全 文 :植物科学学报 2014ꎬ 32(3): 228~235
Plant Science Journal
DOI: 10 3724 / SP J 1142 2014 30228
基于核糖体 DNA内转录间隔区 ITS序列
的广义蓼属及近缘属分子系统学研究
孙 伟1ꎬ2ꎬ 安 超3ꎬ 郑希龙4ꎬ 万和文2ꎬ 陈延松2ꎬ6ꎬ 李大卫5ꎬ 周忠泽2∗
(1. 中国中医科学院中药研究所ꎬ 北京 100700ꎻ 2. 安徽大学资源与环境工程学院ꎬ 合肥 230601ꎻ
3. 住房城乡建设部城乡规划管理中心ꎬ 北京 100835ꎻ 4. 中国医学科学院药用植物研究所海南分所ꎬ 海南万宁 571533ꎻ
5. 中国科学院武汉植物园ꎬ 中国科学院特色农业重点实验室ꎬ 武汉 430074ꎻ 6. 合肥师范学院生命科学系ꎬ 合肥 230009)
摘 要: 通过对广义蓼属及近缘属共 32 个代表种内转录间隔区 ITS序列的分子系统学分析ꎬ 尝试研究备受争议
的广义蓼属及近缘属的物种族、 属、 组级的划分问题ꎬ 结果显示ꎬ 广义蓼属在系统发育树上并不能形成一个单
系类群ꎬ 这些物种共聚为 3大支ꎬ 分别对应春蓼族、 蓼族及荞麦族ꎬ 其中荞麦属与翅果蓼属形成了一支独立于
春蓼族及蓼族之外的类群ꎮ 在春蓼族中ꎬ 冰岛蓼属与分叉蓼组形成一个单系类群ꎮ
关键词: 系统学ꎻ 蓼属ꎻ ITS序列ꎻ 蓼科
中图分类号: Q949 745 1 文献标识码: A 文章编号: 2095 ̄0837(2014)03 ̄0228 ̄08
收稿日期: 2013 ̄07 ̄01ꎬ 修回日期: 2013 ̄09 ̄30ꎮ
基金项目: 公益性行业(农业)科研专项(201303117)ꎮ
作者简介: 孙伟(1981-)ꎬ 男ꎬ 博士ꎬ 助理研究员ꎬ 研究方向为药用植物技术 (E ̄mail: tcmsunwei@outlook com)ꎮ
∗通讯作者(Author for correspondence E ̄mail: zhouzz@ahu edu cn)ꎮ
Phylogenetic Analysis of Polygonum L. s. lat. and Related
Genera (Polygonaceae) Inferred from nrDNA Internal
Transcribed Spacer ( ITS) Sequences
SUN Wei1ꎬ2ꎬ AN Chao3ꎬ ZHENG Xi ̄Long4ꎬ WAN He ̄Wen2ꎬ
CHEN Yan ̄Song2ꎬ6ꎬ LI Da ̄Wei5ꎬ ZHOU Zhong ̄Ze2∗
(1. Institute of Chinese Materia Medicaꎬ China Academy of Chinese Medical Sciencesꎬ Beijing 100700ꎬ Chinaꎻ
2. School of Resources and Environmental Engineeringꎬ Anhui Universityꎬ Hefei 230601ꎬ Chinaꎻ 3. Urban ̄Rural Planning and
Management Centerꎬ Ministry of Housing and Urban ̄Rural Development of the Peoples Republic of Chinaꎬ Beijing 100853ꎬ Chinaꎻ
4. Hainan Branch Institute of Medicinal Plant Development Chinese Academy of Medical Sciencesꎬ Wanningꎬ Hainan 571533ꎬ Chinaꎻ
5. Key Laboratory of Plant Germplasm Enhancement and Specialty Agricultureꎬ Wuhan Botanical Gardenꎬ Chinese Academy
of Sciencesꎬ Wuhan 430074ꎬ Chinaꎻ 6. Biological Sciences Departmentꎬ Hefei Normal Universityꎬ Hefei 230601ꎬ China)
Abstract: Phylogenetic analyses of 32 species of Polygonum L. and related genera were
conducted on the basis of nrDNA ITS sequences using maximum parsimony. Results
suggested that Polygonum did not constitute a monophyletic groupꎬ and that one monophyletic
clade of Fagopyrum and Parapteropyrum named tribe Fagopyreae was placed outside the two
major clades corresponding to tribes Persicarieae and Polygoneae. Furthermoreꎬ Koenigia
and sect. Aconogonon composed a monophyletic group with a close relationship to sect.
Bistorta.
Key words: Phylogenyꎻ Polygonumꎻ ITS sequencesꎻ Polygonaceae
The genus Polygonum L. (Polygonaceae) is
comprised of approximately 230 species of herbs
distributed throughout the world. All members of
the genus are annual and perennial herbsꎬ rarely
shrubsꎬ and bearing unique ocrea. The morpho ̄
logical characteristics of the Polygonum genus
are extremely difficult to qualifyꎬ with many bota ̄
nists following traditional classification at the
supra ̄specific level.
The first classification was made by Gross[1]ꎬ
who divided Polygonum ̄like plants into seven
genera ( Pleuropterusꎬ Pteroxygonumꎬ Pleurop ̄
teropyrumꎬ Polygonum sensu strictoꎬ Bistortaꎬ
Fagopyrum and Persicaria) on the basis of vege ̄
tativeꎬ reproductiveꎬ and pollen morphological
characteristics. Steward[2] made a comprehen ̄
sive revision of the subfamily Polygonoideae in
Asia. Polygonum was subdivided into sections
Aviculariaꎬ Bistortaꎬ Persicariaꎬ Cephalophilonꎬ
Tiniariaꎬ Aconogononꎬ Fagopyrum and Echincau ̄
lon based on acheneꎬ perianthꎬ inflorescenceꎬ
and ocrea features. In additionꎬ Tovara and Koe ̄
nigia were established as two different genera.
The classification presented by Hedberg[3] divid ̄
ed Polygonum into seven genera based on the
variation of pollen morphological features (Koeni ̄
giaꎬ Persicariaꎬ Polygonum sensu strictoꎬ Pleu ̄
ropteropyrumꎬ Bistortaꎬ Tiniaria and Fagopy ̄
rum) . Haradlson[4] developed the subfamily Poly ̄
gonoideae based on the anatomical features of
stemsꎬ petiolesꎬ leaves and trichomes. The rep ̄
resentatives of Polygonum and its related genera
were placed into three different tribes ( Polygo ̄
neaeꎬ Persicarieaeꎬ and Coccolobeae) [4] .
Ronse De Craene and Akeroyd[5] investiga ̄
ted a number of floral characters (stamenꎬ tepal
and floral nectaries) and concluded that Polygo ̄
num and related genera could be split into two
tribes: Polygoneae (containing Polygonum s. s.ꎬ
Fallopia Adans.ꎬ Oxygonum Burch.ꎬ Pteropyrum
Jaub. & Spach.ꎬ Atraphaxis L. and Calligonum
L.) and Persicarieae ( containing Fagopyrum
Mill.ꎬ Harpagocarpus Hutch. & Dandyꎬ Persicar ̄
ia Mill and Koenigia L.) . The surveys were based
on tepal surface morphological featuresꎬ and
supported Ronse De Craenes conclusion that a
division of Polygoneae and Persicarieae was rea ̄
sonable. Howeverꎬ the tepal surface morphologi ̄
cal features of some Fagopyrum species are dif ̄
ferentꎬ and tepal surface morphological features
support the uncertain systematic position of
Fagopyrum[6] .
Ronse De Craene et al.[7] investigated fruit
morphological features in tribes Persicarieae and
Polygoneae. Results showed that pericarp anato ̄
my was a valuable feature in the genus for delimi ̄
ting genera and sections. The conclusion from
this study almost corresponded to previous re ̄
ports except for (1) promoting Aconogonon and
Bistorta from section to genus level and (2) pro ̄
moting the genus Fagopyrum to new tribe Fago ̄
pyreae from Persicarieae[7] .
Polygonaceae was treated as a sister group
of Plumbaginaceae in Caryophyllales[8ꎬ9] though
the positions of Muehlenbeckia and Fagopyrum
remain unclear[10] . rbcL analysis indicated that
Fagopyrum was less closely related to Polygo ̄
num than to Rumiceaeꎬ suggesting that Polygo ̄
num was paraphyletic[11] . While the monophyly of
Polygonaceae has been supported by morpho ̄
logical and molecular analysesꎬ the relationships
among its genera have long been controver ̄
sial[12] . The previously recognized subfamilies
Eriogonoideae and Polygonoideae were not re ̄
vised within the current subfamily delimitation
using chloroplast evidence[11ꎬ12] . Recent evi ̄
dence supported a monophyletic tribe Persicarie ̄
aeꎬ with members of clustered Fagopyrum not
included. The Polygoneae tribe has been catego ̄
rized as paraphyletic since the acceptance of evi ̄
dence supporting Muehlenbeckia as a sister to
Fallopia[11ꎬ12] . Previouslyꎬ Muehlenbeckia was
recognized as a member of the tribe Coccolobe ̄
ae[13] . Currentlyꎬ Sanchez and Korn have ex ̄
panded the scope of subfamily Eriogonoideae to
include Antigonon Endl.ꎬ Brunnichia Banks ex
922 第 3期 孙 伟等: 基于核糖体 DNA内转录间隔区 ITS序列的广义蓼属及近缘属分子系统学研究(英文)
Gaertn.ꎬ Coccoloba L.ꎬ Ruprechtia C. A. Meyerꎬ
Triplaris Loefl. ex L. and Eriogonoideae s s.[12] .
This demonstrated that the tribe Coccolobeae
Dum. Emend. Hara. recognized by Brandbyge
was not monophyleticꎬ and some genera data of
tribe Triplarieae Meisn. was transferred from sub ̄
family Polygonoideae to Eriogonoideae.
In this study we aimed to: (1) construct the
phylogeny of Polygonum and related genera
using ITS region analysis to provide a more com ̄
prehensive understanding of tribe circumscrip ̄
tionꎻ and (2) understand the systematic position
of Fagopyrumꎬ Muehlenbeckiaꎬ Parapteropyrum
and retesting Pteroxygonum by investigating
more taxon.
1 Materials and methods
Species sampling followed a strategy to (1)
include materials of all sections of Polygonum
and related genera following classification[13]ꎬ
and ( 2 ) include representatives of all pollen
types of Polygonum and related genera[14] . The
plant materials used in this study are listed in
Table 1.
Table 1 Information of ITS sequences from Polygonum L. and related genera
Taxa Source Voucher GenBank
Polygonum aviculare L. Daliꎬ Yunnan W. Sun & Z. Z. Zhou (ANU 05410) DQ406624
P. runcinatum Buch. Ham. ex D. Don Daliꎬ Yunnan W. Sun & Z. Z. Zhou (ANU 05395) DQ406629
P. japonicum Meisn. Daliꎬ Yunnan W. Sun & Z. Z. Zhou (ANU 05396) DQ406634
P. orientale L. Dabieshanꎬ Anhui W. Sun & Z. Z. Zhou (ANU 05442) DQ406631
P. griffithii Hook. Deqinꎬ Yunnan H. W. Wan & Z. Z. Zhou (05443) DQ406632
P. sinomontanum Sam. Daliꎬ Yunnan H. W. Wan & Z. Z. Zhou (ANU 05163) EU718495
P. macrophyllum D. Don. Daliꎬ Yunnan H. W. Wan & Z. Z. Zhou (ANU 05177) EU718496
P. polystachyum Wall. ex Meisn. Jiazhaꎬ Tibet M. Z. Liu & Z. Z. Zhou (ANU 05232) EU718497
P. divaricatum L. Jiazhaꎬ Tibet M. Z. Liu & Z. Z. Zhou (ANU 05225) EU718498
P. bungeanum Turcz. Changchunꎬ Jilin Z. Z. Zhou (ANU 05222) DQ406674
P. nepalense Meisn. Yaoluopingꎬ Anhui W. Sun & Y. S. Chen (ANU 05343) DQ406675
P. cyanandrum Diels. Deqinꎬ Yunnan W. Sun & Z. Z. Zhou (ANU 05422 ) DQ406626
P. campanulatum Hook. f. Deqinꎬ Yunnan W. Sun & Z. Z. Zhou (ANU 05168) DQ406630
P. viviparum L. Lijiangꎬ Yunnan H. W. Wan & Z. Z. Zhou (ANU 05171) DQ372903
P. perfoliatum L. Hefeiꎬ Anhui H. W. Wan & Z. Z. Zhou (ANU 05174) DQ372904
P. hydropiper L. Dabieshanꎬ Anhui W. Sun & Z. Z. Zhou (ANU 05110 ) DQ346665
P. forrestii Diels Daliꎬ Yunnan H. W. Wan & Z. Z. Zhou (ANU 05334) DQ406633
P. sagittatum L. Yaoluopingꎬ Anhui W. Sun (ANU 06110) DQ006031
Pteroxygonum giraldii Damm. et Diels Songshanꎬ Henan Z. Z. Zhou (ANU 04323) DQ406627
Koenigia islandica L. Deqinꎬ Yunnan H. W. Wan & Z. Z. Zhou (ANU 05391) DQ406625
Fallopia scandens (L.) Holub Hefeiꎬ Anhui H. W. Wan & Z. Z. Zhou (ANU 05400) DQ406651
Reynoutria japonica Houtt. Hefeiꎬ Anhui W. Sun (ANU 054110) DQ406667
Parapteropyrum tibeticum A. J. Li Jiazhaꎬ Tibet Z. Z. Zhou (ANU 054111) EU718499
Rumex acetosella L. GenBank AF189730
R. nepalensis Spreng GenBank AF338219
P. filiforme (Nakai) . Ohwi GenBank U51276
P. neofiliforme Nakai GenBank U51273
Fagopyrum lineare (Sam.) Harald. GenBank AB000330
Fa. statice (Lévl.) H. Gross GenBank AB000322
Fa. tataricum Gaertn. GenBank AB000341
R. sachalinensi (F. Schmidt) Ronse Decr. GenBank AF040073
Fal. dentate ̄alata (Fr. Schm.) Holub GenBank AF040066
Muehlenbeckia rhyticarya F. Muell. GenBank AF189739
032 植 物 科 学 学 报 第 32卷
Total genomic DNA was extracted from silica
gel dried leaf materials or herbarium specimens
( Table 1) following the CTAB procedure with
modifications[15] . The two internal transcribed
spacers ( ITS ̄1ꎬ ITS ̄2) and 5 8S rDNA were
amplified using primers P18S (5′ ̄CGTAACAAG ̄
GTTTCCGTAGGTGAAG ̄3′) and P26S (5′ ̄TTAT ̄
TGATATGCTTAAACTCAGCGGG ̄3′) . We added
1 5 μL template DNAꎬ 1 μL 10 pmol of each
primerꎬ 0 5 μL Taq DNA polymeraseꎬ 3 μL 10 ×
bufferꎬ 1 8 μL MgCl2ꎬ 2 μL dNTPs (5 U / μL)ꎬ
and 19 2 μL H2O into 30 μL PCR reaction mix ̄
ture. The PCR reactions were carried out by the
following procedure: initial denaturation at 95℃
for 4 minꎻ 33 cycles at 95℃ for 1 minꎻ one cycle
at 52℃ for 1 minꎻ and at 72℃ for 1 minꎬ fol ̄
lowed by a final extension at 72℃ for 10 min. The
PCR products were purified on 1% agarose gels
using a QIAquick purification kit and directly se ̄
quenced on an ABI 3770 automated sequencer
( Invitrogen Biotechnology Co.ꎬ Ltd and Sangon
Biotechnology Co.ꎬ Ltd ) . Sequencing primers
were the same as those of the previous PCR and
used singly in forward and reverse reactions.
The sequences were aligned using CLUSTAL
W with minor manual adjustments. Parsimony
analyses were carried out using PAUP∗ 40b4a
( PPC ) [16] . Characters were weighted equally
and character states were treated as unorderedꎬ
and gaps were treated as missing data. To
search for islands of the shortest treesꎬ a heuris ̄
tic search was conducted using 1000 random
taxon addition replicatesꎬ with one tree held at
each step during stepwise addition. Other tree
search options included TBR branch swappingꎬ
and steepest descent of MulTrees on and no
upper limit of MaxTrees. Internal support was
evaluated with bootstrap analyses using 1000 re ̄
sampling replicates and the same tree search
procedure as described aboveꎬ except for sim ̄
ple sequence addition[17] .
2 Results
The fragment length of the ITS sequenceꎬ
including the 5 8S geneꎬ varied from 680 bp to
700 bp. The ITS region phylogeny was estab ̄
lished with the basal groups of Fagopyrum and
Parapteropyrum ( Figure 1 ) . The ingroup was
split into two large clades. Clade Ⅰꎬ which was
moderately supportedꎬ contained Fallopia through
to Polygonum sect. Polygonumꎬ while Clade Ⅱ
( bootstrap < 50%) contained Pteroxygonum
through to Koenigia. Within Clade Ⅰꎬ Polygonum
sect. Polygonum was sister to the rest of the
cladeꎻ Fallopia was paraphyletic and Muehlen ̄
beckia was nested within Fallopia. In Clade Ⅱꎬ
the Pteroxygonum specimen formed subclade 1
on its ownꎬ while the restꎬ comprised of six sub ̄
cladesꎬ were weakly supported ( bootstrap =
61%) . Subclade 2 and 3 contained P. sagittatum
and P. perfoliatumꎬ respectively. Subsequentlyꎬ
subclade 4 comprised sect. Persicaria and Ante ̄
noron. Subclade 5 consisted of P. runcinatum
and P. nepalense (bootstrap = 84%)ꎬ which cor ̄
responded with sect. Cephalophilon. Section Bis ̄
torta was included in subclade 6ꎬ and subclade
7 was comprised of sect. Aconogonon and Koe ̄
nigia. The monophyly of sect. Bistorta was sup ̄
ported ( bootstrap = 95%)ꎬ and Koenigia was
nested within sect. Aconogonon in subclade 7.
3 Discussion
Our molecular data confirmed that Polygo ̄
num L. s. lat. was not monophyleticꎬ as sugges ̄
ted by Ronse De Creane and Akeroyd[5] . The
major clades corresponded to previous tribe clas ̄
sification of Polygonum and related genera refer ̄
ring to tribes Persicarieae and Polygoneaeꎬ with
the exception of Fagopyrum[5-7] . The position of
Fagopyrum was inconsistent based on differing
132 第 3期 孙 伟等: 基于核糖体 DNA内转录间隔区 ITS序列的广义蓼属及近缘属分子系统学研究(英文)
Fagopyrum
Parapteropyrum
subclade 7
Koenigia
AconogononSect.
subclade 6
Sect. Bistorta
subclade 5
Sect. Cephalophilon
subclade 4:
Sect. Persicaria
Antenoron
subclade 2,3:
Sect. Echinocaulon
subclade 1:
Pteroxygonum
Fallopia
Muehlenbeckia
PolygonumSect.
Clade :Ⅱ
Tribe Persicarieae
Clade :Ⅰ
Tribe Polygoneae
Rumex acetosella
R. nepalensis
Fagopyrum linear
Fag. statice
Fag. tataricum
Parapteropyrum tibeticum
Polygonum forrestii
Koenigia islandica
P. cyanandrum
P. campanulatum
P. divaricatum
P. polystachyum
P. griffithii
P. macrophyllum
P. viviparum
P. nepalense
P. runcinatum
P. hydropiper
P. japonicum
P. bungeanum
P. orientale
P. filiforme
P. neofiliforme
P. perfoliatum
P. sagittatum
Pteroxygonum giraldii
Reynoutria japonica
R. sachalinensis
Fallopia dentatealata
Fal. scandens
Muehlenbeckia rhyticarya
P. aviculare
100
71
100
98
94
91
95
74
95
85
78
69
50
50
61
60
62
57
100
50
L ( length) = 451 stepsꎬ CI (consistency index) = 0. 533ꎬ RI ( retention index) = 0. 6892
and RC ( rescaled consistency index) = 0. 4080.
Fig 1 Strict consensus of the 12 most parsimonious trees resulting from analysis of the ITS dataset
(117 parsimony informative characters)
232 植 物 科 学 学 报 第 32卷
morphological ̄based research. Fagopyrum has
been considered closely related to Polygonum in
subfamily Polygonoideae[3] . Howeverꎬ Gross[1]
introduced the possibility that Fagopyrum was
closely related to Fallopiaꎬ mainly due to their
similar habit. Haraldson[4] found a similarity in the
petiole anatomy between Fallopia and Fagopy ̄
rum. Ronse De Craene and Akeroyd[5] believed
that Fagopyrum occupied a basal position in the
tribe Persicarieaeꎬ using the similar features of
tepal venationꎬ epidermal cellꎬ nectary as sup ̄
port evidence. Another proposal established by
Ronse De Creae et al.[7] further suggested a new
tribe Fagopyreae due to the aberrations of Fago ̄
pyrumꎬ including its parenchymatic exocarp and
thickened mesocarp. Lamb and Korn[5] construc ̄
ted a phylogeny of Polygonaceae using rbcLꎬ
and suggested that Fagopyrum was closely relat ̄
ed to Polygonum and the tribe Rumiceae. Our
molecular results were inconsistent with the rbcL
resultsꎬ and supported Fagopyrum to be a dis ̄
tinctive position from Polygonum. In additionꎬ our
ITS evidence supported the close relationship be ̄
tween Parapteropyrum and Fagopyrumꎬ which
was also supported by their same topology tree
based on the trnL ̄F region (Sun et alꎬ unpub ̄
lished)ꎬ and similar pollen morphology ( fine re ̄
ticulate ornamentationꎬ 3 ̄colporate) .
3 1 Clade Ⅱ: tribe Persicarieae
Recent taxonomic revision of Pteroxygonum
by Sun et al.[18]ꎬ supported the inclusion of
Pteroxygonum in the tribe Persicarieae based on
morphological and molecular data[5ꎬ6] and the
transfer of Pteroxygonum from Fagopyrum to be
established as a monotypic genus[3ꎬ13] . In this
studyꎬ we selected more samples of Polygonum
and related genera to verify the above conclu ̄
sionꎬ which supported Pteroxygonums formation
of its own subclade.
In parsimony analysesꎬ the tribe Persicarieae
clade included several smaller subclades. The
species within each subclade generally shared
similar morphological featuresꎬ with the exception
of P. sagittatum and P. perfoliatum in sect. Echi ̄
nocaulon. In subclade 2 and 3 of sect. Echino ̄
caulonꎬ we found that all species had recurvedꎬ
spine ̄like trichomes[4] . Subclade 4 contained all
species of Antenoron and sect. Persicaria. Ante ̄
noron was recognized as a distinct taxonꎬ andꎬ
based on evidence of a persistent hooked style
and distinct pollen ( fine reticulate ornamentationꎬ
12 or 30 ̄pantocolpate)ꎬ as a genus as well[2ꎬ14] .
Howeverꎬ surveys done in other experiments
have reported different conclusionsꎬ namely that
Antenoron was a section of Persicaria based on
anatomical and floral features[4ꎬ5] . Our molecular
results supported a close relationship between
Antenoron and sect. Persicaria. We supported
Antenoron as a section of Persicaria from analysis
of its ITS region and their shared geographic dis ̄
tribution throughout East China. Subclade 5 com ̄
prised two species of sect. Cephalophilonꎬ which
shared features of capitate inflorescences[13] .
Several authors hold differing opinions regarding
the relationship between sect. Bistorta and sect.
Aconogonon. Some consider sect. Bistorta and
sect. Aconogonon as two sections of Polygonum
or Pericasica[2ꎬ5ꎬ13] . Recentlyꎬ Ronse De Craene
et al.[7] reinvestigated the tribes Persicarieae and
Polygoneae based on fruit morphology and ana ̄
tomy studiesꎬ and found that Bistorta and Acono ̄
gonon were grouped in a single genus as a sister
to Koenigia and Persicaria. Our data indicated
that sect. Bistorta and sect. Aconogonon should
be treated as two genera of tribe Persicarieae
(BS = 95% bootstrap support and 62% bootstrap
supportꎬ respectively ) . Particularlyꎬ the repre ̄
sentatives of sect. Aconogonon and Koenigia
were clustered in subclade 7ꎬ and data also
showed a relationship between sect. Aconogonon
332 第 3期 孙 伟等: 基于核糖体 DNA内转录间隔区 ITS序列的广义蓼属及近缘属分子系统学研究(英文)
and Koenigia. Furthermoreꎬ sect. Bistortaꎬ sect.
Aconogonon and Koenigia are distributed in a
similar geographic region of Southwest China.
They are all found in shrubbery and grassland
habitats located on mountain slopes. The position
and scope of Koenigia has been debated for a
long time. The scope of Koenigia has been inves ̄
tigated based on pollen morphologyꎬ gynoecium
morphologyꎬ anatomyꎬ basic chromosome num ̄
ber and atpB ̄rbcL region analyses[4ꎬ5ꎬ19ꎬ20] . The
genus contains K. islandicaꎬ K. delicatula subsp.
Relictaꎬ K. delicatula subsp. dlicatulaꎬ K. ne ̄
palensisꎬ K. pilosaꎬ K. forrestiiꎬ and K. nummu ̄
larifolia[19] . Evidence from ITS sequences provid ̄
ed strong support to transfer P. forresti (sect. Ac ̄
onogonon) and P. cyanandrum ( sect. Cephalo ̄
philon) into Koenigia (100% bootstrap support) .
Thereforeꎬ we support Hedbergs conclusion.
From our dataꎬ Koenigia seemed to be an ex ̄
treme evolutionary form of sect. Aconogonon.
Howeverꎬ sampling the putative large scope of
Koenigia species as a whole is necessary for elu ̄
cidating the relationships of individuals within it.
3 2 Clade I: tribe Polygoneae
Haraldson[4] combined Reynoutriaꎬ Fallopiaꎬ
Harpagocarpusꎬ Muehlenbeckiaꎬ Coccolobaꎬ
Antigononꎬ Brunnichiaꎬ Podopterus into tribe
Coccolobeae. Ronse De Craene and Akeroyd[5]
combined Polygonum s. s.ꎬ Polygonellaꎬ Fallo ̄
piaꎬ Oxygonumꎬ Atraphaxiaꎬ Pteropyrum and
Calligonum into tribe Polygoneaeꎬ using similar
filament morphological featuresꎬ vasculature of
tepalsꎬ shape of outer tepal and tepal epidermis
morphology as evidence. Hong et al.[6] stated
that the genera (Polygonum s. s.ꎬ Polygonellaꎬ
Fallopiaꎬ Parapteropyrumꎬ Pteropyrumꎬ Atra ̄
phaxis and Calligonum ) of tribe Polygoneae
shared the same tepal morphological features.
Howeverꎬ current molecular investigations sug ̄
gested that Polygonoideae was a non ̄mono ̄
phyletic group[11ꎬ12] . For exampleꎬ Coccolobaꎬ
Triplarisꎬ Ruprechtiaꎬ and Antigonon were trans ̄
ferred from subfamily Polygonoideae to subfamily
Eriogonoideae[11ꎬ12] . Unfortunatelyꎬ the position of
Muehlenbeckia is still uncertain. Jaretzky[21] stat ̄
ed Muehlenbeckia was derived from Fallopia
sect. Pleuropterusꎬ citing its chemical character ̄
istics as evidence. Haraldson[4] placed Muehlen ̄
beckia into tribe Coccolobeaeꎬ and found it had
a close relationship with Fallopia. Chloroplastid
molecular evidence supported the inclusion of
Muehlenbeckia in a monophyly consisting of Atra ̄
phaxisꎬ Muehlenbeckiaꎬ Fallopiaꎬ Polygonum
s. s.ꎬ and Polygonella[11] . Our data supported the
close relationship among Fallopiaꎬ Muehlenbec ̄
kia and Polygonum s. s. in the tribe Polygoneae.
Howeverꎬ our data also supported the es ̄
tablishment of the position of Parapteropyrumꎻ an
opinion that differs from any preexisting construc ̄
ted opinions. Thusꎬ the relationship among Ptero ̄
pyrumꎬ Atraphaxisꎬ Calligonumꎬ and Parapteropy ̄
rum is still unclear. Our results seemed to affirm
that these genera do not correspond to any mem ̄
bers of tribe Polygoneae[5ꎬ7] or Atraphaxideae[13] .
More samples must be collectedꎬ including sam ̄
ples of Polygonellaꎬ Pteropyrumꎬ Atraphaxisꎬ
and Calligonumꎬ to thoroughly investigate the
monophyly of tribe Polygoneae using expanded
sampling at the generic level[5ꎬ7] .
References:
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[18] Sun Wꎬ Zhou ZZꎬ Liu MZꎬ Wan HWꎬ Dong X.
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532 第 3期 孙 伟等: 基于核糖体 DNA内转录间隔区 ITS序列的广义蓼属及近缘属分子系统学研究(英文)