3. “ A simple tissue is made up of similar
type of cells which have common origin
and function”
4. Three types of simple tissues are
1. Parenchyma
2. Collenchyma
3. sclerenchyma
5. Parenchyma is a Greek word
Para means “beside”& en
means “to pour”
parenchyma tissues is
composed of living cells which
are variable in their morphology
& physiology
6. It occurs in
Pith
Mesophyll of leaf
Pulp of fruit
Endosperm of seed
Xylem and Phloem
7. It consists of unspecialized cells with thin cell
walls
these are living, with a large central vacuole
intercellular spaces between
them.
Oval ,rounded & polygonal
in shapes
8. Arenchyma
In aquatic plants large
air cavities are present
which give buoyancy to
the plants and help
them to float
Chlorenchyma
It contains chlorophyll &
performs
photosynthesis.
9. 1. It provides support to plants and also stores
food in the form of starch grains fats & oils
2. Air spaces in parenchyma also facilitate
exchange of gases
10. They are elongated living cells with small
intercellular spaces. Their cell walls are made of
cellulose and pectin.
It occur in the peripheral regions of stems and
leaves.
It allows easy bending in various parts of a plant
(leaf, stem) without breaking.
mature collenchyma are living & contain
protoplast
13. 1. Angular
In this type cells are irregularly
arranged e.g ficus
2.Lamellar
Cells are arranged in tagential
rows(plate like arrangement)
e.g sambucus
3. tubular
Tube like arrangement,
intercellular spaces are
present
14. It provides mechanical support and flexibility
in plants.
Helps in photosynthesis
15. The sclerenchyma is a
Greek word
Sclerous means “hard”
& enchyma means
“infusion”
16. Sclerenchyma are long, dead cells with a
deposit of lignin in their cell wall.
They have no intercellular spaces.
This tissue is present in stems, around
vascular bundles, in the veins of leaves and in
the hard covering of seeds and nuts.
Thick walled cells
Don’t possess living protoplast at maturity
17.
18. It provides strength to the plant parts.
it maintain the turgidity of plants
20. elongated sclerenchyma cells,usually with
pointed end
The wall of fibres are usually lignified
Pits of fibres are always small,round,or silt
like
At maturity the protoplast disappear &
permanent cells becomes dead or empty
It occurs in patches
Average length of fibres is 1to 3mm
21.
22. Two types of fibres are
Xylem fibres
Extraxylary fibres
23. the fibres develop from the same
maristematic tissues as the other xylem cells
or
The fibres which originated from xylem
24. These are related to phloem that form
continous cylinder in monocotyledon stem arise
in the ground tissue under the epidermis at
variable distance
TYPES:
1.Phloem fibres (originating primary & secondary
phloem)
2.Cortical fibres ( originating in the cortex)
3.Perivascular fibres( originated in the peripheral
region of vascular cylinder
25. - Sclerenchymatous cells which are short and
possess extremely thick,
lamellated, lignified walls with long
singular piths. They are called sclerides
Its is commonly found in cortex and pits of
gymnosperms
Types:
1.Brachysclereids
2.Macrosclereids
3.Osteosclereids
26. 4.Astrosclereids
1.brachysclereids
stone cells are short &
more or less isodiametric.
These are commonly found in
cortex ,phloem,& pulp of fruit
2.macrosclereids
more or less rod like cells found in
xerophytic leaves
27. 3.osteosclereids
theses are bone shaped & found in the
hypodermal layer of seeds & fruits
4.Asterosclereids
these are star shaped found in
intercellular spaces of the leaves & stem of
hydrophytes
