Fungi-Cell wall & Range of Thallus Structure

This PPT intends to explore the basic cell structure and modification of thallus of fungi.

1. MYCOLOGY
Welcome to Cell Wall & Thallus structure of Fungi
By
N. Sannigrahi, Associate Professor
Department of Botany
Nistarini College, Purulia (W.B) India

2. FUNGAL CELL
Fungiareeukaryotesandhaveacomplexcellularorganization.
Aseukaryotes,fungalcellscontainamembrane-boundnucleus
wheretheDNAiswrappedaroundhistoneproteins.Afew
typesoffungihavestructurescomparabletobacterialplasmids
(loopsofDNA).Fungalcellsalsocontainmitochondriaanda
complexsystemofinternalmembranes,includingthe
endoplasmicreticulumandGolgiapparatus.
Unlikeplantcells,fungalcellsdonothavechloroplastsor
chlorophyll.Manyfungidisplaybrightcolorsarisingfrom
othercellularpigments,rangingfromredtogreentoblack.
ThepoisonousAmanitamuscaria(flyagaric)isrecognizable
byitsbrightredcapwithwhitepatches.Pigmentsinfungiare
associatedwiththecellwall.Theyplayaprotectiverole
againstultravioletradiationandcanbetoxic.

3. INSIDE FUNGAL CELL
Cellsmaybeuninucleate(Yeast)ormultinucleateforming
coenocytescondition
Nucleuscontainoneormorenucleoli
Cytoplasmiscolorlessandgranulartoreticulateinappearance
Glycogen,manyenzymes,oildropletsarefoundincytoplasm
Cytoplasmcontainsmanybigbutirregularvacuoleswhereas
inhighermembranessinglelargevacuoleisfoundwhich
becomescentralinposition,
Thecellmembranecontainsergosterolthatreplacesthe
cholesterolfoundinanimalcells,
Insomefungi,thenucleuscontainsadensechromatinbody
surroundedbynuclearenvelope.

4. PLANT CELL & FUNGAL CELL

5. CELL WALL-COMPOSITION
Thefungalcellwallisuniquelycomposedofmannoproteins
chitins,andα-andβ-linkedglucansandservesmany
functions,includingprovidingcellrigidityandshape,
metabolism,ionexchange,andinteractionswithhostdefense
mechanisms.Thecompositionofthecellwallvariesbetween
speciesoffungibutamajorcomponentofmanyfungalcell
wallsisβ1,3-glucan.Theechinocandinssemi-synthetic
lipopeptidesderivedfromfungi,non-competitivelyinhibit
β1,3-d-glucansynthase,blockingthesynthesisofβ1,3-glucan.
Thislessenscellularstructuralintegrityandmorphologyand
ultimatelyresultsinosmoticlysisofthecell

6. CELL WALL OF FUNGI

7. THALLUS OF FUNGI
Thethallusstructure-Myxomycota(Slimemoulds)&
eumycotadiffers.
Myxomycotaiseithersinglelargemultinucleateprotoplast(
plasmodium)orpseudoplasmodium-anaggregationofmany
smalluninuclateprotoplast
InEumycota,thalluscontainsnetworkofmuchbranchedthin
filaments(Hyphae)andtangledmassofhyphaecalled
mycelium;theymaybeseptateoraseptate.
Itmaybeholocarpicoreucarpic,eithermonocentricor
polycentric(manysporangia)
Hyphae-Substratehyphaeandaerialhyphae,bothbranched,
mayformstolonandhaustoria.

8. MODIFICATIONS OF HYPHAE -TYPES
Normally, the fungal hyphae are loosely interwoven but
undergo modifications as below:
Prosenchyma
Pseudoparenchyma
Rhizomorph
Sclerotia
Sporophores
Stroma
Appresorium
Snares(Fungal trap)

9. MODIFICATIONS-TYPES
PROSENCHYMA
Loosely interwoven hyphal mass
Mass retain their individual identity
Run more or less parallel to each other
Cells are elongated called plectanchyma
PSEUDOPARENCHYMA
Hyphae are intertwined to form a compact mass
Loose their identity and the walls of the hyphae are fused
Appear to be uniform in structure consisting of isodiametric or
oval cells giving the appearance of parenchyma tissue called
pseudoparenchyma, found in the fructification of higher fungi
like Basidiomyctes

10. DIFFERENT FRUCTIFICATIONS
RHIZOMORPH
Interwovenhyphaetoformropelikestructure,darkbrownin
color,
Hyphaetightlypacked,
Rhizomorphsarethickandgelatinousinwhichthehyphae
growparalleltoeachotherandloosetheirindividuality,
Outerhardblackexternallayerofrhizomorphcalledrind,
Eachrhizomorphcontainsagrowingtip,
Ithelpstowithstandadverseconditionsandenabletosurvive
manyyears,
Giverisetonewmyceliaonreturnoffavorableconditions.

11. Rhizomorph

12. DIFFERENT FRUCTIFICATIONS
SCLEROTIA
Specially modified for storage, pernnatioin and vegetative
propagation
Compact, rounded, cushion shaped, cylindrical or irregular in
nature, dense mass of thick walled short hyphae gives
pseudoparenchymatous appearance,
Cells are polyhedral in shape
Outer surface becomes dark brown or black and crust like
The size of the sclerotia may vary from a pin head to large size
having several inches in diameter.

13. Sclerotia

14. DIFFERENT FRUCTIFICATIONS
SPOROPHORE
Sporebearingstructureslookdifferentfromthenormal
hyphaeandalsomodifiedandgroupedtoformspecial
structurelikepycnidia,sporodochia,hymenia,acervulietc
Aerial,erectandarisefromtheprostratehyphae
Branchedorunbranchedandbearconidiaorsporangiaon
them,
Sporebearingsporophorescalledsporangiophoresandconidia
bearingcalledconidiophores
STROMA
Stromacompactmassofpseudoparenchymatoushyphae,flat
orcushionlike
Severalfructificationsarepresentinembeddedinthem.

15. Sporophore

16. DIFFERENT FRUCTIFICATIONS
APPRESORIUM
Foundinparasiticfungilikerusts,powderymildews,
Adherestothesurfaceofthehostandhelpinpenetratingthe
hyphae,
Infectionpegisoriginatedfromtheappresorium,
Terminalorlobedswollenstructureoftheofthegermtubeof
theinfectinghyphae.
HAUSTORIUM
Intracellularabsorbingtissueoftheobligateparasites,
Sizeandshapevaries,
Knoblike,elongated,fingerlikeorbranched,
Secretespecialenzymestohydrolysestheproteinsand
carbohydratesofthehosts.

17. Haustoria

18. THANKS FOR YOUR PLEASURE
ACKNOWLEDGEMENT:
Google for images and information
A text book of Botany-Hait, Bhattacharya,
Ghosh
Botany for degree students(Fungi)-Vasistha&
Sinha
Mycology & Phytopathology-Mishra& Dash
This PPT has been developed for the academic interest of the undergraduate students of India & abroad
without any business interest