PLANT
ANATOMY
The science of the structure of the
organized plant body learned by dissection
is called Plant Anatomy.
In general, Plant Anatomy refers to study of
internal morphology, pertaining to different
tissues. the study of plant cell and tissue
structure
The anatomy is one of branches of
appearance Morphology where he
teaches a plant form of the study of plant
form apparent (abroad) is attributable to
the taxonomy
)Taxonomy= internal morphology(
)Anatomy = internal morphology(
Plant tissues Systems
Like other organisms, plant cells are grouped
together into various tissues. These tissues can
be simple, consisting of a single cell type, or
complex, consisting of more than one cell type.
Classification of tissues :
Can be divided into plant tissue in the body
based on the following :
1- Position
2- Type of cells
3- origin
4- Function
Tissue is a mass of similar or dissimilar
cells performing a common function.
Tissues of Meristems:
Meristematic tissues are composed of cells
that divide continuously
Function Meristems
- Cell division
- Cell elongation
- Cell differentiation
Classification of meristems
Apical meristems: located at the growing points of stems
and roots e.g. those present in stem and root apices.
Intercalary meristems: present between two permanent
zone, present at base of internodes e.g. sugarcane and
maize.
Lateral meristems : present laterally and cause increase
in diameter of plant.
Located parallel to the longitudinal axis of the member
plant
Classification of meristems
Apical meristems
Intercalary meristems
Lateral meristems
Different types of mature tissues:
a- Parenchyma
b- Collenchyma
c- Sclerenchyma
d- Epidermis
h- Pericycle
f- Endodermis
j- Laticiferous tissue
r- Cork (phellem)
t- Tracheary tissue
i- Sieve tissue
s- Secretory structures n- Vascular tissue
k –Nectaries
Permanent Tissues (Mature Tissues(
The permanent tissues are formed by the
differentiated cells, which become specialised
to perform specific functions like protection,
support, storage and conduction. The
permanent tissues always differentiate from the
meristematic cells, during the process of growth.
The three kinds of mature tissues are dermal,
vascular, and ground tissues. Primary dermal
tissues, called epidermis, make up the outer
layer of all plant organs (e.g., stems, roots,
leaves, flowers). They help deter excess water
loss and invasion by insects and
microorganisms.
Types of Permanent Tissues
The permanent tissues can broadly be
distinguished into two types, namely
1. Simple permanent tissue:
Tissues which are composed of two or more types of cells but
contribute to a common function are called complex tissues.
Xylem and phloem are the complex permanent tissues. They
together form the vascular bundle.
This tissue consists of only one type of cells, e.g. parenchyma,
collenchymas and sclerenchyma.
2. Complex permanent tissue:
This tissue is composed of more than one type of cells.
Complex Tissue:
Tissues which are composed of two or more types of cells but
contribute to a common function are called complex tissues.
Xylem and phloem are the complex permanent tissues. They
together form the vascular bundle.
Parenchyma:
Characters:
1- Simple living cells.
2- Have primary
cellulosic thin wall
with simple pits.
3- Have intercellular
spaces.
4- They may be
elongated,
isodiametric or
lobed.
Occurrence:
1- In cortex and pith
of stems and roots.
2- Associated with
xylem and phloem.
3- In leaves and
fruits.
Function:
1- In aeration.
2- In photosynthesis.
3- Storage of water,
protein, minerals,
etc..
4- May become
meristematic and
divide.
2- Collenchyma
Characters:
1- Simple living tissue.
2- Have primary cellulosic thick wall with
simple pits.
3- May have intercellular spaces.
4- They are elongated cells.
Types:
Lamellar: thickening
on tangential walls.
Angular: thickening
on angles between
the cells.
Lacunar: thickening
on walls facing the
intercellular spaces.
Occurrence:
1- Under epidermis of
stems.
2- Cortical tissue and
pericycle of
leaves.
Function:
They are plastic
tissue used for
mechanical
support of soft
plants.
sclerenchyma
They are dead cells when mature with thick
secondary walls, they are elastic tissue
used for mechanical support.
Sclerenchyma has two types; fibres and
sclereids.
A- Fibres
They are dead
cells have pitted
walled with narrow
Lumina and
pointed apices,
xylary fibres are
lignified while
extraxylary fibres
may be lignified or
non-lignified.
B- Sclereids
They are dead cells short, isodiametric,
elongated or branched thick walled, pitted,
lignified with branched lumina.
Vascular system in the plant
Plants have two different types of 'transport' tissue
Xylem and phloem. Both xylem and phloem are the
vascular system.
Xylem transports water and solutes from the roots to
the leaves, phloem transports food from the leaves to
the rest of the plant.
Xylem
 Xylem
tissue : Water and
mineral transport from roots to aerial parts
(leaves) of the plant
Xylem consists of :
 Tracheary elements .
 Tracheids .
 Vessels .
 Xylem fibers .
 Xylem parenchyma .

1- Vessels
Each vessel is formed from a series of vessel
elements jointed end by end, 2ry wall is
deposited in different forms:
a- Annular: 2ry wall deposits as rings in
narrow vessels.
b- Spiral: 2ry wall forms a spiral in slightly
wider vessels.
c- Reticulate: 2ry wall forms network.
d- Sclariform: 2ry wall has elongated pits in
vertical series.
e- Pitted: 2ry wall is pitted and is formed in
wider vessels.
Functions: vessels are used for transport and
mechanical support.
2- Tracheids
Gymnosperms have tracheids only
but in angiosperms the xylem
consists of tracheids and vessels.
The tracheids are shorter than vessels
and have bordered pits on their
common walls.
The function of tracheids is water
transport and mechanical
support.
5- Phloem
Phloem is the food conducting tissue which is formed of
four elements; sieve elements, companion cells,
parenchyma and fibres.







Phloem tissue consists of :
sieve elements :
sieve cells .
sieve tube .
companion cell .
Phloem parenchyma .
Phloem fibes .
1- Sieve elements
these include two types:
a- Sieve cells:
They are present in gymnosperms and lower
vascular plants.
They are long cells with tapering ends,
having sieve areas on their walls.
They have thin lining layer of cytoplasm, a
large vacuole and they contain no
nucleus.
b- Sieve tubes:
They are present in angiosperms.
They are arranged end by end in a long
series.
The common walls have sieve plate with
sieve area.
The sieve pores are transversed by
protoplasmic strands which connect the
protoplast of neighboring sieve elements.
Sieve tubes contain no nucleus.
2- Companion cells
these are special parenchyma cells
associated with the sieve tubes of dicots
and monocots.
A sieve tube may has one or more
companion cells.
The sieve tubes and companion cells are
connected by plasmodesmata.
A mature companion cell has a nucleus, so
there is a physiological relation between it
and the sieve tube.
• Functions of phloem :
1)sieve tubes transport
organic compounds,
2)companion cells helps
to regulate the metabolic
activities of the sieve tube
elements,
3)the phloem fibres give the
plant mechanical strength,
4)the phloem
parenchyma stores
compounds such as starch.
Tissue
Process
What is moved
Function
Xylem
Transpiration
Moves water and
minerals from roots to
leaves
‫التوصيل والدعامة‬
Phloem
Translocation
Moves food
substances from
leaves to rest of plant
‫التوصيل‬
6- Epidermis
It occurs on the surface of plants and it is a
complex tissue consisting of epidermal
cells, stomata and trichomes (hairs).
Function of epidermis:
1- Protect the plant from water
loss in transpiration.
2- It acts as boundary tissue
surrounding the plant.
3- Exchange of gases through
the stomata.
4- Storage of water and
metabolic products.
1- Epidermal cells
Shape: tabular in
side view,
isodiametric or
elongated in
surface view.
Cell wall:
straight, wavy
walls.
Cuticle: epidermal cells are covered by an
impermeable layer known as cuticle
which varies in thickness. The cuticle may
be smooth as in Stramonium or striated as
in Belladonna.
The cuticle is formed mainly of cutin which
is an aggregate of modified fatty acids,
partly combined with alcohols.
2) Stomata
These are openings in the epidermis of
stem and leaves. They occur in both
surfaces or only on lower surface. In water
plants they occur in upper surface.
Types of stomata:
The types are indicated either with regard
to the characters of the guard cells or with
regard to the epidermal cells surrounding
the stomata.
3) Trichome
Epidermal cells are sometimes extended
outwards forming projections of variable
shape and size. If it is short and conical it is
called papillae and the epidermis is
described as papillosed e.g. Coca, but if
the projections are long and well protruding
they form trichomes or hairs.
The part of trichome embedded in the
epidermis is called foot while the free part
is the body. Hairs are classified into
glandular and non-glandular or covering
hairs.
Non-glandular hairs
Unbranched
Branched
Unicellular e.g. cottony hair,
cystolitic hair
e.g. Lavender.
Non-glandular hairs
e.g. Calendula.
e.g.Cumin.
e.g.
Belladonna
Unbranched
,
stramonium
1- Simple
branched
Branched
e.g. Tobacco.
2- Stellate
3- Peltate:
e.g. Karkadeh
e.g. Olea
4Candelabra
e.g.
Verbascum
Glandular hairs
a- Uniseriate stalk
e.g. Belladonna.
b- Biseriate stalk
c- Pluriseriate
stalk
d- Branched
stalk