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DERMAL TISSUES
Function of dermal tissues:





Protection
Regulate gas exchange
Prevent water loss
Lower the rate of
evapotranspiration
 Protect plants from
herbivory
 Increase water uptake
 Aids in cell recognition

HYPOSTOMATIC
EPISTOMATIC
AMPHISTOMATIC

Stomata are confined in
the lower epidermis
Stomata are confined in
the upper epidermis
Stomata are confined to
both upper and lower
epidermis

Components of dermal tissues





Ordinary epidermal cells
Stomatal apparatus
Trichomes
Root hairs

ORDINARY EPIDERMAL CELLS
 no particular content, same morphology and
structure

UNISERIATE EPIDERMIS

Nerium oleander- can be found in dry regions
XEROPHYTIC- can live in scanty amoun of water

CUTICLE
COMPOSITION OF
CUTICLE

MULTISERIATE EPIDERMIS

EPISTICULAR WAX –
responsible for
enhancing the
ability of the surface
to shed water

Single layer of epidermis
Example: Lingustrum

CUTIN- lipid
polymer

Multiple layer of epidermis
Example
...

IDIOBLAST
 A cell that difers significantly from neighboring
cells because of its content and morphology
 Responsible for detoxification
 Silica + crystals in rays, Cordia glabrata

 Protrude, forms on the cuticle
 For protection against dehydration and retard
the rate of evapotranspiration, since it has a
thick cuticle

STOMATAL APPARATUS
 STOMA\STOMATA- holes, opening
 GUARD CELLS- pair, flanks the opening
 NEIGHBORING CELLS- cells that surrounds the
guard cells
 SUBSIDIARY CELLS- neighboring cells which is
morphologically different from other
neighboring cells, different shape and size
compare to others

TYPES OF STOMATA
*First classification of stomata is based on the location,
shape, size and arrangement of subsidiary cells
...

Usually has 3 subsidiary cell of
differing sizes (decreasing) that
surrounds the guard cells
has 2 subsidiary cells parallel to
the two long axis of the guard
cells

CARYOPHYLLACEOUS
Carnation Family,
Dianthus

ANOMOCYTIC

OTHER NAME
RANUNCULACEOUS
Genus Ranunculus
CRUCIFEROUS
Cabbage Family,
Crucifers
RUBIACEOUS
Family Rubiasi
(Dona Aurora, Santan ,
Vinda, Lugumes or
Bean)

has
2
subsidiary
cells
perpendicular to the guard cells

* 30 OR MORE CLASSIFICATIONS ARE ADDED SINCE
BOTANIST STUDY OTHER ORGANISMS
TYPE

ACTINOCYTIC
CYCLOCYTIC
TETRACYTIC

OTHER NAME

DESCRIPTION
Subsidiary cells
radiating from the
guard cells cells are
Subsidiary cells that
encircling the guard
cells
COMMELINASSEAE 4 subsidiary cells =
(Setcreasea, Rheo) 2 Parallel + 2
Perpendicular
...
Their
subsidiary cells
have non-sinuous
walls and crescent
shape
...

Cannot be seen in an epidermal peel since it only shows
the face view
...


FICUS AND
CONIFERS (Pine
Tree, needle like
leaves have
SUNKEN
STOMATA

SUNKEN STOMATA- have a depression then the guard
cells before the opening , adaption for extreme
environments (Low Temperature)
ADELFA,
ORLEANDER
LEAF has
STOMATAL
CRYPTS

PARASITIC (dependent on a host) AND SUBTERRANEAN
(under the ground, opposite epiterranean) PLANTS plants without stomata
LOCATION OF THE STOMATA
***Placement of stomata has something to do with the
kind of environment they have
AQUATIC PLANTS- Epistomatic (stomata on upper
epidermis)
...
Ex
...
Have a deep
depression lined by trichomes (adaptation for warm
environment, drying effect of air which makes
evapotranspiration faster) before the stomata
...
Like the
spongy parenchyma

kafir-lily (Clivia, an
ornamental
monocot)
...
Adaptation with warm
environments

TRICHOMES outgrowth of the epidermis
SIMPLE- can be a
unicellular\uniseriate
or multicellular

MARIJUANA (CANNABIS SATIVA)- have calcium
carbonate crystal to prevent herbivory
...

Example
...


Procumbent Glandular Trichomes- horizontal
Erect Glandular Trichomes- vertical

STELLATE- star shape,
radiates from the
center

PELTATE
TRICHOMES
(Olive leafs, Olea
purpurea)
ARABIDOPSIS
Example of branching
trichomes

Multicellular hairs
and glandular
trichomes in tomato
(Lycopersicum
lycopersicon)
...


FUNCTION: they retain water by
inhibiting air movement near the
stomata;
they make it difficult for many
animals to walk on the leaf, and
most fungal spores would land on
these trichomes, far away from the
living cells of the leaf

GROUND TISSUES
PARENCHYMA

COLLENCHYMA

SCLERENCHYMA

Alive at maturity
Thin Primary Cell
wall

Alive at maturity
Thick Primary Cell
wall
Flexibility
With lumen

among plants, has similar characteristics
with parenchyma
...
No collenchyma and
sclerenchyma can be found

Dead at maturity
Both primary and
secondary wall
Strength
Almost no lumen

With bigger
lumen

Bryophyte
(Buckiella undulata)
Shoots and internal
structure

Parenchyma


1) Origin- from ground meristem, procambium or
cambium, from phellogen
 From ground meristem, procambium since it
gives rise to xylem and phloem which is a
collective term and may have parenchyma,
and phellogen or the cork cambium

Parenchyma is considered primitive
ontogenetically (Ontogeny- Developmental
history), since in all fundamental tissues,
parenchyma is the only tissue which is
similar to meristematic cells and have
thinner cell walls

6) Varies in shape and arrangement
7) Structure and content

2) Location: as continuous masses, as vertical strands
in vascular tissues, or as horizontal strands (rays) in
SVTs


occur as a continous mass (Cortex of stem
or roots) or vertical strand (xylem
parenchyma), or horizontal strand(
secondary vascular tissues)

3) Little specialization; various physiological functions




Exhibits little specialization unlike
sclerenchyma and collenchyma
...
Like meristem
which can be converted to another type of
cells
...
Patches are
sclerenchyma (thick walls are lignified)
When you stain (Phloroglucinol) a cell with
secondary wall (Sclerenchyma, vessels,
sclereids and fibers) it has a lignin which
react and take up most of the stain, so it
appear darker compare to others

***Root of monocot- has a pith in the middle
***Root of a dicot- has a cross, or some have star
shapes in the middle

AERENCHYMA






Aer means spaces
...

Almost spaces can be seen
...

Nymphea- astrosclereids ( kind of
sclerenchyma), water hyacinth (Eichornia)

RAY PARENCHYMA


It occurs as parts of secondary vascular
tissues
...





Palisade and spongy layer (Loosely
arranged)
Site of photosynthesis

PRIMARY FIT FIELD
 holes, area of concentration of
plasmodesmata (openings on the cell wall)

TYLOSES





Another parenchyma characteristic - when
plant is injured, especially the xylem, xylem
parenchyma produce outgrowths for
plugging the portion with injury
After plugging, pathogenic microorganisms
will have a hard time to enter
...


Collenchyma

*** You can observe one or three types on one
specimen
...

Most common
Petiole of vitis
(Grapes), stem of
begonia, coleus

located on the
tangential walls of
the cells
...
, in Vitis
 Divided by septa and pitted
 They have living protoplast unlike most
fibers (sclerenchyma)
 Alive at maturity

1
...
COMPRESSION WOOD – found in monocots
(GYMNOSPERM), reaction wood below the
bent part
 Podocarpus

GELATINOUS OR MUCILAGINOUS
FIBERS
 The innermost layer of secondary cell
wall (Parts: S1, S2 AND S3 (Innermost,
closes to the lumen) is poor in lignin and
relatively porous (Have spaces, so it
takes up and absorbs more water)
...
When they grow, there is a
tendency that it is not straight, they are
tilted
...
For their stem
not to break they produce reaction

Gelatinous fibers are common in coiling tendrils
(Climbing) and twining vines





Lina (Woody)
Clematis sp
...

- Manufacture of lifebuoys and belts,
waistcoats and other naval lifesaving appliances

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