This document summarizes plant tissue systems. It describes the three main types of tissues - meristematic, permanent and secretory. Permanent tissues are further divided into simple tissues like parenchyma, collenchyma and sclerenchyma, and complex tissues like xylem and phloem. Parenchyma is the most common simple tissue and performs many functions. Xylem conducts water and minerals throughout the plant and consists of tracheids, vessels, fibers and parenchyma. Phloem transports organic compounds and consists of sieve elements, companion cells, parenchyma and fibers. The document also discusses secretory tissues and their structures.

1. PLANT TISSUE SYSTEMS
Mentor: Dr. T. Annie Sheron
Assistant Professor of Botany
Kakatiya Govt. College, Hanamkonda
Ms. D. Shilpa
II Yr. B. Sc. (Bt.B.C.)
Kakatiya Govt. College,
Hanamkonda

2. • A group of cells with common origin, structure
and function is known as Tissue.
• The group of tissues which perform only one
important function is known as Tissue system.
• The study of tissues is known as Histology.
• Depending upon their nature, structure and
function tissues are divided into three categories.
1.Meristematic tissue
2.Mature or permanent tissue
3.Secretory tissue

3. MATURE TISSUES
• In this type of tissues growth is ceased either
temporarily or permanently.
• They lost their divisional capacity temporarily or
permanently and perform specialized functions
• These cells may be living or dead with thin or
thick cell walls.
• Based on the number of kinds of cells involved
in the composition of a tissue, permanent
tissues are of 2 types. 1.Simple tissue
2.Complex tissue

4. SIMPLE TISSUES
• Homogeneous in nature and composed of
structurally and functionally similar cells.
• The common simple tissues are
1. Parenchyma
2. Collenchyma
3. Sclerenchyma

5. PARENCHYMA
→ Repair the wounds
( Totipotency)
→ Buoyancy
→ Photosynthesis
→ Storage
→ Transport
→ Integral part of Vascular Tissue
Most common tissue
Simple and living with different shapes
Perform many physiological functions

6. Types of Parenchyma
1.Chlorenchyma
2.Storage parenchyma
3.Aerenchyma
5.Idioblasts
6.Transfer cells

7. Chlorenchyma Storage Parenchyma
Storage of Proteins, Fats, Oils & Water
in Roots, Tubers (eg. Potato), Seed
Endosperm (eg; Cereals) & Cotyledons
Aerenchyma

8. IDIOBLASTS
• An idioblast is an isolated plant cell that differs
from neighboring tissues.
→ Storage of reserves, excretory materials,
pigments, minerals, secondary metabolites like
tannins, mineral substances, myrosin, oil
substance etc.

9. Transfer Cells
• Specialized parenchyma cells that have an
increased surface area, due to infoldings of the
plasma membrane.
• Short-distance high-volume transport of
materials

10. COLLENCHYMA
• Living tissue but performs only one type of
function .
• Location: Aerial parts of the plants -Below the
epidermis
•Function: Provides
strength & flexibility
in herbs, young and
mature parts of the
plant body.
•Structure: Thick deposits
of Cellulose, Hemi cellulose
& Pectin in their cell walls

11. Angular: Only
longitudinal
walls have
thickenings
Annular:
uniformly
thickened cell
walls
Lamellar: Primary cell thickenings in the internal
and external tangential walls
Lacunar: Wall thickenings restricted around the
intercellular spaces

12. SCLERENCHYMA
• Hard, rigid and dead tissues
• Location: Cortex of stems and in leaves
• Structure: Thick cell wall due to deposition of lignin.
Have various sizes & shapes
Function:
Provides mechanical
support as well as
rigidity to plant body

13. Types of Sclerenchyma
1.Sclerides
2.Fibers

14. SCLERIDES:
• Occur in all plants of the plants especially in soft
parts.
• Have extremely thick wall of lignin with narrow
lumen
• Usually dead cells. But remain as living cells in the
respective parts for a long time.
• Associated with phloem.

17. FIBERS
• Elongated cells with narrow lumen & tapering ends
• Thick secondary walls and oblique end walls
• Lignification of cell walls
• Present in pericycle of many dicots and secondary
xylem and phloem tissue.
• According to position types of fibers are
1. Xylary fibers
2. Extra xylary fibers

18. XYLARY FIBERS/ WOOD FIBERS
• Integral part of the xylem.
• Develop from same meristematic mother cells
along with the tracheary elements.
• Types of xylary fibers based on the cell wall
thickenings and pits
1.Libriform fibres
2.Fibre tracheids

19. LIBRIFORM FIBERS
→longer than tracheids with
thick walls and narrow
lumen
→Presence of very short and
slit like simple pits
FIBRE TRACHEIDES
→Intermediate structures
between fibres & tracheids.
→Secondary wall thickenings is
less than libriform fibers but
more than tracheids .
→These are living fibres and
mucilagenous fibers.

20. EXTRA XYLARY FIBERS
• Found in various parts of the plant body other than
xylem
• Based on their occurance these are classified into 3
groups . They are
1. Phloem fibres or bast fibres
2. Cortical fibers
3. Perivascular fibers
Ex: Commercial fibers like jute, flax, ramie etc.

21. Cannabis sativa (hemp)
Gossyjpium sp. (cotton) Corchorus sp. (jute) Ramie
Linum usitatissimum (flax)

22. COMPLEX TISSUES
• Made up of more than one type of cells
• Different cells perform different functions in only one
system.
• Composed of only parenchyma and sclerenchyma
1.xylem
2.pholem
They are both occur side by side in the plant and
form conducting tissues and constitute a vascular
bundle.

24. XYLEM:
• Appeared for the first time in the pteridophytes.
• Conducts water and minerals from the roots to the
leaves and stem (One way transport)
• Xylem is a complex tissue. It consists of 4 types of
tissues.
1. Dead tracheids
2. Vessels
3. Fibers
4. Living parenchyma
On the basis of components xylem can be classified into
primary xylem and secondary xylem

25. TRACHEIDS
• Basic cell type in the xylem.
• Main water conductive cells of
Pteridiophytes, Gymnosperms
primitive Angiosperms
• Elongated dead cells with tapering
ends. Large & empty lumen
• Show longitudinal cell walls
• Walls show various types of
thickenings (pits) due to deposition
of lignin.

26. VESSELS/ TRACHEA
• Most active water conducting
elements in all higher angiosperms
• Long cylindrical dead cells,
characterised by a thick cell wall
consisting of a primary (cellulose) and
a secondary walls (Lignin)
• The character of the vessel element is
the presence of pores in the end
walls. The porous region is known as
perforation plate.

27. Xylem vessels exhibit different types of secondary
thickenings.
1.Annular - in the form of
rings
2.Spiral - helix or coil
3.Scalariform - cross bands
like steps of a ladder
4.Reticulate – network
5.Pitted - depressions on
the primary wall
Helps in conduction of water, mechanical support &
formation of wood (hard wood or porous wood)

28. XYLARY FIBRES:
• Dead sclerenchymatous cells
• Long, narrow with thick lignified wall and tapering
ends.
• Helps in mechanical support
Types :
1.Libriform fibres
(with simple pit)
2. Fibre tracheids
(with bordered pit)

29. • XYLEM PARENCHYMA:
• This is only the living tissue in the xylem.
• Participate in conduction of mineral salts directly or
indirectly.
• Meant for storage
of reserve food.

30. PHLOEM/ BAST/ LEPTOME
• Permanent living complex tissue.
• Helps in translocation of organic food (sucrose) from
leaves to various parts of the plant.
• The primary phloem has its origin procambium &
Secondary Phloem from vascular cambium.
• Consists of 4 types of elements
1. Sieve elements
2. Companion cells
3. Phloem parenchyma
4. Phloem fibers

32. • SIEVE ELEMENTS
• First discovered by the forest botanist Theodor
Hartig in 1837
• Highly organized tissue that transports organic
compounds made during photosynthesis.
• Types of Sieve elements
1. Sieve cells - longer and narrower with smaller area
for nutrient transport . Found in gymnosperms.
2. Sieve tubes - shorter and wider with greater area
for nutrient transport. Found in angiosperms.
Between two sieve tubes there are present
perforated sieve plates with many sieve pores

33. COMPANION CELLS
• Specialized cells, appear only in angiosperms .
• Sieve tube and companion cells are originated
from the same mother cell.
• Associated with the sieve
areas.
• Sieve tubes and companion
cells are connected through
pits.
• In Gymnosperm, albuminous
cells are present in place of
companion cells.
• Helps in transport of food along with sieve tubes.

34. PHLOEM PARENCHYMA
• Cells of the phloem parenchyma appear long and
vertically oriented as in the primary phloem .
• Also called as Transfer cells or border parenchyma
• Involved in the transport of foods.
• On the basis of arrangement they are classified
1. Axial parenchyma
2. Ray parenchyma

35. PHLOEM FIBRES
• Also called as Bast Fiber or
Skin Fiber
• Fibres are more significant in
primary as well as secondary
phloem.
• Presence of only simple pits
• Support the conductive cells
of the phloem and provide
strength to the stem.
commercially useful because of its great tensile
strength and pliability Ex: Fibers of Flax , hemp, jute

38. SECRETORY SYSTEM
• Some of the cells in plants produce several by products.
• These by products not at all beneficial to the plants.
• These products are eliminated as excretory substances
from the protoplasm of the cells.
• These substances which are formed in the elimination
process are determined as secretions.
• Secretory structures are located in different parts of
the plants.

40. Glandular Trichomes
EXTERNAL SECRETORY STRUCTURES
Hydathodes

41. INTERNAL SECRETORY STRUCTURES
Lysigenous cavity is formed by the
destruction or dissolution of cells.
Schizogenous cavity is formed by the
displacement of cells to the peripheral regions

42. Laticiferous tissue