全 文 ：ConductingTissueofLeavesinNageiaandPodocarpus
SUNTong-xing＊
CollegeofLifeScienceandBiotechnology, YanchengTeachersUniversity, Yancheng224002
Abstract TheconductingtissuestructureoftransverseandlongitudinalsectionswasobservedonleavesofPodocarpusandNageia.Resultsshowed:in
Podocarpusleaves, thereisonlyonemidrib, thexylemtracheidofmidribvascularbundleismulti-form, transfusiontissuebelongstoCycas-typeandtrans-
fusiontracheidsareisodiametric, theaccessorytransfusiontracheidsbetweenpalisadetissueandspongetissuearedeveloped;inNageialeaves, thereare
plentyofparalelleaves, thexylemtracheidsofeachveinarerelativelysimple, transfusiontissuebelongstoTaxus-typeandtransfusiontracheidsarelonger
inlongitudinalsectionthanthatintransversesection, theaccesorytransfusiontissuebetweenpalisadetissueandspongetissueisabsent.Consideringoth-erdiferencesthatinleavesofPodocarpustherearethreeresinductsundervascularbundleofmidrib, mesophylcelsarediferentiatedintopalisadetissue
andspongetissue;inleavesofNageia, thereisonlyoneresinductundervascularbundleineachveinandnoobviousdiferentiationinmesophylcels,
palisadetissuecanbefoundonbothsides, andsclereidscanalsobefoundinmesophyltisue.Theanatomicaldiferencesofleafveinsandmesophylsbe-
tweenNageiaandPodocarpusmentionedabovesupporttheviewpointthatNageiaandPodocarpusaretwoindependentgenera.
Keywords Nageia;Podocarpus;Leafconductingtissue
Received:August25, 2008 Accepted:October8, 2008
SupportedbytheBasicNaturalScienceResearchFundationofthe
JiangsuHigherEducationInstitutionsofChina(06KJD180201).
＊Correspondingauthor.E-mail:scaulxsun@sina.com
SincetheestablishmentofGaertner(1788), thereis
frequentdisputeonsystematicpositionofPodocarpaceaeand
Nageia.InFloraReipublicaePopularisSinicae, Podocarpus
isclasifiedintosect.NageiaEndl.ofPodocarpus[ 1] .The
biggestdiferencebetweensect.NageiaEndl.andothersec-
tionsofPodocarpusisthattheformerleafisspacious, along
withnomidribandmanyparalelveins, whiletheleafof
othersectionsinPodocarpushasoneobviousmidrib.There-
fore, DeLauberfels[ 2] andPage[ 3] holdthatNageiaisunique
inconifersanditshouldbeanindependentgenus.Whilein
FloraofChina, sect.NageiaEndl.ispromotedtoNage-
ia[ 4] .Accordingtothecharacteristicssuchasnomidrib,
plentyofparalelveinsandfemalereproductiveorganof
nearlyoriginalstripstructure, FUDe-zhiholdsthatNageia
shouldbeseparatedfromPodocarpaceae, anditshouldbea
newfamily———Nageiaceae[ 5] .
Inthisstudy, diferentspeciesfromNageiaandPodo-
carpuswereselected, conductingtisueofleafveinwasob-
servedandthisresearchwiloferanatomicalreferencefor
corectclasificationandresourceutilizationofNageia.
MaterialsandMethods
Podocarpuswereintroductioncultivatedplantsfrom
gymnospermzoneofShenzhenFairylakeBotanicalGardenin
Shenzhen.NageiaformosensiswerecolectedfromBotanical
GaredenEdinburgh, N.nagiandN.fleuryiwerefromZhao-
qingofGuangdongProvince, andotherthreespeciesof
NageiawerefromherbariumspecimensofSpecimensMuseum
inBotanicalGardenEdinburgh.VouchersareinTable1.
FreshmaterialswerefixedwithFAA.Herbariumspeci-
menswerefirstlyre-hydratedin5% NaOHinovenat60 ℃
for2 h, andthenfixedwithFAA.Usingparafinsection
method, intermediatesectionofeachmatureleafwasmade
into2 sectionsof8-10 μm:oneverticalandtheotherone
paraleltovein.ThenthesesectionswerestainedwithSafra-
nineandFastGreen, coveredbygeneralclaritygum, ob-
servedwithLeicaDMIBmicroscope, andthenphototaking
bydigitalcamera.
Table1 Experimentalmaterialsandvouchers
Species Voucher
PodocarpuswangiC.C.Chang SUNTong-xing(T.X.Sun)200201(YCTC)
P.costalisC.Presl. SUNTong-xing(T.X.Sun)200202(YCTC)
P.forestiGraibetW.W.Smith SUNTong-xing(T.X.Sun)200203(YCTC)
P.annamiensisN.E.Gray SUNTong-xing(T.X.Sun)200204(YCTC)
P.macrophylus(Thunb.)Sweet SUNTong-xing(T.X.Sun)200205(YCTC)
P.macrophylusvar.angustifoliusBlumeSUNTong-xing(T.X.Sun)200206(YCTC)
P.macrophylusvar.makiSieboldet SUNTong-xing(T.X.Sun)200207(YCTC)
Zuccarini.
P.henkeliStapfexDalimetJacks SUNTong-xing(T.X.Sun)200208(YCTC)
P.falcatusThunb.R.Br.exMirb. SUNTong-xing(T.X.Sun)200209(YCTC)
P.graciliorR.Pilger. SUNTong-xing(T.X.Sun)200210(YCTC)
NageiawalichianaO.Kuntze JSinclair38991(E)
N.motleyideLaubenfels. JSinclair40798(E)
N.fleuryideLaubenfels. SUNTong-xing(T.X.Sun)2004015(YCTC)
N.nagiO.Kuntze SUNTong-xing(T.X.Sun)2004016(YCTC)
N.nankoensisR.R.Mil JMain530(E)
N.formosensisC.N.Page SUNTong-xing(T.X.Sun)2003029(YCTC)
E.SpecimenmuseuminEdinburghBotanicalGarden;YCTC.Specimenroomin
YanchengTeachersUniversity.
ResultsandAnalysis
InPodocarpusleaf, thereisonlyonemidrib.Theveinstruc-
turesofthese10speciesleavesareverysimilarontransverse
andlongitudinalsection.Althedevelopedvascularbundles
arecomposedofxylemandphloemofradialalignment, xy-
lemisclosetoadaxialsideandphloemisclosetoabaxial
side.Therealwaysbe20-35 columnsofxylemandphloem
inwhichparenchymacelscanbefound(Fig.1A).Transfu-
siontisuewhichisuniqueonlyingymnospermcanalsobe
foundineachsideofvascularbundle, anditevolveswater
andnutrientstransportationbetweenvascularbundleandme-
sophyl[ 6] .TransfusiontissueofPodocarpusiscomposedof
transfusiontracheid, proteinandtransfusionparenchyma
cels.Morphologyoftransfusiontracheidvariesfromdiferent
species, suchastransverseorradicalarangement(Fig.1A,
arow).Transfusiontracheidisbasicalysecondarywal
Horticulture, GardenandForestryAgriculturalScience＆Technology, 2008, 9(4):92-95Copyright 2008, InformationInstituteofHAAS.Alrightsreserved.
DOI :10.16175/j.cnki.1009-4229.2008.04.032
plinthitethickening(Fig.1B).Anun-conspicuousbundle
sheathexitsinthesuroundingsofvascularbundleandtrans-
fusiontisue.Developedaccessorytransfusiontissueoftrans-
versearangementwhichisdistributedtoleaftipcanbe
foundbetweenpalisadetissueandspongetissueintheout-
sideregionofmidrib.Accessorytransfusioniscomposedof
tracheidsverticaltorachis.Elongatedsimplepitsexitontra-
cheidwal(Fig.1E).AccordingtotheconceptionfromHU
Yu-shiandYAOBi-jun(1981)[ 7] , transfusiontisueofPod-
ocarpusbelongstoCycas-type.Besides, Cycas, Dacrydium
andGinkgoalsobelongtoCycas-type[ 6] .Inlongitudinalsec-
tion, vascularbundlexylem ofPodocarpusismulti-form
whichpresentstobespiraltracheid, tracheidofbordered
pitsinspirals, borderedpitstracheid(Fig.1G)andfiber
tracheidofthicksecondarywal(figureD, G, arrow).Cir-
cularandeliptictypesofborderedpitsexitintracheidwal
ofborderedpitsinspirals(Fig.1D, G).Spiraltracheidand
borderedpitstracheidmainlyexitinprotoxylemandmetaxy-
lem(Fig.1D, G).Fibertracheidplaysaroleintransporta-
tionandmechanicalsupport.Transfusiontissuecelsarere-
ticulatedtracheidofequal-diameterortransverseelongation
andshortenedlongitudinalside(Fig.1C).Thereareelonga-
tedparenchymacelssimilartoaccesorytransfusiontissuein
mesophylofPodocarpus(Fig.1E).Whethertheseparen-
chymacelswhichhavebeenfoundinCephalotaxus, Ketele-
ria, Pseudolarix, Taiwania, AmentotaxusandToreyahave
thesamephysiologicalfunctionwithaccessorytransfusiontis-
suehasnoverdict[ 7] .
1.TransversesectionthroughtheleafmidribofPodoucarpusmacrophylus, showingthexyleminvascularbundle, thevascularbundlesheathandtransfu-
siontissuesatlateralsidesofthevascularbundle(arow)(100×);2.TransversesectionthroughtheleafmidribofP.forestii, showingthetransfusion
tissuesattherightsideofthevascularbundle(300×);3.LongitudinalsectionoftheleafmidribofP.costalis, showingthetransfusiontissues(350×);
4.LongitudinalsectionoftheleafmidribofP.macrophylus, showingtracheidsinxylem(arowshowsborderedpitsonthelateralwalsoftracheids(300
×);5.TransversesectionoftheleafofP.macrophylusvar.angustifoliusmacrophylus, showingtheaccessorytransfusiontissue(250×);6.Longitudi-
nalsectionoftheleafmidribofP.macrophylus, showingthevascularbundlesheathandtracheidswithborderedpitsandbelicalthickeninginprotoxy-
lem(200×);7.LongitudinalsectionoftheleafmidribofP.macrophylus, showingtracheidsintheprotoxylemandfibertracheids(arow)inthemetaxy-
lem(220×);8.TransversesectionoftheleafofNageianagi, showingthexyleminvascularbundleandtransfusiontissues(arow)atlateralsidesofthe
vascularbundle(180×);9.LongitudinalsectionoftheleafofN.nankoensis, showingtracheidsinthetransfusiontissue(200×);10.Longitudinalsec-
tionoftheleafofNageianagi, showingtheprotoxylemandthemetaxylem(150×).
Fig.1 Microscopeobservationresultsofsections
93SUNTong-xing.ConductingTissueofLeavesinNageiaandPodocarpus
InNageiaflatleaves, thereareplentyofparalelveins.
Vascularbundlesofthesamesizearearangedinthetrans-
versesection.Ineachvascularbundle, xylemandphloemare
arrangedoppositely, xylemisclosetoadaxialsideandphloem
isclosetoabaxialside(Fig.1H).Butthexylemandphloem
arenotsodevelopedthanthatinPodocarpus:xylemwhichis
composedofprotoxylemandmetaxylemhasonlyseveralcol-
umnsoftracheids;undevelopedtransfusiontissuewhichhas
onlyseveraltracheids(Fig.1H, arow)andparenchymacels
alsoexitineachsideofvascularbundle.Bundlesheathis
moreobviousthanthatinPodocarpus, andaccessorytransfu-
siontissueisabsentinmesophyl.Accordingtotheconcept
fromYAOBi-junandHUYu-shi[ 8] , tissueofNageiabelongs
toTaxus-type.Besides, Glyptostrobus, Metasequoia, Sequoia,
Taxodium, Amentotaxus, Pseudotaxus, TaxusandToreyaalso
belongtoTaxus-type[ 6] .AndPodocarpusimbricatusbelongsto
Araucaria-type[ 8] .Inlongitudinalsection, vascularbundle
xylemofveiniscomposedofspiraltracheidsandborderedpits
tracheidswhichisnotcommon(Fig.1J).Butinlongitudinal
section, transfusiontracheidsofNageiawhicharemainly
composedofspiraltrachiedsandreticulatedtracheidspresent
long-tubular, andarelongerthanthatinPodocarpus.Elonga-
tedparenchymacelscanalsobeseen(Fig.1I).
Conclusion
InFloraReipublicaePopularisSinicae, Podocarpaceae
containsPodocarpusandDacrydium, andPodocarpuscontains
sect.DacrycarpusEndl., sect.NageiaEndl.andsectPodo-
carpusEndl[ 1] .InFloraofChina, DacrycarpusandNageia
areindependentlikePodocarpus[ 4] .ThePodocarpusleafhas
onemidribandⅡ typeofleaf, whileNageialeafisspacious,
morevinesandⅣ typeofleaf[ 8] .InleavesofPodocarpus
therearethreeresinductsundervascularbundleofmidrib,
mesophylcelsarediferentiatedintopalisadetissueand
spongetissue;inleavesofNageia, thereisonlyoneresin
ductundervascularbundleineachveinandnoobviousdifer-
entiationinmesophylcels, palisadetissuecanbefoundon
bothsides, andsclereidcanalsobefoundinmesophyltis-
sue[ 9] .ProtoxylemandmetaxyleminvascularbundleofPodo-
carpushavemoremulti-formoftracheids, whileprotoxylem
andmetaxyleminvascularbundleofNageiaarerelativelyun-
developed.TransfusiontisueofPodocarpuswhichbelongsto
Cycas-type[ 7] iscomposedofreticulatedtracheidofequal-di-
ameter, accessorytransfusiontisueiscomposedofdeveloped
pitedtracheid;transfusiontisueofNagieawhichbelongsto
Taxus-type[ 7] iscomposedofelongatedreticulatedtracheid
andspiraltracheid.Aboveal, theanatomicaldiferencesof
leafveinsandmesophylbetweenPodocarpusandNageiasup-
portedtheviewpointthatNageiaandPodocarpusaretwoinde-
pendentgenera.
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竹柏属和罗汉松属叶输导组织的观察
孙同兴＊ (盐城师范学院生命科学与技术学院 ,江苏盐城 224002)
罗汉松科 (Podocarpaceae)竹柏属 (Nageia)自 Gaertner
(1788)建立以来 ,其系统位置一直存在争议。笔者选取多种竹
柏属和罗汉松属植物 ,主要对其叶脉输导组织进行细致观察 ,为
竹柏属的正确分类和资源利用提供解剖学方面的参考依据 。
1 材料与方法
罗汉松属植物采自深圳仙湖植物园裸子植物区 ,为引种栽
培植物 ,窄叶竹柏采自英国爱丁堡植物园 ,竹柏和长叶竹柏采自
广东肇庆 ,另外 3种竹柏采自爱丁堡植物园标本馆腊叶标本 ,凭
证标本见表 1。
新鲜材料采用 FAA固定 ,腊叶标本先经 5%NaOH水溶液
60 ℃烘箱中复水 2h,再用 FAA固定 。采用常规石蜡制片法 ,将
每种成熟叶片中间部分做成与叶脉垂直和平行 2种切片 ,切片
94 AgriculturalScience＆TechnologyVol.9, No.4, 2008
厚度 8 ～ 10 μm,番红 -固绿染色 ,中性树胶封片 ,在 LeicaDMIB
显微镜下观察 ,数码相机拍照。
2 结果与分析
罗汉松属植物叶片只有 1条主脉 ,在横切面和纵切面上看 ,
10种植物叶脉的结构非常相似 ,均由木质部和韧皮部构成发达
的维管束 ,木质部靠近近轴面 ,韧皮部靠近远轴面 ,木质部韧皮
部成径向排列 ,较为发达 ,通常由 20 ～ 35列构成 ,各列之间为薄
壁组织细胞 [图见第 93页 Fig.1A:罗汉松叶主脉横切面示维管
束木质部、维管束鞘和两侧转输组织(箭头)(100×)] ,在维管
束的两侧各有一团转输组织 。转输组织是裸子植物所特有的一
种组织 ,被认为与维管束和叶肉之间水分及养分的运输有关。
罗汉松属转输组织主要由转输管胞 、蛋白质细胞及转输薄壁细
胞 3部分构成 ,转输管胞的形态随种类不同略有差异 ,如管胞横
向排列和竖向排列(图见 Fig.1A,箭头所示),但管胞的类型均
以次生壁网纹加厚为主 [图见第 93页 Fig.1B:大理罗汉松叶主
脉横切面示维管束右侧转输组织(300×)] 。在维管束和转输组
织的周围有一圈不明显的维管束鞘。在主脉的外方栅栏组织和
海绵组织之间还具有横向排列的副转输组织 ,此种组织非常发
达 ,能够一直分布到叶尖 ,通常由与叶轴垂直的管胞组成 ,管胞
壁上通常为伸长的单纹孔 [图见第 93页 Fig.1E:狭叶罗汉松叶
横切面示副转输组织管胞(250 ×)] 。依据胡玉熹和姚壁君
(1981)的定义 ,罗汉松属转输组织属于苏铁型(Cycas-type)。转
输组织属于该类型的植物还有苏铁科的苏铁属(Cycas)、罗汉松
科的陆均松属(Dacrydium)以及银杏科的银杏属 (Ginkgo)等。
在纵切面上 ,罗汉松属植物维管束木质部结构比较发达 ,从上至
下为螺纹管胞 、螺纹间有具缘纹孔的管胞、具缘纹孔管胞 [图见
第 93页 Fig.1G:罗汉松叶脉纵切面示原生木质部管胞和后生木
质部纤维管胞(箭头)(220×)]和次生壁甚厚的纤维管胞 [图见
第 93页 Fig.1D:罗汉松叶脉纵切面示木质部管胞(箭头所示管
胞壁上具缘纹孔形态)(300×),箭头所示 ] ,其中 ,螺纹间有具
缘纹孔的管胞壁上的具缘纹孔形态有圆形和长椭圆形 2种 (图
见第 93页 Fig.1D, G),螺纹管胞和螺纹间有具缘纹孔的管胞主
要存在于原生和后生木质部中 [图见第 93页 Fig.1F:罗汉松叶
脉纵切面示维管束鞘 、原生木质部带有具缘纹孔和螺纹加厚的
管胞(200×)] ,具缘纹孔管胞和纤维管胞则存在于后生木质部
中(图见第 93页 Fig.1D, G),纤维管胞起输导和机械支持作用 。
而转输组织细胞一般为等径或横向伸长而在纵向面较短的网纹
管胞 [图见第 93页 Fig.1C:兰屿罗汉松叶脉纵切面示转输组织
(350×)] 。罗汉松属植物在叶肉中还有与副转输组织相类似的
伸长薄壁组织细胞(图见第 93页 Fig.1E),这种薄壁组织细胞曾
在三尖杉属(Cephalotaxus)、油杉属(Keteleeria)、金钱松属(Pseu-
dolarix)、台湾杉属(Taiwania)以及穗花衫属 (Amentotaxus)和榧
树属(Toreya)中发现 ,此等细胞与副转输组织细胞是否有相同
的生理功能 ,目前尚无定论 。竹柏属植物叶片扁平 ,具有多数平
行细脉 ,在横切面可以看到多个大小几乎相等的维管束排列 ,每
个维管束中 ,木质部和韧皮部也是相对排列 ,木质部靠近近轴
面 ,韧皮部靠近远轴面(图见第 93页 Fig.1H:竹柏叶横切面示维
管束木质部 、两侧转输组织(箭头)(180×)),但木质部和韧皮
部都没有罗汉松属的发达 ,木质部仅有几列管胞 ,由原生木质部
和后生木质部构成 ,在维管束的两侧也有冀状的转输组织 ,但转
输组织不发达 ,仅有几个管胞(图见 Fig.1H,箭头所示)和薄壁
组织细胞 ,维管束鞘较罗汉松属的明显 ,叶肉中没有副转输组
织。依据姚壁君和胡玉熹(1982)的定义 ,竹柏属转输组织属于
红豆杉型 (Taxus-type), 同属于此类型的还有杉科的水松属
(Glyptostrobus)、水杉属(Metasequoia)、红杉属(Sequoia)、落羽杉
属(Taxodium),红豆杉科的穗花杉属 、白豆杉属(Pseudotaxus)、
红豆杉属(Taxus)、榧树属等 ,而罗汉松科的鸡毛松属则属于南
洋杉型 。在纵切面上 ,叶脉维管束木质部主要有螺纹管胞和具
有具缘纹孔的螺纹管胞 ,而具缘纹孔管胞不多见 [图见第 93页
Fig.1J:竹柏叶纵切面示原生木质部和后生木质部(150×)] 。
但在纵切面上 ,竹柏属转输组织管胞呈长管状 ,纵向伸长 ,比罗
汉松属植物的长 ,主要为螺纹管胞和网纹管胞 ,另外还可见伸长
的薄壁组织细胞 [图见第 93页 Fig.1I:台湾竹柏叶纵切面示转
输组织管胞(200×)] 。
表 1 研究材料和凭证标本
种名 凭证标本
小叶罗汉松PodocarpuswangiC.C.Chang 孙同兴 (T.X.Sun)200201(YCTC)
兰屿罗汉松P.costalisC.Presl. 孙同兴 (T.X.Sun)200202(YCTC)
大理罗汉松P.forrestiGraibetW.W.Smith 孙同兴 (T.X.Sun)200203(YCTC)
海南罗汉松P.annamiensisN.E.Gray 孙同兴 (T.X.Sun)200204(YCTC)
罗汉松 P.macrophylus(Thunb.)Sweet 孙同兴 (T.X.Sun)200205(YCTC)
狭叶罗汉松P.macrophylusvar.angustifoliusBlume 孙同兴 (T.X.Sun)200206(YCTC)
短叶罗汉松P.macrophylusvar.makiSieboldetZuccarini. 孙同兴 (T.X.Sun)200207(YCTC)
贺氏罗汉松P.henkeliiStapfexDalimetJacks 孙同兴 (T.X.Sun)200208(YCTC)
镰叶罗汉松 P.falcatusThunb.R.Br.exMirb. 孙同兴 (T.X.Sun)200209(YCTC)
洛杉矶罗汉松 P.graciliorR.Pilger. 孙同兴 (T.X.Sun)200210(YCTC)
肉托竹柏 NageiawalichianaO.Kuntze JSinclair38991(E)
马来竹柏 N.motleyideLaubenfels. JSinclair40798(E)
长叶竹柏 N.fleuryideLaubenfels. 孙同兴 (T.X.Sun)2004015(YCTC)
竹柏 N.nagiO.Kuntze 孙同兴 (T.X.Sun)2004016(YCTC)
台湾竹柏 N.nankoensisR.R.Mil JMain530(E)
窄叶竹柏 N.formosensisC.N.Page 孙同兴 (T.X.Sun)2003029(YCTC)
注:E.爱丁堡植物园标本馆;YCTC.盐城师范学院植物标本室。
3 结论
《中国植物志 》中罗汉松科包括罗汉松属和陆均松属 ,罗汉
松属包括鸡毛松组、竹柏组和罗汉松组 。 FloraofChina中鸡毛
松属和竹柏属则独立出来 。罗汉松属植物叶 1条主脉 ,叶型Ⅱ,
而竹柏属植物叶广阔扁平、多脉序 ,叶型Ⅳ。罗汉松属植物主脉
维管束下面有 3个树脂道 ,叶肉分化为栅栏组织和海绵组织 ,而
竹柏属植物每个叶脉维管束下面有 1个树脂道 ,叶肉分化不明
显 ,两面都有栅栏组织 ,叶肉中还具有大量石细胞等特征 。罗汉
松属维管束内原生木质部和后生木质部均较发达 ,具有多种类
型的管胞分子 ,而竹柏属植物每个维管束原生木质部和后生木
质部都相对不发达。罗汉松属转输组织为苏铁型 ,主要由等径
的网纹管胞构成 ,副转输组织有发达的孔纹管胞构成 ,而竹柏属
转输组织为红豆杉型 ,主要有等纵向伸长的网纹和螺纹管胞构
成。综上所述 ,罗汉松属和竹柏属在叶脉、叶形态和结构方面存
在明显的差异 ,因此 ,笔者认为 2个属分开比较合理。
基金项目 江苏省高校自然科学基础研究项目(06KJD180201)。
作者简介 孙同兴(1962-),男,山东青岛人, 博士,副教授, 从事植物
资源研究。 ＊通讯作者。
收稿日期 2008-08-25 修回日期 2008-10-08
95SUNTong-xing.ConductingTissueofLeavesinNageiaandPodocarpus