基于核核糖体DNA ITS序列的真藓科系统发育新证据

主要是利用核基因组的核糖体DNA内转录间隔区（nrDNA ITS）序列数据探讨了Buck和Goffinet（2000）限定的真藓科内各属间及属内种间的系统发育关系。ITS序列的最大简约法（MP）及贝叶斯推论（BI）分析结果显示：不支持Cox（1999）利用rps4/trnL-trnF数据分析将丝瓜藓属移至提灯藓科的结论。ITS数据分析与Holyoak（2007）利用trnL-F,trnG和atpB-rbcL序列数据分析将Bryum algovicum、B.caespiticium、B.capillare、B.pseudotriquetrum和Plagiobryum zierii划归Ptychostomum的结论一致,同时,为Spence(2005)依据形态学特征将B.pallescen、B.pallens、B.uliginosum、B.amblyodon和B.lonchocaulon划归Ptychostomum提供ITS分子证据支持。基于以上研究,建议将以上提到的真藓属种和平蒴藓移至Ptychostomum。     

丝瓜藓属(Pohlia Hedw.)的系统位置及属内种间关系探讨

丝瓜藓属的系统地位及属内种间关系存在争议。本研究首次利用核糖体DNA内转录间区(ITS)序列数据对丝瓜藓属及相关科属植物进行系统发育分析。最大简约法,最大似然法及贝叶斯推论法构建的系统树均表明,ITS序列数据不支持将丝瓜藓属划归提灯藓科。丝瓜藓属植物与缺齿藓属植物构成一个单系分支。Brotherus(1903),Ochi(1959),Shaw(1984)及Hill等(2006)等学者提出的丝瓜藓属属下分类均不是单系类群。     

中国新记录种——摩拉维采真藓(新拟)

该文首次报道了摩拉维采真藓(新拟)在中国的分布。研究表明:(1)摩拉维采真藓的主要识别特征为:叶常聚集在茎顶成莲座状,叶倒卵状披针形至匙形,具长毛尖,具分化边缘,中肋消失于叶尖下,叶细胞长菱形至六边形,叶腋处着生大量单列细胞构成的分枝或不分枝的丝状芽胞。(2)通过对摩拉维采真藓的命名和系统位置的讨论,确认该种是真藓属细叶真藓组的有效种。(3)摩拉维采真藓与近缘种细叶真藓和幽美真藓有诸多相似特征:莲座状的茎顶、有分化边和菱形至六边形中上部细胞的倒卵形叶,但该种以具有大量叶腋生丝状芽胞和叶中肋不及顶等特征区别于细叶真藓的无腋生芽胞、叶中肋突出叶尖成长芒状,以具有叶湿时平展、干时卷曲和叶腋有芽胞等特征区别于幽美真藓的叶湿时内凹、干时紧贴于茎和无腋生芽胞;拟三列真藓、圆叶真藓和灰黄真藓的部分种群都曾报道有与摩拉维采真藓相似的腋生丝状芽胞,但摩拉维采真藓的假根集生于植株基部、叶有狭分化边、叶缘平直、中肋消失于叶尖下而区别于拟三列真藓的茎中下部密被假根、叶有宽分化边、叶缘背卷、中肋及顶或短出,摩拉维采真藓有分化边和长毛尖的倒卵状披针形区别于圆叶真藓叶有无分化边和圆钝叶尖的卵圆形叶,区别于灰黄真藓有中肋及顶和短尖的卵状披针形叶;柔叶真藓有与摩拉维采真藓相似、中肋不及顶的叶,但无芽胞而易与新记录种区分。(4)该种在北温带有较广泛分布,形成欧洲-北亚-中亚-西亚和北美两个主要分布区;作者在四川和新疆等地的发现可以推测摩拉维采真藓在中国可能有更广泛的分布。     

新疆真藓科（Bryaceae）植物新记录

采用经典分类学方法,对1987~2015年采自新疆地区的400余份真藓科植物标本进行了整理和鉴定。结果发现：新疆分布有真藓科植物5属37种,其中3种为新记录种,即尖叶短月藓（Brachymenium acuminatum Harv.）、拟纤枝真藓（Bryum petelotii Thér. & Henr.）和下延真藓（Bryum weigelii Biehler）。该文对此3个新记录种的重点识别特征、生境、地理分布及其与相近种的特征比较作了阐述,并绘制了基本形态特征墨线图。凭证标本存放于河北师范大学植物标本室（HBNU）。     

中国真藓属孢子形态的研究

通过光学显微镜和扫描电子显微镜观察了中国真藓属Bryum Hedw．13种孢子的形态特征。根 据外壁纹饰可分为:类型I,棒状突起顶端圆钝;类型Ⅱ,棒状突起顶端尖或具微突起;类型Ⅲ,棒状突 起顶端膨大成半球形。根据孢子直径的大小,可分3个类群。以上显示了物种间的遗传分化及其相似 性,证明真藓属确为一个自然分类群,真藓属孢子的形态比丝瓜藓属Pohlia Hedw．进化。这给苔藓的孢子形态研究及分类和系统演化的研究提供了新的资料。     

中国红蒴真藓复合群和一个新记录种

该研究以经典分类学方法探讨了中国红蒴真藓复合群(Bryum atrovirens Brid. complex),重点关注根生芽胞特征在分类中的价值。以期厘清中国红蒴真藓复合群的特征和物种组成;明确各物种之间的分类界限和地理分布。结果表明：(1)中国该复合群共有9种,即毛状真藓(B.apiculatum Schw?gr.)、红蒴真藓(B.atrovirens Brid.)、瘤根真藓(B.bornholmense Wink.&R. Ruthe)、棒槌真藓[B.clavatum(Schimp.) Müll. Hal.]、球根真藓(B.radiculosum Brid.)、齿缘真藓(B.rubens Mitt.)、沙氏真藓(B.sauteri Bruch&Schimp.)、星形真藓(B.stellituber Arts)和土生真藓(B.tuberosum Mohamed&Damanhuri),其中星形真藓为中国新分布种,首次观察到该种的孢子体以及红蒴真藓和齿缘真藓的中国标本产生根生芽胞。(2)该类群是适应临时环境的短命植物,主要通过根生芽胞进行无性繁殖,最主要的识别特征...     

拟纤枝真藓(Bryum petelotii)的地理新分布与分类地位探讨

报道了中国大陆新记录种——拟纤枝真藓(Bryum petelotii Thér.et Henr.)在贵州、云南的分布;描述了本种的形态特征和地理分布,并讨论了本种与相近种真藓(Bryum argenteum Hedw.)和纤枝短月藓［Brachymenium exile(Doz.et Molk.) Bosch et Lac.］的关系;基于文献和相关标本的研究,阐述并讨论了Ochi H.和B.C.Tan等关于该种分类地位的观点,并赞同将拟纤枝真藓置于真藓属(Bryum Hedw.)的观点。     

中国短月藓属植物一新记录种和真藓属一新记录变种

通过对采自贵州全省的700余份真藓科(Bryaceae)植物标本的整理和鉴定,发现其中的一标本为中 国短月藓属(Brachymenium)新记录种:黄肋短月藓(新拟名)(BrachymeniummacrocarpumCard.)和真藓属 (Bryum)一新记录变种:拟三列真藓短尖变种(新拟名)(Bryumpseudotriquetrum(Hedw.)Gaerth.var.ela tumNog.)。     

缺齿藓(真藓科)的形态特征和地理新分布

通过对内蒙古自治区与宁夏回族自治区交界处——贺兰山苔藓植物的调查采集和室内鉴定,发现了缺齿藓(Mielichhoferia mielichhoferiana)的一个新的地理分布记录。该文讨论了缺齿藓的形态特征和地理分布,将其与喜马拉雅缺齿藓、日本缺齿藓和中华缺齿藓进行了比较分析,并提供了该种的图版和中国缺齿藓属的分种检索表。该种的发现不仅丰富了中国缺齿藓属的研究资料,同时也说明了贺兰山的植物区系成分与喜马拉雅成分具有一定的关联。     

中国拟缺齿藓属Haplodontium Hampe(真藓科)的分类学研究

报道了中国新记录属--拟缺齿藓属（Haplodontium Hampe）分类学的研究进展。目前本属在中国分布有3种,其中包括1新种：臧氏拟缺齿藓（Haplodontium zangii X.R.Wang&J.C.Zhao）,2个新组合：喜马拉雅拟缺齿藓[H.himalayanum（Mitt.）X.R.Wang&J.C.Zhao]和中华拟缺齿藓[H.sinensis（Dix.）X.R.Wang&J.C.Zhao]。笔者对中国拟缺齿藓属3种植物的形态学特征绘制了墨线图,在光学显微镜和电子显微镜下拍摄显微形态照片,并对每种的主要识别特征、生境和地理分布以及与相似种的形态学比较进行了讨论。     

Phylogeny of Ptychostomum （Bryaceae,Musci） inferred from sequences of nuclear ribosomal DNA internal transcribed spacer （ITS） and chloroplast rps4

The phylogeny of Ptychostomum was first spacer （ITS） region of the nuclear ribosomal （nr） DNA DNA rps4 sequences. Maximum parsimony, maximum undertaken based on analysis of the internal transcribed and by combining data from nrDNA ITS and chloroplast likelihood, and Bayesian analyses all support the conclusion that the reinstated genus Ptychostomum is not monophyletic. Ptychostomum funkii （Schwagr.） J. R. Spence （≡ Bryum funkii Schwaigr.） is placed within a clade containing the type species of Bryum, B. argenteum Hedw. The remaining members of Ptychostomum investigated in the present study constitute another well-supported clade. The results are congruent with previous molecular analyses. On the basis of phylogenetic evidence, we agree with transferring B. amblyodon Mull. Hal. （≡ B. inclinatum （Brid.） Turton≡ Bryum archangelicum Bruch ＆ Schimp.）, Bryum lonchocaulon Mull. Hal., Bryum pallescens Schleich. ex Schwaigr., and Bryum pallens Sw. to Ptychostomum.     

A Study on the Spore Morphology of Bryum Hedw. in China

Spore morphology of thirteen species of the genus Bryum Hedw. were observed by LM and SEM. The results show that the ornamentation of spore exine could be divided into three types: Type I , blunt at the top of baculate processes, to which four species belong: Bryum argenteum, B. lonchocaulon , B. uliginosum and B. arcticum. Type Ⅱ, sharp or with small processes at the top of baculate processes, represented by seven species: B. pallescens, B. caespiticium, B. pallens, B. pseudotriquetrum, B. paradoxum, B. alpinum and B. thomsoii. Type Ⅲ, expanded into hemispherical-shaped at the top of baculate processes, represented by two species: B.coronatum and B.sauteri. The Bryum species may also be divided into three groups according to the variation of spore diameter. Group I , with spore diameter under 10 μm, including one species, B. uliginosum. Group Ⅱ, with spore diameter 11～20 μm, including seven species: B. argenteum, B. alpinum, B. coronatum, B. pallens, B.paradoxum, B.sauteri, B.thomsonii. Group Ⅲ, spore diameter 21～30 μm, with five species: B. pallescens, B. caespiticium, B. pseudotriquetrum, B. lonchocaulon, B. arcticum. There are resemblances of spore morphology and exine ornamentation among the thirteen species. In the view of palynology, the genus Bryum is a natural taxon which is more advanced than the genus Pohlia Hedw. But spores of thirteen species are different at some characters such as diameter, shape ofproximal leptoma, etc., which indicates the genetic differentiation in the genus Bryum.     

药用真菌金耳的rDNA ITS序列分析与鉴别

研究了两个居群的金耳Tremella aurantialba以及近似品的rDNAITS区碱基全序列的特征及其差异,首次报道了金耳的ITS和5.8SrDNA完整序列,序列总长度为467~468,长度变异较少。聚类分析表明两个居群金耳亲缘关系非常密切,金耳药材和近似品金黄银耳形成一个稳定的独立分支,近似品黄金银耳形成另一个分支。ITS序列的差异为金耳的鉴别提供了可靠的分子标记,为金耳菌类药材基原入药建立了遗传基础。     

Molecular characterization of Fasciola gigantica from Mauritania based on mitochondrial and nuclear ribosomal DNA sequences

Fasciolosis caused by Fasciola hepatica and Fasciola gigantica (Platyhelminthes: Trematoda: Digenea) is considered the most important helminth infection of ruminants in tropical countries, causing considerable socioeconomic problems. From Africa, F. gigantica has been previously characterized from Burkina Faso, Senegal, Kenya, Zambia and Mali, while F. hepatica has been reported from Morocco and Tunisia, and both species have been observed from Ethiopia and Egypt on the basis of morphometric differences, while the use of molecular markers is necessary to distinguish exactly between species. Samples identified morphologically as F. gigantica (n = 60) from sheep and cattle from different geographical localities of Mauritania were genetically characterized by sequences of the first (ITS-1), the 5.8S, and second (ITS-2) Internal Transcribed Spacers (ITS) of nuclear ribosomal DNA (rDNA) genes and the mitochondrial Cytochrome c Oxidase I (COI) gene.Comparison of the sequences of the Mauritanian samples with sequences of Fasciola spp. from GenBank confirmed that all samples belong to the species F. gigantica. The nucleotide sequencing of ITS rDNA of F. gigantica showed no nucleotide variation in the ITS-1, 5.8S, and ITS-2 rDNA sequences among all samples examined and those from Burkina Faso, Kenya, Egypt and Iran. The phylogenetic trees based on the ITS-1 and ITS-2 sequences showed a close relationship of the Mauritanian samples with isolates of F. gigantica from different localities of Africa and Asia. The COI genotypes of the Mauritanian specimens of F. gigantica had a high level of diversity, and they belonged to the F. gigantica phylogenically distinguishable clade. The present study is the first molecular characterization of F. gigantica in sheep and cattle from Mauritania, allowing a reliable approach for the genetic differentiation of Fasciola spp. and providing basis for further studies on liver flukes in the African countries.     

Phylogenetic Relationship ofPopulusSections by ITS Sequence Analysis

ITS sequences of 15 representative species of five sections in the genus Populus L. were determined. By using direct sequencing of PCR product, it was found that the fragments of internal transcribed spacers (ITS) are about 594 bp in length. The length of ITS-1 and ITS-2 is about 220 bp and 210 bp, respectively, while that of 5.8s is 164 bp. Its G+C content is about 69.0%. The number of phylogenetically informative loci is higher in ITS-2 than in ITS-1. Transversion and transition are two main factors that drive the ITS evolution, and more insertions and deletions occurred in ITS-2. Taking Salix matsudana Koidz. and Salix suchowensis Cheng as outgroups, phylogenetic analysis of ITS sequences using PAUP 4.0 software indicated that Populus is monophyletic group and can be divided into two main clades. One is the section Leuce , and the other is the remaining sections.     

Internal transcribed spacer polymorphism in Pseudo-nitzschia multistriata (Bacillariophyceae) in the Gulf of Naples: recent divergence or intraspecific hybridization?

The planktonic diatom Pseudo-nitzschia multistriata is a potentially toxic species recorded during late summer-autumn in the Gulf of Naples (Tyrrhenian Sea, Italy). We analysed the genetic structure by amplifying the internal transcribed spacer (ITS-1-5.8S-ITS-2) region of the ribosomal DNA of 44 strains isolated along 2 years. Polymorphism in the ITS region was detected by direct sequencing and the PCR-products from selected strains were thus cloned to assess intra-strain ITS variability. Strains clustered into three main types: type A and B - differing by 0.6% sequence divergence - and type A/B, showing both A and B variants within the same genome. The three types showed no differences in the large subunit sequences (LSU) of the rDNA, ultrastructure of the valve, secondary structure of ITS-1 and ITS-2, ploidy level and they were sexually compatible. Based on the results of these multiple approaches, we can state that the three ITS-types belong to the same reproductive unit (or "species" sensu Mayr [(1942). Systematics and the Origin of Species. Columbia University Press, New York]). We suggest that ITS polymorphism in P. multistriata may be related to the contemporary occurrence of different but still inbreeding populations which either diverged recently or originated in different geographic areas and became sympatric in the studied area.     

ITS sequence analysis used for molecular identification of the Bupleurum species from northwestern China

Radix Bupleuri (Chaihu), a famous Traditional Chinese Medicine, is derived from the dried roots of Bupleurum chinense DC. and B. scorzonerifolium Willd. But nowadays, other nine species and varieties from genus Bupleurum are also used as Radix Bupleuri in northwestern China. The authentic identification of dried roots of B. chinense and B. scorzonerifolium, however, is difficult to just base on the appearance and morphology. A molecular genetic method was developed to help discriminate the original species of Radix Bupleuri. The ITS sequences ( approximately 600 bp) were amplified by the PCR technique from genomic DNA isolated from all the collected samples. According to analyzing the information given by ITS sequences, the conclusion can be made that ITS sequence could serve as markers for authentication of Radix Bupleuri.     

枇杷属内栽培种和部分野生种ITS序列分析

对不同栽培区的25种普通枇杷品种以及7种枇杷属野生种的ITS序列进行扩增并测序,采用邻接法和最大简约法进行系统发育树的构建并对枇杷属内不同种间的遗传关系进行了分析。结果表明:枇杷属植物ITS序列ITS1+5.8S rDNA+ITS2总长度为592 bp或594 bp,长度变化发生在ITS2。所有样本的ITS1和5.8S rDNA长度一样,都是223 bp和168 bp;而ITS2为201 bp或203 bp。5种枇杷属野生种的ITS序列长度为594 bp,包括栎叶枇杷、大渡河枇杷、南亚枇杷、南亚枇杷窄叶变种和大瑶山枇杷;其余2种枇杷属野生种(麻栗坡枇杷、小叶枇杷)和普通枇杷栽培种的ITS序列长度都为592 bp。所有样本ITS序列的GC含量为64.2%~64.5%,其中ITS1为64.1%~65.5%,ITS2为68.1%~72.6%。对所有样本的ITS序列比对产生44个可变位点,其中38个为简约信息位点,其中11个位于ITS1,5个位于5.8S rDNA,22个位于ITS2。最大的种间序列差异为7.7%,最小的种间差异发生在麻栗坡枇杷和小叶枇杷之间,仅为0.2%。普通枇杷种内的ITS序列差异很低,25种普通枇杷栽培种之间的序列差异为0~1.5%。所研究的枇杷属植物可分为3个分支。分支Ⅰ包括所有普通枇杷品种,分支Ⅱ包含5种野生枇杷种,包括栎叶枇杷、大渡河枇杷、南亚枇杷、南亚枇杷窄叶变种和大瑶山枇杷;分支Ⅲ由2个野生枇杷种(麻栗坡枇杷、小叶枇杷)组成。该研究结果表明ITS序列对枇杷种间鉴定和系统发育分析具有一定意义,但对普通枇杷栽培种间的鉴定作用不大。     

Intraspecies Analysis: Comparison of ITS Sequence Data and Gene Intron Sequence Data with Breeding Data for a Worldwide Collection of Gonium pectorale

The morphologically uniform species Gonium pectorale is a colonial green flagellate of worldwide distribution. The affinities of 25 isolates from 18 sites on five continents were assessed by both DNA sequence comparisons and sexual compatibility. Complete sequences were obtained (i) for the internal transcribed spacer ITS-1 and ITS-2 regions of ribosomal DNA and (ii) for each of three single-copy spliceosomal introns, two in a small G protein and one in the actin gene. ITS sequences appeared to homogenize sufficiently rapidly to behave as a single copy gene. Intron sequence differences between isolates in this species reached nucleotide substitution saturation, while ITS sequences did not. Parsimony and evolutionary distance analysis of the two types of DNA data gave essentially the same tree conformation. By all these criteria, the group of G. pectorale isolates fell into two main clades, A and B. Clade A, with isolates from four continents, was comprised of four subclades of quite closely related isolates, plus one strain of ambiguous affinity. Clade B was comprised of two subclades represented by South African and South American isolates, respectively; thus, only subclades of clade B showed geographical localization. With respect to mating, all isolates except one homothallic strain and one apparently sterile strain fell into either one or the other of two mating types. Pairings in all possible combinations revealed that isolates from the same site formed abundant zygotes, which germinated to produce new, sexually active organisms. Zygotes were also formed in many pairings of other combinations, including crosses of clade A with clade B organisms, but none of the latter produced viable germlings. The ability to mate and produce viable progeny that were themselves capable of sexual reproduction was restricted to members of subclades established on the basis of DNA sequence similarities. Thus, the grades of difference in both nuclear intron sequences and rDNA ITS sequences paralleled those observed in the sexual analysis. Received: 9 March 1998 / Accepted: 1 June 1998