This PPT explores the different type of plant tissue systems and their good coordination for the sake of structural and functional integrity along with other attributes.

1. STRUCTURE & DEVELOPMENT OF PLANT
BODY: The Three Tissue Systems
By N.Sannigrahi, Associate Professor,
Department of Botany, Nistarini College, Purulia
(W.B) 723101, India
“All the tissues of a plant which perform the same
general function, regardless of the position & continuity
in the body, may be considered to form together , a tissue
system”.
A vascular plant comes in existence morphologically
from a single unicellular zygote and by further
development , the zygote develops into the embryo, the
embryo in due course give the mature sporophyte.The
division of labor is the natural rule in higher multi-
cellular entity and the tissues enjoyed a division of labor
interacting together to form a tissue systems.

3. Type of Tissue systems
• The arrangement of cells and tissues in the plant body
maintain topographic continuity or physiologic
similarity, or both together. The units are called tissue
systems. Each system usually consists of one tissue or
in Association of tissues which perform a common
function and have the same origin. According to
Sachs(1875), the three main tissue system are
recognized-
• 1. The dermal or Epidermal tissue system,
• 2. The fundamental or ground tissue systems,
• 3. The Vascular tissue systems

4. The Epidermal Tissue System
• The Epidermal tissue systems derived from the
Epidermis(Permanent tissue)-a derivative of protoderm
(Meristematic tissue).
• The protective covering of the plant body, primarily as
epidermis and in course of secondary growth as periderm.
• The epidermis undergone modifications to form series of
structure-Stomata. Trichomes, Bulliform cells, salt glands etc.
• Epidermis generally derived from protoderm or dermatogens
or tunica(Opinion differs), single layered but multiple-
epidermis(Ficus, Nerium), Velamen as Orchid root, thin walled
but thick lignified wall as gymnosperms, may be cuticularised
or waxy, horizontally flattened and remain parallel to surface
of the organ without intercellular spaces, calcium crystals of
the epidermis called Cystoliths or lithocysts, have silica
deposition in the bracts of rice etc.

5. How does it look?

6. Different types-------
• Epidermal hairs-Present in roots, stems, leaves, floral
parts, seeds, stamens
• Trichoblasts protrude to form unicellular or multi-
cellular root hairs, stellate or dendroid or papillae.
• Bulliform cells-Large epidermal cells in monocot
leaves, fan shaped appearance, thin walled, hyaline,
cuticularised to unroll leaves, periodical turgor
pressure change for opening and closing of mature
leaves, mechanical rigidity due to cuticularisation.
• Stomata-a pair of guard cells having the diurnal
changes of water potential value

7. Epidermal------
• As far position
• Amphistomatous-Both the surface fewer on the upper
surface
• Hypostomatous-only on the lower surface( Ficus)
• Epistomatous-Only on the upper surface specially on
free floating leaves( Nympheae)
• Stomatal frequency(Number of stomata per unit area)
varies species wise
• Stomatal frequency= Stomatal frequency/Number of
stomata+number of epidermal cells per unit area*100

8. Ground tissue systems

10. GROUND TISSUE SYSTEMS
• The ground or fundamental tissue systems consists of
main bulk of plant body and extends from below
epidermis to the centre, leaving vascular bundles
apart. The cortex, medullary or pith rays, endodermis,
pericycle and pith are the site of the distribution of
ground tissues.
• CORTEX: Usually the cortex consists of thin walled
parenchyma cells with abundant intercellular spaces
with starch, tannins, crystals and other common
substances, it may be collenchymas sclerenchyma and
sclerides , very often hypodermis present
.Collenchymas develops early but sclerenchymatous
cells are usually late in maturity.

11. Ground tissue systems
• ENDODERMIS: Delimiting the cortex from stele,
uniseriate, barrel-shaped cells arranged quite close to
each other without intercellular spaces-primary thin
walled & secondary thick walled (Casparian
strips).Among the thick walled cells of endodermis,
in roots, isolated thin walled cells usually opposite to
the protoxylem elements called passage or transfusion
cells.
• Sort of accessory inner epidermis for protection
• Acts as an air dam to prevent diffusion of air into
vessels and escape from closing
• Storage

12. Ground tissue
• PERICYCLE: Thin cylinder of tissue completely
encircling the vascular bundles and the pith, mostly
parenchyma but pericyclic fibres(Cannabis, Linum)
• In dicot roots, pericycle becomes meristematic to
form vascular cambium and phellogen but some
storage tissues like Laticiferous cells, secretory cells
and other specialised cells may remain also present.
• PITH: Central region of root & stem, the extensions
of pith in the form of narrow parenchymatous strips
called medullary rays or pith rays , possess tannin and
crystal, serve as mechanical and storage.

14. VASCULAR TISSUE SYSTEMS
• Consists of number of vascular bundles found to be
distributed in the stele
• Each VB consists of xylem & phloem, Radial,
conjoint or Concentric;, Open or closed ; Endarch or
exarch;
• The function of the system is to conduct water and
other nutrients from roots to leaves through the xylem
and translocation of the prepared carbohydrates from
leaves to the other storage organs and growing
regions of the plant body through the phloem
• Cortical bundles are those with cortex enriched with
VB.

15. Thank you for your journey