CHAPTER 2
TISSUE
Compendium
1. Introduction
a. Tissue
b. Importance of tissue
c. Various types of tissue
2. Why do plants and animals have different types of tissue?
3. Plant tissue
a. Meristematic tissue
i. Apical
ii. Intercalary
iii. Lateral
b. Permanent tissue
i. Simple
- Parenchyma
- Collenchyma
- Sclerenchyma
ii. Complex
- Xylem
- Phloem
4. Protective tissues of plant
a. Epidermis
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b. Cork
5. Bird’s-eye view
6. Solve examples
7. Practice yourself
8. Solutions
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1. Introduction
Tissue is a group of cells that are similar or dissimilar in
structure having a common origin and usually perform a
common function is called Tissue.
The word tissue comes from the Old French word tissu, meaning
'woven.'
Fig : 1 Microscopic
view of connective
tissue (Woven)
Importance of tissues:
1. The workload of an individual cell is decreased.
2. Tissues become organised to form organs and a group of organs
forms an organ system.
3. Formation of tissues has brought about the division of labour in
multicellular organisms.
4. Multicellular organisms have now higher survival due to improved
body organisation and higher efficiency of functions.
Various types of Tissue:
• The living organisms can be either unicellular [e.g. Bacteria,
Amoeba, Chlamydomonas] or multicellular [e.g. Man, Horse, Dog].
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• Each unicellular organism can perform all those vital activities as
shown by a multicellular organism like digestion, respiration,
excretion, reproduction.
• The multicellular organisms, on the other hand, are composed of
millions of cells. All the cells of a multicellular organism are not
involved in performing all functions of the body; instead, they
undergo differentiation, and every kind of cell becomes
specialised for a limited number of a specific type of services. For
examples, in human beings:I. Muscle cells cause movements through contraction and
relaxation.
II. Nerve cells or neurons are involved in receiving and sending
impulses.
III. Blood transports oxygen, nutrients, hormones and waste
materials inside the body.
Importance of tissues in multicellular organisms:As the degree of multicellularity increased in
living beings, it became difficult for each cell
to perform all types of physiological functions
of the body efficiently. Hence, a group of cells
of a similar type of cells called tissues
performed a specialised function. Thus, the
use of tissues in multicellular organisms is
to perform specific functions of the body.
4
Fig : 2 Xavier Bichat,
French anatomist (Father
of modern Histology)
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Did you know?
• Xavier Bichat introduced the term 'tissue'.
• Karl Mayer, a German anatomist and physiologist, introduced the term
'Histology'.
• Study of tissue is called histology.
• Marcello Malpighi, an Italian biologist and physician, is the 'Founder of
Histology'.
• Frederik Ruysch introduced the term 'epithelium'.
2. Why do plants and animals have different types
of tissue?
Plants
Plants are stationary or fixed to
Animals
Animals exhibit locomotion.
a substratum.
They have to be upright. Hence Animals comparatively require
a large quantity of stationary
less rigid tissue for support as
tissue is needed.
they are mobile.
Comparative study of plant and animal tissue
Tissue organisation is towards
Tissue organisation is towards
stationary or fixed habit.
active locomotion.
Most of the plant tissues are
Most of the animal tissues are
dead tissue and provide
living.
support.
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In plants, growth takes place in In animals, growth takes place
certain specific regions where
throughout the body.
growing tissues are present.
Checkpoint 1
1. Who introduced the term tissue?
(a) Bichat
(b) Robert Brown
(c) Aristotle
(d) Leuwenhoek
2. Study of Tissue is called?
(a) Cell Biology
(b) Tissue biology
(c) Histology
(d) Tassology
3. Why Plants and Animals have different types of tissue?
(a) Plants are upright always
(b) Plants need more supportive Tissue
(c) Animals need less supportive Tissue
(d) All of the above
4. Which of the following are types of Plant Tissue?
(a) Permanent
(b) Meristematic
(c) Totipotent
(d) All of the above
5. What do you mean by ‘division of labour’?
6. What is the use of tissues in multicellular organisms?
7. Supportive tissue is dead in case of ________ (Plant/Animal)
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3. Plant tissues
Based on their dividing capacity plant tissues are of two types:1. Meristematic Tissue (Growing tissue)
2. Permanent Tissue
Types of meristematic tissue
a. Based on Position/Location
b. Based on Origin
Characteristics of Meristematic Tissue
• They are living tissues, composed of immature cells that are
capable of division throughout life.
• These tissues are present in growing regions of plants.
• Cells have a thin cell wall.
• Cells contain dense cytoplasm without vacuoles.
• Cells contain a prominent and large nucleus.
• Cells are metabolically highly active, so stored food is absent.
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• Cells are compactly arranged as they do not have any intercellular
spaces.
• Function: Meristematic tissue cause growth in length and width
(girth) of the plant body.
Apical meristem
Intercalary meristem
Lateral meristem
Fig : 4 Meristematic Tissue / Meristem
Fig : 3 A Typical Meristematic Tissue
Types of meristematic tissue based on position/location:
Apical meristem: It is present at the tip of growing stems and roots.
of the plant. They are responsible for the increase in the length of
plant organs.
Significance
• It causes primary growth or lengthening of plant.
• It is also responsible for the production of new leaves and flowers.
Fig : 5 Apical Meristem
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Types of apical meristem:
Fig : 6 Types of Apical Meristem
Intercalary meristem :
• Intercalary meristem is the part of
apical meristem which is left
behind during the growth period
of plant.
• These are short-lived and gets
converted into permanent tissue.
• These are present at the base
where the leaf is attached or
Fig : 7 Intercalary Meristem
internode of the blade.
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• Intercalary meristem may be present either at the node as is
present in mints, bamboo, grasses or the base of Pinus leaves.
• Growth in length of plant organs is due to this meristem.
• This type of meristem occurs only in monocots, particularly
grass family (rice, corn, sugarcane, bamboo, etc.).
Significance: It serves as an adaptive mechanism against herbivory.
Fig : 9 Examples of plant stems with intercalary
meristem
Fig : 8 Intercalary Growth
Lateral meristem
• Found in all woody plants and some
herbaceous ones.
• It is found on the lateral sides of stem and
root (longitudinal axis) of the plant.
• Lateral meristem allows the plant to grow
out, or laterally.
• It is responsible for the increase in
Fig : 10 Thickness due to
Lateral Meristem
diameter of the organ.
• Significance: It helps in increasing the diameter (girth or width)
of the plant. Hence helps in secondary growth.
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Mental floss!
Lateral Meristem is responsible for secondary growth.
Characteristics
Position
Apical
Intercalary
Meristem
Meristem
Shoot
Lateral Meristem
apex At the base of leaf Lateral
and root apex
sides
of
sheath of monocots. stem and root
E.g. Grasses
Type of growth
Longitudinal
Longitudinal growth Growth
growth
diameter
in
or
girth/width
Mental floss!
• When plants begin flowering, the
shoot apical meristem is
transformed into an inflorescence
meristem.
• It produces the floral meristem,
which produces the sepals, petals,
stamens, and carpels of the flower.
Fig : 11 floral meristem
Types of meristematic tissue based on origin:
Promeristem
• The first formed and youngest meristematic tissue.
• It originates from the embryo.
• The primary meristem arises from the promeristem.
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• It is present in the root and the shoot tip of the plant.
Primary meristem
• It arises from the promeristem.
• Cells undergo division actively.
• It is present below the promeristem.
• It forms the permanent tissue.
Secondary meristem
• It originates from the primary meristem.
• These permanent tissue forms from the secondary meristem.
Checkpoint 2
1. Which Plant Tissue will keep on dividing?
(a) Meristematic
(b) Permanent
2. Apical, Intercalary and Lateral are classified as meristem on the
basis of ____________
3. What is the Importance of Meristematic Tissue?
4. Which of the following is not correct for meristematic tissue?
(a) It has living thin-walled cells
(b) Cells have dense protoplasm
(c) They have no intercellular spaces
(d) They store reserve food material
5. Which of the following will need more supportive tissue?
(a) Plant
(b) Animal
6. What are the two types of plant tissue based on division capacity?
7. Apical, Intercalary and Lateral are classified based on?
(a) Origin
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(b) Plane of Division
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(c) Position
(d) Chronology
8. What is the importance of Meristematic Tissue?
9. Where is Apical Meristem present?
(a) Tip of Shoots
(b) Tip of Roots
(c) Both
10. Which of these can produce an entire plant?
(a) Apical Meristem
(b) Shoot Apical Meristem
(c) Root Apical Meristem
(d) None of the above
11. Root Apical Meristem is present in all type of Roots.
(a) True
(b) False
12. Which of these tissues can grow in both directions?
13. The apical meristem of the root is present
(a) Only in radicles
(b) Only in taproots
(c) Only in adventitious roots
(d) In all the roots
14. Elongation of internodes of the stems of grasses is facilitated
by____________ meristem.
15. Assertion: Intercalary Meristem serves as an adaptive mechanism
in herbivory
Reason: These Tissue help in the growth of grass very fast
(a)Both assertion and reason are true statements, and the reason is
the correct explanation of assertion.
(b)Both assertion and reason are true statements, but the reason is
not the correct explanation of assertion.
(c)The assertion is true, and the reason is false.
(d)The assertion is false, and the reason is true.
16. Assertion: Lateral meristems are present in plants.
Reason: These help in the healing of wounds in plants
(a)Both assertion and reason are true, and the reason is the correct
explanation of assertion.
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TISSUE
(b)Both assertion and reason are true, but the reason is not the
correct explanation of assertion.
(c)The assertion is true, and the reason is false.
(d)The assertion is false, and the reason is true.
17. Compare all three types of the meristem.
18. Which plant tissue is metabolically active always?
19. Which tissue is composed of immature cells?
20. What is the position of shoot apical meristem?
21. Which is the tissue that lies at the base of internode of plants?
22. Which type of meristem is responsible for an increase in the
length of plants?
23. Which meristem is responsible for the increasing girth of
plants?
Permanent tissue
• These are permanent cells which have lost their capacity to
divide and hence are permanent.
• They are also known as differentiated cells.
• The matured cells are incapable of division. The cells are fully
differentiated. The cell wall is relatively thick. Small nucleus.
• Large central vacuole is present. Intercellular space is present.
• Division and differentiation of meristematic tissue lead to the
formation of permanent tissue.
• They are composed of those cells which have temporarily or
permanently lost the power of division and attain a permanent
shape, size and function.
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• Cells will be living or dead.
• Cells can be oval, rounded, polygonal or elongated.
Mental floss!
Plants, unlike most animals, continue to grow throughout
their entire life span because of the unlimited division of
meristematic regions.
Permanent tissues are of two types:-
(a) Simple permanent tissue- They can be classified into
sclerenchyma, collenchyma and parenchyma based on their
purpose.
(b) Compound or complex permanent tissue- These tissues include
phloem and xylem.
(a) Simple permanent tissueSimple permanent tissue is further classified into three types:
Parenchyma
• The cells have a round or oval-shaped.
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• The cell wall is thin and is made up of hemicellulose or cellulose.
• The cells have vacuoles for storage and very small nucleus.
• It is found in all parts of the plant.
• The protoplasm of cells is living and dense.
Fig : 12 (a) Parenchyma (i) transverse section, (ii) longitudinal section; (b)
Collenchyma (i) transverse section, (ii) longitudinal section; (b) Sclerenchyma (i)
transverse section, (ii) longitudinal section.
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Types of parenchyma:(a)
Chlorophyll
containing
parenchymatous
cells
are
called
chlorenchyma. They are present in the mesophyll of leaves.
(b) Parenchyma, which comprises of big air voids (spaces) are called
aerenchyma. In aquatic plants, aerenchyma helps them float, e.g.
petiole of water hyacinth.
Fig : 13 Modification of Parenchyma
Collenchyma
• Cells are long and thick-walled.
• The cell wall of the cells in this tissue is made up of cellulose and
pectin.
• It is found in vascular bundle of dicot leaf and hypodermis of dicot
stem.
• The amount of chloroplast is less in the cells.
• Intercellular spaces are very less or absent between cells of this
tissue.
• Cells of this tissue are living. The cells are elongated or vary in
structure.
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• Cells of this tissue are irregularly thickened at the boundaries due
to the deposition of pectin.
• It is the present herbaceous stem in the form of the hypodermis
and below the epidermis of the leaf.
Functions
• Storage of food and provide support to the plant
• Gives flexibility
• Bending of plant parts like tendrils and stems of climbers without
breaking.
Mental floss!
Collenchyma is usually absent in monocots and roots. Cells
of collenchyma contain few chloroplasts.
Checkpoint 3
1. Which is the tissue that is formed by division and differentiation of
meristematic tissue?
2. Which is the universal plant tissue?
3. Which type of parenchyma is seen in mesophyll tissue of leaves?
4. Write the function of chlorenchyma.
5. Write the function of aerenchyma?
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Sclerenchyma
• Sclerenchyma cells are dead cells which are devoid of
protoplasm.
• The cell wall of cells in sclerenchyma tissue are highly thickened
uniformly with deposition of lignin (lignified).
• Due to excessive thickening of the wall of a sclerenchyma cell, its
cavity or lumen is nearly absent.
• The cells of sclerenchyma are tightly packed without any
intercellular spaces.
• They are found in veins of leaves, stems (around the vascular
bundle), roots, hard coverings of seed and nuts.
• These are dead tissues which are very hard and rigid in texture.
• Cells are of various size and shapes.
• These provide rigidity and mechanical support to the plant.
Function:• It is the main mechanical tissue which provides mechanical
support.
Sclerenchyma cells are of two types in structure:
1. Fibres
2. Sclereids
Sclerenchyma fibres:- They are highly elongated (1 mm to 550 mm in
length), narrow and spindle-shaped with oblique or pointed end walls.
• The fibres are closely packed without intercellular spaces.
• The walls of fibres are often very thick that the cell cavity or lumen
is highly reduced.
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• Oblique thin areas are found in their wall are called pits.
Functions:The major mechanical tissue of the plants is constituted by
sclerenchyma fibres and are abundantly found in plants. Commercial
fibres obtained from plants (e.g. Jute, Flax, Hemp, Husk of coconut
etc.) usually are sclerenchyma fibres.
Sclereids (grit or stone cells):- They are highly thickened and
irregularly shaped dead cells.
• They are found in various parts of the plant such as cortex, pith,
phloem, hard seeds etc.
• The grittiness in the pulp of some fruits (such as guava, apple,
pear, etc.) is due to the presence of sclereids in it.
Functions:-The primary function of sclerenchyma is to provide
mechanical support to the plants.
Sclereids provide strength to seed covering and grittiness to the
pulp of many fruits.
Checkpoint 4
1. Which is the tissue which provides flexibility and mechanical
strength?
2. Which tissue forms hypodermis of herbaceous dicot plants?
3. What are the functions of collenchyma?
4. Write the name of simple permanent tissue which have lignified
elongated dead cell.
5. Which tissue is found in the husk of coconut?
6. Which chemical is deposited in the cell wall of sclerenchyma cells?
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Compound or complex permanent tissue:
The complex tissues consist of more than one type of cells. All these
cells coordinate to perform a common function. Functions performed
by complex tissues include transport water, mineral salts (nutrients)
and food material to various parts of the plant body.
Two types of Complex tissues are :
(I) Xylem or wood
(II) Phloem or bast
Fig : 14 Transport in Tree
Fig : 15 Xylem and Phloem
Fig : 16 Xylem and phloem Tissue
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Comparison between Xylem and Phloem
Xylem
Phloem
Made of mostly
Dead Cells
Living Cells
Cell wall
Thick
Thin
Cell wall made of
Lignin (rigid)
Cellulose
Permeability
Impermeable
Permeable
Cytoplasm
None
Cytoplasm absent in
fibres and sieve tubes
Transports
Water & Minerals
Food
Transports to
Leaves
Growing parts and
storage organs
Direction of flow
Unidirectional
Bidirectional (Upwards
(Upwards)
& Downwards)
Xylem
•
Xylem is important for the transportation of water and solvable
constituents.
•
Xylem is made up of:
a. Xylem Parenchyma- Living Element
b. Xylem Fibres- Dead Element
c. Xylem Vessels- Dead Element
d. Tracheids- Dead Element
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1. Tracheids: Tracheids are
elongated cells with tapering
ends. They conduct water since
tracheids are not open-ended
like the vessels, so the water has
to pass from cell to cell via the
pits.
2. Vessels or tracheae: They are
very long tube-like structures
formed by a series of cells placed
end to end. They form
continuous channels or water-
Fig : 17 Types of xylem Tissue
pipes as the transverse walls between
the vessels are completely dissolved.
• Functions: Tracheids and vessels help
in long-distance conduction of water
and minerals upward from the root
system to various parts of the plant.
• Tracheids
and
vessels
provide
mechanical support.
Xylem
fibre: These are dead and
lignified sclerenchyma cells which are
Fig : 18 Types of phloem Tissue;
mainly supportive in function.
Xylem parenchyma: It is formed of living parenchymatous cells
which help in the storage of food and lateral conduction of water
and minerals.
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Phloem
• Phloem is important in the translocation of food particles.
• Phloem consists of:
a. Phloem parenchyma
b. Phloem fibres
c. Companion cells
d. Sieve cells
e. Sieve tubes.
Fig : 19 A: Longitudinal section B. Transverse section
1. Sieve tubes
• Sieve tubes are slender structures composed of elongated thinwalled cells, placed end to end.
• Their end walls are perforated and are called sieve plates. Walls
of sieve tubes are perforated.
• On maturity of a sieve cell, nucleus degenerates at maturity.
However, cytoplasm persists in the mature cell.
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• The cytoplasm of adjacent sieve elements is continuous by
cytoplasmic connections passing through the pores of the sieve
plate.
2. Companion cells:
• These are associated with sieve tubes.
• These cells are smaller, having a prominent nucleus and dense
cytoplasm.
• There is conduction of food material from companion cells to the
sieve tubes.
• Sieve cells & companion cells are so-called sister cells because they
originate from a single mother cell.
3. Phloem parenchyma :
•
These are living and thin-walled cells.
•
It is also known as bast parenchyma.
•
It helps in the conduction of food in a radial direction.
•
It stores various materials, e.g. Resin, Latex, Mucilage,etc.
4. Phloem fibres:
• These are dead and sclerenchyma cells. Commercial fibres, e.g.
Jute, Hemp, Flax, are phloem or bast fibres of these plants.
• They provide mechanical support to the conducting elements.
The function of phloem: Phloem transport food materials prepared
photosynthetically from the leaves to the growing regions and
storage organs of the plant body.
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Did you know?
The common name of Xylem is wood.
The common Name of Phloem is bast.
Checkpoint 5
1. Name the plant tissue concerned with the conduction of water.
2. Give the name of different types of elements found in the xylem.
3. Name the xylem element helps in storage of food.
4. Name the plant tissue concerned with the transportation of food.
5. Name the different types of elements found in phloem.
6. Write the name of the main conducting elements of phloem.
4. Protective tissue of plants
These tissues are primarily protective in function. They are of two
types :
(1) Epidermis
(2) Cork
1. Epidermis:
• It forms the outermost layer of all organs of the plant body, which
is formed from parenchymal cells.
• It protects the underlying tissue from mechanical injuries and
entry of germs.
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• Cuticle: The outer wall of the
epidermis of aerial parts of the
plant is deposited with a fatty
substance, called cutin which
forms a waterproof layer called
the cuticle which checks the
Fig : 20 Epidermis along with cuticle
loss of water by transpiration.
• The lower epidermis of dicot leaves has a large number of
microscopic aperture called stomata.
Stomata: Each stoma is an elliptical aperture bounded by two
kidney-shaped guard cells which regulate opening and closing
stoma.
• Guard cells are kidney-shaped in dicot and dumb-bell shaped in
monocot.
• Stomata help in gaseous exchange.
• It helps in transpiration which develops a force called transpiration
pull, that helps in the absorption of water by the roots.
• Root hairs: Epidermis of roots, called epiblema have extensions of
cells called root hairs. Root hair greatly increases its surface area for
absorption of water and minerals.
2. Cork or Phellem :
• Cork is the peripheral tissue of old stems and roots of woody trees
which is formed due to activity of a secondary lateral meristem
called cork cambium or phellogen.
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• Cork cambium produces new cells on its either sides, thus,
forming
phellem/cork
on
the
outer
side
and
the
phelloderm/secondary cortex on the inner side.
• Cork is made up of dead cells with the thick wall which is due to
the deposition of an organic substance (a waxy substance) called
suberin. There are no intercellular spaces.
• Suberin makes these cell impervious to water and gases, and it
also helps in the conservation of water in the trees.
Functions
• Cork is hard and hence protects the underlying tissue.
• Cork prevents desiccation in the plant.
• Cork prevents infection and also protect from mechanical injury.
• Lenticels are pores present in the cork provide aeration to the
inner tissues.
Fig : 21
Commercial Importance of cork :
• Cork is light, highly compressible and does not catch fire easily.
• Hence, it is used in the making of a variety of sports goods such
as cricket balls, table tennis, shuttle-cocks, wooden paddles etc.
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Checkpoint 6
1. Write the names of two protective tissue.
2. Name the microscopic apertures present on the epidermis of the
leaf.
3. Write the name of protective tissue which is formed from the
activity of cork cambium.
4. What is the waxy substance that is seen in the outer wall of the
epidermis of aerial parts of plant.
Comparative study of meristematic tissue and permanent tissue:
Meristematic tissue
1.
Permanent tissue
The cells are capable of The
matured
cells
are
division.
incapable of division.
2.
The cell wall is thin.
The cell wall is relatively thick.
3.
Large prominent nucleus.
Small nucleus.
4.
Vacuoles
absent.
5.
are
small
or Large
central
vacuole
is
present.
Intercellular space is absent. Intercellular space is present.
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Bird’s-eye view
• The tissue is a group of cells which is similar in structure and
function.
• Plant tissues are mainly of two types – meristematic and
permanent.
• Meristematic tissue is the dividing tissue which is present in the
growing regions of the plant. They are undifferentiated tissue.
• Permanent tissues are derived from meristematic tissue and they
lose the ability to divide. They are differentiated tissue. They have
been classified as simple and complex tissues.
• Parenchyma, collenchyma and sclerenchyma are three types of
simple tissues. Xylem and phloem are types of complex tissues.
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Solved examples
1. The term tissue was given by :(A) Robert Hooke
(B) Leeuwenhoek
(C) Bichat
(D) Meyer
2. The advantage of tissues in a multicellular organism is:(A) Faster development
(B) Division of labour
(C) Higher reproductive potential
(D) Body strength
3. Tissue that is absent in monocots is:(A) Aerenchyma
(B) Chlorenchyma
(C) Collenchyma
(D) Sclerenchyma
4. The grit of pear is formed of:(A) Sclereids
(B) Sclerenchyma fibres
(C) Tracheids
(D) Companion cells
5. Which one is made of dead cells:(A) Sclerenchyma
(B) Tracheids
(C) Vessels
(D) All the above
6. A pair of kidney-shaped cells present around stomata are called:(A) Guard cells
(B) Subsidiary cells
(C) Epidermal cells
(D) Trichomes
7. Epiblema bears:(A) Cutinised hair
(B) Uncutinised hair
(C) Root hair
(D) Both (B) and (C)
8. Tracheary elements of xylem are:(A) Vessels
(B) Tracheids
(C) Both A and B
(D) Sieve tubes
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9. Find out the incorrect sentence:(A) Parenchymatous tissues have intercellular spaces
(B) Collenchyma tissues are irregularly thickened at corners
(C) Apical and intercalary meristems are permanent tissues
(D) Meristematic tissues, in its early stage, lack vacuoles
10. Which is not a function of the epidermis?
(A) Protection from adverse condition
(B) Gaseous exchange
(C) Conduction of water
(D) Transpiration
Answers:
1
2
3
4
5
6
7
8
9
10
C
B
C
A
D
A
D
C
C
C
11. What is tissue?
Ans. The tissue is a group of related cells that have a common origin
and perform a specific function.
12. What is the use of tissues in multicellular organisms?
Ans.
(i) Tissues increase efficiency by division of labour in multicellular
organisms.
(ii) Higher organisation- Organs are formed from tissues of similar
kind and organs organises to form organ systems.
(iii) The workload of individual cells will be reduced.
(iv) Increased survival due to higher efficiency and organisation, the
multicellular organisms have high survival.
13. Name types of simple tissues.
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Ans. Three – Parenchyma, collenchyma and sclerenchyma.
(Meristematic tissue is also a simple tissue).
14. Where is apical meristem found?
Ans. Apical meristem occurs at the tip of root and stems.
15. Which tissue is found in the husk of coconut?
Ans. Sclerenchyma.
16. What are the constituents of phloem?
Ans. Sieve tubes, companion cells, phloem parenchyma, are living
constituents and phloem fibres are dead.
17. What are the components of xylem tissue? Name them.
Ans. Xylem tissue is formed of four components. They are tracheids,
vessels, xylem fibres and xylem parenchyma.
18. What are the functions of stomata?
Ans. Functions of stomata. (i) Gaseous Exchange- Stomata are
openings through which the exchange of gases (carbon dioxide and
oxygen) occurs between the plant interior and external environment.
(ii) Majority of transpiration (a process which removes water in the
form of water vapour from the aerial parts of the plant) occurs through
stomata.
19. Which tissue is present in the following: bark of the tree, vascular
bundle.
Ans. The bark of Tree: Cork (Protective tissue), Vascular Bundle:
Complex or vascular tissues, xylem and phloem.
20. Name the regions of a plant in which parenchyma tissue is
present.
Ans. It occurs in almost all non-woody parts of the plants–cortex(of
root and stem), pith(of root and stem), chlorenchyma of leaves,
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CHAPTER 2
TISSUE
flowers, the pith of fruits,
medullary rays of the stem, etc. The
epidermis is a special type of parenchyma.
21. What is the function of the epidermis in plants?
Ans. (i) Protection, (ii) Regulation of transpiration, (iii) Formation of
insulating layer, (iv) Exchange of gases.
22.
Cork act as a protective tissue. How?
Ans. Cells of cork are dead and impermeable due to deposition of
suberin over the cell walls. Intercellular space is absent. It is insulating
(heatproof), fireproof, shockproof, water-resistant and repellent to
microbes and animals.
Multiple Choice Type (Each carries one mark)
1. Increase in the length of the plant is caused by(A) Cork cambium
(B) Vascular cambium
(C) Apical meristem
(D) Permanent tissue
2. Cork cambium is an example of(A) Lateral meristem
(B) Primary meristem
(C) Apical meristem
(D) Intercalary meristem
3. A simple permanent tissue devoid of intercellular spaces and
lignin is-
34
(A) Parenchyma
(B) Collenchyma
(C) Sclerenchyma
(D) All of these
CHAPTER 2
TISSUE
4. Interfascicular cambium is an example of(A) Primary meristem
(B) Secondary meristem
(C) Lateral meristem
(D) Apical meristem
5. Bases of leaves and internodes have(A) Lateral meristem
(B) Apical meristem
(C) Intercalary meristem
(D) None of these
6. Parenchymatous cells which are thickened with cellulose at the
corner are called(A)Collenchyma
(B) Sclerenchyma
(C)Parenchyma and sclerenchyma
(D) None of these
7. The nucleus is not present in(A)Companion cell
(B) Mature sieve tube
(C)Phloem parenchyma
(D) Collenchyma
8. Sieve tubes and companion cells occur in(A)Xylem
(B) Cambium
(C) Meristem
(D) Phloem
9. Elongated lignified cells with pointed ends belong to(A)Collenchyma
(B) Parenchyma
(C)Sclerenchyma
(D) None of these
10. Tissues secreting latex are(A) Laticiferous
(B) Glandular
(C) Meristematic
(D) Permanent
11. The tissue is defined as(A)Group of similar cells having a common function
(B)Different types of cells performing the same functions
(C)Different types of cells performing different functions
(D)An organised group of cells performing many functions.
12. Which tissue provides mechanical strength to plants?
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CHAPTER 2
TISSUE
(A) Sclerenchyma
(B) Parenchyma
(C) Collenchyma
(D) Chlorenchyma
13. Name the tissue where the cells are living, thinly walled,
isodiametric with intercellular spaces.
(A)Collenchyma
(B) Parenchyma
(C)Aerenchyma
(D) Sclerenchyma
14. In sclerenchyma, the cell wall is(A) Lignified
(B) Suberised
(C) Pectinised
(D) Cutinised
15. Which of the following cells is dead?
(A) Parenchyma
(B) Collenchyma
(C) Sclerenchyma
(D) All of these
16. Which of these cells is most likely to divide?
(A) Epidermis
(B) Parenchyma
(C) Meristem
(D) Xylem
17. Companion cells are associated with(A) Sieve tubes
(B) Sclerenchyma
(C) Vessels
(D) Parenchyma
18. The tissue that takes part in the transport of food materials is(A) Parenchyma
(B) Phloem
(C) Xylem
(D) None of these
19. Xylem takes part in(A) Conduction of water in the plant body.
(B) Conduction of food material
(C) Providing mechanical support
(D) Both (A) and (B)
20. Which of the following are characteristics of angiosperms?
36
CHAPTER 2
TISSUE
(A)Xylem
(B) Vessels
(C) Sieve tubes
(D) Cambium
Very Short Answer Type (Each carries two marks)
1. Give one example of (i) Apical meristem and (ii) Lateral meristem.
2. What is the main function of parenchyma?
3. Which substance is deposited at the corner of cells in collenchyma?
4. Which chemical is deposited in the cell wall of sclerenchyma?
5. Give one main function of collenchyma.
6. Name the complex tissue which helps in : (a) Conduction of water
and minerals, (b) Conduction of food.
7. What is the common name of (a) Xylem (b) Phloem?
8. Name the cell which is attached to the lateral side of the sieve tube.
9. Which type of simple tissue is used for making ropes?
10. Give one example of protective tissue in the plant.
Short Answer Type (Each carries three marks)
11. Write a short note on intercalary meristem.
12. Write one important function of
(a) Apical meristem
(b) Lateral meristem
13. What are simple tissues? Explain their three different types.
14. Draw a well-labelled diagram of phloem.
15. Give two functions of collenchyma.
16. Distinguish between xylem and phloem.
17. Explain the different types of elements present in phloem.
18. What are the tracheary elements? Describe their functions.
19. What is the function of xylem?
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CHAPTER 2
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Long Answer Type (Each carries four marks)
1. What is tissue? Why are plant and animal tissues different? Give
the importance of tissues.
2. Explain meristematic tissue and its classification based on its
position in the plant body.
3. Explain simple tissue and their classification with appropriate
diagrams.
4. Explain complex tissue and their classification with appropriate
diagrams.
5. Name and describe two protective tissues of plants. Give their
other functions as well.
Fill in the blanks
1. ................... are forms of complex tissue.
2. ................... have guard cells.
3. Cells of cork contain a chemical called...................
4. The husk of the coconut is made of ................... tissue.
5. ................... and ................... are both conducting tissues.
6. ................... gives flexibility in plants.
7. Xylem transports ................... and ................... from the soil.
8. Phloem transports ................... from leaves to other parts of the plant.
9. ................... have tubular cells with perforated walls and are living in
nature.
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CHAPTER 2
TISSUE
10. The epidermis in desert plants has a thick waterproof coating of
................... over it.
Match the columns
Match the contents of the columns A with B (single matching).
Column A
Column B
a.
Parenchyma
1.
Thin walled, packing cells
b.
Photosynthesis
2.
Carbon fixation
c.
Aerenchyma
3.
Localised thickening
d.
Collenchyma
4.
Buoyancy
e.
Permanent tissue
5.
Sclerenchyma
Match the contents of the columns-I, II and III (Double matching)
Column -I
Column-II
Types of tissue
Column-III
Position
Function
(A)
Apical meristem
i
Base of
e
Store food
(B)
Intercalary
ii
internode
f
Growth in length
(C)
meristem
iii
All soft part
Parenchyma
of plant
of plant
g
Root apex
Growth in length
of internode
True and false
1. Vacuoles are absent in meristematic plant cells.
2. Sclerenchyma has irregularly thickened cells.
3. Root hair increases the absorptive surface areas of roots.
4. Cells of cork are dead, suberised and compactly arranged.
5. Aerenchyma is modified parenchyma and occurs in aquatic plants.
39
CHAPTER 2
TISSUE
6. Sieve tube cells are found in xylem, while vessels are found in
phloem.
7. Apical meristem helps in longitudinal growth, while lateral
meristem helps in secondary growth.
8. Collenchyma cells are deposited with lignin, while sclerenchyma
cells are deposited with pectin.
9. Tracheids and vessels are collectively called tracheary elements.
10. The husk of the coconut is made up of sclerenchyma tissue.
Multiple Choice Type (Each carries one mark)
1. Prosenchyma is a type of:(A) Chlorenchyma
(B) Collenchyma
(C) Parenchyma
(D) Sclerenchyma
2. Tracheary elements are:(A) Full of dense cytosol
(B) Suberised
(C) Elongated with walls containing lignin
(D) Small and
numerous
3. The growth in plants is:(A) Caused by every cell of the body
(B) Limited to certain regions
(C) Caused by non-dividing regions
(D) Uniform
4. Angiosperms contain:(A) No sieve tubes
(B) No vessels
(C) Tracheids only
(D) Vessels
5. Which one of these is not a plant fibre:(A) Coir
(B) Flax
(C) Hemp
6. Secondary growth occurs through:40
(D) Silk
CHAPTER 2
TISSUE
(A) Formation and division of meristematic cells
(B) Vascular region
(C) Cortical region
(D) Both 2 and 3
7. In which of the following part of a plant, growth is subapical?
(A) Root
(B) Shoot
(C) Pedicle
(D) Petiole
8. Cork cells are:(A) Photosynthetic
(B) Elongated and participate in movement
(C) Meristematic
(D) Dead
9. Dendrochronology is the study of determining:(A) The diameter of a tree
(B) Age of a tree by counting the number of annual rings in the
main stem
(C) Height of a tree
(D) Age of tree by counting the number of leaves in the main stem
10. The youngest layer of secondary phloem in woody dicot stem is
located:(A) Just outside the vascular cambium
(B) Just on the inner side of the cambium
(C) Between periderm and primary cortex
(D) Just outside pith
11. Mesophyll tissue is well-differentiated into spongy tissue and
palisade tissue in:(A) Dicot leaves
(B) Xerophytic stem
(C) Hydrophytic stem
(D) Monocot leaves
12. What is cork tissue also called?
41
CHAPTER 2
TISSUE
(A) Phellogen
(B) Phelloderm
(C) Phellem
(D) Periderm
13. In desert plants, the rate of water loss gets reduced due to the
presence of:(A) Cuticle
(B) Stomata
(C) Lignin
(D) Suberin
14. The tissue that helps in the conduction of water sideways in the A
long tree has several branches is:(A) Collenchyma
(B) Xylem parenchyma
(C) Parenchyma
(D) Xylem vessels
15. If the tip of the sugarcane plant is removed from the field, it still
can grow in length. This is due to the presence of:(A) Cambium
(B) Apical meristem
(C) Lateral meristem
(D) Intercalary
meristem
Unscramble the words
1. Sterimeticma- Dividing tissue
2. Nenperntma- Non-Dividing tissue
3. Chymalenclo- Gives flexibility to Plants
4. Renreamaych- Provide buoyancy to aquatic plants
5. Srenelcamych- Gives strength to plants
42
CHAPTER 2
TISSUE
Crossword
Across
2. Tissue that has lost the ability to divide.
5. Tissue that increases the girth of the stem is called ________
meristem.
6. Tissue that provides mechanical support.
8. Actively dividing tissue of plants.
9. Parenchymatous tissue that contains chlorophyll.
11. Meristematic issue present at nodes and internodes.
12. Organisms having no internal tissues/organs.
14. Tissue that provides flexibility to the plants.
15. Simple tissue containing dense protoplasm.
16. Group of cells.
43
CHAPTER 2
TISSUE
Down
1. Tissue that transports food.
3. Tissue that provides buoyancy in aquatic plants.
4. Tissue that transports water.
7. Organisms which exhibit division of labour.
10. If a tissue can divide and differentiate into any type of tissue in the
body of an organism, it is said to be __________.
13. The meristem that is present at the root/shoot tip is called
__________ meristem.
44
CHAPTER 2
TISSUE
Solutions
Checkpoint 1
1
2
3
4
7
A
C
D
D
Plants
Checkpoint 2
1
2
4
5
7
9
A
Position
D
A
C
C
10
11
12
13
14
15
B
A
Root apical
D
Intercalary
B
meristem
Meristem
16
18
21, 22
23
B
Meristematic
Intercalary
Lateral
Meristem
meristem
Checkpoint 3
1
2
3
Permanent tissue
Parenchyma
Chlorenchyma
Checkpoint 4
1, 2
4, 5
6
Collenchyma
Sclerenchyma fibres
Lignin
45
CHAPTER 2
TISSUE
Checkpoint 5
1
3
4
6
Xylem
Xylem
Phloem
Sieve tubes
parenchyma
Checkpoint 6
1
2
3
4
Epidermis &
Stomata
Cork
Suberin
Cork
Novice level
MCQs
1
2
3
4
5
6
7
8
9
10
C
A
B
B
C
A
B
D
C
A
11
12
13
14
15
16
17
18
19
20
A
A
B
A
C
C
A
B
A
B
Very short answer type
1. (i) Apical meristem: Root Apical Meristem
(ii) Lateral meristem: Cambium
2. Main function of parenchyma: Store food
3. Pectin
4. Lignin
46
CHAPTER 2
TISSUE
5. Provide flexibility to plant.
6. (a) Conduction of water and minerals: Xylem
(b) Conduction of food: Phloem
7. (a) Xylem: Wood
(b) Phloem: Bast
8. Companion cell
9. Sclerenchyma fibres
10. Epidermis / Cork (both are protective
Advance level
Fill in the blanks
1. Xylem and phloem
2. Stomata
3. Suberin
4. Sclerenchyma
5. Xylem, phloem
6. Collenchyma
7. Water, minerals
8. Food, leaves
9. Sieve tubes
10. Cutin
Match the columns
1. (a)–(i),(b)–(ii),(c)–(iv),(d)–(iii),(e)–(v)
2. (A)–(iii,f),(B)–(i,d),(C)–(ii,e)
47
CHAPTER 2
TISSUE
True or false
1
2
3
4
5
6
7
8
9
10
T
F
T
T
T
F
T
F
T
T
1
2
3
4
5
6
7
8
9
10
C
C
B
D
D
D
A
D
B
A
11
12
13
14
15
A
C
B
D
D
MCQs
Unscramble the words
11. Meristematic
12. Permanent
13. Collenchyma
14. Aerenchyma
15. Sclerenchyma
Crossword
END
48