Cytology and its systematic implications in Sinosenecio (Senecioneae-Asteraceae) and two closely related genera

Liu, Ying; Yang, Qin‐Er

doi:10.1007/s00606-010-0365-3

Cited by 13 publications

(12 citation statements)

References 19 publications

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“…Therefore, x = 18 appears to be the ancestral number in Dolomiaea and all related genera, and from this number, independent decreases led to x = 17 or other numbers in the different genera (Table 1, Figure 4). Similarly high basic chromosome numbers resulting from such paleopolyploidization events and aneuploid decreases also occurred in Ligularia and related genera (Liu 2004), Sinosenecio and related genera (Liu and Yang 2011), Leontopodium (Meng et al 2012) and a number of other genera or tribes (Robinson et al 1997;Carr et al 1999). …”

Section: Discussionmentioning

confidence: 99%

Chromosomal studies on the alpine genusDolomiaea(Asteraceae: Cardueae) from the Qinghai-Tibet Plateau and adjacent regions

et al. 2013

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Chromosomal characteristics are important for our understanding of the evolutionary history of species diversification. However, these characteristics are as yet unknown for some plant genera, especially those in alpine regions. In this study, our aim was to investigate the chromosome numbers and karyotypes of Dolomiaea, an alpine genus occurring in the Qinghai-Tibet Plateau and adjacent regions, for the first time. We report the chromosome numbers and karyotypes of 10 species originally assigned to Dolomiaea, one species which has been suggested should be transferred to this genus and one species from the closely related genus Himalaiella. Two chromosome numbers, i.e. 2n = 36 and 2n = 34, were found in these 12 species. One B chromosome was observed in two species. Karyotypes of all the species examined are relatively asymmetrical, and are classified as Stebbins' types 3B and 2B. These findings suggest that polyploidization events played a minor role in species diversification in this alpine genus. Aneuploidy and karyotypic differentiation at the diploid level, instead, contributed greatly to species diversification in this genus. However, many lines of evidence indicate that the ancestor of the genus originated from an ancient polyploidization event. In addition, our results provide cytological evidences of the transference of Frolovia frolovii and Saussurea costus to Dolomiaea, a recent proposal based on molecular phylogenetic context.

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Section: Discussionmentioning

confidence: 99%

Chromosomal studies on the alpine genusDolomiaea(Asteraceae: Cardueae) from the Qinghai-Tibet Plateau and adjacent regions

et al. 2013

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“…In morphological terms, the genus is circumscribed mainly based on a densely crowded capitula on a thick and hollow stem, with two layers of phyllaries, where the outer layer are much smaller (Stebbins 1940). Molecular phylogenetic analyses indicate that Syncalathium might be the sister group of Soroseris , in line with their similarity in morphology, such as densely crowded capitula (Zhang et al 2011), the chromosome number and the preferred habitat in high altitude (Zhang et al 2007; Ying and Yang 2011; Yang et al 2017).…”

Section: Introductionmentioning

confidence: 84%

Radiation of members of the Soroseris hookeriana complex (Asteraceae) on the Qinghai-Tibetan Plateau and their proposed taxonomic treatment

Heng¹,

Zheng²,

Zhao³

et al. 2018

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The existence of intermediate types is a major obstacle that can hinder the circumscription of species. Elucidating the mechanism responsible for intermediate types is essential for achieving a reasonable taxonomical treatment. In this study, we explored the evolutionary history and taxonomic treatment of the Soroserishookeriana (C.B.Clarke) Stebbins complex, which comprises six named taxa that may be taxonomically distinct and are all native to the Qingha-Tibetan Plateau (QTP). We made an investigation across the distribution range of Soroseris Stebbins and sampled 27 populations, mostly from the complex. Internal transcribed spacer (ITS) and two chloroplast loci were sequenced and analysed using the neighbour-joining and Bayesian inference methods. The resulting phylogenies show no well supported inconsistence in topologies, in line with the lack of incongruence detected by the length difference test. However, all the trees were largely unresolved within S.hookeriana complex, irrespective of the optimality criterion employed. We interpret these results as an experience of radiation, which is a common process for native genera on the QTP. Thus, we suggest that all of the morphotypes might be different forms, generated by incipient speciation due to recent explosive differentiation, possibly triggered by the drastic environmental changes of the QTP. Given their evolutionary history, we propose a pragmatic method for treating all of these species as subspecies with a total of four new combinations.

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“…Chromosome numbers are well known to have significant taxonomic value at subtribal and generic levels in Senecioneae (Robinson & al., 1997), and we have successfully used them for the re‐delimitation of Sinosenecio B.Nord. (Y. Liu & Yang, 2011a,b) and Parasenecio (Ren & al., 2017) in the eastern Asian Tussilagininae. Here, L. lancifera was revealed to have 2 n = 58, indicating its phylogenetic position in Ligularia , which has a base chromosome number of x = 29 (e.g., Huang & al., 1996; Gong & al., 2001; J.Q.…”

Section: Discussionmentioning

confidence: 99%

“…& J.Small and Sinacalia B.Nord. In addition, the position of L. songarica is also supported by its chromosome number, a character very useful in generic taxonomy in eastern Asian Tussilagininae (Y. Liu & Yang, 2011a,b; Ren & al., 2017). Ligularia songarica has n = 30 (Afzelius, 1949), which is incongruent with the base chromosome number of x = 29 in Ligularia (e.g., Huang & al., 1996; Gong & al., 2001; J.Q.…”

Section: Introductionmentioning

confidence: 99%

Circumscription and phylogenetic position of Ligularia sect. Stenostegia (Asteraceae: Senecioneae) based on morphological, cytological, and molecular phylogenetic evidence

Ren

Wang

Illarionova

et al. 2020

TAXON

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Ligularia sect. Stenostegia (Asteraceae: Senecioneae) has been questioned about its monophyly and phylogenetic position in our previous study. To settle the dispute, we here verify the phylogenetic pattern of L. sect. Stenostegia with a much denser taxon sampling in the section. The results have corroborated our previous hypothesis, by showing that L. sect. Stenostegia is monophyletic only after excluding L. lancifera, and that the core L. sect. Stenostegia is more closely related to Parasenecio and Sinacalia than to Ligularia. The relationships are further supported by evidence from morphology and geographical distribution, and the results of cytological studies and statistical topology tests in this study. The core L. sect. Stenostegia, with the absence of expanded leaf sheaths and a base chromosome number of x = 30, is substantially different from Ligularia, while congruent with Parasenecio and Sinacalia. Its concentrated distribution in eastern Central Asia also readily sets it apart from Ligularia, which is mainly distributed in eastern Asia, with the center of species diversity in the Himalayas and the Hengduan Mountains region in southwestern China. In contrast, L. lancifera has greatly expanded leaf sheaths, a chromosome number of 2n = 58, and a distribution in eastern Xizang (Tibet) in China, all perfectly matching the features of Ligularia. The AU and SOWH statistical topology tests also strongly favor this phylogenetic hypothesis, by significantly rejecting the alternative hypotheses in current classification. Based on all the evidence, L. lancifera is excluded from L. sect. Stenostegia, and the core L. sect. Stenostegia is segregated as an independent genus of its own, with a new name Vickifunkia. Keywords central Asia; chromosome number; eastern Asia; statistical topology test; Tussilagininae; Vickifunkia Supporting Information may be found online in the Supporting Information section at the end of the article.

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Cytology and its systematic implications in Sinosenecio (Senecioneae-Asteraceae) and two closely related genera

Cited by 13 publications

References 19 publications

Chromosomal studies on the alpine genusDolomiaea(Asteraceae: Cardueae) from the Qinghai-Tibet Plateau and adjacent regions

Chromosomal studies on the alpine genusDolomiaea(Asteraceae: Cardueae) from the Qinghai-Tibet Plateau and adjacent regions

Radiation of members of the Soroseris hookeriana complex (Asteraceae) on the Qinghai-Tibetan Plateau and their proposed taxonomic treatment

Circumscription and phylogenetic position of Ligularia sect. Stenostegia (Asteraceae: Senecioneae) based on morphological, cytological, and molecular phylogenetic evidence

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