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Peterson A.,Martin Luther University of Halle Wittenberg | Levichev I.G.,Russian Academy of Sciences | Peterson J.,State Office for Environmental Protection of Saxony Anhalt | Harpke D.,Leibniz Institute of Plant Genetics and Crop Plant Research | Schnittler M.,University of Greifswald
Organisms Diversity and Evolution | Year: 2011

A new region of speciation for the genus Gagea (Liliaceae) was investigated (Bogda-Shan and Urumqi; northwestern Xinjiang, China). Two species were recorded as new for the region (G. rufidula, G. davlianidzeae); three species are described as new to science (G. angelae, G. jensii and G. huochengensis). The description of G. nigra is emendated. Sequence data (cpDNA: TrnL-trnF IGS+psbAtrnH IGS, nrDNA: ITS), including representatives of all Gagea sections, were used to compare the new species with closely related taxa. A nuclear single copy gene region (pCOS At103) was analysed for representatives of the Sects. Minimae and Gagea. Network analysis of cpDNA and nDNA indicates hybridization and recent speciation in Xinjiang. ITS and pCOS At103 sequences reveal gene flow between G. davlianidzeae and G. nigra. A cpDNA haplotype network constructed from representatives of Sect. Gagea was highly informative phylogenetically. Gagea angelae and G. huochengensis, sharing gene flow, are related closely to a basal clade represented by G. ancestralis, G. xiphoidea and G. capusii, which may include the putative progenitor of all other taxa of the large Eurasian Sect. Gagea. Whereas speciation in Sect. Minimae seems to be driven mainly by hybridization, speciation in the Sect. Gagea may be influenced by both hybridization and geographical separation. We confirm the monophyly of Sects. Bulbiferae and Minimae. © Gesellschaft für Biologische Systematik 2011.

Peterson A.,Martin Luther University of Halle Wittenberg | Harpke D.,Leibniz Institute of Plant Genetics and Crop Plant Research | Levichev I.G.,RAS Komarov Botanical Institute | Beisenova S.,L.N.Gumilyov Eurasian National University | And 2 more authors.
Plant Systematics and Evolution | Year: 2016

The most important center of speciation in the genus Gagea is thought to be in Central Asia. Here, we focus on species diversity in southeastern Kazakhstan (around Almaty, Ili-Alatau range of the Western Tian-Shan mountains). We studied an elevational transect, reaching from lowland steppes to the alpine zone (500–2750 m a. s. l.), and carried out detailed morphological and molecular investigations for populations of Gagea spp. Nine species were identified in different altitudinal zones; one of these (Gageaalmaatensis) is described as new to science. We could detect two altitudinal contact zones between closely related species: G. filiformis and G.granulosa (sect. Minimae), and G. almaatensis and G.kuraminica (sect. Gagea). Morphological and molecular investigations (ITS data and cpDNA networks) indicate ongoing hybridization of co-occurring G. filiformis into G. granulosa and putative bidirectional hybridization events between G. almaatensis and G. kuraminica. © 2016 Springer-Verlag Wien

Beisenova S.,L.N.Gumilyov Eurasian National University | Peterson A.,Martin Luther University of Halle Wittenberg | Peterson J.,State Office for Environmental Protection of Saxony Anhalt | Bersimbaev R.I.,L.N.Gumilyov Eurasian National University | And 2 more authors.
Flora: Morphology, Distribution, Functional Ecology of Plants | Year: 2015

The life history of the geophyte Gagea bulbifera (Pall). Salisb. was studied by quantitative analyses of plant structures, estimation of resource allocation by measuring the nitrogen content of different plant organs, and employing Amplified Fragment Length Polymorphism (AFLP) analyses for an estimate of genetic diversity. The species occurs in arid steppes and semi deserts in large populations with densities of 50-250(-400) individuals per square meter. Adaptations on this extreme habitat include (i) sclerified roots protecting the dormant bulb against summer desiccation, (ii) extremely high seed set compared to other species of the genus, and (iii) only occasional formation of a single basal bulbil. Less than 9% of adult, flowering plants formed a basal bulbil in the studied populations in southern Kazakhstan. Flowering plants are 5-15. cm tall; develop two basal and 2-5 stem leaves, each with a tiny (<0.5. mm) axillary bulbil; 1-2(-4) flowers and 119. ±. 90 seeds. If nitrogen is taken as a proxy for resource allocation, adult plants invest up to 30% of the total nitrogen content in seeds. This amount increases with replacement bulb size and diverts an increasing amount of resources from the latter, explaining the comparatively small size of the plants. Much less (<5%) resources are found in basal and axillary bulbils. Using AFLP we found 48 different genotypes among 53 plants tested, indicating predominant recruitment by seeds. These adaptations, coming close to an annual life style, place G. bulbifera apart from most species of the genus. © 2014.

Peterson A.,Martin Luther University of Halle Wittenberg | Harpke D.,Martin Luther University of Halle Wittenberg | Peruzzi L.,University of Pisa | Tison J.,Promenade des Baldaquins | And 2 more authors.
Plant Biosystems | Year: 2010

Gagea bohemica s.l. (Liliaceae) consists of two morphologically extreme forms (saxatilis and bohemica) which depending on the varying opinions of the authors are considered as separate species, subspecies or as a single variable species. In this study, morphological (form and length of perianth segments, pilosity of pedicles and peduncles) and molecular data (cpDNA trnL-trnF IGS) of 55 samples corresponding to 43 populations from Western Europe to the Mediterranean area and eastern Caucasus were investigated. G. bohemica (Zauschn.) Schult. & Schult. f. represents a highly variable monotypic species from both morphological and karyological (2n = 24, 36, 48, 60, 72) aspects. Based on the molecular and morphological data presented here, a differentiation between specific and infraspecific taxa is not possible. We hypothesize that the morphological variability of this species is largely influenced by different site conditions and ploidy level. © 2010 Società Botanica Italiana.

Frohne T.,University of Wuppertal | Rinklebe J.,University of Wuppertal | Langer U.,State Office for Environmental Protection of Saxony Anhalt | Du Laing G.,Ghent University | And 2 more authors.
Biogeosciences | Year: 2012

An automated biogeochemical microcosm system allowing controlled variation of redox potential (EH) in soil suspensions was used to assess the effect of various factors on the mobility of mercury (Hg) as well as on the methylation of Hg in two contaminated floodplain soils with different Hg concentrations (approximately 5 mg Hg kg -1 and >30 mg Hg kg -1). The experiment was conducted under stepwise variation from reducing (approximately-350 mV at pH 5) to oxidizing conditions (approximately 600 mV at pH 5). Results of phospholipid fatty acids (PLFA) analysis indicate the occurrence of sulfate reducing bacteria (SRB) such as Desulfobacter species (10Me16:0, cy17:0, 10Me18:0, cy19:0) or Desulfovibrio species (18:2ω6,9), which are considered to promote Hg methylation. The products of the methylation process are lipophilic, highly toxic methyl mercury species such as the monomethyl mercury ion [MeHg +], which is named as MeHg here. The ln(MeHg/Hgt) ratio is assumed to reflect the net production of monomethyl mercury normalized to total dissolved Hg (Hgt) concentration. This ratio increases with rising dissolved organic carbon (DOC) to Hgt ratio (ln(DOC/Hgt) ratio) (R 2 Combining double low line 0.39, p 0.0001, n Combining double low line 63) whereas the relation between ln(MeHg/Hgt ratio and lnDOC is weaker (R 2 Combining double low line 0.09; p 0.05; n Combining double low line 63). In conclusion, the DOC/Hgt ratio might be a more important factor for the Hg net methylation than DOC alone in the current study. Redox variations seem to affect the biogeochemical behavior of dissolved inorganic Hg species and MeHg indirectly through related changes in DOC, sulfur cycle, and microbial community structure whereas EH and pH values, as well as concentration of dissolved Fe 3+/Fe 2+ and Cl seem to play subordinate roles in Hg mobilization and methylation under our experimental conditions. © 2012 Author(s).

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