Vikasana – Bridge Course 2012 - KEA · Microsoft PowerPoint - GV Tonapi Biology 23.05.12.ppt [Compatibility Mode] Author: KEA Created Date: 5/31/2012 2:34:55 PM

Vikasana – Bridge Course 2012

DefinitionsAnatomy is the branch of biology dealswith study of internal structure oforganismsorganisms

A tissue is a group of cells having acommon origin and usually performing acommon origin and usually performing acommon function.


TYPES OF TISSUES


An angiosperm plant body is composed of two basic

types of tissues namely meristematic and permanenttypes of tissues namely meristematic and permanent

tissues.

Meristematic cells are undifferentiated compactly

arranged. They have thin cell wall abundantarranged. They have thin cell wall abundant

cytoplasm and prominent nucleus.


Based on origin Meristem can beBased on origin,Meristem can bedistinguished into primary meristem and

d i tsecondary meristem


Meristematic TissueMeristematic Tissue

Primary meristemPrimary meristempresent right from present right from

secondary meristemsecondary meristemappears later in theappears later in the

the embryonicthe embryonicstage and continues stage and continues

to be active throughout to be active throughout the life of a plantthe life of a plant

life cycle of a plant. life cycle of a plant. develops by a processdevelops by a processcalled dedifferentiation called dedifferentiation

In the permanent tissuesIn the permanent tissuesthe life of a plant.the life of a plant. In the permanent tissues.In the permanent tissues.Vikasana – Bridge

Course 2012

Based on position, meristem can be distinguished into apical, intercalary and lateral.



Apical Meristem Intercalary Meristem Lateral meristem

Occurs at the tips of roots and shoots

MeristemOccurs between

mature tissue

Occurs in the matureregions of roots and

shoots


Based on differentiation, meristem can be distinguished into gprotoderm,procambium and ground meristemmeristem



ProtodermDifferentiates

Ground Meristem ProcambiumDifferentiates into theDifferentiates

into protective structures

like epidermis

Differentiates into ground tissue components

Differentiates into thevascular tissues

like xylem and phloem. like epidermis. p


Permanent or mature tissues are formed by

differentiated cells which are specialized towardsdifferentiated cells, which are specialized towards

various functions.

Permanent tissues can be broadly differentiated into

simple or homogenous tissues and complex orp g p

heterogenous tissues.


Permanent Tissue

Simple Complex Tissue Tissue

Parenchyma Collenchyma sclernchyma Xylem Phleom


Simple permanent tissues are composed of identical

cells These tissues can be distinguished into 3 types cells. These tissues can be distinguished into 3 types

parenchyma, collenchyma and sclerenchyma.

Complex permanent tissues are composed of different

types of cells. They are distinguished into two types yp y g yp

xylem and phloem.


Parenchyma is a simple, living, storage tissue

occurring in every part of the plant body It also takesoccurring in every part of the plant body. It also takes

part in photosynthesis, respiration, transpiration and

secretion.


Collenchyma is a simple, living, mechanical tissue thatoccurs only in the shoot system. It has cells haveuneven thickenings which provide mechanical supportuneven thickenings which provide mechanical supportand protection.


Sclerenchyma is a simple, dead, mechanical h ll d d dtissue. The cells are dead at maturity due to

deposition of lignin.Sclerenchyma performs l h i l f ti h t ti only mechanical functions such as protection

and support.


Xylem is the water conducting tissue of the plant body. It has four cellular elements tracheids, tracheae, fibres and parenchyma of which only xylem parenchyma is and parenchyma of which only xylem parenchyma is living.


Phloem is the food conducting tissue in the plant

body. It has four cellular elements sieve tubes,

companion cells, phloem parenchyma and phloem

fibers of which only phloem fibers are dead cellsfibers of which only phloem fibers are dead cells.


Sieve tubes are the most active food conducting

elements They are composed of rows of sieve tubeelements. They are composed of rows of sieve tube

cells separated by perforated sieve plates


The tissue systems

Tissue Systems:D l (E id l)Ti S t ti i Dermal (Epidermal)Tissue System: tissues covering outer surface of the plantVascular Tissue System: tissues responsible for Vascu a ssue Syste : t ssues espo s b e otransporting materials within the plantGround Tissue System: all other plant tissues



Dermal Tissue System

Epidermis - Single layer of tightly packed cells (one or)more)

Covers and protects entire body ("skin" of the plant)Secretes a waxy coating called cuticle to help retainSecretes a waxy coating called cuticle to help retainwater


Ground Tissue System

Filling spaces between the dermal and vascular tissues

Responsible for metabolic functions

Consists of:

Parenchyma cells (majority) …and Pith

Collenchyma cells

Sclerenchyma cells


Vascular Tissue System

Responsible for transporting water mineral nutrientsResponsible for transporting water, mineral nutrients,

and organic molecules between roots and shoots

They are arranged in strands called vascular bundles




DIFFERENCE BETWEEN MONOCOT STEM AND DICOT STEM

MONOCOT STEMMONOCOT STEM DICOT STEMDICOT STEMMONOCOT STEMMONOCOT STEM DICOT STEMDICOT STEM

The ground tissue is made up The ground tissue is made up of similar cellsof similar cells

The ground tissue is differentiated The ground tissue is differentiated into cortex, endodermis, pericycle into cortex, endodermis, pericycle and pith.and pith.

The vascular bundles are The vascular bundles are scattered throughout thescattered throughout the

The vascular bundles are arranged The vascular bundles are arranged in a broken ring (Eustele).in a broken ring (Eustele).scattered throughout the scattered throughout the

ground tissue(ground tissue(AtactosteleAtactostele).).in a broken ring (Eustele).in a broken ring (Eustele).

Vascular bundles are closed, Vascular bundles are closed, d d bd d b

Vascular bundles are open, without Vascular bundles are open, without b dl h h d db dl h h d d h dh dsurrounded by surrounded by

sclerenchymatous bundle sclerenchymatous bundle sheath, oval or rounded in sheath, oval or rounded in

bundle sheath and wedgebundle sheath and wedge--shaped shaped outline.outline.

shape. shape. Vikasana – Bridge Course 2012

MONOCOT STEMMONOCOT STEM DICOT STEMDICOT STEMMONOCOT STEMMONOCOT STEM DICOT STEMDICOT STEMSecondary growth is absent.Secondary growth is absent. The stem shows secondary growthThe stem shows secondary growth

Stomata have dumb bell shapedStomata have dumb bell shaped Stomata have kidneyStomata have kidney--shaped guardshaped guardStomata have dumb bell shaped Stomata have dumb bell shaped guard cellsguard cells

Stomata have kidneyStomata have kidney shaped guard shaped guard cells.cells.


Monocot stem Dicot stemo ocot ste cot ste


DIFFERENCE BETWEEN MONOCOT Root AND DICOT Root.

MONOCOT ROOTMONOCOT ROOT DICOT ROOTDICOT ROOTMONOCOT ROOTMONOCOT ROOT DICOT ROOTDICOT ROOTCortex is very wideCortex is very wide Cortex is comparatively narrow.Cortex is comparatively narrow.Endodermal cells are highlyEndodermal cells are highly Endodermis is less thickenedEndodermis is less thickenedEndodermal cells are highly Endodermal cells are highly thickened Casparian strips are thickened Casparian strips are visible only in young roots.visible only in young roots.

Endodermis is less thickened Endodermis is less thickened casparian stripes are more casparian stripes are more prominent.prominent.

Xylem and phloem are more Xylem and phloem are more than six and varies (polyarch).than six and varies (polyarch).

The xylem and phloem bundles The xylem and phloem bundles are 2 to 6are 2 to 6

Well developed pith is presentWell developed pith is present Pith is absent or very smallPith is absent or very smallWell developed pith is presentWell developed pith is present Pith is absent or very smallPith is absent or very small


Monocot root Dicot root


DIFFERENCE BETWEEN MONOCOT LEAF AND DICOT LEAF

MONOCOT LEAFMONOCOT LEAF DICOT LEAFDICOT LEAFMonocot leaf is an Monocot leaf is an isobilateral leaf.isobilateral leaf.

Dicot leaf is a dorsiventral leaf.Dicot leaf is a dorsiventral leaf.

Presence of undifferentiated Presence of undifferentiated mesophyll. mesophyll.

Mesophyll differentiated into upper Mesophyll differentiated into upper palisade parenchyma and lower palisade parenchyma and lower spongy parenchyma. spongy parenchyma. p gy p yp gy p y

The stomata are equally The stomata are equally distributed on both sidesdistributed on both sides

Generally stomata are absent or Generally stomata are absent or less abundant on the upper side.less abundant on the upper side.

B dl h h i iB dl h h i i B dl h h i iB dl h h i iBundle sheath extension is Bundle sheath extension is sclerenchymatous. sclerenchymatous.

Bundle sheath extension is Bundle sheath extension is collenchymatouscollenchymatous..


Monocot leaf Dicot leaf


SECONDARY GROWTH IN DICOT STEM

A i i h i h (di ) i lAn increase in the girth (diameter) in plantsVascular cambium and cork cambium are involved in secondary growthsecondary growthFormation of cambium ringFormation of secondary xylem and secondary phloem from cambium ring


Formation of spring wood and autumn woodFormation of heart wood and sap woodDevelopment of cork cambium


Secondary growth in dicot roots

Secondary growth in dicot roots occurs with the activityy g y

of vascular cambium.The cambium produced in stele

and cortex resulting in the increase in girth dicot roots


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Vikasana – Bridge Course 2012 - KEA · Microsoft PowerPoint - GV Tonapi Biology 23.05.12.ppt [Compatibility Mode] Author: KEA Created Date: 5/31/2012 2:34:55 PM