植物形态与系统学（2 根-茎）

主讲

张志翔2006年11月MorphologyandsystematicsofPlants植物形态与系统学Batrachium

bungeirosette11/3/20231

2.2茎茎的形状：多为圆形，少为其他形状，如莎草科（三棱形）、唇形科（四棱形）。特殊的如仙人掌。从力学角度讲，圆的形状具有最大的应力。茎（枝）的概念：说法不一，此处做一概括。广义：维管植物地上主干及地上的各级分枝系统称为茎。狭义：指维管植物地上部分的主干及主枝（大的分枝）。有的学者认为枝和叶是茎的附属物，将地上部分的全部称为茎。11/3/20232我们知道，在种子中有由受精卵发育形成的胚。在其简单的构造中，可以分辨出典型茎的发育。种子萌发发育形成幼苗。根据种子萌发时子叶，是否出土有两种类型：子叶出土幼苗：子叶留土幼苗：2.2.1茎的发育和类型Friday,November3,20233不论是那种类型，通过上胚轴的生长，形成茎。然后在节(node)出上生长出叶子。节与节之间成为节间（internode)。节间的长度的变化决定了茎的长短。在植物的个体发育中，节间本身的变化叶是一些植物中的特征。因此，根据节间的生长将茎划分出一些典型的生长类型。

11/3/20234TypesofShoots莲座状茎

rosetteform

鳞茎

Bulb叶状茎

Cladodeorphylloclade长短枝

Longshoot-shortshoot根茎

Rhizome水螅根

Stolon卷须Tendril（攀缘茎）块茎Tuber11/3/20235莲座状茎

(rosetteform)植物的主茎极短或无,其叶和其他附属物在基部辐射状排列,形成莲座状。根据生长方式，莲座状的植物可区分为：11/3/20236

半莲座状植物：在营养生长中为莲座状，直到开花时节间伸长长出带叶的花葶。这种生长方式称为一次开花植物(hapaxanthicplant)

这些植物多为两年生。在第一年进行营养生长形成莲座状，到第二年，通过节间的生长形成带叶的茎，顶端为一顶生花序。如：Lactucasativa莴苣11/3/20237

莲座状植物：这些植物在整个生长中都为莲座状，开花时，抽出无叶的主枝---花葶,顶端着生一朵花或一个花序。根据花序的位置，将莲座状分为有限莲座状和无限莲座状。有限莲座状花或花序从主茎顶端伸出。生于侧茎或上部的芽进行植株的更新。无限莲座状花或花序是从丛生叶腋中侧枝生出。如如11/3/20238Primula

elatior

Cultivated,atGreifswald(Germany)BotanicalGarden(wholeplant)有限莲座状11/3/20239Agava

americana

龙舌兰属有限莲座状11/3/202310Taraxacum

officinale

无限莲座状11/3/202311白药谷精草Eriocaulon

cinereumB.Br.无限莲座状11/3/202312TypesofShoots莲座状茎

rosetteform鳞茎

Bulb

叶状茎

Cladodeorphylloclade长短枝

Longshoot-shortshoot根茎

Rhizome水螅根

Stolon卷须Tendril（攀缘茎）块茎Tuber11/3/202313

鳞茎

(bulb)鳞茎是一种生于地下的莲座状茎。在这种茎中，叶片基部或整片叶片加厚一储存养肥。其主要功能是使植物安全越冬。鳞茎的主茎极不发育，称之为鳞茎盘（座）。在茎盘上，丛生肥厚的叶片。叶片之间可发育用于更新的芽。因此，见这种生活型成为鳞茎地下芽植物（goephyta

bulbosa）。11/3/202314鳞茎的结构如洋葱(Allium

cepa)11/3/20231511/3/202316

鳞茎主要发生在单子叶植物中。尤其在百合科(Liliaceae)、石蒜科（Amaryllidaceae)中。但在双子叶植物中也有出现，如伞形科(Umbelliferae)回香属中。但是生长在地上。Foeniculum

vulgarevar.azoricum11/3/202317TypesofShoots莲座状茎

rosetteform鳞茎Bulb叶状茎

Cladodeorphylloclade

长短枝

Longshoot-shortshoot根茎

Rhizome水螅根

Stolon卷须Tendril（攀缘茎）块茎Tuber11/3/202318叶是植物特有的、扁平器官，其功能是进行光合作用。但是，在一些植物类群中，代替叶片的是扁平的、绿色的茎。这类茎称之为叶状茎。Thetypicalflattenedphotosyntheticorganofavascularplantistheleaf,butsomeplantgroupsinsteadhaveflattenedgreenstemsasthechiefphotosyntheticorgans.Thesearecalledeithercladodesorphylloclades("leaf-likebranches").Christmascactus,Schlumbergera

truncata,anepiphytefromSouthAmerica,hasflattened(two-ribbed)succulentstems11/3/202319AyoungshootofRuscus

hypoglossum,butcher'sbroomorCaesar'slaurel,showsthepresenceofasmall,vestigial,scaleleafandthebroad,leaf-likecladodearisingintheaxilofthatleaf.Oddly,fromthecenterofthecladodetheflowerofthisplantforms.Ruscus

hypoglossum，

Ruscaceae

Hutch(Liliaceae)anativeofWesternEuropetoIran,isacompactevergreen

shrubwithacreepingrootstock.leaf-like

cladodescaleleafflowerflower长叶假叶树11/3/202320Ruscus

hypoglossumleaf-likecladodeflower11/3/202321Incertainfamiliarcases,thecladodesoresemblesaleafthatthecasualobserverwouldhavenoreasontosuspectotherwise.GrowinginshadedcanopiesofwetforestsisthisCentralAmericanepiphyticcactusspeciesofDisocactus.Itsflattenedgreenstemsaresothinthattheycaneasilyfoolacollectorintothinkingatfirstthattheseareleaveswithcoarselyserratemargins,butflowerseventuallyappearinthesinuses,wheretheaxillarybudislocated.Disocactus

，CACTACEAE

Leaforstem?11/3/202322Theproperwaytoidentifyaphyllocladeistoexaminecarefullyarapidlygrowingvegetativeshoot,onwhichleavesarestillpresent.Aphyllocladeissubtendedbyaleaf,normallyonethatissmallorscale-like,andtheleavesofthesespeciesareephemeralandsoonabscise.Atiny,ephemeral（短命的）scaleleafcanbeobservedalongthemainaxisofbutcher'sbroom,Ruscus

aculeata(FamilyRuscaceae),andfromtheaxillarybudformstheleaf-likecladode.如何正确鉴定叶状茎？生于叶腋（叶痕）；叶常常为鳞性；这类植物的叶片是短命的，早落。11/3/202323itsphyllocladeshavehorizontallines(perpendiculartotheveins),showingthepositionsofthenodes,andfromtheaxillarybudsatnodesarewheretheflowersarisealongthephyllocladeedges.Ofthecultivatedexamples,theapply-namedtapewormplant,Homalocladium

platycladum

竹节蓼(Muehlenbeckia

platyclados,Polygonaceae);hasthemostconspicuoustriangular-lanceolateleaves既有叶状茎，也有明显的叶片。11/3/202324Occasionallyauthorshavereferredtotheseplantsashavingepiphyllousflowers（叶生花）("onleaf"),butthisistechnicallywrong,giventhatphyllocladesarestems.ThephyllocladouswoodyspeciesofPhyllanthus(FamilyEuphorbiaceae)areother,strikinglysimilardicotyledonousexamples(Thegenusnamemeans"leafflowers.").Disocactus

nelsonivar.hondurensis.Themembersofthisgenushave2-ribbedstems,whichalmostappearlikeleaves,andmultipleflowersformedfromasingleareole.Disocactus

nelsoniihybrids11/3/202325Amongmonocotyledons,severalgenerawithcladodesarewidelycultivated.SpeciesofAsparagusgenerallyhaveneedle-likecladodes,althoughinsomespeciesofasparagustheycanbeflattened(seealsoMyrsiphyllum).Theneedle-likestructuresofthetypicalSouthAfricanspeciesofAsparagus(FamilyAsparagaceae)arecladodes.Thesubtendingscale-likeleafisvirtuallyunnoticedontheseplants.11/3/202326ThecloselyrelatedfamilyRuscaceae(eightspecies),includingbutcher‘sbroom

(Ruscus

aculeatus，假叶树),Caesar'slaurel(R.hypoglossum

长叶假叶树),Alexandrianlaurel(Danae

racemosa

),andclimbingbutcher'sbroom(Semele

androgyna),hascladodesthat,again,appeartoformflowersonleavesbutinrealityhaveflowersproducedfromnodes.

11/3/202327Semele

androgyna(FamilyRuscaceae)hasdarkgreen,broadcladodesthatbearflowersalongtheirmargins.Larger,claspingleaves,eachwithaprominentleafbase,formalongtherapidlygrowingclimbingstems,beforethelateralshootswithcladodesareproduced.11/3/202328OnSemele

androgyna(FamilyRuscaceae)thestructuresthatlooklikedarkgreen,broadleavesare,infact,cladodes,i.e.,flattenedstems,whichbearflowersalongthecladodemargins.Aminutescaleleafisformedatthebaseofeachcladode,barelydiscerniblehere.Thisspeciesalsoformslarger,claspingleaves,eachwithaprominentleafbase,alongtherapidlygrowingclimbingstems,beforethelateralshootswithcladodesareproduced.11/3/202329Semele

androgyna11/3/202330ThegenusPhyllocladusisanAustralasiangymnospermgenushavingscale-likeleavesandlobedphyllocladesthatresemblepinnatelycompoundleaves.Phyllocladus

trichomanoides11/3/202331Foliage:Theultimatefoliarshootsareflattenedintocladodesor'phylloclades'whichinvolveacentralaxisandseveralalternateside'shoots'.Inoutlinethesecladodescanbeoval,triangular,deeplylobed,orcompoundandsmallmarginalhooksrepresentingreducedleavescansometimesbeseen.Phyllocladsreachseveralcminlengthorcanbeaggregatedalongbranchesincomplexestomorethan20cmlongortransitionalasalargedeeplylobedphylloclad.Shootswhicharetocontinuegrowth,whetherasecondaryaxisoralobedcladode,terminateinaglobularbudformedofoverlappingtriangularscales.Theseinturndevelopintoshortshootscoveredwithlinearlanceolate

caducousscale-leavesintheaxilsofwhichnewcladodesorfertilestructuresmaybeproduced.Seedlingsbearspirallyarranged,single-veined,linear,acutebifaciallyflattenedleavesupto1cmlongfollowedgraduallybysmaller,morelanceolateformsuntiltheadultscalesareproduced.11/3/202332Phyllocladus

aspleniifolius11/3/202333Phyllocladus

toatoa

Thisisasmalltreerecognizedbyitsverylargephyllocladesandverysymmetricalshape.

11/3/202334Mostgeneraofcladode-producingplantsoccurinthecactusfamily(Cactaceae).Morethan200speciesaretheplatyopuntias(a.k.a.pricklypears)andnopaleasofthegenusOpuntiainsubfamilyOpuntioideae.Rhipsalis

rhombeaherehasflattened,succulent,photosyntheticstemsthatfunctionlikeleaves.Spinesofthisunusualcactusaretotallyabsentonthesestems;hence,theydonotblocklightinterceptionbythegreenstemtissues.Flowersareformedfromtheaxillarybuds(areoles)alongthered-tingedstemedges.ThisepiphyticspeciesisnativetowesternSouthAmerica.Platyopuntiasarespeciesofcacti(FamilyCactaceae)possessingcladodes，i.e.,flattenedstems,whichareprotectedbyspines.Thesespinesareleafspines,producedonanareole.flattenedstems仙人掌科多数属具有叶状茎11/3/202335Thesearecomparativelythickcladodes,withpadsoftenexceeding1cminthickness,andtheflattenedpads,alsocalledjoints,havenodesonthetwoflatsurfacesaswellasalongtheedges,arrangedinahelicalpattern.相对较厚的叶状茎Strophocactus

wittii,

大约有1cm厚。Strophocactus

wittiiisaflatepiphytewhichwrapsaroundthehosttrunkorbranch.Ithasdistinctiveredcolorationandfinespinesalongthetworibmargins.11/3/202336Thetermphyllocladeshouldnotbeconfusedwithcladophyll("branch-likeleaf"),i.e.,aphyllode.Acladophyllisaflattenedpetioleorrachisofaleaf,notastem.扁平的叶状体，不一定是茎的变态，还有叶状柄。如Acacia属。Koa(Acaciakoa,FamilyMimosaceae)hasjuvenilebipinnatelycompoundleavesandadultphyllodesbutalsoformstransitionalleaveshavingsomeleafletsandsomeflattenedleafaxes.11/3/202337Acacia

koa

Phyllode

叶状柄11/3/202338TypesofShoots莲座状茎

rosetteform鳞茎Bulb叶状茎

Cladodeorphylloclade根状茎

Rhizome长短枝

Longshoot-shortshoot水螅根

Stolon卷须Tendril（攀缘茎）块茎Tuber11/3/202339根状茎

（rhizome)许多草本植物具有地下生长的分枝茎，称之为根状茎。根状茎在地下水平生长。根状茎通过其产生无性繁殖的芽点和节于根与区别。也可以通过解剖结构中的维管束类型和叶痕与根区别。根状茎的叶极大多数为鳞形或为苞片。根状茎具有贮藏功能。也具有繁殖和分枝功能。11/3/202340TypesofShoots莲座状茎

rosetteform鳞茎Bulb叶状茎

Cladodeorphylloclade根茎

Rhizome长短枝

Longshoot-shortshoot水螅根

Stolon卷须Tendril（攀缘茎）块茎Tuber11/3/202341Aneasilyrecognizedshootdesignistermedlongshoot-shortshootorganization,whereinthecanopyconsistsortwodistinctclassesofshoots:(1)majoraxesthathavelonginternodes,(2)lateralaxesthathavenointernodesandthereforeappearasveryshortprojections.Theclassicexampleoflongshoot-shortshootorganizationisthedeciduousgymnospermGinkgobiloba,themaidenhairtree(FamilyGinkgoaceae).11/3/202342Manyplantsofhigh-lightdesertandsemidesertcommunitiesexhibitlongshoot-shortshootorganization,whereasmostofthesmallleavesareformedyearafteryearonstubby,lateral,shortshoots,whichexperiencenoelongationoftheinternodes.11/3/202343Small,spatulateleavesareproducedontheprominentshortshootsofJatropha

spathulata(FamilyEuphorbiaceae),adesertshrubofNorthAmerica.Notethesteminternodesalongthemainaxis,theoriginallongshoot.11/3/202344Longshootsarerapidlygrowingshoots,producedmainlyattheouteredgeoftheplant'scanopytoachieveatallerorbroadercanopyreachingintothehighlightenvironment.Fromthewidelyspacedaxillarybudsalongthelongshootformlateralbranchesthatareshortshootswithcrowdedleaves,becausesteminternodesdonotform.Shortshootsmaybedeterminate,i.e.,theyformamaturestructureandthenterminateapicalvegetativegrowth,orindeterminate,inwhichtheapicalmeristemoftheshortshootformsleavesyearafteryear.11/3/202345ShortshootsofthisNorthAmericandesertJatropha(FamilyEuphorbiaceae)showhowtheleavescanbeformedclosetothemainbranch,therebyexposingthesmallleavestofullsunduringmostofthedaytime.11/3/202346Someplantshavelongshootsandspur（距状）shoots,onwhichfloweringoftenoccurs.Aspurshoottendstohavesomeinternodalelongation,henceitsdistinctionfromshortshoots,whichlackinternodalelongation.Someauthorsdescribeshortshootsorspurshootsashaving"fascicledleaves."Chamise,Adenostoma

fasciculatum(FamilyRosaceae),isaverycommonandoftendominantplantofCaliforniachaparral.Itsevergreenleavesarestiffandlinearandclusteredonshortshoots,oftendescribedasbeingfascicled.11/3/202347Themoleculartriggersforlongshoot-shortshootorganizationneedtobecarefullystudiedtodeterminewhatgenesareinvolved.Studiesfromthepreviousgenerationofplantphysiologistsobservedthatdifferenttreatmentsofgrowthsubstances(planthormones)canbeusedtocauseaplanttoproducelongshootsversusshortshoots,andinternodalgrowthisapparentlysuppressed（限制）whenalowerthannormallevelofauxin（茁长素）ispresent.植物生理学家用植物激素将短枝变成长枝。11/3/202348Longshoot-shortshootorganizationhasnotbeenstudiedintensivelyfromanecologicalandevolutionaryperspective.Indesertandsemiarid,fullsunhabitatsiswheremanyexamplesoflongshoot-shortshootorganizationcanbeobserved.Thereareseveralpossiblebenefitsofthisdesign.Desertspeciesoflimberbush,suchasJatropha

cuneata(FamilyEuphorbiaceae),havelongshoot-shortshootorganization,whereinaclusterofleavesisformedeachyearonstuntedshortshoots,withoutforminglonginternodes.长短枝的形成与环境的关系研究不多。11/3/202349Especiallyindeserts,adormantshrubortreecanproduceacropofphotosynthesizingleaveswithinseveraldaysfollowinganeffectiverainfallevent.Growthismorerapidbecause,basically,nostemtissuesneedtobeformed.（沙漠中的灌木和树雨后几天内长叶不长枝，目的光合作用）Woodyplantswithlongshoot-shortshootorganization,becausetheyhavefewerbranches,tendtopermitsunlighttopenetratedeeplythroughtheplant,ratherthanonlystrikingtheuppermostcanopyandcanopy（树冠）margins.（木本植物生长短枝有利于阳光能透过树冠）。11/3/202350Inflorescencesareformedontheshortshoots,ashortdistancefromtheleavessupplyingthenutrients.（花序生长在短枝上，利于营养从叶到花和未来的果实短距离运输）。Leavestendtohavelittledevelopmentofpetiolesandareclusteredsoclosetothestemthattheremaybesomebenefitsinavoidingwindshearoftheleaves.（叶子以发育少的叶柄并集聚在枝条上，可能以避免风对叶片的危害）。11/3/202351ExamplesofLongShoot-ShortShootOrganization11/3/202352Amonggymnosperms,therearefourtypesoflongshoot-shortshootorganizationfoundinliving(extant)species.11/3/202353deciduousneedlesinthegeneraLarix(larches;longshoot,youngshortshoots,andshortshootsonanolderbranchofL.laricinaandwesternlarch,Larix

occidentalis)andPseudolarix(goldenlarch)(FamilyPinaceae)11/3/202354RapidlygrowinglongshootsofthelarchLarix

laricina(FamilyPinaceae)enabletheplanttogrowtallerandlateralbranches,whereasthemajorityoftheleavesontheplantformonoldershortshoots.ShortshootsofthisNorthAmericanlarch,Larix

laricina(FamilyPinaceae),bearlinearleaves,whicharedeciduousduringfall.AwoodybranchofLarix

laricina(FamilyPinaceae),hereseeninsouthernMichigan,canhaveshortshootsbearingthedeciduouslinearleaves.11/3/202355Thewesternlarch,Larix

occidentalis(FamilyPinaceae),isavaluableconiferousforesttreeofwesternNorthAmericahavingitsdeciduousleavesproducedonshortshoots.11/3/2023562.evergreenneedlesinthegenusCedrus(FamilyPinaceae)Evergreen,linearleaves(needles)oftheAtlasbluecedar(Cedrus

atlantica,FamilyPinaceae)areformedonshortshoots,lateralbranchesthathavenointernodalelongation.Thisresultsintheclusteredappearanceofleavesalongthisoldshoot.Thegrowingtipsofthemainbranchesformlongshootwithsoft,longleavesseparatedbyinternodes,andinsubsequentyearstheshortshootsdevelopfromaxillarybudsalongthelongshoottoproducemostoftheleavesonthetreeandfromwhichconesalsodevelop.11/3/2023573.themaidenhairtree,Ginkgobiloba(FamilyGinkgoaceae),whichhasdistinctivefan-shaped(flabelliform)leaves,sometimesdeeplybilobed

longshootswithdeeplylobedleavesoldshortshootswithfan-shapedleavesmalestructuresandyoungleaves,springgrowthonshortshoots11/3/202358Fan-shapedandbilobedleaveshaveformedonthislongshootofGinkgobiloba(FamilyGinkgoaceae).Thelongshoothaswell-developedsteminternodes.Eachshortshootwillsubsequentlyoriginatefromtheaxillarybud,whichishereeasilyobserved.Thefan-shaped(flabelliform)leavesofGinkgobilobahavebeenproducedontheseoldandwell-developedshortshoots,whichlacksteminternodes.11/3/202359Fan-shaped(flabelliform)leavesofthedeciduousgymnospermGinkgobiloba(FamilyGinkgoaceae)areproducedonstubbyshortshoots,whichhavenointernodes.Inthismanner,leavesareproducedinclustersalongthemainstems,eachclusterseparatedbyafewinches.Thepollen-producing(male)structuresalsoemergewiththeyoungleaves.Ginkgoisdioecious,i.e.,ithasseparatemaleandfemaleplants.11/3/2023604.pines(Pinus,FamilyPinaceae),whichhasdeterminateshortshoots,the"fascicle"ofneedles,onetofivephotosyntheticleavesandseveralscale-likeleaveswrappingthebasesoftheleaves(fasciclesoffiveneedles,e.g.,Pinus

flexilis,limberpine,andP.aristata,bristleconepine);thetreesareevergreen,andtheshortshootsabsciseaftertwoormoregrowingseasons11/3/202361LeaffasciclesofJeffreypine,Pinus

jeffreyi(FamilyPinaceae),havethreeleaves(needles)perfascicle.Theunitoffoliageleavesandleavesaroundthebaseisashortshoot.11/3/202362Limberpine,Pinus

flexilis(FamilyPinaceae),hasfiveshortleaves(needles)perfascicle.Theunitoffoliageleavesandleavesaroundthebaseisashortshoot.11/3/202363Foliageleaves(needles)areproducedinfasciclesoffiveontheColoradobristleconepine,Pinus

aristata(FamilyPinaceae),asubalpineandalpinepineofArizona,Colorado,andNewMexico.Theselong-livedleaffasciclesaredeterminateshortshoots.11/3/202364TypesofShoots莲座状茎

rosetteform鳞茎Bulb叶状茎

Cladodeorphylloclade根茎

Rhizome长短枝

Longshoot-shortshoot

水螅根

Stolon

（匍匐茎）

卷须Tendril（攀缘茎）块茎Tuber11/3/202365stolonisaspecializedtypeofhorizontalabove-groundshoot,acolonizingorganthatarisesfromanaxillarybudnearthebaseoftheplant.Thestolondiffersfromthetypicalvegetativeshootofthatsameplantinhavingmuchlongerand,typically,thinnerinternodes（节间稀疏）,andthehorizontalstolonalsohasastrongtendencytoformadventitiousrootsatthenodes(节间不定根发达）.STOLON11/3/202366Whiteandrose-coloredstolonsarethemeansforcloningofyerba

mansa,Anemopsis

californica(FamilySaururaceae),abroad-leavedaquaticplantofthesouthwesternUnitedStatesandadjacentMexico.Thisspeciesoccursinwetmeadowsandevendesertspringsasmonospecificstands.ThisplantwasphotographedalongHighway395inOwensValley,California.节间稀疏11/3/202367Thethinstolon(runner)ofSaxifraga

stolonifera(FamilySaxifragaceae)isrose-pinkandherebearsayoungplantletatthetip.thinstolonyoungplantlet11/3/202368Thestrawberryplant(Fragaria)clonesduringspringtimebyproducingstolonsaroundthemotherplant.Thisspecieshastrifoliateleaves.草莓在早春产生匍匐茎，进行无性繁殖。11/3/202369TypesofShoots莲座状茎

rosetteform鳞茎Bulb叶状茎

Cladodeorphylloclade根茎

Rhizome长短枝

Longshoot-shortshoot

水螅根

Stolon卷须

Tendril（攀缘茎，缠绕茎）

块茎Tuber11/3/202370攀缘茎为藤本植物的一种生活方式，多为木本植物。与缠绕植物不同，常在茎的节间出常有不定根（凌霄花，Campsis

grandiflora)，或侧枝变成吸盘（爬山虎,Parthenocissus）或卷须（葡萄，Vitis

vinifera），对有些植物则靠也卷须（豌豆,

Pisum

sativum）11/3/20237111/3/202372茎的变态：吸盘11/3/202373茎卷须11/3/2023