Search results for "Tree"
showing 10 items of 1841 documents
Phytoscreening as an efficient tool to delineate chlorinated solvent sources at a chlor-alkali facility
2017
Chlorinated ethenes (CE) are among the most common volatile organic compounds (VOC) that contaminate groundwater, currently representing a major source of pollution worldwide. Phytoscreening has been developed and employed through different applications at numerous sites, where it was generally useful for detection of subsurface chlorinated solvents. We aimed at delineating subsurface CE contamination at a chlor-alkali facility using tree core data that we compared with soil data. For this investigation a total of 170 trees from experimental zones was sampled and analyzed for perchloroethene (PCE) and trichloroethene (TCE) concentrations, measured by solid phase microextraction gas chromato…
Evaluation of historical atmospheric pollution in an industrial area by dendrochemical approaches
2019
International audience; We conducted a dendrochemical study in order to evaluate the exposure of territories and 19 populations to different types of pollutants and to characterise the history of pollution in one of the 20 most intensely industrialised areas of Europe: the industrial port zone of Fos, also heavily 21 urbanised. 22 To perform the study, two tree species have been selected, Pinus halepensis and Populus nigra, on arural plot located roughly 20 km away from the industrial harbor, an urban plot located in the city of Fos-sur-Mer and an industrial plot. Our study indicated that poplar was a more relevant model forthe dendrochemical studies exhibiting a higher bioaccumulation capa…
Assessment of the possibility of using deciduous tree bark as a biomonitor of heavy metal pollution of atmospheric aerosol
2019
The aim of the research was to assess the possibility to use deciduous tree bark in the biomonitoring of urban areas. The tree bark taken from various deciduous tree species growing in the Opole Province (south-western Poland) was used for the research. The bark was collected from tree trunks in the period of June 2–26, 2017. Concentrations of the heavy metals were determined in the barks by flame atomic absorption spectrometry (FAAS). On the basis of the research, it was determined that type of tree, distance from pollution source, elevation off the ground and the side of trunk from which bark was sampled all influence the research results. A comparison of the values of coefficient of vari…
Soil mutagens are airborne mutagens: variation of mutagenic activities induced in Salmonella typhimurium TA 98 and TA 100 by organic extracts of agri…
2000
As our hypothesis was that soil mutagens are airborne mutagens, possibly modified by soil microorganisms, we checked solvent extracts from agricultural and forest soils collected during late summer in the environment of Mainz, a region highly charged by anthropogenic air pollution, or near Bayreuth, a rural low charged region of Germany, or in a remote region of western Corsica without anthropogenic air pollution for the presence of mutagenicity in Salmonella typhimurium. Levels of mutagenic activities were quantified by calculation of revertants/g from the initial slope of dose-response curves applying tester strains S. typhimurium TA 98 and TA 100 in the absence and presence of an activat…
Influence of De-Icing Salt on K Supply and Street Trees Ecological Status in Riga, Latvia
2009
The study was conducted to evaluate the toxic effect of soil and plant pollution with Na and Cl− on K supply and ecological condition of the street trees (Tilia × vulgaris H.) in Riga during 2005 and 2007. The results revealed that the ecological status of street trees could be characterized as seriously injured due to high concentrations of Na and Cl− in soil (maxNa 1,568.1 mg/kg; maxCl 744.9 mg/kg) and lime leaves (maxNa 1.93%; maxCl 3.00%). The concentrations of Na and Cl− in lime leaves demonstrated a marked tendency to increase during summer, while the concentrations of K in leaves decreased (min. 0.15%). There were close correlations between the concentration of Na and Cl− in lime lea…
Conflicting molecular phylogenies of European long-eared bats (Plecotus) can be explained by cryptic diversity
2002
Abstract Conflicting phylogenetic signals of two data sets that analyse different portions of the same molecule are unexpected and require an explanation. In the present paper we test whether (i) differential evolution of two mitochondrial genes or (ii) cryptic diversity can better explain conflicting results of two recently published molecular phylogenies on the same set of species of long-eared bats (genus Plecotus). We sequenced 1714 bp of three mitochondrial regions (16S, ND1, and D-loop) of 35 Plecotus populations from 10 European countries. A likelihood ratio test revealed congruent phylogenetic signals of the three data partitions. Our phylogenetic analyses demonstrated that the exis…
Minimal Absent Words in Rooted and Unrooted Trees
2019
We extend the theory of minimal absent words to (rooted and unrooted) trees, having edges labeled by letters from an alphabet \(\varSigma \) of cardinality \(\sigma \). We show that the set \(\text {MAW}(T)\) of minimal absent words of a rooted (resp. unrooted) tree T with n nodes has cardinality \(O(n\sigma )\) (resp. \(O(n^{2}\sigma )\)), and we show that these bounds are realized. Then, we exhibit algorithms to compute all minimal absent words in a rooted (resp. unrooted) tree in output-sensitive time \(O(n+|\text {MAW}(T)|)\) (resp. \(O(n^{2}+|\text {MAW}(T)|)\) assuming an integer alphabet of size polynomial in n.
Recent mathematical approaches to reconstruct phylogenies: A chemosystematist's and botanist's view
1989
Some basic problems of mathematical phylogenetics are discussed. While algorithms regularly depend on the principle of parsimony, some features of phylogenesis interfere with that principle. Nonrandomness of the distribution of mutations as well as the inconstancy of the molecular clock in time and within a given sequence can bias the calculated relationships of closely related taxa. True comparability of sequences is difficult to establish, since this requires defining of homology of positions and of functions of amino acids as well. Parallelism and convergence can give rise to errors in establishing homology. Furthermore, they are difficult to be integrated into a consistent mathematical …
Cracking the nut: Geographical adjacency of sister taxa supports vicariance in a polytomic salamander clade in the absence of node support
2008
The urodelan genus Lyciasalamandra, which inhabits a relatively small area along the southern Turkish coast and some Aegean islands, provides an outstanding example of a diverse but phylogenetically unresolved taxon. Molecular trees contain a single basal polytomy that could be either soft or hard. We here use the information of nuclear (allozymes) and mitochondrial (fractions of the 16S rRNA and ATPase genes) datasets in combination with area relationships of lineages to resolve the phylogenetic relationships among Lyciasalamandra species in the absence of sufficient node support. We can show that neither random processes nor introgressive hybridization can be invoked to explain that the m…
Sorption of Cadmium and Zinc in Selected Species of Epigeic Mosses
2014
The sorption abilities of seven moss species growing on the area of Bory Stobrawskie forest (southern Poland) were tested in laboratory. Sorption was carried out in solutions of Zn and Cd chlorides. It has been shown that the sorption properties depend on the moss species and increases in the series as follows: Polytrichum commune < Leucobryum glaucum < Eurhynchium praelongum < Thuidium tamtariscifolium ≤ Dicranum scoparium ≤ Pleurozium schreberi < Sphagnum sp. With help of microscope images, it was also demonstrated that one of the factors affecting the sorption properties of mosses was the level of their surface development. The determined sorption capacity of Zn varies according to speci…