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11.
An allozyme analysis of 67 Pinus sylvestris L. populations distributed over the entire species range has provided a basis for determining locations of 12 hypothetical Pleistocene refugia (HPRs) in its southern marginal part and estimating their relative contributions to the gene pools of seven phylogeographic population groups (PPGs) in the glaciated zone of the range. Using Nei’s (1978) minimum genetic distances (DN78 < 0.015) reflecting similarities and differences in allele frequencies between PPGs and the refugia, it has been shown that the main contributions to the P. sylvestris gene pool in Central Europe, Scandinavia, and the Russian Plain were probably made by the Balkan and Southern Ural refugia, and in Western and Central Siberia, by the Southern Ural, Turgai, and Southern Siberian mountain refugia.  相似文献   
12.
Comparative allozyme analysis of 26 marginal island populations of Pinus sylvestris L. and 20 populations from the center of the species range has confirmed, at the species level, the Wright-Dubinin “island model” of automatic genetic processes and Mayr’s hypothesis about homozygotization of small isolated populations at range boundaries. It has been shown that the polymorphism of isolated populations sharply decreases when their area is reduced below 15–20 km2 and increases to the level observed in the center of the range when the population area exceeds 50–100 km2. A chorogenetic classification of marginal P. sylvestris populations is proposed.  相似文献   
13.
Environmental Science and Pollution Research - This article delves into the factors that may influence radon flux, such as soil properties and weather conditions, on the example of two experimental...  相似文献   
14.
Nei's genetic distances (Nei, 1972, 1978) between 12 Scotch pine (Pinus sylvestris L.) populations were determined using isozyme analysis. The gradients of these distances along the 1500-km meridional transect in the Transural Region and Northern Turgai from the pre-forest-tundra subzone (the Synya River basin) to the southern steppe (the Naurzumskii forest) were calculated. We discovered that the genetic distance gradients (GDGs) progressively increase in the direction from the northern boundary of the range to the southern boundary of the forest-steppe zone and sharply increase in the insular forests growing in the steppe zone. The results of cluster analysis and Mahalanobis distance gradients with respect to a set of morphological characters of the cones provide evidence that Scotch pine populations of the forest zone share somewhat the same gene pool, whereas the group of Scotch pine populations in the insular forests of Northern Turgai is obviously differentiated phenogenetically from the insular forests of the Tobol region, which grow farther to the north.  相似文献   
15.
The thesis of the genetic divergence of Pinus sylvestris L. populations that have spread to bogs from the original dry-land populations has been deduced from the concept of the cyclicity of helio- and geophysical processes, derivative postulates on climatic cycles, formation of Holocene high bogs, contrasting differentiation between their environment and that of dry meadows, and the resultant changes in the vectors of microevolutionary factors and strong reproductive isolation between these populations. Logical genetic, ecological-phenotypical, and geographic consequences of this theory have been verified by factual data and general laws known to date. The interpolational and predictive roles of the new theory are demonstrated.  相似文献   
16.
The allozyme analysis of six local populations of Pinus mugo Turra and six populations of P. sylvestris L. in the Ukrainian Carpathians, Swiss Alps, and Schwarzwald has shown a higher polymorphism and greater interpopulation differentiation of the Carpathian group of P. mugo populations compared to the Alpine group (Nei’s genetic distance DN 78 at the level of geographic population group is −0.023). A genetic differentiation of DN 78 = 0.049 between these populations, which are isolated by a distance of more than 1000 km, has been found. This confirms the existence of the subspecies P. mugo ssp. mugo and P. mugo ssp. uncinata in the Carpathians and Alps, respectively. The hypothesis is put forward that the former subspecies has been formed in the Balkans and the latter, in the Pyreneans. It has been demonstrated that regional populations and geographic groups of P. sylvestris are less differentiated than those of P. mugo.  相似文献   
17.
The genotoxic action of copper (Cu) on the polytene chromosomes of Chironomus riparius was investigated by analysing structural and functional chromosome aberrations of fourth instars larvae hatched from eggs subject to acute (48 h) exposure with three environmentally relevant concentrations of aqueous Cu (0.005, 0.01, 0.05 mg/l). A dose dependent relationship was observed between Cu concentration and frequency of chromosomal aberrations. A significantly higher frequency of functional alterations, specifically decondensed centromeres and telomeres, and reduction in activity of Balbiani rings, was observed in treated material compared to control. A comparison of breakpoints resulting from treatment with chromium and lead from earlier studies with those Cu-induced identified a series of chromosomal weak points particularly vulnerable to trace metals. We also show that the appearance of structural and functional chromosome aberrations are more sensitive indicators of acute Cu toxicity in chironomid larvae than changes in external morphology.  相似文献   
18.
- A previously unknown pollutant in river water was identified to be 2-mercaptobenzothiazole (2-MBT) by interpretation and simulation of its GC/LRMS spectrum. Further GC/HRMS measurement of the isotope composition of the molecular ion verified this structure. 2-MBT is a well-known agent for corrosion inhibition and a stable metabolite of several other benzothiazoles. The present 2-MBT trace was most probably a metabolite of the wood preservative TCMTB which leaked from an upstream sawmill. The metabolite had been detected earlier in urine of the sawmill workers, but now was identified in the recipient water environment for the first time.  相似文献   
19.
The distribution of nine chloroplast DNA haplotypes in four insular North-Atlantic and four European coastal Atlantic populations of Calluna vulgaris in the glacial zone of the range has been analyzed in comparison with that in six marginal southern populations in the nonglacial zone of the Atlantic and Mediterranean regions. As a result, two hypothetical Pleistocene refugia (HPRs) for this C. vulgaris population group have been revealed, one in the Cévennes mountain range and the other in the Southern Alps (Trento). Judging from the 1–FST value, it has been found that the group of populations in the glacial Atlantic zone and adjacent European coastal Atlantic region is genetically similar to the HPR in the Cévennes at a highly significant level (p ≥ 0.999) and less similar to the HPR in Trento; however, it differs significantly from other Mediterranean and Atlantic populations. It has been concluded that the most probable hypothetical Pleistocene refugium for the recent C. vulgaris populations of the northeastern Atlantic and European coastal Atlantic regions was in the west of the Mediterranean, in the Cévennes, while the additional refugium was in the Southern Alps. Possible directions of the postglacial dispersal and recolonization of habitats by C. vulgaris populations from the western Mediterranean to the northeast of the Atlantic and to Scandinavia have been revealed.  相似文献   
20.
This paper focuses on the embeddedness of energy poverty – understood as the inability to secure a socially and materially necessitated level of energy services in the home – in the socio-technical legacies inherited from past development trajectories, as well as broader economic and institutional landscapes. Using Hungary as an example, we explore the recent expansion of energy poverty across different demographic and income groups. While much of the mainstream literature focuses on cases where energy poverty affects distinct social groups and issues, our analyses examine the systemic implications of a form of deprivation that involves a much wider range of social and spatial strata. We develop a framework that highlights the different ways in which inadequate access to energy services has resulted in the emergence of new political reconfigurations among a variety of actors, while prompting the articulation of household strategies with far-reaching structural consequences.  相似文献   
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