【作者】 闵运江；

【导师】 周忠泽；

【作者基本信息】 安徽大学 ， 生态学， 2013， 博士

【摘要】 广义蓼属(Polygonum L. s. lat.)是1753年由瑞典分类学家林奈建立的,是一个存在持续争论与挑战的、松散的、但并不完全成功的属级分类单位。许多学者试图将该属分成更多的如亚属、组或属等不同等级的自然单元,而这些等级单元是否应该被应用,还有许多争论,一直没有获得令人信服的结论。《中国植物志》25卷第1分册及《Flora of China》第5卷记载我国蓼科植物有13属,235(/238)种37变种,主要依据形态特征将蓼科分为两个亚科：即蓼亚科Subfam. Polygonoideae和酸模亚科Subfam. Rumicoideae,将蓼亚科分为2个族：蓼族Trib. Polygoneae和木蓼族Trib. Atrophaxideae。其中蓼族分为7属：即冰岛蓼属(Koenigia L.)、蓼属(Polygonum L.)、何首乌属(Fallopia Adans.)、虎杖属(Reynoutria Houtt.)、金线草属(Antenoron Rafin.)、荞麦属(Fagopyrum Mill.)和翼蓼属(Pteroxygonum Damm. et Diels)(该论文涉及的研究范围主要是上述的蓼族各个属)。然而,其分类系统中存在许多争议性的问题有待解决。植物分子系统学,是采用分子生物学的各种实验手段,以获取各类分子性状,从而,探讨植物分类、类群之间的系统发育关系及其进化过程和机制。它仅仅用了20多年,就对过去花费200多年依据植物形态性状而建立起来的系统分类关系作出了令人信服的评价。论文选取了被广泛用于植物分子系统学研究的nrDNA ITS和叶绿体基因组的trnL-trnF及atpB-rbcL3个基因间区的DNA片段序列,从广义蓼属每个组,及蓼族(《中国植物志》定义的蓼族范畴)的各个属共选77个代表种,以酸模亚科的山蓼属、酸模属和大黄属中共选7个代表种作外类群,总计84种(含变种),分别进行了3个片段的DNA提取、扩增、序列测定,测序数据用PAUP及MrBayes分析软件,分别对单个基因和2个叶绿体基因以及3个基因的联合数据矩阵进行了MP、NJ和B1分子系统树构建。再以文献报道的蓼属及酸模属的最早的地层花粉年代为标尺,用BEAST软件包中的系列程序,计算3个片段联合数据分子树的各个节点的分歧时间。从而探讨了广义蓼属在系统分类上长期存在的争论性问题。另外,为了进一步讨论广义冰岛蓼属的系统地位,及其属内的种间关系问题,将已计算出的分子树上与广义冰岛蓼属亲缘关系较近的属：金线草属(Antenoron)、刺蓼属(Truellum)、春蓼属(Persicaria)、头状蓼属(Cephalophilon)、神血宁属(Aconogonon)、拳参属(Bistorta)每个属选定种类同前计算广义蓼属的分子系统树的选样种类,且广义冰岛蓼属(Koenigia s. lat.)每种选1-8个居群样品(共计82个样)。同样进行单基因和多基因的MP、NJ和B1分子树的构建,以及各关键结点的歧化时间估算。得出了以下主要结论：原广义蓼属并非单系群,且其内的分组应分别成立为属级单位,部分种类在各属中的位置应当适当调整。具体建议如下：(1)西伯利亚蓼应该从神血宁属(分叉蓼组)独立出来,支持将西伯利亚蓼升为西伯利亚蓼属Knorringia Tzvel.,西伯利亚蓼也应更名为Knorringia sibirica Tzvel.。(2)虎杖属与首乌属亲缘关系较近,推测二者来自于同一祖先,而其在进化中较早的一支向直立的虎杖属方向演化；另一支向蔓生或缠绕藤本的方向演化进而分化出了首乌属。支持将二者分别独立为属的处理,即虎杖属Reynoutria Houtt.和首乌属Fallopia Adans.。(3)支持翼蓼属的属级地位的处理,即红药子属Pteroxygonum Damm. et Diels,但红药子属(翼蓼属)并非单种属的概念,至少应包含翼蓼和酱头(齿叶蓼)两个种,建议将酱头从首乌属移到红药子属,更名为齿叶翼蓼Pteroxygonum denticulata。(4)支持将翅果蓼从原木蓼族移出,撤销其属级地位,并入荞麦属(Fagopyrum Mill.),为一木本荞麦类型,更名为翅果荞麦Fagopyrum tibeticum。(5)原蓼属神血宁组升为神血宁属Aconogonon Reichb.,且原位于该属的西伯利亚蓼应独立成西伯利亚蓼属；铜钱叶蓼和大铜钱叶蓼应移出,并入到广义冰岛蓼属；得到了周忠泽教授按花粉神血宁属暂且划分成3个组：多穗蓼组Aconogonon Sect. Polystachyum、分叉蓼组Aconogonon Sect. Aconogonon和钟华蓼组Aconogonon Sect. Campanulatum的支持。(6)原位于头状蓼组(属)的小叶蓼Polygonum delicatula,从分子树上看,显然既远离头状蓼属,也与广义冰岛蓼属明显间隔开来,似乎与神血宁属更近；但小叶蓼、神血宁属与冰岛蓼属始终位于同一个大支上,可以推测为三者来自同一祖先,首先进化为小叶蓼,再分化出神血宁属,进而其中某一类又进而分化出了冰岛蓼属,而小叶蓼始终保持了冰岛蓼属的一些最重要特征,如刺状花粉等,分布区也与冰岛蓼属一致。因此,支持将其归入广义冰岛蓼属,为细冰岛蓼Koenigia delicatula (Meisn.)Hara.。(7)支持春蓼组和刺蓼组独立为属,即春蓼属Persicaria Mill和剌蓼属Truellum Houtt.;但原位于刺蓼组的柳叶刺蓼Polygonum bungeanum应从刺蓼属移出,并入春蓼属,采用名：Persicaria bungeana (Turcz.) Nakai。(8)金线草属与春蓼属、刺蓼属亲缘关系紧密,但与刺蓼属、春蓼属为平行的属级关系。因此,金线草属不应放在春蓼属,而应为独立的属级地位,即金线草属Antenoron Rafin.。(9)除将原属于头状蓼组的小叶蓼移入广义冰岛蓼属外,将细茎蓼、柔毛蓼、腺点柔毛蓼(陕甘蓼)、蓝药蓼和青藏蓼移入广义冰岛蓼属,头状蓼组其余种类构成头状蓼属Cephlophilon Spach。(10)拳参组为单系群,支持将拳参组升级为拳参属Bistorta Adans.。(11)广义冰岛蓼属(Koenigia L. emend Hedberg)除小叶蓼(Koenigia delicatula)外所有选定种,包括拟发表的两个新种,全部聚为一支。表明广义冰岛蓼属(除小叶蓼外)为一单系群,因此,承认广义冰岛蓼属(Koenigia s.lat.)的概念,该属是在青藏高原隆升后由于高原特殊环境(生境内陆岛屿化)而由神血宁属的某些祖先特化而来,并逐渐分化出属内各个种的较年轻的属；广义冰岛蓼属应包含约8-10种。其属下暂可划分为3个组：细冰岛蓼组Koenigia sect. Delicatula、大连线茎冰岛蓼组Koenigia sect. Forrestii和冰岛蓼组Koenigia sect. Koenigia o(12)最后,以分子系统树的计算结果为依据,对中国产蓼科植物的分类系统作出了重新划定。更多还原

【Abstract】 The genus of Polygonum L. s. lat. was established by Linnaeus, a swedish taxonomist, in1753. However, this is a controversial and not fully successful taxonomy system and it has remained challengging and problematic for taxonomists in the field to use this classification method. As such, many researchers have tried to subdivide the genus into more natural units at generic and subgeneric levels. It is still debating and inconclusive whetehr or not to use those new classification units due to lack of sufficient and cruical evidence.There are235(or238) species belong to13genera in the family of Polygonaceae recorded in《Flora of China. Those plants are subdivided into two subfamilies (i.e., Polygonoideae and Rumicoideae) based on their morphological characteristics. The tribes of Polygoneae and Atrophaxideae belong to the subfamily of Polygonoideae. The tribe of Polygoneae is subdivided into seven genera, including Koenigia L., Polygonum L., Fallopia Adans., Reynoutria Houtt., Antenoron Rafin., Fagopyrum Mill., and Pteroxygonum Damm. et Diels. However, there are many controversial problems in this classification system. This thesis focuses on the tribe of Polygoneae, attempting to establish a new classification method for those genera.Many researchers have tried to study the classification system of Polygonum genus in China using methods of morphology, pollen morphology, micro-morphology, anatomy, cytology and molecular biology. By doing so they have reached some important conclusions. Plant Molecular systematics applies various experimental methods of molecular biology to obtain all kinds of molecular information and based upon those information to further explore the phylogenetic relationships between different plant taxa and their evolutionary processes and mechanisms involved. This new classification method moves the studies of plant system development and evolution to molecular level. Although plant molecular systematics has been established for only20years, it has led to the most dramatic and important changes in higher-level angiosperm taxonomy that had been established using traditional methods in the past200years and it has provided unparalleled insights into relationships at all levels of plant phylogeny.The sequences of nrDNA ITS and two spacer regions of cpDNA trnL-trnF and atpB-rbcL are widely used in plant molecular systematics studies. Those genetic markers are selected for the studies in this thesis. The experimental samples consist of84species:5-10species from every section of Polygonum s.lat. and the genera in tribe Polygoneae (e.g., Fallopia Adans., Fagopyrum Mill. and Koenigia L. emend Hedberg),1-2species from the satellite genera (e.g.,Reynoutria Houtt., Antenoron Rafin.) and Pteroxygonum Damm. et Diels, as well as1-2species from the genera in the tribe of Atrophaxideae (e.g., Atrophaxsis L., Calligonum L. and Parapteropyrum Damm. et Diels). The out-group (do you mean unrelated group? or control group?) consists of6-7species which are selected from genus Rumex L., Rheum L. and Oxyria Hill in the tribe of Rumiceae Damm. The chromosome DNAs were first extracted from those plants, and then the aforementioned three DNA segments were PCR amplified, and finally sequenced. The three single gene data, two chloroplast segments combination datasets, and three segments combination datasets were calculated to obtain their Maximum Parsimony (MP) trees, Neighbor-joining (NJ) trees with the software PAUP*v.4.0b10. At the same time, the Bayesian inference (BI) trees were calculated with the software MrBayes*v.3.1.2by the plugin imported into the software platform of Geneious4.8.3for above five data matrixes. Then a series of procedures was operated to calculate the divergence time of the important nodes in the software package of BEAST v1.6.2using the method of earliest pollen age scales of genus Polygonum and Rumex as described in the papers listed in the stratum reference.The systematical status of genus Koenigia s.lat. and the relationship between the species within the genus were further studied by calculating the MP, NJ, BI trees and the divergence time of the important nodes as above. Calculations for the MP, NJ, BI trees and divergence times were conducted from a total of82taxa from the close relatives taxa, such as genera of Antenoron, Echinocaulon, Persicaria, Cephalophilon, Aconogonon and Bistorta. By comparing with data from each1-8population samples from the genus of Koenigia s.lat, the main results are acquired as below.The genus Polygonum s.lat. is not a monophyletic group instead of a polyphyletic group; and the sections in this group should be set up as genus units. Some species positions in the genera should be adjusted according to the below suggestions:(1) Polygonum sibiricum should be removed from the genus of Aconogonon and be promoted to the genus of Knorringia Tzvel.(2) Reynoutria and Fallopia have a close genetic relationship, suggesting that they probably came from a same ancestor. It is likely that in the evolution process, one branch is evolved towards the genus of Reynoutria that has an erect stems while the other branch is evolved towards the genus of Fallopia that has either sprawling or twining stems. The results support that they both are a separated genus, i.e., either Reynoutria Houtt. or Fallopia Adans.(3) The results support that Pteroxygonum Damm. et Diels is a status of genus but it is not a single species genus and it should include at least two species: Pteroxygonum giraldii and Fallopia denticulata. As such, Fallopia denticulata should be emended as Pteroxygonum denticulata.(4) The results show that Parapteropyrum tibeticum should be removed from the genus of Parapteropyrum and moved to the genus of Fagopyrum and the annul status of Parapteropyrum. It should be emended as Fagopyrum tibeticum.(5) Polygonum Sect. Aconogonon should be promoted to a status of Aconogonon Reichb.; and Polygonum sibiricum should be removed from the genus of Aconogonon and be moved to the genus of Knorringia. The results also support the classification proposed by Professor Zhou that the genus of Aconogonon should be subdivided into three sections:Aconogonon sect. Polystachyum, Aconogonon sect. Aconogonon and Aconogonon sect. Campanulatum.(6) Polygonum delicatula is a species of Polygonum section Cephalophilon. However, the molecular trees show that it is obviously apart from the Polygonum section Cephalophilon and it should not belong to the genus of Koenigia. Polygonum delicatula appears to be a close relative of the genus of Aconogonon. Interestingly, Polygonum delicatula is always in the same big branch as Aconogonon and Koenigia genus. So it is likely that they came from the same ancestor, and then first evolved into Polygonum delicatula, and further into the genus of Aconogonon. Moreover, some species of Aconogonon might be differentiated into the genus of Koenigia. However, Polygonum delicatula keeps some of the most important characteristics ofKoenigia genus, such as spiny pollen. Also, it has the same distribution area with the species of genus Koenigia. Thus, it should be admitted as a species of Koenigia and it should be emended as Koenigia delicatula (Meisn.) Hara.(7) The results show that Polygonum sect. Persicaria and Polygonum sect. Echinocaulon are a status of genus, i.e., the genus of Persicaria Mill. and the genus of Truellum Houtt. At the same time, Polygonum bungeanum, which is a species of Polygonum section Echinocaulon, should be moved into the genus of Persicaria and it should be emended as Persicaria bungeana (Turcz.) Nakai.(8) The genus of Antenoron is a close relative to the genus of Persicaria Mill. and it has a parallel relationship with the genus of Truellum Houtt. Therefore, Antenoron should not be in the genus of Persicaria. Instead, it should be an independent status, i.e., the genus of Antenoron Rafin.(9) Polygonum delicatula is moved into the genus of Koenigia that was a species of Polygonum section Cephalophilon previously. In addition, Polygonum nepalensis, Polygonum sparsipilosum, Polygonum sparsipilosum var. hubertii, Polygonum cyanandra and Polygonum fertile should also be moved to the genus of Koenigia which were species of Polygonum section Cephalophilon previously. The remaining species constitute the genus of Cephlophilon Spach.(10) Polygonum Sect. Bistorta is undisputedly as a single group, and it should be promoted to the genus of Bistorta Adans.(11) Except for Koenigia delicatula, all the selected species from the genus of Koenigia L. emend Hedberg and two new species (in press) form a monophyletic group. This result indicates that the genus of Koenigia L. emend Hedberg is a natural taxa and that it is a young genus which is derived from some of the ancestors of Aconogonon due to the uplift of the Qinghai-Tibet Plateau and the change of special environment (interior islands of habitats), and then gradually evolved into various species of the genus of Koenigia. The genus of Koenigia L. emend Hedberg contains about8-10species. This genus should be subdivided into three sections:Koenigia sect. Delicatula, Koenigia sect. Forrestii and Koenigia sect. Koenigia.(12) Finally, a new classification system of family Polygonaceae plants from China is established based on the results of molecular phylogenetic tree analyses.更多还原