Plant Tissues

Plant Tissues
Raymond C.
Baldonado

Tissue- a group of cells with the same
structure and performs the same function.
Plant Tissues may be simple and are
composed of only one type of cells
(Uniseriate) or complex and are composed
of two or more types of cells (Multiseriate).
Plant Tissues are grouped into 5:
1. Protective Tissues
2. Meristematic Tissues
3. Mechanical Tissues
4. Conducting Tissues
5. Specialized Tissues

Protective Tissues
These are tissues that give outmost
covering of the plant for protection.
1. Epidermis- the outermost layer of
cells of any organ of a young plant.
 Parenchymatous or sclerenchymatous
2. Periderm- tissue commonly found in
mature dicot and gymnosperm stems
and roots.

Meristematic Tissues
These tissues are basically capable of
cellular division.
2 Kinds of Meristematic Tissue:
1. Apical Meristem- tissues that grow in
upward and downward direction.
 Root Apical Meristem (RAM)- give rise
to root
 Shoot Apical Meristem (SAM)- give
rise to stem and leaves
2. Lateral Meristem- tissues that grow in
sideward direction.

Meristematic Tissues:
1. Protoderm- epidermis
2. Ground meristem- cortex, pith
3. Procambium- pericycle, primary phloem,
vascular cambium, primary xylem
4. Pericycle- branch root, cork
cambium(phellogen) in dicot root
5. Vascular cambium-secondary phloem,
secondary xylem
6. Cortex-cork cambium (phellogen) in dicot
stem
7. Phellogen- cork(phellem), cork
parenchyma(phelloderm)

Developmental Sequence of
Tissue Differentiation in Dicot
Root
Apical
meristem
Protoderm Epidermis
Ground
meristem
Cortex
including
endodermis
Procambium
Pericycle
Branch root
Cork cambium
(Phellogen)
Cork
(Phellem)
Cork
parenchyma
(Phelloderm)
Primary
phloem
Vascular
cambium
Secondary
phloem
Secondary
xylem
Primary xylem
Pith

Developmental Sequence of
Tissue Differentiation in Dicot
Stem
Apical
Meristem
Protoderm Epidermis
Ground
meristem
Cortex
Cork cambium
(Phellogen)
Cork
(Phellem)
Cork
parenchyma
(Phelloderm)
Pith
Procambium
Primary
phloem
Vascular
cambium
Secondary
phloem
Secondary
xylem
Primary xylem

Mechanical Tissue
These are tissues that provides support for the
plant.
Plant Cell Types:
1. Parenchyma-thin-walled cells that are
basically isodiametric. Function for
metabolism.
2. Collenchyma-have irregular primary wall
thickenings. Function for plasticity.
3. Sclerenchyma- function for elasticity and
have thick-walled cells of 2 types:
 Fibers- shorter in length
 Sclereids- longer in length and stronger

Kinds of Parenchyma Cells
1. Aerenchyma- for gas
exchange/aeration
2. Chlorenchyma- contain chroloplast
 Palisade layer- columnar in shape
and compact
 Spongy layer- circular in structure
3. Meristematic parenchyma- for cell
division
4. Storage parenchyma- for storage

Conducting Tissues
These tissues transport water and food
throughout the plant.
1. Phloem- food-conducting tissue. Composed
of sieve tube, companion cell, phloem
parenchyma and phloem fibers.
 Sieve tube- has no organelle and function
for transport
 Companion cell- has organelles,
considered as the transfer cell and function
for metabolic processes
 Phloem sap- composed of sieve tube
member and sieve cell which can be found
from leaves to sinks.
 Sinks in plant can be the fruit, stem and
root.

Conducting Tissues
2. Xylem- water-conducting tissue.
Composed of tracheids, vessels, xylem
parenchyma and xylem fibers.
 Transport of water and food can be Axial
(upward) or Lateral (sideward) in
direction.
 Transpiration- is the transfer of water
from root to leaf from higher water
potential to lower water potential through
cohesion-adhesion property of water.

Conducting Tissues
Transpiration Pathway
Xylem of root
Xylem of stem
Xylem of petiole
Xylem of midrib
Xylem of veinlets
Mesophyll layer

Specialized Tissues
It prevents water evaporation and gives
additional protection.
1. Trichomes- cutinized epidermal
appendages found in the leaf, stem,
flower and fruit. Serve to protect and
prevent evaporation of water.
2. Root Hairs- Uncutinized epidermal
appendages used to increase the
water absorbing capacity of the roots

Morphology and
Anatomy of the Root

Morphology and Anatomy of the
Root
Root- the underground organ of the plant
for anchorage and water/nutrient
absorption .
Types of Root Based on Origin:
1. Primary Root- develops from the
hypocotyl, or its lower end tip, the
radicle of the embyo
2. Secondary/Branch Root- originates
from the pericycle of the primary root
3. Adventitious Root- directly develop
from the stems or leaves of the plants

Primary root
Secondary
root
Adventitious root

Two Basic Root System
1. Tap Root System- characteristic of
dicot plants.
 The primary root grows more
extensively than any of its branches
 Primary root constitutes the central
axis from which the smaller branches
arise
2. Fibrous Root System- characteristic
of monocot plants
 There is no distinct central axis

3 Types of Fibrous Root
System
a. Diffuse- in rice and corn
b. Wiry- in coconut and betel nut
c. Clustered fleshy(fascicled)-
lawiswis kawayan and asparagus

Structure of the Root Tip
1. Zone of Cell Division- region of the
root which has dense cells
2. Zone of Elongation- region of the
root which has elongated cells
3. Zone of Maturation- region of the
root where there is a presence of
specialized cell called root hairs

Anatomy of the Root
1. Periderm/Epidermis- outermost layer
of cells
2. Cortex-the cells right after the
epidermis
3. Endodermis- the inner boundary line
of the cortex
4. Pericycle- meristematic tissue on the
inner side of the endodermis that gives
rise to the branch root
5. Vascular Cambium-conducting tissue
composed of xylem and phloem

Anatomy of the Root
Dicot Root
Monocot Root

Protective Mechanism
 Mucigel- for prevention of water
evaporation
 Root cap- for deeper penetration on
the soil and trap different
microorganisms.

Modified Roots
For food storage and asexual
reproduction:
1. Tubercular- e.g. Sweet potato
2. Napiform- e.g. Turnip
For food storage only:
3. Fusiform- e.g. Radish
4. Conical- e.g. Carrot
5. Fasciculated- e.g. Cassava

Modified Roots
Function for Support:
6. Clinging root- e.g. Gabi
7. Brace root- e.g. Corn
8. Prop root- e.g. Pandan
9. Green root- functions for
photosynthesis
 e.g. Pandan
10. Pneumatophore- functions for
exchange of gases
 e.g. Mangrove

Morphology and
Anatomy of the Stem

Stem
 Functions for support and
translocation
 Generally, an aerial organ of the plant
that is derived from the development
of the epicotyl of a germinating seed.
 The stem also performs other
functions such as food storage, food
production, asexual reproduction,
support and protection. Such stem
performing additional function is called
Methamorphosed or Modified Stem.

Morphology of the Stem
1. Node- point on the stem where a leaf
is attached.
2. Internode- distance between two
nodes.
3. Terminal/Apical bud- a bud found at
the tip or apex of the twig/branch that
may develop into a flower or as an
extension of the stem.
 Responsible for the phenomenon
called Apical Dominance

4. Lateral /Auxillary bud- a bud found
at the leaf axil.
5. Leaf axil- the angle formed between
the attached leaf and the stem.
6. Leaf- a lateral growth of the stem for
photosynthesis.
7. Leaf scar- mark left when a leaf falls
off.
8. Bundle scar- mark found within the
leaf scar that represents the broken
ends of veins at leaf fall.

9. Bud scale- a leaf-like structure
covering and protecting the bud.
10. Bud scale scar- a mark left when a
bud scale falls off.
11. Lenticels- small, raised/elevated
dots or ridges found on the matured
portion of the stem for exchange of
gases in dicot stems. In monocot
plants, exchange of gasestake place
through the stomata.

Type of Wood
1. Summer wood- also called “late
wood”, small vessel formed, small in
diameter.
2. Spring wood- also known as “early
wood”, large vessels formed, bigger in
diameter.
3. Sapwood- is the living, outermost
portion of a woody stem or branch.
4. Heartwood- is the dead, inner wood,
which often comprises the majority of a
stem's cross-section.

Methamorphosed Stem
For food storage and asexual
reproduction:
1. Tuber- e.g. Potato
2. Bulb- e.g. Onion
3. Corm- e.g. Gabi
4. Rhizome- e.g. Ginger
For asexual reproduction:
5. Runner- e.g. Bermuda grass

Methamorphosed Stem
For protection:
6. Thorns- e.g. Bogombilya
7. Spines- e.g. Cactus
For support:
8. Tendril- e.g. Ampalaya
9. Twiner- e.g. Sitaw
10. Pseudostem- (whole plant support)
e.g. Banana
For photosynthesis:
11. Green stem- also called cladophyll
(small leaves) e.g. Stick plant

Morphology and
Anatomy of the Leaf

Leaf
 One of the three basic organs of the plant
and the other two are the roots and the stem.
 Mainly for food production or photosynthesis
but other functions are performed also. These
are :
a. To protect developing vegetative buds
(cataphylls)
b.To protect developing inflorescence
(hypsophylls)
c. To protect individual flowers (sepals)
d. To store nutrients for the embryo
(cotyledons)
 The collective term for all the leaves of a
plant is called Phyllome

Morphology of the Leaf
For a simple dicot leaf the following
parts are present:
1. Petiole- attaches the leaf to the stem
2. Pulvinus- enlargement at the base of
petiole
3. Blade- flat, green, expanded portion
for photosynthesis
4. Base- lower-edge portion of the leaf,
both monocot and dicot possess this
structure.

5. Stipule- leaf-like structure at the
pulvinus
6. Apex- tip of the leaf with opening
called hydathode
7. Midrib- biggest vein at the center of a
leaf
8. Veinlets- small veins at the surface of
the blade
9. Margin- edge portion that surrounds
a leaf

Morphology of the Leaf (Simple dicot
leaf)

For monocot leaf the following parts are present:
1. Blade
2. Margin
3. Midrib
4. Veinlets
5. Apex/Axil
6. Base
7. Leaf sheath- a structure that attaches the leaf
to the node
8. Ligule- hairy structure at the junction between
the leaf sheath and the blade
 For protection by preventing drops of water into
sipping to the enclosed part of the leaf sheath
to avoid dessication

Morphology of the Leaf (Monocot
leaf)

Compound Leaf
 It is one in which the blade is subdivided
into partition called leaflet.
Compound leaf has the following parts:
1. Rachis- part where the petiolule is
attached
2. Leaflet- subdivision of blade
3. Petiolule- attaches the leaflet into the
main rachis
4. Stipel- leaf-like structure at the base of
the petiolules

Types of Compound Leaves
1. As to no. of leaflets:
a. Pair pinnate/even pinnate
b. Impair pinnate/odd pinnate
2. As to rachilla:
a. Bi-pinnate- leaflets are attached to
second rachilla
b. Tri-pinnate- leaflets are attached to
third rachilla

Characteristics of Petiole
Number of
Petiole
Number of
Leaf
Term
1 1 Unifoliate
1 2 Bifoliate
1 3 Trifoliate
1 4 Quadrifoliate
1 5 Pentafoliate
1 6 Hexafoliate
1 7 Heptafoliate
Next Compound Leaves
*Sessile- it is a leaf without stalk/petiole.

Venation
 It is the system of vein arrangement
The dicot leaf is characterized by a netted
venation.
Netted venation has three types:
1. Palmately netted- the main veins radiate
from a central point at the petiole. Each
main vein extends from the petiole to the tip
of a lobe.
2. Pinnately netted- leaf veins are produced on
either side of the central main vein (midrib),
which extends from the petiole to the leaf
tip.
3. Reticulately netted-reticulate or net-veined

Netted Venation(Dicot leaf)
Pinnat
e
Palmat
e
Reticulat
e

Parallel Venation
 It is the kind of venation present in a monocot
leaf and characterized by three types:
1. Veinlets run on the same direction as the
midrib;
2. Veinlets form an angle with the midrib;
3. Veinlets are perpendicular to the midrib
 Dichotomous venation is a kind of venation
that was proved to be related to monocots.
It occurs in Gingko where numerous veins
radiate from the base of the leaf that branch
near the upper leaf surface to form a Y.

Parallel Venation
Paralle
l
Dichotomous

Phyllotaxy
 It is the arrangement of leaves in a
plant and the functions are:
1. All leaves must be equally exposed
to light for maximum light absorption
2. Minimum overlapping of leaves

Different Phyllotaxes
1. Alternate
2. Oppposite
3. Wholed
4. Distichous
 Alternate in 2 ranks
5. Deccusate
 Opposite in 2 ranks
 Opposite in 4 ranks

Anatomy of the Leaf
Leaf has the following structures:
1. Upper epidermis- outmost covering of
the leaf
2. Lower epidermis- just after the upper
epidermis
3. Mesophyll layer- composed of palisade
and spongy layers
4. Vein- located between the upper and
lower epidermis
5. Stomata- for the exchange of gases in
the leaves

Mesophyll Layers
 Palisade layer- composed of columnar
upright compact parenchyma cells
with chlorophyll called chlorenchyma.
 Spongy layer- composed of circular
loosely arranged cells.

Action of Stomata
 When the guard cells are turgid/full of
water, the stoma is open.
 When the guard cells are flaccid/small
amount of water, the stoma is close.
Condition Stomatal Action
1. Humid Open
2. Hot Close
3. CO2 depletion Open
4. Light Open
5. Wind velocity Close
6. Drought Close
7. Circadian rhythms Open/Close

Types of Stomata
Types of Stomata based on location:
1. Epistomata- located on the upper
epidermis
2. Hypostomata- located on the lower
epidermis
3. Amphistomata- located on both
epidermis of the leaf

Types of Stomata
Types of Stomata based on the
characteristics of the subsidiary cells:
For Dicots,
1. Anomocytic- (irregular-celled,
ranunculaceous)subsidiary cells are
absent
2. Anisocytic- (unequal-celled,
cruciferous)
three subsidiary cells, one distinctly
smaller than the other two, surround the
stoma
3. Paracytic- (parallel-celled, rubiaceous)
three subsidiary cells occur on eitherside

Types of Stomata
4. Diacytic- (cross-celled,
caryophyllaceous) two subsidiary cells
enclose the stomata
5. Actinocytic- with subsidiary cells
arranged along the radii of a circle

Types of Stomata
For Monocots,
1. Type 1- with four to six subsidiary
cells around the guard cells in all four
directions
2. Type II- with four to six subsidiary
cells, two of which are roundish and
smaller than the rest.
3. Type III- with two subsidiary cells
lateral to the guard cells
4. Type IV- without subsidiary cells

Specialized Leaves
1. Showy/Brightly colored leaves- for
insect attraction
e.g. Bogambilya
2. Plantlet at a notch- for asexual
reproduction
e.g. Kataka-taka
3. Expanded petiole- added site of
photosynthesis
e.g. Suha
4. Float- for buoyancy
e.g. Lotus

Specialized Leaves
5. Insectivorous leaf- for insect trapping
e.g. Pitcher plant
6. Tendril on a leaf
e.g. Cabbage
7. Fleshy/Succulent leaves- for food
e.g. Celery

Morphology and
Anatomy of Flowers

Flower
 It is the sexual reproductive structure
of plant
 Serve to attract insects for pollination
4 Whorls of Flowers

4 Whorls of Flower
1. Sepals- usually green and leaf-like
- serve to protect the more delicate
tissues that develop within the bud
 Calyx- collective term for sepals
2. Petals- usually colorful
- serve to attract insects for
pollination
 Corolla- collective term for petals
 Perianth- a term refers to both sepals
and petals

4 Whorls of Flower
3. Stamen- male reproductive part
 Androecium- collective term fro
stamen
Consists of:
 Filament- the stalk of the stamen
which bears the anther
 Anther- the pollen-bearing portion of
the stamen

4 Whorls of Flower
4. Pistil- female reproductive part of a
flower
 Gynoecium- collective term for carpel
Consists of:
 Stigma- receptive part of pollen grain
 Style- stalk of pistil
 Ovary- enlarged portion of pistil
containing the ovule
 Ovule- inside the ovary carries the
female gametes

Other Parts
 Peduncle- flower stalk of a solitary
flower
 Receptacle- part of the flower stalk
bearing the floral parts

Classification of Flowers
a. Based on whorls of parts present
1. Complete
2. Incomplete
2. Incomplete
b. As to sex organ present
1. Perfect
2. Imperfect
c. As to symmetry
1. Regular
2. Irregular

d. As to origin
1. Lateral bud
2. Terminal bud
e. As to type of ovary
1. Hypogynous
2. Epigynous
3. Perigynous

f. As to sex expression
1. Monoecious
2. Dioecious
g. As to the structure of petals
1. Apetalous
2. Gamopetalous
3. Polypetalous

h. As to pollinator
1. Entomophilous
2. Ornithophilous
3. Anemophilous
4. Chiropterophilous
5. Hydrophilous

Inflorescence
 Clusters of flowers
 The flower stalk is called pedicel

Fruits/Seeds
Fruit- is the ripened ovary, result of
pollination
Seed- is a fertilized ovule, result of
double fertilization

Classification of Fruit
Fruit as to origin
1. Simple
2. Aggregate
3. Multiple
4. Accessory
Fruit as to consistency
1. Fleshy
a. Berry
b. Hesperidium
c. Pepo
d. Drupe
e. Pome

2. Dry-dehiscent
a. Legume/Pod
b. Follicle
c. Silique
d. Capsule
Poricidal
Septicidal
Loculicidal
Circumcissile

3. Dry-indehiscent
a. Samara
b. Caryopsis/Grain
c. Nut
d. Achene
e. Cypsella
f. Schizocarp

Seed Dispersal
1. Hydrochory
2. Anemochory
3. Chiropterochory
4. Ornithochory
5. Autochory
6. Mammaliochory
Ectochory
Endochory
7. Myrmecochory

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