Adaptive & protective tissue system in plants

This Power point presentation intends to explore the epidermal tissue systems of plants as means of protection of the plants.

1. PLANT ANATOMY
Welcome to
Adaptive & Protective Tissue System: Epidermal
Tissue system
By
N.Sannigrahi, Associate Professor of Botany,
Nistarini College, Purulia(W.B) India

2. ADAPTATION FOR PROTECTION: NEED FOR SURVIVAL
•AnEcosystemisanaturalunitanddynamicwholecomposedofplantsthatliveinitand
anaturalenvironment.Acontinuousinteractionoccursbetweenplantsandinbetween
plantsandthenon-livingphysicalfactorsofenvironmentuponwhichtheyallare
interdependent.So,thereisacloserrelationshipbetweenplantstructureandthephysical
environmentinwhichtheplantgrows.
•Inanecosystem,thereexistsadefinitehabitatandthehabitatischaracterisedby
temperature,humidity,illumination,soilcondition,andwatersupply.Ahabitatby
traditionregardedasnormalandfavourableforplantgrowthwherethereexistsgood
wateranndnutrientsupplyandamediumoftemperaturerange.Mesophytesoccurinthis
habitat.Plantsalsolive,competeandsurviveunderconditionswhicharteextremeinone
respectoranotherincontrasttonormalhabitat.Theseplantsthrievebecauseofa
combinationofseveralmorphological,anatomicvalandphysiologicalconditions.The
adaptationsaresocloselyinterrelatedthattheanatomyalonecannotbedealtwithout
consideringthemorphology&Physiology.Theadaptationsarethoughttobeblessings
forecologicalbenefitforthesakeoftheirsurvival.

3. MESOPHYTES

4. GENETICALLY LABELED PLANTS
•Theadaptationsofmanyplantsaregeneticallylabeled-Xerophytes,Mesophytes,
Hydrophytesetc.Theyenjoyawiderangeofadaptationsinthisregardbytheir
morphologicaladaptations.Theadaptationsaretheadmixturesofnumberof
modifiedinternalorganizationaspredeterminedbythegeneticallyconsequences.
•HYDROPHYTES :Itembracesallthedifferentvaryingplantformsthatadaptedto
liveunderdirectinfluenceoffreewaterorinwaterloggedsoil.Anumberof
characteristicsareobservedbythehydrophytes–
•Increaseinleafsurfacethathelpsplantsforfloatation
•Presenceofairchamberstoassistbuoyancy
•Non-functionalstomataandreductionofxylem,mechanicaltissuesandprotective
tissueaswatersupportsthem,
•Thincuticle,piliferouslayernotcutinized.Anumberofmodificationsinepidermal
tissuesystemsareobservedforthesakeofadaptationinthisregard.

5. HYDROPHYTES

6. GENETICALLY LABELED PLANTS
•XEROPHYTES:Theseplantsevolvedtosurvivedinanecosystemwherethe
deficiencyinavailablewaterspeciallysubjectedtodroughtlikedesertsduetolow
rainfallandinmanycasesduetophysiologicallydrysoil.Thedroughtavoidance,
droughttoleranceandsucculentsarethreemaincategoriesandeachofthemare
effectiveagainstextremelowwateravailability,desiccatingwindsandhigh
fluctuatingtemperature.Thedifferentadaptivestrategiesareevolved.Thewell
developedrootsystem,roothairsextendedtotiptoincreasesurfacearea,much
reducedleavestoavoidsurfaceradiations,leavepolymorphism,reductionof
transpirationbyhardandrigidleaveswithsunkenstomata,physiological
modificationsbyCAMmechanismsandotherfeaturesaredeservedmentioning./The
bulboushabitisalsoassociatedinthisregard.Succulentsnatureofleaveswith
parenchymatoussphericalcellsinthegroundtissuesalongwithproliferationof
xylemparenchymaarealsonoticedhere.

7. XEROPHYTES

8. ADAPTATIONS -MORPHOLOGY, ANATOMY,PHYSIOLOGY
•Adaptationsarethechangesoccursinthedifferentlevelforthesakeofthe
survivalinthepassageoftheevolution.Thechangesarederivedfromtheinner
urgebasicallyderivedfromthegeneticlevelasapathoftheDarwininan
evolution.Theadaptationsaresocloselyinterrelatedthattheanatomyalonecan
notbedealtwithjwithoutconsideringmorphologyandphysiology.The
adaptationsarethoughttobeofecologicalbenefit.Theadaptationsaregenetically
labeled,oftendominantandformthediagnosticcharacterofthefamily,genusand
species.
•Theanatomicalfeaturesingeneralandepidermaltissuesystemsinparticularplay
averyimportantroletoconferadaptationsinthisregardinordertosurviveinthe
harshecologicalconditions.Anumberoforgansareassociatedwithit-
Stomata,HairorTrichomes(Stinging,glandular,PeltateorScale)Endodermis,etc
playanimportantroletoextendadaptationsinsuchecologicalconditions.

9. EPIDERMIS
•Oneofthedermaltissuescontinuouslyspreadingallovertheplantsurfacesdevelops
fromtheprotodermandexpandsbyanticlinaldivisionbutmultiseriateepidermis
originatesfromprotoderm,
•Varyinshape,sizeandarrangements,nointercellularspacesinbetween,cells
havingcentralvacuolewiththinprotoplasm,
•Wallofepidermalcellswithvariablethickness,wallcontainspitsand
Plasmodesmata,
•Cuticularlayerofvariedthicknessandwaxoverthecuticularlayerinsomespecies,
•Adcrustationonepidermalwallwithsuberinandcutin;incrustationintheepidermal
walloccursbyimpregnationinsomeplantslikemembersofCyperaceae,
•Unicellularroothairsasanextensionofepidermalcells–epiblemaorpiliferuslayer
orrhizodermis,
•InsomemembersofPoaceae,bulliformcellsandcystolithinsomemembersof
Acanthaceae

10. CUTICLE
•Plantcuticlesarecomplexstructuresandarecomposedofamacromolecularscaffold
ofcutinandavarietyoforganicsolvent-solublelipidsthataregenerallynamed
waxes(YeatsandRose,2013),togetherwithpolysaccharides(Fernándezetal.,2016;
Segadoetal.,2016).Theplantcuticlehasbeentraditionallyconsideredtobean
independentstructure,distinctfromthepolysaccharidecellwallunderneath(Yeats
andRose,2013),butthetwostructuresarephysicallyassociatedandhavesome
overlappingfunctions.Therefore,itwouldnotbewrongtoconsiderthecuticleasa
specializedlipid-modificationofcellwall,justaslignificationisacommon
modificationofsecondarycellwallinplants(YeatsandRose,2013;Fernándezetal.,
2016;Niklasetal.,2017).
•Thestructureandcompositionofcuticleishighlycomplexandcanvarywidely
amongplantspeciesandwithinplantspeciesindifferentorgananddevelopmental
stages.Thisiswellillustratedinthetypicalrangeofthickness(1–10μm)and
quantity(100–1000μgcm−2)ofdepositedcuticle(RiedererandMuller,2006).

11. CUTICLE-SOURCE & FUNCTION
•Cuticleisresistanttodeacyanditiswellpreservedinfossils.Itoftenpreservesthe
characteristicfeaturesoftheepidermaqlcellssurfacessuchasthetypeand
distributionofthehairsandstomata.hus,thefossilplantsmaybeidentifiedby
cuticularstudies.Thecuticleisimpervoioustowaterandbeingprotectivein
funcyion.Agoodnumberofplantsexhibitthisfeatures-
•ThickcuticleisfoundinAcerStem,Smilaxstem,Vaccinumstem,Cornusstemetc.
•Theprimaryfunctionoftheplantcuticleisasawaterpermeabilitybarrierthat
preventstheevaporationofwaterfromtheepidermalsurface.
•Italsopreventsexternalwaterandsolutesfromenteringthetissues.Itpreventsthe
contaminationofplanttissueswithexternalwater,dirtandmicroorganisms.
•ThecuticleofNelumbonuciferahaveultrahydrophobicandselfcleaningproperties.
•Aplantcuticleisaprotectivefilmcoveringtheepidermisofleaves,youngshoots
andotheraerialplantorganswithoutperiderm.

12. CUTICLE & EPICUTICULAR WAX

13. EPICUTUCULAR WAXES
•Waxesareeitherdepositedwithinthecuticle,whicharecalledintracuticularwax,or
accumulateonitssurfaceasepicuticularwaxcrystals,orfilms.Theepicuticular
waxesconferdistinctmacroscopicsurfacepropertiestotheplantsurfaceandare
responsiblefortheglossyappearanceofmanyleavesandfruits,whileepicuticular
waxcrystalsaccountforthedull,glaucousappearance(YeatsandRose,2013)and
serveastheinterfaceoftheplantwiththeexternalenvironment.Theseepicuticular
waxesarehighlyapolarinnature,mayprovideamajordegreeofroughness
(FernandezandKhayet,2015),andareefficientbarrierstotranspirationalloss
(BernardandJoubès,2013).
•Themainfunctionsoftheepicuticularwaxaretodecreasesurfacewettingand
moistureloss.Otherfunctionsincludereflectionofultravioletlight,assistinginthe
formationofanultrahydrophobicandself-cleaningsurfaceandactingasananti-
climbsurface.

14. TRICHOMES-UNICELLULAR, MULTICELLULAR
•Someoftheepidermalcellsofmostplantsgrowoutintheformofhairsor
trichomes.Theymaybefoundsinglyorlessfrequentlyingroups.Theymaybe
unicellularormulticellularandoccurinvariousforms.Theyvaryfromsmall
protuberancesoftheepidermalcellstocomplexbranchedorstellatemulticellular
structures.
•Thecellsofthehairsmaybedeadorliving.Veryfrequentlythehairslosetheir
protoplasmintheircells.
•Trichomesmaybeclassifiedintodifferentmorphologicalcategories.Onecommon
typeisreferredtoashair.
•Thehairsmaybesubdividedinto:
•(i)Unicellular-Hairsaremadeupofsinglecell
•(ii)Multicellular-singleorseveralrowscellsconstitutethisappearence

15. HAIRS

16. TRICHOMES-GLANDULAR & NON -GLANDULAR
•Theunicellularhairsmaybeun-branchedorbranched.Multicellularhairsmay
consistofasinglerowofcellsorseverallayers.Somemulticellularhairsare
branchedindendroid(tree-like)manner;othershavebranchesorientedlargelyinone
plane(stellatehairs)treelikee.gVarbascumsp.
•StingingHairs:
•Theyareoneofthemostinterestingtypesofthetrichomes.Itcontainsapoisonous
liquidandconsistsofabasalbulblikeportionfromwhichastiff,slenderand
taperingstructureisgivenout.Thistaperingstructureendsinasmallknoblikeora
sharppoint.
•Thetipisusuallysomewhatoblique,andasthebodyofananimalorhumanbeing
comesinitscontactwithsomeforce,thetipisbrokenoff,andthesharppointedend
readilypenetratestheskinoftheanimal,andfluidisbeingtransferredfromthebasal
knobofthehairtothebodyoftheanimal.

17. GLANDULAR HAIRS

18. GLANDULAR & PELTATE HAIR
•Manyplantspossessglandularhairs.Thesehairsmaysecreteoil,resinor
mucilage.Atypicalglandularhairpossessesastalkandanenlargedterminalportion,
whichmaybereferredtoasgland.Theglandularhairsmaybeuniormulticellular.
•Activesecretorycellsofglandulartrichomeshavedenseprotoplastsandelaborate
varioussubstances,suchasvolatileoils,resinsandmucilage’s,andgums.These
substancesareexcretedandaccumulatebetweenthewallsandcuticle.Theirfinal
removalfromthehairoccursbyruptureofthecuticle(e.gMenthapiperata).
•ScaleorPeltateHair:
•Acommontypeoftrichomeisthescale,alsocalledpeltatehair(fromthelatin
peltatus,target-shapedorshieldlike,andattachedbyitslowersurface).Ascale
consistsofadiscoidplateofcells,oftenborneonastalkorattacheddirectlytothe
foot(leavesofOleasp).

19. HAIRS ON Tomato Plant

20. SOME EXAMPLES OF HAIRS
•Thetricomesmaybeunicinate,clavate,moniliform,cylindrical,papillate,peltateetc
havinghighdegreeoftaxonomy.Thedensecoveringofwoolytrichomescontrolsthe
rateoftranspoirationandreducetheheatingeffectofsunlightandprotectfrom
injuries.
•SharphairsofLantanasp.
•LobedhairsofAmaranthussp.
•WoodyhairsofBanksiasp.
•HairsofLycopersiconsp.
•HairofSunflower,Helianthussp.
•HairsofMimosasp.
•DendroidhairsofPlatanussp.
•StellatehairofAlthaeasp.
•T-shapedhairsofDicrasussp.
•PeltatehairsofOleasp.

21. STOMATA-CLASSIFICATION

22. STOMATA-AN ORGAN
•Thestomataareaperturesintheepidermis,eachboundedbytwoguardcells.In
Greek,stomameans“mouth”,andthetermisoftenusedwithreferencetothe
stomatalporeonly.Esau(1965,p.158)usesthetermstomatoincludetheguardcells
andtheporebetweenthem,andwewilluseherdefinition.Thepluralofstomais
stomata.Thereisnosuchwordas“stomates”.Stomataoccurinvascularplants.
Vascularplantsincludethelowervascularplantssuchashorsetails(Equisetum),
ferns(classFilicinae),gymnosperms,andangiosperms.Asnotedbefore,the
angiospermsarethefloweringplantsandthisgroupconsistsofthetwolargeclasses:
Monocotyledonous(monocotyledons)andDicotyledoneae(dicotyledons)(Fernald,
1950).Bychangingtheirshape,theguardcellscontrolthesizeofthestomatal
aperture.Theapertureleadsintoasub-stomatalintercellularspace,thesub-stomatal
chamber,whichiscontinuouswiththeintercellularspacesinthemesophyll.Inmany
plants,twoormorecellsadjacenttotheguardcellsappeartobeassociated
functionallywiththemandaremorphologicallydistinctfromtheotherepidermal
cells.Suchcellsarecalledsubsidiary,oraccessory,cells(Esau,1965,p.158).

23. STOMATA-COMPONENTS

24. TYPES OF STOMATA
•Anomocytic(irregularcelled)orRanunculaceous:Inthistype,thestomataremains
surroundedbylimitednumberofsubsidiarycellswhicharequitealiketheremaining
epidermalcells.
•Example:Ranunculaceae,Malvaceae,Papaveraceae
•2.Anisocytic(Unequalcelled)orCruciferous:Inthisstomataremainssurroundedby
threesubsidiarycellsofwhichoneisdistinctlysmallerthantheothertwo.
•Example:Cruciferacea,Solanum,Nicotianaetc.3.Paracytic(Parallelcelled)or
Rubiaceous:Inthistype,thestomatasurroundedbytwosubsidiarycellswhichare
paralleltothelongitudinalaxisofporeandguardcells.4.Diacytic(Crosscelled)or
Caryophyllaceous:Inthistype,thestomataremainssurroundedbyapairof
subsidiarycellswhosecommonwallisatrightanglestotheguardcells.Example:
Acanthaceae,Caryophyllaceae

25. CONTINUED
•5.Antinocytic:Thesestomataaresurroundedbyfourormoresubsidiarycells,
elongatedradiallytothestomata.
•Example:Araceae,Musaceae,Commelinaceae
•6.Cyclocytic:Thestomataaresurroundedbyfourormoresubsidiarycellsarranged
inanarrowringaroundthestoma
•Example:Palmae,Pandanus,Cyclanthaceae
•7.Graminaceoustype:Thestomataguardcellsaredumbbellshaped.Theyare
surroundedbysubsidiarycellswhicharelyingparalleltothelongaxisofthepore.
•Example:InthemembersofPoa
•The different type of stomata play a very important role as far taxonomic point of
view because of this microscopic features, the different genus at the level of family,
genus and species level becomes a easy tool for identification

26. CONTINUED
Onthebasisofthestomatatoservephysiologicalfunction,itmaybe5categories-
Hypostomatic(Lowersurfaceofleaf,Apple,peach),Potatotype(moreonlower
surface;potato,cabbage),Epistomatic(ontheuppersurface,Nymphaea),Astomatic(
Totallyabsentorvestigial,Potomogeton)andAmphistomatic(Onlyontheupper
surface;maize,oat,grass).Stomatahelpinexchangeofgasesalongwithtoeconomise
theneedofwaterbytranspirationregulationmechanisms.
Onthebasisofdevelopment,stomataareofthreetypes-
Mesogynoustype-Guardcellsandsubsidiarycellsdevelopfromonemothercell(
Rubiaceae,Brassicaceae),
Perigynoustype-Guardcellsfromonemothercellsandthesubsidiarycellsfrom
nearbymothercells(Cucurbitaceae),
Mesoperigynoustype-Guardcellsandonesubsidiarycellfromonemothercelland
othersubsidiarycellsindependently(Rananculaceae,Caryophyllaceae).

27. DIFFERENT TYPES OF STOMATA

28. CONCLUSION
•Thus,theprotectivetissuesystemsofplantsenrichedwiththediversetypesof
modifiedepidermaltissuesplayaverycrucialroleinordertothesurvivalofthe
plantstoextendthenormalfunctionsalongwithtoadaptitselfinthediverse
ecologicalconditions.Thechangeofthedifferentedaphicfactorsmaybecomea
seriousconcerntotheplantsfortheirsuirvival.But,theprotectivesystemsas
nourishedbythegeneticmachineryoftheplantscorrespondingtothehabitatisa
kindadaptationforthelongtermsurvivalalongwiththesurvivaloftheprogenyin
thelongpassageofevolution.
•ACKNOWLEDGEMENT :
•Googleforimages
•Plantanatomy-B.P.Pandey
•AnatomyofAngiosperms-Mishra&dash
•PlantAnatomy-PijushRoy
•THANKSFORYOURJOURNEY