Table of Contents
  • Volume 48 Issue 3

    Cover illustration: Juniperus sabina L. (Cupressaceae). Photographed by Chang-Long LI in Wushen banner, Nei Mongol, China. See Guo et al., pp. 153–160 in this issue.
      
      Research Articles
    • Yu-Peng GUO, Ru ZHANG, Cui-Yun CHEN, Dang-Wei ZHOU, Jian-Quan LIU
      2010, 48 (3): 153–160
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      In this study, we aimed to study the phylogeographical pattern of Juniperus sabina, a shrub species commonly occurring in the northern, northwestern and western China. We sequenced three chloroplast DNA fragments (trnL-trnF, trnS-trnG and trnD-trnT) for 137 individuals from 16 populations of this species. Five chloroplast DNA (cpDNA) chlorotypes (A, B, C, D and E) were identified and they showed no overlapping distribution. The population subdivision is very high (GST = 0.926, NST = 0.980), suggesting distinct phylogeographical structure (NST > GST, P < 0.05). Phylogenetic analyses of the five chlorotypes clustered into three clades which were consistent with their respective distributions in three separate regions: northern Xinjiang, western Xinjiang and northern-northwestern China. However, within each region, the inter-population differentiation is extremely low. These results as well as statistical tests suggested distinct allopatric differentiations between regional populations and independent glacial refugia for postglacial recolonization. The deserts developed during the late Quaternary might have acted as the effective barriers to promote genetic differentiation among these regions. However, the low diversity dominated by the single chlorotype within each fragmented region suggested that all current populations were derived from a common regional range expansion respectively.
    • Kristen E. BAIRD,Vicki A. FUNK,Jun WEN,Andrea WEEKS
      2010, 48 (3): 161–174
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      Leibnitzia comprises 6 species of perennial herbs that are adapted to high elevation conditions and is one of only two Asteraceae genera known to have an exclusively disjunct distribution spanning central to eastern Asia and North America. Molecular phylogenetic analysis of Leibnitzia and other Gerbera-complex members indicates that Leibnitzia is monophyletic, which is contrary to our expectation that American Leibnitzia species, L. lyrata and L. occimadrensis, would be more closely related to another American member of the Gerbera-complex, Chaptalia. Ancestral area reconstructions show that the historical biogeography of the Gerbera-complex mirrors that of the entire Asteraceae, with early diverging lineages located in South America that were followed by transfers to Africa and Eurasia and most recently to North America. Intercontinental transfer of Leibnitzia appears to have been directed from Asia to North America. Independent calibrations of nuclear (rDNA internal transcribed spacer region) and chloroplast (trnL-rpl32 intron) DNA sequence data using relaxed clock methods and either mean rate or fossil-based priors unanimously support Miocene and younger divergence times for Gerbera-complex taxa. The ages are not consistent with most Gondwanan vicariance episodes, and thus the global distribution of Gerberacomplex members must be explained in large part by long-distance dispersal. American species of Leibnitzia are estimated to have diverged from their Asian ancestor during the Quaternary (ca. 2 My) and either migrated overland to North America via Beringia and retreated southwards along high elevation corridors to their present location in southwestern North America or were dispersed long-distance.

    • Julio V SCHNEIDER, Marilu L HUERTAS
      2010, 48 (3): 175–182
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      Palaua (Malveae, Malvaceae) comprises 15 species endemic to the hyperarid coastal desert of Chile and Peru. So far, chromosome counts have been known for two diploid species (2n = 2x = 10) only. Here we report new chromosome numbers for 12 species of Palaua and four of its sister group Fuertesimalva. Karyotypes including DAPI/CMA3 fluorescent banding are presented for selected species representative of each of the main clades of Palaua. An important finding is the discovery of polyploids in one exclusively tetraploid species (P. trisepala) and four species with mixed diploid and tetraploid cytotypes (P. dissecta, P. mollendoensis, P. moschata, P. tomentosa). The diploid and tetraploid karyotypes are all unimodal, symmetrical and show one or two pairs of satellite chromosomes with their associated CMA+/DAPI- band depending on the cytotype. For some of the tetraploids an autopolyploid origin is suggested.
    • Jakub SAWICKI, Vítězslav, PLÁŠEK, Monika SZCZECIŃSKA
      2010, 48 (3): 183–194
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      Two Orthotrichum species of the subgenus Orthophyllum were compared with other representatives of this genus using the internally transcribed spacer regions 1 and 2, the chloroplast trnH-psbA region and ISSR and ISJ DNA markers. The applied DNA markers revealed many bands and mutations specific only to O. gymnostomum and O. obtusifolium. A phylogenetic analysis clearly supported the previous concepts postulating that species of the subgenus Orthophyllum should be recognized as separate genus Nyholmiella.

    • Qiu-Shi YU, Qian WANG, Ai-Lan WANG, Gui-Li WU,Jian-Quan LIU
      2010, 48 (3): 195–206
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      Pugionium (Brassicaceae) is a small genus occurring in the Central-Asian deserts. The interspecific delimitation and taxonomic treatments of this genus are disputed and its phylogenetic origin remains elusive. In this study, we examined these issues based on the morphological and molecular data obtained for the first time. We used statistical methods to examine interspecific and intraspecific morphological variations and the results suggested that only two species, P. dolabratum and P. cornutum, can be warranted for all examined populations and specimens while the three species (P. calcaratum, P. cristatum and P. pterocarpum) should be incorporated into P. dolabratum. This delimitation was further supported by the molecular data: all populations of P. dolabratum, P. calcaratum, P. cristatum and P. pterocarpum shared the same ITS genotype while those from P. cornutum had the other type. Phylogenetic analyses of Pugionium and representative genera of Brassicaceae based on ndhF sequences suggested that this genus was sister to the genus Megacarpaea, which together comprised a well supported lineage with Farsetia, Lobularia, Iberis and Ionopsidium, while other two genera (Isatis and Bunias), which were previously suggested to be closely related to this genus, were placed in the other lineages. We further discussed the origin of this genus and suggested that it probably originated in the central Asia when the climate became arider since the late Miocene.
    • Xin WANG
      2010, 48 (3): 207–214
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      Caytoniales are an important group of seed plants, and the nature of their female reproductive organ may influence interpretations of the seed plant phylogeny and the origin of angiosperms. Although not convincingly demonstrated by clear evidence, cupules on previously described specimens were interpreted as being distichously arranged, implying that the cupule bearing organ in Caytoniales was a pinnate megasporophyll. Here a female reproductive organ of Paracaytonia hongtaoi gen. et sp. nov. (Caytoniales) is reported from Liaoning, China. The well preserved specimen clearly demonstrates a spiral arrangement of cupules along the reproductive axis suggesting that the cupule-bearing organ in Caytoniales is not a megasporophyll but a branch. This new information on axial nature of the cupule-bearing organ in Caytoniales has significant implications on the placement of Caytoniales in the seed plant phylogeny and interpretation of the relationship between Caytoniales and angiosperms.
    • Kadry N. ABDEL KHALIK*
      2010, 48 (3): 215–223
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      The seed morphology of nine taxa of Juncus from Egypt has been investigated by using light and scanning electron microscopy, to determine the importance of seed coat features as taxonomic characters. Macro and micromorphological characters, including seed shape, colour, size, seed appendages, epidermal cell shape, anticlinal boundaries, outer periclinal cell wall and secondary cell wall sculpture are presented. Four types of seed appendages are recognized: (1) seeds with two appendages; (2) seeds without appendages; (3) seeds with minutely a piculate at one end; and (4) seeds with minutely a piculate at both ends. Two types of anticlinal cell wall boundaries, (1) raised-channeled, straight and (2) raised, straight or sinuous, and three different shapes of outer periclinal cell wall are described: (1) flat; (2) concave; and (3) flat to slightly concave. The secondary sculpture of the cell wall varies from striate to micro-reticulate or reticulate, and smooth to finely folded. Seed characters provide useful data for formulating the taxonomy of Juncus both on the subgeneric and sectional level. A key for the identification of the investigated taxa based on seed characters is provided.
Editors-in-Chief
Song Ge
Jun Wen
Impact Factor
2.779
JCR 2019 IF ranking: 56/234 (Plant Sciences, top 23.72%, Q1 quartile)
Journal Abbreviation: J Syst Evol
ISSN: 1674-4918 (Print)
1759-6831 (Online)
CN: 11-5779/Q
Frequency: Bi-monthly

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