Aim Although whole‐genome duplication (WGD) is an important speciation force, we still lack a consensus on the role of niche differentiation in polyploid evolution. In addition, the role of genome doubling per se vs. later divergence on polyploid niche evolution remains obscure. One reason for this might be that the intraspecific genetic structure of polyploid complexes and interploidy gene flow is often neglected in ecological studies. Here, we aim to investigate to which extent these evolutionary processes impact our inference on niche differentiation of autopolyploids. Location Europe. Taxon Arabidopsis arenosa (Brassicaceae). Methods Leveraging a total of 352 cytotyped populations of diploid‐autotetraploid A. arenosa, we examined differences among climatic niches of diploid and tetraploid lineages both globally, and independently for each tetraploid lineage with respect to the niche of its evolutionary closest relative. Then, we tested whether there was an effect of additional interploidy introgression from other sympatric but ancestrally divergent diploid lineages of A. arenosa on climatic niches of tetraploids. Results Ecological niche shift of tetraploids is only detected when the assignment of populations to intraspecific genetic lineages is considered. We found different patterns of climatic niche evolution (i.e. niche conservatism, contraction or expansion) in each tetraploid lineage when compared to its evolutionary closest relatives. We observed an effect of interploidy gene flow in patterns of climatic niche evolution of the tetraploid ruderal lineage of A. arenosa. Main conclusions The niche shift of tetraploids in A. arenosa is not driven by WGD per se but rather reflects dynamic post‐WGD evolution in the species, involving tetraploid migration out of their ancestral area and interploidy introgression with other diploid lineages. Our study supports that evolutionary processes following WGD—which usually remain undetected by studies neglecting evolutionary history of polyploids—may play a key role in the adaptation of polyploids to challenging environments.

Aim: Although whole genome duplication (WGD) is an important speciation force, we still lack a consensus on the role of niche differentiation in polyploid evolution. In addition, the role of genome doubling per se vs. later divergence on polyploid s niche evolution remains obscure. One reason for this might be that the intraspecific genetic structure of polyploid complexes and interploidy gene flow is often neglected in ecological studies. Here, we aim to investigate to which extent these evolutionary processes impact our inference on niche differentiation of autopolyploids. Location: Europe. Taxon: Arabidopsis arenosa (Brassicaceae). Methods: Leveraging a total of 352 cytotyped populations of diploid-autotetraploid A. arenosa, we examined differences among climatic niches of diploid and tetraploid lineages both globally, and independently for each tetraploid lineage with respect to the niche of its evolutionary closest relative. Then, we tested if there was an effect of additional interploidy introgression from other sympatric but more ancestral diploid lineages of A. arenosa on climatic niches of tetraploids. Results: Ecological niche shift of tetraploids is only detected when the assignment of populations to intraspecific genetic lineages is considered. We found different patterns of climatic niche evolution (i.e. niche conservatism, contraction or expansion) in each tetraploid lineage when compared to its evolutionary closest relatives. We observe an effect of interploidy gene flow in patterns of climatic niche evolution of tetraploid ruderal plants of A. arenosa. Main conclusions: The niche shift of tetraploids in A. arenosa is not driven by WGD per se but rather reflects dynamic post-WGD evolution in the species, involving tetraploid migration out of their ancestral area and interploidy introgression with other diploid lineages. Our study supports that evolutionary processes following WGD – which usually remain undetected by studies neglecting evolutionary history of polyploids – may play a key role in the adaptation of polyploids to challenging environments.

Single-phase Pr 2 CBr was prepared by heating a mixture of PrBr 3 , Pr and C (1 : 5:3) to 1140 • C for 18 d. The crystal structure was investigated by X-ray single crystal diffraction (space group P6 3 /mmc, a = 3.8071 (3), c = 14.7787(12)Å). In the structure the Pr atoms form C-centered octahedra condensed into Pr 2 C sheets via common edges; these sheets are separated by the Br atoms which are in a trigonal prismatic environment of Pr atoms. Pr 2 CBr is a black shiny compound with metallic conductivity. It is a ferromagnet with T c = 13.8(5) K.

Rūrāne I., Evarts-Bunders P., Nitcis M., 2018: Distribution trends of some species of the Brassicaceae family in Latvia. - Botanica, 24(2): 124-131. The aim of this paper was to clarify and analyse the distribution trends of some Brassicaceae species (Bunias orientalis, Sisymbrium volgense, Barbarea arcuata, Draba nemorosa and Camelina alyssum) in Latvia. Field studies and the herbarium material analyses were carried out. The distribution trends were analysed by comparing all selected species in three time periods: by 1940, from 1941 to 1990, and from 1991 to the present. The study shows that the distribution of Brassicaceae species such as Bunias orientalis, Sisymbrium volgense, Barbarea arcuata and Draba nemorosa has increased significantly in Latvia during the time period from 1991 to the present, and these species are mostly found on railway, ruderal areas and roadsides, which are important habitats for species distribution. The occurrence of Camelina alyssum has considerably declined or perhaps the species has even disappeared from the flora of Latvia, which has been affected greatly by changes in the cultivation of agricultural crops as well as in agricultural land management.