Karyotype studies in thirty‐two species of Lilium (Liliaceae) from China1

Fifty‐two populations representing thirty‐two taxa of Lilium L. from China are karyologically analyzed. The results showed that all populations have the same basic chromosome number x=12, and all species are diploid except Lilium tigrinum, which is triploid with 2n=36. In addition, one population of L. sulphureum is aneuploid with 2n=23. The karyotype evolution in the genus Lilium is mainly in terms of alterations of the fine structure of the chromosomes, not in ploidy or basic chromosome number variation. When combining previous studies and our results, we consider the major driving forces for evolution of Lilium to be an increase in karyotypic asymmetry, and unequal translocation and formation of secondary constrictions. The existence of intercalary satellites on the two largest pairs of chromosomes is correlated with the geographic distribution pattern of Lilium across the world. The Hengduan Mountains is a modern diversity and differentiation center of Lilium and it also could be the center of origin for this genus. In addition, some taxonomic conclusions were verified on the subgenus level. Among the species investigated, the chromosome number and karyotypes of 13 taxa were documented for the first time.     

Contributions to the pollen morphology and taxonomy of the Liliaceae

Pollen of 34 species from 7 genera of the Liliaceae were examined by LM and SEM with respect to the taxonomy of the family. Detailed pollen­morphological characteristics are given for all genera in the family on the basis of the results presented here together with data from the literature. The genera Tulipa and Lilium are heterogeneous in both aperture type and exine ornamentation. Pollen of Tulipa is monosulcate, 3-aperturate or inaperturate, with a microreticulate-striate, reticulate-implecto-striate, scabrate, perforate-rugulate, perforate-striate exine surface. Pollen of Lilium is monosulcate and 3-porate with a macroreticulate exine. The other genera are homogeneous in possessing of single longitudinal aperture (type monosulcate). The pattern of exine ornamentation and the structure of the aperture and its membrane are peculiar features for species and genera. Pollen of Erythronium and Tulipa are occasionally operculate, while in other representatives of the Liliaceae an operculum is lacking. Pollen morphological data support the division of the family into 3 tribes, namely Lloydieae, Lilieae, and Tulipeae.     

基于比较核型分析方法追溯百合族 (百合科) 二型性核型的起源

百合族具有非常一致的二型性核型,由4条长染色体以及20条短染色体组成。目前有两个假说解释其二型性核型的来源,着丝粒横裂和多倍化。但是,具体是哪一种机制起主要作用仍然不清楚。根据文献以及自己的实验结果,我们整理并重新分析了百合亚科和美德兰亚科所有属的核型资料。比较核型分析结果表明,来自单条染色体的特征、染色体臂数、核型不对称性以及染色体的相对长度诸方面的证据都支持着丝粒横列是百合族核型进化的主要机制,但不能排除其它的机制也在起着作用,如臂间倒位和易位。臂间倒位和易位可能在郁金香族的核型进化中起着主要的作用。另外,本研究还报道了三个种的核型,粗茎贝母 (Fritillaria crassicaulis)、准格尔郁金香 (Tulipa suaveolens) 和尖果洼瓣花 (Gagea oxycarpa)。     

Chromosome diversity and evolution in Allium (Allioideae,Amaryllidaceae)

Despite extensive literature on the diversity of karyotypes in Allium is available, no attempt to analyse these data together, within a robust phylogenetic framework, has been carried out so far. Thus, we examined patterns and trends in chromosome evolution across the genus. Based on literature survey, karyo-morphometric features for 207 species belonging to 12 subgenera of Allium were obtained. Included in the data-set were basic chromosome number (x), somatic chromosome number (2n), total haploid (monoploid) chromosome length (THL) and three different measures defining karyotype structure: CV_CI, measuring how heterogeneous are centromeres positions in a karyotype, CV_CL and M_CA, quantifying interchromosomal and intrachromosomal karyotype asymmetry, respectively. Trends in karyotype evolution were analysed by phylogenetic regressions and independent contrasts. Mean karyotypes highlighted differences and similarities in karyotype structure between the 12 subgenera. Further differences were noted when the two parameters for analysing karyotype asymmetry were assessed. In addition, by examining the effects of increasing karyotype dimensions (a proxy for genome size) on karyotype structure and asymmetry, it was shown that in Allium species, the DNA was added proportionally to their arm lengths. Overall, p = 8 and somehow intermediate karyotype asymmetry levels seem to represent plesiomorphic character-states in Allium.     

基于淫羊藿属(Epimedium L.)核型似近系数的聚类分析及其系统演化意义

为揭示淫羊藿属(Epimedium L.)植物染色体组遗传与进化,阐明该属植物系统亲缘关系和现代地理分布格局形成。该文对淫羊藿属植物51个分类群(43种、1亚种、6变种和1个栽培品种)和2种温哥华属(Vancouveria Morren et Decne.)植物的根尖进行了有丝分裂中期染色体核型分析,并运用核型似近系数聚类分析方法对这53个分类群植物的核型进行了聚类研究。结果表明:所有种类的染色体数均为12,二倍体(2n=2x=12),第1对同源染色体均为随体染色体,核型均为Stebbins的2A或1A型。可见,淫羊藿属植物染色体组在遗传进化中确实较为保守,种间核型非常相似。核型似近系数聚类分析为淫羊藿属植物系统进化研究提供了一些明显的线索。分析结果完全支持该属属下两个亚属(Subgen.Rhizophyllum和Subgen.Epimedium)的划分。亚属Epimedium的核型似近系数聚类结果显示,该类群物种间的系统亲缘关系与地理分布密切相关。核型似近系数分析结果还发现,来自东亚地区的淫羊藿属植物染色体组具有明显的变异,显示了更高的遗传多样性。基于上述研究结果,推断了淫羊藿属植物现代地理分布格局的形成过程。该研究结果可为淫羊藿属植物的资源利用、系统分类和遗传演化等领域的研究提供参考。     

Nucleolar organiser region (NOR) location in karyotypes of Australian ground frogs (family Myobatrachidae)

Nucleolar organiser regions (NORs) were examined in over 90% of the species of Australian ground frogs (familiy Myobatrachidae), including representatives from all twenty currently recognised genera and the three subfamilies. Throughout the family, location of the NOR within the karyotype showed considerable variation yet karyotype morphology showed uniformity. The precise mechanism(s) whereby variation in NOR location evolved while karyotype morphology was unchanged remains uncertain. Comparison of the two major subfamilies showed that the Limnodynastinae had a greater diversity of NOR location than the Myobatrachinae. The limnodynastine genus,Heleioporus, was the only one to show multiple NOR sites in several species. NOR location was particularly stable within most polytypic genera. Differences in NOR location within the remaining polytypic genera (Heleioporus, Limnodynastes, Neobatrachus, Philoria andRanidella) pointed to taxonomic discriminations that were generally consistent with recent proposals based on other criteria.     

A survey of C-band patterns in chromosomes ofLilium (Liliaceae)

C-band patterns are described for 20Lilium spp. distributed across six sections. All species have a similar basic karyotype (n = 12) but C-bands differ markedly between them. The patterns are characterized by a dispersed scattering of thin intercalary bands as well as centric and NOR bands. Only one species,L. canadense, shows a clear equilocal pattern with intercalary C-bands occurring proximally in all of the longer chromosome arms. Comparing species, similar patterns are revealed forL. regale andL. sulphureum, forL. formosanum andL. longiflorum (all in sect.Leucolirion) and to a lesser extent forL. hansonii, L. martagon, andL. tsingtauense (sect.Martagon). The pattern forL. henryi (previously classed in sect.Sinomartagon) matches those ofL. regale andL. sulphureum quite well and its transfer to sect.Leucolirion is proposed. This is consistent with results from interspecies hybrids betweenL. henryi andL. regale (and related species) which are reportedly fertile. No other clear similarities in C-band patterns were seen across species. It seems that C-band patterns change rapidly inLilium and hence their usefulness in classification will be restricted to identifying closely related species.Dedicated to Prof.D. G. Catcheside on the 80th anniversary of his birth.     

中国西南地区鹿药属4种15居群核型研究

对产于中国西南部的鹿药属（Maianthemum）4种植物进行了细胞学研究,包括染色体数目,多倍化,非整倍性和随体染色体,以及核型不对称性和核型进化。结果表明：1）除了在云南丽江采集的Maianthemum tatsienensis染色体数目为2n=72之外,其余的居群全为2n=36;2）核型在居群间存在变异,特别是在具中部染色体和近中部染色体的数目以及随体染色体的数目和位置上。此外,M．nanchuanense和M．szechuanicum的核型是首次报道,B染色体也是首次在该属中发现。我们推测鹿药属的进化方式包括频繁的染色体畸变以及不同水平上的多倍化,而中国西南部是该属的分化中心。     

Satellite DNA probes of Alstroemeria longistaminea (Alstroemeriaceae) paint the heterochromatin and the B chromosome,reveal a G-like banding pattern,and point to a strong structural karyotype conservation

Alstroemeria species present a well-conserved and asymmetric karyotype. The genus is divided into a Chilean clade, rich in heterochromatin, and a Brazilian clade, poor in heterochromatin. We investigated the distribution of the main repetitive sequences in the chromosomes of the Brazilian species A. longistaminea (2n = 16 + 0-6B) aiming to evaluate the role played by these sequences on the structural organization of the karyotype. In situ hybridization of the three most abundant retrotransposons, corresponding to ~ 45% of the genome, was uniformly distributed. Three satellite DNA sequences, representing near half of the whole satellite fraction (1.93% of the genome), were mainly concentrated on the heterochromatin and one of them painted the whole B chromosome. Noteworthy, some satellites were located on euchromatin, either dispersed or concentrated in clusters along the chromosomes, revealing a G-band-like pattern. The two satellites that presented more C-band- and G-band-like labeling were also hybridized in situ in two other Alstroemeria species. They revealed astonishing similar patterns of distribution, indicating an unusually structural karyotype conservation among Brazilian species.

     

PRESCOTTIELLA,A NEW GENUS OF ASYMMETRICAL DESMIDS (CHLOROPHYCEAE)1

Bipolar asymmetry has been considered a morphological characteristic sufficient for differentiation of genera among the Desmidiaceae. Therefore, Micrasterias sudanensis Grönbl., Prowse & Scott, the only species of Micrasterias showing such asymmetry, is made the type of a new genus, Prescottiella, gen. nov.     

A Molecular Phylogeny of Lilium in the Internal Transcribed Spacer Region of Nuclear Ribosomal DNA

Phylogenetic relationships among 55 species of Lilium, Cardiocrinum giganteum, and Nomocharis saluenensis were inferred from nucleotide sequence variations in the internal transcribed spacer (ITS) regions of 18S–25S nuclear ribosomal DNA. The phylogeny derived from ITS sequences estimated using maximum-likelihood methods indicated that (1) most of the species construct their own clade according to the classification based on morphological features at the section level; (2) section Daurolirion is not independent of Sinomartagon, and it is appropriate to integrate two sections as Sinomartagon; (3) it is appropriate that L. henryi and L. bulbiferum are classified into subsection 6a and Sinomartagon–Daurolirion, respectively; (4) subsection 6b is much closer to Sinomartagon than subsection 6a and Archelirion, and it arose directly from Sinomartagon; and (5) Lilium is much closer to Nomocharis than Cardiocrinum. Phylogenetic estimation using sequences of the ITS region is suitable at the levels of genus, section, and most of subsection. Received: 18 December 1998 / Accepted: 14 March 1999     

Giemsa C-banded karyotypes inCapsicum (Solanaceae)

Giemsa C-banding is applied for the first time inCapsicum, allowing preliminary karyotype differentiation of six diploid species. Comparison of interphase nuclei and heterochromatic C-bands reveals striking differences between taxa and contributes to their taxonomic grouping. Therefore, C-banding appears to be a powerful tool for the cytogenetics and karyosystematics of the genus. Banding patterns are characterized by the omnipresence of centromeric bands and a variable number of smaller to larger distal bands, with the addition of intercalary bands in some cases. Satellites are always C-positive. Relationships between species and possible trends of karyotype evolution are discussed, with special reference to the origin of x = 13 from x = 12 and the increase of heterochromatin, regarded as advanced features.Chromosome studies inCapsicum (Solanaceae), III. For the first and the second part seeMoscone (1990, 1993).     

DESCRIPTION OF A NEW GENUS OF PFIESTERIA‐LIKE DINOFLAGELLATE,LUCIELLA GEN. NOV. (DINOPHYCEAE), INCLUDING TWO NEW SPECIES: LUCIELLA MASANENSIS SP. NOV. AND LUCIELLA ATLANTIS SP. NOV.1

A new genus of Pfiesteria‐like heterotrophic dinoflagellate, Luciella gen. nov., and two new species, Luciella masanensis sp. nov. and Luciella atlantis sp. nov., are described. These species commonly occur with other small (<20 μm) heterotrophic and mixotrophic dinoflagellates in estuaries from Florida to Maryland and the southern coast of Korea, suggesting a possible global distribution. An SEM analysis indicates that members of the genus Luciella have the enhanced Kofoidian plate formula of Po, cp, X, 4′, 2a, 6″, 6c, PC, 5+s, 5?, 0p, and 2″″. The two four‐sided anterior intercalary plates are diamond shaped. The genus Luciella differs from the other genera in the Pfiesteriaceae by a least one plate in the plate tabulation and in the configuration of the two anterior intercalary plates. An SSU rDNA phylogenetic analysis confirmed the genus as monophyletic and distinct from the other genera in the Pfiesteriaceae. The morphology of Luciella masanensis closely resembles Pfiesteria piscicida Steid. et J. M. Burkh. and other Pfiesteria‐like dinoflagellates in size and shape, making it easily misidentified using LM. Luciella atlantis, in contrast, has a more distinctive morphology. It can be distinguished from L. masanensis and other Pfiesteria‐like organisms by a larger cell size, a more conical‐shaped epitheca and hypotheca, larger rhombic‐shaped intercalary plates, and an asymmetrical hypotheca. The genus Luciella is assigned to the order Peridiniales and the family Pfiesteriaceae based on plate tabulation, plate pattern, general morphology, and phylogenetic analysis.     

Karyotype variation in 11 species of the Vernonieae Cass. tribe (Asteraceae Bercht. & J. Presl)

The Vernonieae tribe presents strong taxonomic delimitation problems as it is considered one of the most complex groups of the Asteraceae family, comprising approximately 1100 species distributed across 129 genera. In this study, a comparative analysis of the Vernonieae species was performed to understand the events involved in the chromosome evolution of these species and to further deduce their taxonomy. The representatives were cytogenetically characterized via analyses of morphology, karyotype asymmetry and differential staining with fluorochromes CMA and DAPI as well as FISH. According to morphometric data, all species showed symmetrical karyotypes with prevailing metacentric chromosomes, even in species belonging to different genera. Variability in diploid chromosome number was detected (2n = 18 to 2n = 60), and chromosome sizes were observed to be between 1.00 and 4.09 μm. Additionally, variation in the pattern of heterochromatin was observed mainly in relation to CMA⁺ bands, in which the number varied from 4 to 16 heterochromatic regions. Only one species, Vernonia scorpioides, presented positive DAPI bands, which were located in the terminal position in most of the chromosomes. The differences in the sizes and quantities of heterochromatic bands may be related to small structural rearrangements during karyotype evolution of the Vernonieae tribe.     

Neoleptonema yongpilii E.-Y. Lee & I.K. Lee,gen. et sp. nov. (Phaeophyceae), based on morphological characters and RuBisCO spacer sequences

An elachistacean epiphyte, Neoleptonema yongpilii E.-Y. Lee & I.K. Lee, gen. et sp. nov., is reported from Korean coasts. The plants are distinguished by having unbranched assimilatory filaments with intercalary plurilocular sporangia as well as lateral plurilocular sporangia from the cortex. The new genus differs from the genera Leptonematella P. Silva and Halothrix Reinke by having pod-shaped plurilocular sporangia on the medulla, and from Elachista Duby and Proselachista Y.P. Lee & Garbary by having intercalary plurilocular sporangia and a poorly developed medulla. The phylogenetic relationships of Neoleptonema yongpilii were inferred from the spacer sequences between the genes coding for the large and small subunits of the RuBisCO gene. The new genus is a member of a poorly resolved clade consisting of several genera within the Elachistaceae, within which it is more closely related to Halothrix and Elachista nipponica than to Leptonematella.     

Major Lineages of the Genus <Emphasis Type="Italic">Lilium</Emphasis> (Liliaceae) Based on nrDNA ITS Sequences,with Special Emphasis on the Korean Species

We present most comprehensive phylogenetic analysis of 196 accessions of Lilium representing 83 species and 14 varieties of Lilium and three outgroup genera (Cardiocrinum, Notholirion, and Fritillaria) to investigate infrageneric relationships within Lilium as well as to determine the origin and evolution of Korean species of Lilium. We used the internal transcribed spacer sequences of nuclear ribosomal DNA and phylogenetic analysis using maximum parsimony and Bayesian inference identified several major lineages within Lilium. Only one section, Martagon, turned out to be monophyletic in the study. Three sections, Archelirion, Liriotypus, and Pseudolirium, are not monophyletic because two, one, and two species in each section were placed in other lineage, respectively. Two major lineages of section Leucolirion were confirmed in this study, and as several previous studies suggested, section Sinomartagon is highly polyphyletic. The origin of Lilium hansonii, a Korean endemic to Ullung Island, is perplexing given the fact that it has ribotype of Martagon, while its cpDNA haplotype is similar to Sinomartagon. The origin of another endemic, Lilium amabile, is equally elusive and additional phylogenetic and phylogeographic studies will shed light on their evolutions in Korea. We determined that Lilium callosum var. flavum originated from L. callosum in Southern Korea.     

Molecular evidence places the swallow bug genus Oeciacus Stål within the bat and bed bug genus Cimex Linnaeus (Heteroptera: Cimicidae)

The genera Cimex Linnaeus and Oeciacus Stål (Heteroptera: Cimicidae) are common haematophagous ectoparasites of bats or birds in the Holarctic region. Both their phylogenetic relationship and the systematics of the entire family previously were based on data from morphology and host relationships. Relationships among nine species of the genus Cimex and three species of the genus Oeciacus were analysed here using two mitochondrial and three nuclear genes. Cimex was shown to be paraphyletic with respect to Oeciacus. Oeciacus is thus proposed as a synonym of Cimex. The characteristic phenotype of Oeciacus results from the specific host association with different species of swallows (Hirundinidae). The morphological characters that have been used as diagnostic for the genera were shown to be valid and can be further used for determination at species level. The present analyses recovered the four traditional morphologically defined species groups of the genus Cimex. However, their relationships were poorly resolved – only the C. hemipterus group showed a well‐supported relationship to the C. pipistrelli group. The molecular differentiation within the Palaearctic C. pipistrelli and the Nearctic C. pilosellus species groups correlates with their karyotype differentiation. Furthermore, the analyses suggest poly‐ or paraphyly of the former genus Oeciacus. Either way this indicates there is a large amount of host‐associated phenotypic convergence in either bat‐ or bird‐associated groups of species. The probability of host choice and subsequent switch in Cimicidae are discussed and possible scenarios of the evolution of host association in species of Cimex are suggested.