botany 322: fruit dissection what am i eating?botany 322: fruit dissection what am i eating?...

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Name:___________________________________Date:__________________Per:_____Botany322:FruitDissection

What Am I Eating? Objectives:•Tobecomefamiliarwiththewaysthatflowerandfruitstructuresvaryfromspeciestospecies•Tolearnthefloraloriginofthevariousstructuresofafruit•Tounderstandthefruitstructureofavarietyoffamiliarfruitsand"vegetables"Introduction:flowersandfruitsinperspective

Flowersarethereproductivestructuresoffloweringplants(Angiosperms).Flowerscanrangefrombeingverycolorfulandconspicuous,suchasaroseororchid,tobeingverysimple,reducedandinconspicuous,suchasthoseofgrasses,oaks,andelms.Thefunctionofafloweristoproducethereproductivecellsoftheplant(eggsandpollen)andthenproduceseeds,thedormantyoungplantofthenextgeneration.

Theseedsoffloweringplantsaresurroundedbyatissuecalledthefruit,whichmaybefleshyordry.Theculinarydesignationof“vegetable”isbasedontheuseoftheplantpart(eatenaspartofthemaincourseinameal).Vegetablesareactuallyvariousplantparts;somearefruits(e.g.,tomatoesandpeppers),leafstalks(celery),leafblades(spinach),lateralbuds(Brusselssprouts),youngshoot(asparagus),massivefloweringstructureinbudstage(broccoli),root(sweetpotato),undergroundstoragestem(whitepotato).Functionsoffruit

Althoughfruitscomeinallshapesandsizes,theyallfunctioninprotectingtheseedsinsideandinaidingseeddispersal.Protectionmaybeaffordedbyhardeningofthefruittomakeaccessingtheseedsmoredifficult,orbyaccumulationofacidsorothertoxins.Fleshycoloredfruitattractbirdsandanimals;seedspassthroughthegutunharmed.Sometypesofseedscannotgerminateunlesstheyhavefirstpassedthroughthedigestivetractofananimal.Manyfruitspromotewinddispersal.Otherfruitshavehooks,spines,andbristlesthatreadilyclingtofurandclothing—justwalkyourdoginanoldfieldinautumnandsee!Fruitscalledpodsdryoutastheymatureandripopen,flingingouttheseeds.Figure#1Withintheovary,theovulesmayhavedifferentarrangementswithinchamberscalled“locules”.Ovary:femalereproductivestructureofflower,whichusuallydevelopsintothefruit.Ovule:egg-bearingstructureoftheflowerthatdevelopsintoaseed.Locule:internalchamberoftheovary.Thestructureoftheovaryisoftenreflectedinthestructureofthefruitthatdevelopsfromit.

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Figure#2A“fruit”isthetissuesthatsurroundtheseed.Thoselayersthatdevelopfromtheovaryarecalled“pericarp”.Ovary:femalereproductivestructurethatusuallydevelopsintothefruit.Pericarp:layersoffruitderivedfromtheovaryandsurroundingtheseeds.Seeds:developfromtheovuleswithintheovary.Insomeflowers,otherpartsoftheflowermayalsodevelopintopartsofafruit.Figure#3Thearrangementoftheovulesinthechambers(locules)oftheovarydetermineshowtheseedsarearrangedinthefruit.Ovary:femalereproductivestructureofflowerthatusuallydevelopsintothefruit.Pericarp:fruittissuessurroundingtheseedsthatarederivedfromtheovary.Ovule:egg-bearingstructureoftheflowerthatdevelopsintoaseed.Figure#4Thefruitmaybefleshyordry.Somefruitsmaybedrywhenmature,althoughwemaybemorefamiliarwithanimmaturepericarp(suchasbeanpods),whichweeatbeforeripening.Thepericarpofsomefoodsmayberemovedbeforemarketing(suchasforwalnutsandcoconuts).

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Figure#5Botanistsgenerallyconsider‘fruit’tobestructuresderivedfrompericarp,whichmayformfleshyorhardlayers.Berry:anentirelyfleshyfruitcontainingoneormoreseeds.Incommonusage,‘berry’maybeusedinaccurately(e.g.,seediscussionofstrawberrybelow).Pod:adrypericarpthatsplitsintwo;seedsusuallyalignedinarow.Hesperidium:aberrywithathickleatheryrindandmanyinternalsectionsthatformlocules.Nut:inatruenuttheentirepericarpformsasingleharddrywallaroundasingleseed.Drupe:Theinnerlayerofthepericarp(nottheseeditself)formsahardlayer.Theouterlayersmaybefleshyordry.Achene:Asmalldrypericarpthatdriesleavingemptyspacearoundasingleseed.Donotconfusethiswithapod,whichwhendrymayleavespacearoundoneormoreseeds. Figure#6Thetissuesofsomefruitsdevelopfromflowerstructuresotherthantheovary.Pome:theoutertissuearisesfromthereceptacleandisusuallydiscerniblefromtheinnertissueofthepericarp.Pepo:theoutertissueisnotpericarp,andformsatough,skin-likeoutercovering.Pericarp:layersoffruitderivedfromtheovaryandsurroundingtheseeds.InferiorOvary:ovaryislocatedwithinthereceptacle.

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Figure#7An“aggregatefruit”developsfrommanypistilsthatarepresentinasingleflower.Fleshyreceptacle:Thereceptaclebecomesfleshyandtheseedsareinachenes.

Clusterofberries:Eachovaryformsafleshydrupe-likefruit.

Hip:Seedsandpericarpsformwithinafleshyreceptacle.Ovarywasinferior.Achene:Ahardpericarpthatdriesleavingavoidaroundtheseed.Receptacle:topofflowerstalkonwhichtheflowerresides. RememberfromtheFlowerDissectionLab....Figure#8:Arrangementofovaryandflowersrelativetothereceptaclecanvary.Superiorovary:ovaryrestsabovereceptacle.Inferiorovary:ovaryisembeddedwithinthereceptacle.Inflorescence:manyseparateflowersclusteredtoareceptacleorastem.

Station A. Define—ReferringtoFigures1–3,whatare:Ovules:

Pericarp:

Receptacle:

Locule:

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Station B. TOMATO –aberrytypefruit(seeFigure#5)Cutatomatoinhalfvertically,andthendrawàààà intothediagramandlabelthearrangementofthesepals,pericarpandseeds.Envisionhowtheovulesandloculewerearrangedintheoriginaltomatoflower,andthendrawààà howtheywouldhaveappeared(seeFigure3):Wastheovarysuperiororinferior?________________(ExamineFigures2and6):Explainwhythisisclassifiedasaberrytypefruit(seeFigure5):________________________________________________________________

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Station C. OLIVE –adrupetypefruitCutaoliveinhalfvertically,andcomparewithFigure5.Completethediagramandlabelallofthepartsoftheolivethatarepartofthepericarp.Useanutcrackertoopentheolive“pit”–ifyoucan.Intheseconddiagram,labelthepericarpandtheseed.Allofthesepartsdevelopfromthe___________oftheflower.

Therewas/were______ovule(s)intheovaryoftheoliveflower.

Station D. ORANGE/CITRUS –ahesperidiumDescribethedistinguishingtraitsofahesperidium(Figure5):

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________________________________________________________________Slicetheorangecrosswise,andinthediagramdrawtheappearanceofthefleshytissueshowingthesectionsandseeds.Therindandjuicyfleshbotharepartofthe_______________,whichdevelopedfromthe_______________oftheflower.

Therewere______loculesintheoriginalflower

Peelpartoftherind;foldthepeelingoverwiththeorange-sideoutward,andpinchittosharplykinkitandnoticethefinemistoffragrantoilssquirtingintotheair.Citrusfruitscontainavarietyofsharp-tastingchemicalsintherindandahighconcentrationofcitricacidintheinnerfluids.(...nextpage)

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Rereadthesectiononfruitfunctionintheintroductionandthenexplainhowthesecontributetothefunctionofthefruit:_________________________________________________________________________________________________________________________

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Station E. BLACKBERRY --an“aggregate”typefruitExamineablackberryandexplainwhythisisclassifiedasanaggregatetypefruit(seeFigure7):

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Slicetheblackberryinhalfvertically,andthencompletethediagramtotherighttoshowhowtheovarieswereoriginallyarrangedontheflowerreceptacle.Explainhowyouwoulddeterminethenumberofovariesthatwereoriginallypresentontheflowerreceptacle:

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Station F. STRAWBERRY --anotheraggregatefruitExamineastrawberry,sliceitinhalfandcomparetoFigure7.Doesthisaggregatefruithaveaclusterofberriesorafleshyreceptacle?___________________________________________________

Fromwhichflowerpartsdidthefollowingfruitpartsdevelop?

thecollarofgreenleafyparts:_________________theredflesh:________________

Thelittlehardstructuresonthesurfaceare“achenes”(seeFigure5)Whyisitincorrecttocallthese“seeds”?

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Station G. APPLE –apometypefruitSliceanapplefromtoptobottom,andcomparetoFigure6.Drawtheappearanceofthetwofleshytissuelayersinthediagramtotheright.Labelthetissuesoriginatingfromthe ovaryandreceptacle.Thepositionoftheovaryintheappleflowerwas______________.(ExamineFigures8and6)(superiororinferior)Whatotherpartsoftheflower(indicatedbythearrow)remainson

thematureapple?__________________________________________________

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Holdingtogetherthetwohalves,slicetheapplecrosswise.Intheseconddiagram,againdrawtheappearanceoftheofthetwofleshytissuelayers,seedsandseedchambers.Therewere________loculesand________ovulesintheoriginalappleflower.Station H. Examine the types of fruit on display in the lab. CHOOSE5Iseachanachene,aggregate,berry,drupe,hesperidium,nut,pepo,orpome?

FruitName FruitType Explanation(ReviewFigures5&6)

Station I: Based on what we’ve learned about the different parts of plants, identify whether you think each item is a root, stem, leaf, f lower, or fruit. Herearesomesamplequestionstothinkaboutandhelpyourdecision-making:

• Doesithaveseeds?• Doesithaveleavesorstemsgrowingoutofit?• Doesithaveroots(oraplacewhererootsusedtobe)?

FruitName PlantPart Evidence/Reasoning

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Station J: So, what good is it knowing stuff about flowers and fruits? Predictingpumpkinproduction?Ifyouhaveapumpkinpatch,youcannotpredictthenumberofpotentialpumpkinsbycountingthetotalnumberofflowers.Why?Pumpkinplantshaveseparatemaleflowersandfemaleflowersonthesameplant.Apumpkinfruitdevelopsfromthepistilofafemaleflower.Identifyafemaleflowerbyitsbulginginferiorovaryattheendoftheflowerstalkbeneaththesepalsandpetals.Thus,todeterminethenumberofpotentialpumpkinsthatyouwillbeharvesting,youcountonlythenumberofFEMALEflowerspresent!(Thisistruealsoforthezucchini,squash,cucumber,andmostothermembersofthegourdfamily.)ààQ:Youlookatyourpumpkinpatchinthegardenandthereare7flowers;uponcloserexaminationyoudiscoverthatall7arefemaleflowers.Howmanypumpkinswouldyouexpecttoharvest?Explainthereasoningbehindyourchoice!!!

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Noberriesonyourberrytree?Someplantssuchassassafrasaredioecious,meaningthatanindividualplanthaseitherallmaleflowersorallfemaleflowers.Hollytreesarenearlydioecious,producinganoccasionalperfectflower(havingbothmaleandfemaleparts).Thusifyouwantahollytreethatwillproducelotsofhollyberriesforthewinterbirdsandfordecoration,youneedatreethatispredominantlyfemale.ààQ:Ifahollytreehaslotsofflowersbutproducesonlyacoupleofberrieseachyear,giveonepossibleexplanation:

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Fewornoapplesonyourappletree?Ifyouplantfruittrees,youmustknowwhetheryourvarietyisaSELF-POLLINATORorisSELF-INCOMPATIBLE.Asingletreeofaself-pollinatorvarietywillallowyoutogetafruitharvest.Howeverinself-incompatibleplants,pollenMUSTcomefromanotherindividual.Itsownpollenisnotcapableofpenetratingorgrowingthroughitspistiltissueduetoachemicalincompatibility.Inaddition,insweetcherries,almonds,andsomeapple,pear,andplumcultivatedvarieties,thepollenhastocomenotjustfromanothertreebutfromatreefromadifferentcultivatedvarietyofthatcrop;don’texpecttoharvestacropifyouplantasingletreeofthese!ààQ:Whyisitimportantforself-incompatiblevarietiesofappletreestobepollinatedbyadifferentvarietyofappletree?

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