Weronika Żukowska

Context Black poplar (Populus nigra L.) is a keystone species of European riparian ecosystems that has been negatively impacted by riverside urbanization for centuries. Consequently, it has become an endangered tree species in many European countries. The establishment of a suitable rescue plan of the remaining black poplar forest stands requires a preliminary knowledge about the distribution of genetic variation among species populations. However, for some parts of the P. nigra distribution in Europe, the genetic resources and demographic history remain poorly recognized. Aims Here, we present the first study on identifying and characterizing the genetic resources of black poplar from the Oder valley in Poland. This study (1) assessed the genetic variability and effective population size of populations and (2) examined whether gene flow is limited by distance or there is a single migrant pool along the studied river system. Methods A total of 582 poplar trees derived from nine blac...

The black poplar (Populus nigra L.) is an ecologically and economically important tree species, characteristic for floodplain forests in Europe. It is now considered to be endangered in many European countries due to the loss of its natural habitat caused by the development of river engineering and intensive land use management of riverside areas. Multi-stem specimens can be found occasionally in natural black poplar populations. The percentage of such individuals is low, although in some stands it may be over a dozen percent. The origin of multi-stem trees may be different. As a consequence, trunks being part of such a tree can have the same or different genotypes. The study aimed to find out whether all trunks of multi-stem black poplars are ramets of the same genet or if their genotypes are different, in which case they increase the gene pool of the population. We used 13 microsatellite nuclear markers to analyze the genotypes of 83 trunks belonging to 34 multi-stem black poplar ...

The rychtal pine is one of the most valuable ecotypes of Scots pine (<em>Pinus sylvestris</em> L.) approved for the breeding purposes in Poland. However, it occupies stands typical for oaks and beeches as shown by the compatibility analysis of species composition in relation to the habitat type in which they occur. Such result raises some doubts in terms of the naturalness of the rychtal pine and calls its history and origin into question. In the present study, we used the set of nuclear microsatellite markers to characterize and compare the gene pool composition of the selected seed tree stands of the rychtal pine with 200−year−old pine trees which grow at the Syców Forest District (SW Poland). We aimed to know to what extent the set of alleles specified for the group of the oldest trees from natural habitats is represented in the younger forest tree stands of the rychtal pine. The analysis of molecular variance (AMOVA) and clustering analysis showed that the gene pool ...

A plant growth-promoting rhizobacterium (PGPR) was isolated and identified as Gordonia sp. S2RP-17, which showed ACC deaminase and siderophore synthesizing activities. Its maximum specific growth rate was 0.54 ± 0.12 d(-1) at 5,000 mg L(-1) of total petroleum hydrocarbon (TPH), and its maximum diesel degradation rate was 2,434.0 ± 124.4 mg L(-1) d(-1) at 20,000 mg L(-1) of TPH. The growth of Zea mays was significantly promoted by the inoculation of Gordonia sp. S2RP-17 in the diesel-contaminated soil. Measured TPH removal efficiencies by various means were 13% by natural attenuation, 84.5% by planting Zea mays, and 95.8% by the combination of Zea mays and Gordonia sp. S2RP-17. The S2RP-17 cell counts were maintained at 1 × 10(6) CFU g-soil(-1) during the remediation period, although they slightly decreased from their initial numbers (2.94 × 10(7) CFU g-soil(-1)). These results indicate that rhizoremediation using both Zea mays and Gordonia sp. S2RP-17 is a promising strategy for enhancing remediation efficiency of diesel-contaminated soils.

All tree breeders cope with the same challenge of the very long time interval of a single breeding cycle. What is more, trees are long−lived, with desirable breeding traits expressing late during their life cycle. Increasing problems with climate change, globalization or economic growth have forced us to accelerate tree breeding and improve selection precision, both of which can be achieved by genomic selection (GS). The idea of GS was introduced nearly 20 years ago as an extension of marker−assisted selection (MAS) in order to advance breeding technologies using genetic markers. Unlike MAS, which exploits only a set of marker−trait associations, GS relies on a high number of genetic markers that are spread throughout the entire length of the genome. All markers effects are assessed simultaneously in order to build a precise model that allows prediction of genetic estimated breeding value of a particular individual using genetic data only. GS has already revolutionized dairy cattle ...