
epidermis:
- Beneath cork (outer parts) in bark.
- At the midrib of leaf below and above
vascular bundle.

17. 3- Sclerenchyma: (Greek, skleros, hard; en = in; chin
pour (support cells).
• Characters: Thick walls with cellulose and lignin
to give strength and rigidity.
• Dead at functional maturity (Cannot increase in
length)
• Function: structural strength and support.
• Two types of sclerenchyma:
a. Fibers: which are tough, pliable, strong, elongated
cells with tapering ends.
b. Sclereids: or stone cells, in which cells are not
elongated but give strength and support.

18. Complex plant tissues
1- Xylem: (Greek, xylon - wood).
- Dead at functionally maturity
- - function: Xylem transport water and minerals from
roots
to rest of plant.
- • Comprises:
1) Tracheids:
- Long slender, tapered at the ends, with well developed
lignified walls.
- Less efficient at conducting water. • More like a fiber.

19. 2) Vessel elements:
(1) Annual
(2) Spiral
(3) Scalariform
(4) Reticulate
(5) Pitted vessel
3) Xylem fibers: Add strength to xylem system.
4) Xylem parenchyma:
Function in storage of water and foods.

20. 2- Phloem: (Greek, phloas - bark)
- function translocation of food from leaves to
rest of plant.
• Comprises:
a) Sieve-tube members
b) Phloem fibers
c) Phloem parenchyma: storage cells.

21. Items Xylem Phloem
Made of Dead cells Living cells
Cytoplasm ? None Cytoplasm lining
Tissue also has…. Fibers Companion cells
Cell wall
-Thickness
-Material
Thick
Lignin (rigid )
Thin
Cellulose
Transports….. Water and Minerals Food
Carried to… Leaves Growing parts and Storage
organs
Permeability Impermeable Permeable
Direction of flow Upwards Up and Down

22. 3 -Periderm (Cork)
• Characters: Protective tissue/Replaces epidermis
in stems and roots (woody plants) that have
continuous secondary growth.
• Cork is not living at maturity.
The cell walls are highly suberized (suberin is a fatty
substance which covers lignified primary cell wall).
• Comprises: a) Cork tissue (phellem), b) Cork
cambium (phellogen) and c) Parenchyma
(phelloderm).
• Functions:
1) Protects against mechanical injuries and
excessive loss of internal moisture.
2) Gas exchange between the air and the interior
of the stem.
Cork

23. Cell Wall Chemical Impregnations:
(Latten. cutis – skin) Fatty substance on outer surface of the epidermal
cell walls, where it forms a layer known as cuticle.
A. Cutin
lignin is the most abundant plant polymer. Responsible for strength of
wood. The three common monolignols: paracoumaryl alcohol (1),
coniferyl alcohol (2) and sinapyl alcohol (3)
B. Lignin
Fatty material found in the cell walls of cork tissues and the Casparian
strips of the endodermis.
Suberin functions as a physical barrier, preventing water loss,
protection against pathogens and in wound healing process in plants
C. Suberin
Polymer of polysaccharides
D. Hemicellulose
Component in the cell walls of fungal cell walls, 6 carbon sugar on to
which a nitrogen containing group has been added.
E. Chitin

24. SECRETORY TISSUES
1-Secretory cells
2- Secretory cavities or sacs or internal Glands.
According to die method of formation they may be:
a- Schizogenous: Developed by die separation of the
cells thus enclosing a cavity which then becomes
enlarged and lined by secretary epithelial cells.
b- Lysigenous: Developed by the breaking down of
the cells, forming a cavity, not lined by a definite
secretory epithelium..
c- Schizo-Lysigenous: The cavity develops at first as
schizogenously but, later on, increases in size and
changed to Lysigenous by the breaking down of
bounding cells.

25. 3- Secretory Ducts or Canals:
These are tube like structures containing and
producing secretions. They may extend through
the whole length of the organ. They usually
produce volatile oil or oleo-resin.
4- Laticiferous structures :
cells or vessels containing secretion called latex

26. Herbal medicine Dr. Mostafa Hegazy