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Species boundaries,phylogenetic relationships,and ecological differentiation inAnthriscus (Apiaceae)
Krzysztof Spalik 《Plant Systematics and Evolution》1996,199(1-2):17-32
Species boundaries and phylogenetic relationships of 17 taxa ofAnthriscus (Apiaceae), with special emphasis on the critical sect.Cacosciadium, were explored using morphological data with principal component analysis, phenetics, and phylogenetics. The analyses did not provide satisfactory resolution of taxa from sect.Cacosciadium and only four species were retained. The total number of species was reduced to nine. Sect.Cacosciadium is distinguished by only two synapomorphies while sects.Anthriscus andCaroides are better supported. Present geographic and ecological variation suggests that the radiation ofAnthriscus occurred through divergence of peripheral isolated populations adapting to different habitats: high montane meadows and screes, shady climax forests, and seasonally dry habitats at lower altitudes. The adaptive significance of particular morphological traits is discussed. 相似文献
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The alpine ecosystem is the only terrestrial biogeographic unit that is distributed globally. Studying phylogenetics of the plant species in this widespread ecosystem can provide insights into the historical biogeographic processes that have shaped the global biodiversity. The trans-Pacific disjunct alpine genus Oreomyrrhis (Apiaceae) was investigated using nrDNA ITS sequences to test the taxonomic and biogeographic hypotheses. Phylogenetic analyses using maximum parsimony, maximum likelihood, and Bayesian inference revealed that species of Oreomyrrhis form a weakly supported monophyletic clade that is nested within Chaerophyllum sect. Chaerophyllum (subtribe Scandicinae, tribe Scandiceae). The optimal solutions of dispersal-vicariance analysis indicate that the ancestor of Chaerophyllum sect. Chaerophyllum (including Oreomyrrhis) was distributed in Eurasia and subsequently dispersed to North America and southern Pacific Rim. Based on dating using ITS sequence variation, these dispersal events were most likely recent, probably during late Tertiary to Quaternary. The structure of the ITS haplotype network suggests that a rapid range expansion via long-distance dispersal had been crucial in generating the trans-Pacific disjunction of Oreomyrrhis. Furthermore, evolution toward smaller mericarp size and a transition from outcrossing to selfing during Oreomyrrhis's evolution might have increased the chances for long-distance dispersal, facilitating its range expansion and occupation on alpine environments. 相似文献
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Mahadevan J Xu C Siahaan T Kuczera K 《Journal of biomolecular structure & dynamics》2002,19(5):775-788
Conformations available to a class of cyclic prodrugs and corresponding linear RGD peptidomimetics were explored using 1 ns length molecular dynamics simulations performed with the program CHARMM. Water and octane, modeled explicitly, were used as solvents to mimic the change of the environment experienced by the solutes upon partition from water to membrane in the trans-cellular transport process. In water, the linear peptidomimetics tended to populate extended-like structures, characterized by strong favorable interactions with solvent and low intrinsic stability. In these extended conformations the charged termini are able to assume large distances, above 15 A for the longest systems. These linear peptidomimetics have been found to exhibit the highest potency in experimental studies, in accord with the trends experimentally observed for RGD peptides. In contrast, in octane compact conformers of the linear peptidomimetics were favored, with all charged groups aggregated and shielded from solvent, exhibiting high intrinsic stability and weak solute-solvent interactions. Our calculations predict a large unfavorable energy change for transferring the linear systems from water to octane, in agreement with experimental findings that these compounds are not transported via the trans-cellular pathway. The cyclic prodrugs did not exhibit major structural differences between the simulations in water and octane, adopting turn-like conformations in both solvents. The limited response of the cyclic structures to changes in the environment leads to energies of transfer from water to octane that are also unfavorable, but much less so than for the linear molecules. This effect is in accord with the observed enhanced passive trans-cellular transport of the cyclic prodrugs. 相似文献
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PHYLOGENETIC POSITION OF KOLIELLA (CHLOROPHYTA) AS INFERRED FROM NUCLEAR AND CHLOROPLAST SMALL SUBUNIT rDNA 总被引:1,自引:0,他引:1
Agnieszka Katana Jan Kwiatowski Krzysztof Spalik Boena Zakry Elbieta Szalacha Hanna Szymaska 《Journal of phycology》2001,37(3):443-451
The phylogenetic position of Koliella , a chlorophyte characterized by Klebsormidium type cell division, was inferred from analyses of partial 18S rDNA and partial 16S rDNA. Parsimony and distance analyses of separate and combined data sets indicated that the members of Koliella belonged to Trebouxiophyceae, and high decay indices and bootstrap values supported this affinity. However, the genus appeared to be polyphyletic. Koliella spiculiformis , the nomenclatural type of the genus, was allied with Nannochloris eucaryota and the "true" chlorellas ( Chlorella vulgaris , C. lobophora , C. sorokiniana , and C. kessleri ). The close relatives of Koliella longiseta (≡ Raphidonema longiseta ) and Koliella sempervirens appeared to be Stichococcus bacillaris and some species traditionally classified in Chlorella that were characterized by the production of secondary carotenoids under nitrogen-deficient conditions. This clade was also supported by the presence of a relatively phylogenetically stable group I intron (1506) in the 18S rRNA gene. Because of the presence of Klebsormidium type cell division, some authors regarded the members of Koliella as closely related to charophytes. Molecular analyses, however, did not confirm this affinity and suggested that a Klebsormidium type cell division is homoplastic in green plants. 相似文献
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Marcin Piwczyński Radosław Puchałka Krzysztof Spalik 《Botanical journal of the Linnean Society. Linnean Society of London》2015,178(2):298-313
Evolutionary relationships among 65 Chaerophyllum spp. were inferred from nuclear ribosomal DNA internal transcribed spacer (ITS) sequence variation. Thirty‐one species, represented by 158 mericarp samples, were analysed for fruit anatomical character variation, employing phylogenetic and phenetic methods to explore their congruence with infrageneric divisions based on molecular data. Phylogenetic trees inferred from molecular data using maximum likelihood (ML) and Bayesian inference (BI) methods corroborated the division of the genus into four sections: Chaerophyllum, Dasypetalon, Physocaulis and Chrysocarpum. From among the newly sequenced species, the Greek endemic C. heldreichii was grouped with section Chaerophyllum, whereas the highly variable Asian C. reflexum–C. villosum complex formed an early‐branching paraphyletic assemblage in section Chrysocarpum. The recently described C. karsianum has an identical ITS sequence to C. bulbosum, whereas C. aksekiense was clearly separated from the morphologically similar C. macrospermum. Our study confirmed the postulated synonymy of several species on the basis of morphology, but also demonstrated distant relationships between some morphologically similar species. With the exception of the monotypic section Physocaulis, we were unable to find carpological traits matching sectional divisions. We hypothesize that fruit characters evolved rapidly as a result of diversification of members of the genus in different habitats. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 298–313. 相似文献
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Renata Kurzyna-Młynik Alexei A. Oskolski Stephen R. Downie Rafał Kopacz Aneta Wojewódzka Krzysztof Spalik 《Plant Systematics and Evolution》2008,274(1-2):47-66
Recent molecular systematic investigations suggested that Ferula, an umbellifer genus of about 170 species, is polyphyletic, with its members placed in the apioid superclade and within tribe Scandiceae. We analyzed ITS sequence variation from 134 accessions of Apiaceae, including 83 accessions (74 species) of Ferula to ascertain the phylogenetic position of the genus within the family. Phylogenetic analyses of these data using maximum parsimony, Bayesian, and neighbor-joining methods support the monophyly of Ferula upon the addition of Dorema and Leutea (as Ferula sensu lato) and its placement in tribe Scandiceae. Ferula sensu is closely allied with other major lineages of Scandiceae, corresponding to subtribes Scandicinae, Daucinae, and Torilidinae. Therefore, we recognize the Ferula clade as subtribe Ferulinae. Another addition to tribe Scandiceae is a clade composed of genera Glaucosciadium and Mozaffariania. The three accessions of Ferula misplaced in the apioid superclade represent a species of Silaum. 相似文献
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Kwiatkowska Anna Justyna Spalik Krzysztof Michalak Elżbieta Palińska Anna Panufnik Dorota 《Plant Ecology》1997,129(1):1-10
The change in the species richness following a gradual invasion of Carpinus betulus in the patch of oak forest (Potentillo albae-Quercetum) in Biaowiea was studied between years 1980 and 1994. Species richness and species deletion were compared to the spatial variation in the density and size of C. betulus individuals. The study showed that, in a microscale, (1) the rate of deletion of heliophilous species was similar to that of shade-tolerant ones and was c. 2 species per 4 m2 per 10 years, (2) species richness was negatively correlated with the density and size of C. betulus saplings recruited to the shrub layer, (3) species deletion was positively correlated with the number of saplings in the shrub layer. The results support the hypothesis that the invasion of C. betulus is a proximate cause of the decline of Potentillo albae-Quercetum, and in a microscale, it has three stages: (a) initial colonisation of the ground layer by the seedlings, (b) recruitment of juveniles to the shrub layer, deterioration of light conditions and rapid deletion of species, and (c) closure of the canopy and deletion of remaining heliophilous species and vulnerable shade-tolerant species. Nomenclature: follows Ehrendorfer (1973) and Matuszkiewicz (1981). 相似文献
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Germán A?ez Daniel A. R. Heisey Caren Chancey Rafaelle C. G. Fares Luz M. Espina Kátia P. R. Souza Andréa Teixeira-Carvalho David E. Krysztof Gregory A. Foster Susan L. Stramer Maria Rios 《PLoS neglected tropical diseases》2016,10(2)