Pollen morphology of the genera Polygonum s. str. and Polygonella (Polygoneae: Polygonaceae)

The pollen of 30 taxa (27 species, one subspecies and two varieties) in two genera, viz Polygonum s. str. and Polygonella was investigated with LM and SEM, and some selected taxa with TEM. In all genera investigated the pollen is prolate to spheroidal, and the aperture is mostly tricolporate, rarely panto-hexacolporate (especially Polygonum section Polygonum). The exine sculpturing pattern is the most variable feature. Three types of exine can be recognized. Type 1 (Avicularia-Type, sensu Hedberg) - All species of section Polygonum and section Tephis share the smooth tectate exine with spinules, sometimes the surface is more or less rough (Polygonum afromontanum in section Tephis). Type 2 (Pseudomollia-Type, sensu Hong) - Pollen of Polygonum molliaeforme (section Pseudomollia) has the exine, which is verrucose on both poles and nearby the mesocolpium, and mostly psilate around the ectoaperture. Type 3 (Duravia-Type, sensu Hedberg) - Pollen grains of Polygonum section Duravia and Polygonella have the exine which is semitectate-reticulate at the mesocolpium and the poles, and rugulate/reticulate or sometimes foveolate with microspinules around the ectoapertures. The pollen grains in four taxa (viz Polygonum section Pseudomollia, P. section Duravia and genus Polygonella) have a well-marked dimorphism of the ektexine, which is considered to be a synapomorphic condition. The differences of pollen grain between the genus Polygonella and Polygonum section Duravia are almost non existent and clearly interrelated. It is therefore postulated that the similarity in pollen of both taxa is not the result of convergency, but is interpreted as a homology. It is noteworthy that the pollen of Polygonum molliaeforme (section Pseudomollia) appears as intermediate between the Avicularia-type and the Duravia-type, and is well supported the value of separated section for its own. Additionally, in TEM, some exine ultrastructures (e.g. columellae, foot layer, endexine) appear to be valuable characters for comparison between/among taxa. The systematic potentialities of the pollen data of the studied taxa at various systematic levels are also discussed.     

Peroxidasemuster und Systematik vonArgyranthemum undChrysanthemum s. str. (Asteraceae-Anthemideae)

Leaf extracts of several taxa ofArgyranthemum (nanophaneroand chamaephytes endemic to the Macaronesian Islands) andChrysanthemum s. str. (therophytes of the West Mediterranean region) were subjected to polyacrylamide disc gel electrophoresis and analysis of peroxidase isoenzymes. The differences between the two genera are small; this points to their close affinity. The taxonomic subdivision ofChrysanthemum s. str. is confirmed. ForArgyranthemum the inclusion ofA. callichrysum andA. ochroleucum into sect.Ismelia is suggested.A. foeniculaceum may fit better into the otherwise isolated sect.Monoptera but somewhat approaches sect.Ismelia. Isoenzyme patterns inA. frutescens s. l. seem to reflect a geographical differentiation of the group on 5 Canary Islands.

     

Pollen Morphology of the Platycodonoid Group (Campanulaceae s. str.) and Its Systematic Implications

In this study, we examined the pollen morphology of the platycodonoid group in Campanulaceae s. str. using a scanning electronic microscope. We used pollen grains of 25 accessions representing 24 species of the Codonopsis complex (including Campanumoea, Cyclocodon, Leptocodon, and all three subgenera of Codonopsis), which is extremely controversial among authors for taxonomic treatment. Pollen morphology of all the other genera in the group observed by previous authors is taken into account in our discussion. A total of nine pollen types with two subtypes in the group were recognized and named for the first time. Molecular and morphological data imply that each pollen type corresponds to a natural group at generic level, and thus the mergence of Leptocodon with Codonopsis and the restoration of Cyclocodon as a separate genus are justifiable, and Codonopsis subg. Pseudocodonopsis, subg. Obconicicapsula, and two species of Codonopsis subg. Codonopsis (C. purpurea and C. chimiliensis) may be better classified as three independent genera separate from the core Codonopsis.     

狭义蛇葡萄属东亚支系的系统发生与生物地理演化

狭义蛇葡萄属(Ampelopsis s. str.)是葡萄科的落叶木质藤本植物,主要分布在北半球温带地区,特别是东亚为其重要的分布和演化中心。该研究选取了狭义蛇葡萄属15个种的37个样本,对其5个叶绿体基因片段(trnL-F、rps16、psbA-trnH、atpB-rbcL和trnK-petN)和2个核基因标记(ITS和GAI1)进行了分子测序;利用测序获得的分子数据探讨属内的系统发生关系,叶的性状演化以及生物地理起源演化。结果表明：(1)狭义蛇葡萄属是一个单系类群,属内东亚地区的物种聚成一支。(2)叶绿体基因数据分析结果表明,狭义蛇葡萄属东亚支系分为两支系,这两支系的分布范围大致与东亚植物区系的中国-日本森林和中国-喜马拉雅森林亚区范围相一致。(3)形态演化分析表明,掌状复叶为祖征,叶形态性状存在多次的独立起源和演化,其变化与系统进化没有明显的关系。(4)生物地理分析结果表明,狭义蛇葡萄属起源于北美,渐新世晚期至中新世早期迁移扩散至欧洲,中新世中期随着全球气温回暖迁移至东亚,并进一步在东亚地区快速分化形成多样化中心,这可能与中新世时期的气候温暖、受第四纪冰川影响较少以及东亚地区复杂...     

Seed morphology in Moehringia L. and its taxonomic significance in comparative studies within the Caryophyllaceae

Seeds of 30 species of Moehringia and 12 representatives of the Caryophyllaceae were examined with the Scanning Electron Microscope. High diversity was found in seed coat micromorphology, and a number of novel morphological features have been observed. Comparison with other representatives of the Caryophyllaceae has provided new insight into the potential taxonomic value of discrete morphological characters. Though many characters appear informative within Moehringia, they are affected by a high level of homoplasy when considered in a wider phylogenetic context. Smooth seed is the common condition in Moehringia, except for Eastern Balkan and Iberian species that maintain a secondary ornamentation of the testa cells resembling the plesiomorphic Caryophyllaceae-type. Five types of strophioles were recognized, in accordance with previous literature. Among these, the strophiole of the Iberian species appears very distinctive and a proper strophiole could not be verified in M. glochidisperma and M. fontqueri.     

Systematic significance of tepal surface morphology in tribes Persicarieae and Polygoneae (Polygonaceae)

In order to improve understanding of the systematic relationships between taxa and of tepal-pollinator and tepal-habitat relationships, a detailed scanning electron microscopy (SEW study of the adaxial tepal surface of 135 taxa belonging to c. 14 genera in the tribes Persicarieae and Polygoneae (Polygonoideae-Polygonaceae) was carried out. The tepal surfaces have revealed some striking differences among the genera studied. Three main patterns of sculpturing and cell shape can be recognized. Type I: mostly rectangular to elongate cells with straight or undulating anticlinal walls; the cuticles smooth or striate in longitudinal direction and often continuous (Persicaria, Bistortu, Aconogonon, Koenigia and some species of Fagopyrum). Type II: irregular tesselated to elongated cells, rarely rectangular with mostly sinuate anticlinal walls; the cuticles rarely with longitudinal striation, but with strong orthogonal to reticulate ridges or striae, often without correlation between cells (Polygonum s.s., Polygonella, Fallopia, Parapteropyrum, Pteropyrum, Atraphaxis and Calligonum). Type III: mostly irregular, mammilliform, papillose cells with either longitudinal tightly pressed or randomly ridged cuticles (some species of Fagotyrum and Oxygonum). The present data generally support the division of Polygoneae and Persicarieae by Ronse Decraene & Akeroyd. The mammilliform, papillate epidermis of tepals in Oxygonum and some Fagopyrum is probably well-adapted to entomophily either as a foothold or even as a light-trap, and also shows some correlation with heterostyly. It is noteworthy that the tepal structure of Polygonella (tesselated form) is highly similar to that of Polygonum s. s. (especially P. sect. Duravia). Cuticular striation alone does not appear to have much systematic value, but has a mechanical function in affording extra strength to the cell walls. Some correlations between the degree/shape of cuticles and the pollination mechanisms or the habitat of each taxon are also briefly discussed. It is concluded that the studied tepal characters can be useful in improving the classification of tribes Persicarieae and Polygoneae, arid give additional support at the infrageneric level.     

Systematic significance of seed morphology in veronica (plantaginaceae): a phylogenetic perspective

BACKGROUND AND AIMS: A new infrageneric rearrangement for Veronica has been proposed based on the most recent evidence from DNA sequence data, morphological evidence, and biogeographical considerations. Looking for morphological synapomorphies for each monophyletic subgenus has been problematic, due to difficulties arising from widespread homoplasy (mainly parallel evolution). In an attempt to overcome these difficulties, previously underexplored morphological characters are starting to be studied in more depth. METHODS: A molecular phylogenetic hypothesis was used based on sequences of ITS (nuclear ribosomal DNA) and plastid trnL-F regions, as a framework to test the use of seed coat ultrastructure (studied under scanning electron microscope) in the systematics of the genus. A sample of 132 taxa representing ten of the 13 subgenera in Veronica, excluding the species of the southern hemisphere Hebe complex and the exclusively North American subgenus Synthyris, was studied. KEY RESULTS AND CONCLUSIONS: The results demonstrate that, in many cases, the ultrastucture of the testa can be employed to assess relationships of taxa within the genus, and the character provides additional support for molecular trees. Further characters relevant for the classification of Veronica, i.e. base chromosome number, iridoid chemical data, life cycle, inflorescence position, have been taken into consideration in a discussion where an attempt is made to highlight the best traits to characterize each subgenus investigated.     

Molecular phylogenetics of the tribeInuleae s. str.(Asteraceae), based on ITS sequences of nuclear ribosomal DNA

The sequences of the internal transcribed spacer (ITS) region of 18S–26S nrDNA for a sample of 16 taxa from theInuleae s. str. and two outgroup taxa are analysed cladistically with PAUP. A consensus tree of the four most parsimonious cladograms is presented. Three different tests of cladogram stability are conducted (Bremer support, parsimony jackknifing and bootstrapping); all tests indicate a high degree of support for the basal nodes of the tree. The ITS phylogeny of the tribe is compared with previous hypotheses based on morphological data. The position ofAnisopappus as sister group to the rest of the tribe is supported by the molecular data, but the proposed subdivision ofInuleae s. str. into a paleate grade group and an epaleate clade is not. The interpretation of the character evolution of, e.g. receptacular paleae and pappus features within the tribe is discussed.     

中国蓼科萹蓄属植物花粉形态及其分类意义

利用扫描电镜研究了中国萹蓄属(Polygonum) 13种、1变种、1变型植物的花粉形态.结果表明,中国萹蓄属植物的花粉粒为长球形或超长球形,具三孔沟,外壁纹饰可分为4种类型(1)花粉粒表面具细网状纹饰;(2)花粉粒表面具颗粒纹饰;(3)花粉粒表面仅两端具颗粒纹饰,其余部分光滑;(4)花粉粒表面仅沟间区两端肩部光滑,其余部分具颗粒纹饰.根据花粉形态类型,结合该属植物的习性、叶柄基部及花柄上关节的有无、花柱和柱头的数目以及瘦果形态等特征,参照前人的研究处理意见,将中国萹蓄属植物划分为4个组,即小灌木组section Fruticulosae (Boiss.) F.Z.Li et Y.T.Hou,stat.& comb.nov.、萹蓄组section Polygonum、丝茎萹蓄组section Pseudomollia Boiss.和铁马鞭组section Plebeia Tzvel..     

中国伞形科狭义当归属果实表面微形态特征及其分类学研究

采用扫描电镜方法对中国31种狭义当归属植物的果实表面微形态特征进行了观察比较,结果表明:(1)狭义当归属植物外果皮细胞轮廓均不可见,但依据表面突起度可将其分为粗糙型和平滑型。(2)表面蜡质纹饰主要为粗条状和细线状,并呈现出或疏或密的交错或平行排布。(3)表面附属结构主要包括表皮毛、皮刺以及根枝状和块状结构等,并具有或多或少的颗粒状分泌物。上述果实表面微形态特征均表现出较丰富的多样性和一定的规律性,可作为狭义当归属果实形态研究的重要补充,为其物种鉴别和种间关系研究提供重要的参考依据。据此,该研究将31种狭义当归属植物分为4种类型:类型Ⅰ.果实表面无显著的蜡质纹饰,包括大巴山当归、带岭当归、紫花前胡和峨眉当归等4种;类型Ⅱ.果实表面有蜡质纹饰且较平滑,包括阿坝当归和东川当归等10种;类型Ⅲ.果实表面粗糙并有交错蜡质纹饰,包括城口当归和朝鲜当归等9种;类型Ⅳ.果实表面粗糙并有平行蜡质纹饰,包括东当归和当归等8种。本研究亦对属下的分类鉴定和部分近缘种的鉴别进行了探讨。     

凤仙花属棒凤仙亚属(凤仙花科)植物花粉形态的分类学意义

棒凤仙亚属代表着凤仙花属最先分化出的一支,以多年生草本,多于5朵花的总状花序,侧生萼片4枚,3沟花粉,心皮四室且每室具1枚种子,果实棒锤状,种子椭圆形以及三沟花粉其极面观为三角形而区别于其它种类。该亚属主要分布于中国南部,少数种类辐射分布至华中和中南半岛地区。已有报道证实花粉的形态特征对凤仙花属植物的属下分类具有重要意义,但对棒凤仙亚属的种类少有涉及。为了进一步探讨该亚属花粉的形态特征及其分类学价值,该研究应用扫描电镜技术对国产棒凤仙亚属植物的14种以及凤仙花亚属的窄萼凤仙花的花粉进行了观察。结果表明：棒凤仙亚属的花粉以单粒存在,具3条萌发沟,辐射对称,极面观为三角形或三角状圆形,花粉粒外壁具均匀的网状纹饰,网脊平滑或具波状边缘,网眼中具不同密度的颗粒状突起。棒凤仙亚属的花粉形态与水角属的花粉形态相似,表现出了其原始性;其花粉形态特征与花部形态性状等相关性差,对该亚属的组级分类意义较小,但对于该亚属的种间界定具有重要意义;而其花粉的极面观形状、赤道面观形状以及网状纹饰等变异相对稳定,对于界定该亚属具有重要的分类学价值。     

RAPD patterns,nrDNA ITS sequences and morphological patterns inSilene sectionSedoideae (Caryophyllaceae)

Hierarchical patterns inSilene sect.Sedoideae were investigated using random amplified polymorphic DNA (RAPD), nucleotide sequences of the internal transcribed spacer (ITS) regions of the 18S–28S nuclear ribosomal DNA, and discrete morphological characters. All data sets firmly supported the species recognized. The RAPD data offered the best resolution at the intraspecific level, supporting the current intraspecific classifications ofS. sedoides andS. integripetala. The ITS sequences and the morphological data gave poor resolution within species, and the three data sets disagreed about the relationships among species. The signal from the RAPD data was strongest and remained when the total data set was analysed. The three data sets all support an amphiploid origin ofS. aegaea, with the strongest evidence from the ITS sequences. Incongruences among data sets as well as merits and shortcomings of each are discussed. The robustness of the results can be evaluated using perturbations of data, i.e., bootstrap and jackknife of taxa and characters. These methods should not be taken as methods of statistical inference at the taxonomic level, because unbiased sampling appears impossible. RAPD data, however, come close to being suitable for statistical estimation of hierarchies at the genome level, but several methodological problems have to be solved.     

A taxometric analysis of seed proteins in the genusBriza s. l. (Poaceae)

The species ofBriza L. s. l. are disjunctly distributed between Eurasia and South America. A taxometric analysis has been carried out, using data from electrophoresis of seed polypeptides and published morphological characters. Evidence from a cluster analysis of seed polypeptide data strongly supports the recognition of two different natural groups, a S. American group and a Eurasian group, and is consistent with karyotype data, but does not support the generic groupings of South American taxa derived from the morphological data.     

Taxonomic importance of seed morphology in Gentiana (Gentianaceae)

The seeds of Gentiana show high diversity in size, shape and surface pattern. Until now, seeds of only a limited number of taxa have been studied in detail and their utility in the subgeneric classification of Gentiana has not been evaluated. In this study we investigated seed micromorphology of the poorly known sections Pneumonanthe, Frigidae and Isomeria. In order to evaluate the relevance of seed sculpturing for taxonomy, we selected qualitative characters of seed shape and testa ornamentation of all documented sections and performed cluster analyses based on presence and absence of coded characters. Several new scanning electron microscopy pictures of seeds provided a number of valuable characters for the subgeneric differentiation of Gentiana. The results of the cluster analyses of seed characters generally support the sectional classification given by former authors. However, the European Gentiana asclepiadea does not group together with other taxa of section Pneumonanthe, but clusters near to the strictly European section Gentiana. Gentiana froelichii, endemic to the south‐east Alps and treated traditionally within section Frigidae, clusters together with taxa of the European section Ciminalis. Our results reveal that seed micromorphology supports the reassignment of some taxa incertae sedis within Gentiana. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162 , 101–115.     

Analysis of the clinal variation pattern inSilene latifolia (Caryophyllaceae) pollen morphology

Reticulate and microechinate pollen forms withinSilene latifolia (S. alba, S. pratensis) were first described from N. America, where the species is an introduced weed. A previous study showed that the two forms also exist in Europe and intergrade along a zone roughly congruent with intergradation zones in seed morphology and flavone glycosylation genotypes. The present survey of pollen from herbarium specimens is more extensive and covers localities from nearly the whole of the species' native Eurasian and North African range. The first axis of a detrended correspondence analysis (DCA) of qualitative characterstate data for 11 pollen morphological characters shows a gradient between the two extreme exine types, reticulate and microechinate. When mapped, the co-ordinates of pollen samples on this axis indicate a broad zone of intergradation which coincides approximately with the somewhat sharper transition between low- and high-tubercle seeds in C. and N. Europe, but becomes diffuse in Italy and the Mediterranean region and diverges from the seed transition zone in SW. Asia and the Middle East. The biological significance of the pollen morphs is unknown; the variation pattern in pollen morphology, unlike that in seeds, is not consistently correlated with macroclimate.     

Seed coat structure ofCrocus vernus agg. (Iridaceae)

Cytotypes of theCrocus vernus aggregate differ slightly in their seed surface patterns.Crocus albiflorus may be grouped together withCrocus vernus subsp.vernus, both are relatively easily distinguishable by their seed surface patterns from theCrocus scepusiensis—Crocus heuffelianus group.     

Systematic implication of seed micromorphology in Arenaria (Caryophyllaceae) and allied genera

Variations in seed micromorphology of 64 taxa of Arenaria and allied genera were examined using scanning electron microscopy (SEM) in order to evaluate their diagnostic value for systematic studies in the genus and providing additional evidence on delimitation of natural groups. Significant diversity was found in seed coat morphology both among and within genera. Size, color, and shape of seeds appear to be of low importance at species level but provide useful evidence at generic rank. Cerastium and Stellaria are well distinguished from Arenaria by serrate seed margins and solid columellae on testa cells. The sculpturing pattern renders most characters potentially applicable in taxonomy and phylogeny assessment in Arenaria. The studied taxa show four basic types of sculpturing, viz. colliculate, rugose, papillate, and smooth. The colliculate type which is characteristic for the core group of Arenaria (A. subg. Arenaria) can be further divided into five subtypes. The smooth seed surface with indistinct cell boundaries represents a synapomorphy for A. subg. Leiosperma, whereas the winged seeds along with rugose surface characterize subg. Odontostemma. Otherwise seed micromorphology rarely provides adequate evidence for separation of natural groups, especially at sectional rank. We hypothesize that the seeds are highly polymorphic in certain groups of taxa showing recent adaptive radiation, such as the annual species of Arenaria, and do not provide strong support for natural groups within the genus.     

Nutlet morphology in Hemigenia R.Br. and Microcorys R.Br. (Lamiaceae)

Nutlets of Hemigenia R.Br. and Microcorys R.Br. were examined using SEM. Significant variation, mainly useful at the infrageneric level, was found in nutlet shape, nature of the attachment scar, nature of surface sculpturing, exocarp cell shape and sculpturing, and nature of the indumentum. Typical nutlets are ovoidal, strongly reticulate or rugose. The exocarp cells are isodiametric and convex to papillate. Also common are cylindrical nutlets, often with longitudinal ridging and papillate exocarp cells. Surface pitting and concave exocarp cells are rare. A cladistic analysis of nutlet characters suggests both Hemigenia and Microcorys are polyphyletic, and Microcorys paraphyletic with respect to Westringia Sm. Notwithstanding that, the infrageneric classification of Hemigenia was largely supported, while in Microcorys, there was support for sect. Hemigenioides, but sects Anisandra and Microcorys were not resolved as distinct.     

凤仙花属总状花序组的花粉形态及其分类学意义

总状花序组隶属于凤仙花亚属凤仙花属,以具多花的总状花序、侧生萼片2枚、子房5室、果实为线状圆柱形、种子多数、迈卵形、种皮表面具指状突起等特征区别于该亚属的其他类群。前人对凤仙花花粉形态的研究表明凤仙花属的花粉形态对于属下分类及种间界定具有重要的分类学价值。而对于总状花序组来说,有关花粉形态方面的研究少有报道,为了进一步探讨该组花粉S的形态特征及其分类学意义,该研究应用扫描电镜技术对总状花序组的21种植物的花粉进行了观察。结果表明:总状花序组植物的花粉粒均具4条萌发沟,两侧对称,极面观为矩圆形、长矩圆形或近方形;长赤道面观多为椭圆形至矩圆形,短赤道面观为椭圆形;长、短赤道轴比值多在1.4~2.4范围内;表面具网状纹饰,网眼在花粉粒表面均匀分布或赤道面的网眼较极面观的小,网脊边缘光滑或具波状突起,网眼内具不同密度的颗粒状突起。该组的花粉形态与宏观形态性状相关性较小,但花粉极面观形状、长短赤道轴的比值、网眼的分布、网脊边缘形状、网眼内颗粒物密度等特征具有种水平上的稳定性和特异性,对该组植物种间界定具有重要的意义。     

Chloroplast DNA study of the generaAmbrosia s.l. andHymenoclea (Asteraceae): Systematic implications

The relationship ofAmbrosia (ragweed) andFranseria has long been debated. Their treatment as separate genera has been repeatedly challenged. In this study, chloroplast DNA restriction site variation was examined for species from bothAmbrosia andFranseria as well as taxa from the closely related genusHymenoclea. The chloroplast genomes of members of these three genera were examined using 21 restriction endonucleases and the restriction mutations were used to construct phylogenetic trees. Wagner and Dollo parsimony as well as weighted parsimony were employed to compare the different phylogenies. The results support a close relationship betweenAmbrosia andFranseria, but indicate that the two groups are well separated. Compared toFranseria, Ambrosia is a much more strongly supported group, and the results indicate thatHymenoclea is closer toFranseria than toAmbrosia. The cpDNA phylogeny was used as a framework to examine evolutionary trends in morphology and secondary chemistry.