Search

The goal of this study was to investigate the postglacial recolonization pathways of the white oaks Quercus robur and Quercus petrea in Poland, and especially to evaluate the impact of Iberian refugium in this part of Europe. Chloroplast DNA polymorphism of 310 individuals older than 200 years was analyzed. Six haplotypes in total were found to differentiate three maternal lineages: the Balkan (haplotypes 4, 5, and 7), the Apennine (haplotypes 1 and 2), and the Iberian (haplotype 12). The most abundant were members of the Balkan (71.5% of all samples) and the Apennine lineage (23.1%), and only 5.4% of individuals were of Iberian origin. The geographic distribution of the three lineages is clearly structured. The northernmost territories of Poland are occupied by Apennine (haplotype 1) and Iberian (haplotype 12) lineages, whereas samples in central and southern Poland represents the Balkan lineage. The population structure might be the result of competitive colonization among lineages after migration from different refugia. It is likely that colonization of northernmost parts of Poland by the Balkan lineage was halted or at least hampered due to the arrival of the Apennine populations. The most significant result of this study concerns the presence and status of the Iberian lineage in Poland, which is most likely of natural origin.

The genetic variability of Scots pine was investigated in six populations from Poland representing two maternal populations and their natural and artificial progenies. Thirteen enzyme systems controlled by 25 allozyme loci were analyzed using starch gel electrophoresis. Progeny populations maintained a high and similar level of genetic variation to that observed in the maternal populations. As expected, much closer genetic relationships were observed between maternal populations and their respective progeny than between the two maternal populations themselves. Progeny populations had the same major alleles, but differed in the number of rare alleles. Therefore, probably not all rare alleles were transferred from the maternal stands to the progenies. In addition, new rare alleles appeared in the progeny populations, possibly as a result of external pollen flow into the maternal populations.

The mating system was analysed in the upper and lower crown of two groups of European larch ( Larix decidua

Study aim: The purpose of this study was to investigate changes in the power output and major morphological characteristics during the competition phase. We hypothesised that substantial overloads occurring during this stage cause a decrease in body mass, fat and power output levels in the cyclists.

Disturbances in the vehicle motion may be caused by different factors and in many cases are the reason for dangerous traffic incidents. Disturbances within the human-vehicle system are particularly hazardous. An innovative method was designed for analyzing and simulating the process of loss of vehicle motion stability after interference in the steering system, e.g. by acting on the steering wheel by the passenger. The subject of the study is the theoretical and experimental analysis of the vehicle motion path kinematics together with the duration of the disturbance, driver’s reaction time and steering wheel turning angles. PC-Crash simulation software was employed for the purpose of studying the disturbance characteristics and their influence on the loss of vehicle motion stability. It is recognized that the studied issues are as yet poorly understood, the presented results expand our knowledge base in this area and can be employed for the purpose of analysis of actual traffic accidents.

In order to broaden the database of motor vehicle traction properties in unusual conditions, the research team has performed experimental studies: on wet and snow-covered surfaces. Tests of vehicles equipped with winter tyres with non-skid snow chains have been performed on snow-covered surfaces. It has been shown that on snowy surface chains affect vehicle traction properties, mostly during acceleration. They increase the rate of acceleration up to 50% compared to a vehicle with winter tyres without chains. The results of the performed research can be the basis for the full reconstruction of road accidents under these conditions. Knowledge of traction properties of cars in difficult and unusual conditions is an important cognitive factor and serves to improve road safety.