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With the help of 21 putative isoenzyme loci, the genetic diversity and variations of Viscum album ssp. album L. from 42 species, subspecies, varieties and hybrids of broadleaf trees, Viscum album ssp. austriacum (Wiesb.) Vollmann, from 4 populations of Scots pine (Pinus sylvestris L.) and Viscum album ssp. abietis (Wiesb.) Abromeit, from 8 populations of European silver fir (Abies alba Mill.) were analyzed. On the dendrogram, the three investigated subspecies form three clusters, each clearly separated from the other, so we suggest a revision of the systematic nomenclature proposed to take into consideration a return to an earlier system of dividing the European mistletoe into three species: Viscum album L., Viscum abietis Beck, and Viscum laxum Boiss. et Reut. From among the 21 tested loci only one locus, SOD-A, was monomorphic. The average number of actual alleles (Na) and effective alleles (Ne) was 2.23 and 1.61 respectively. The observed heterozygosity (Ho) varied from 0.199 in V. album ssp. abietis to 0.345 in the V.a. ssp. album populations. Average FST = 0.277 indicates that about 28% of genetic differentiation is due to an interpopulation diversity of Viscum album populations. There is a small gene flux between Viscum album populations with only one immigrant successfully entering a population per two generations (Nm = 0,653).
The evergreen, semi-parasitic pine mistletoe, Viscum album ssp. austriacum (Wiesb.) Volmann, is one of the four subspecies of European mistletoe, Viscum album L. It is frequently encountered on Scots pine communities in Poland. Distribution of pine mistletoe in representative P. sylvestris stand from the central Poland was investigated. The host density and host size to the frequency of Viscum was verified. Within the studied area 46% out of 313 individuals of P. sylvestris trees were infected by mistletoe, among them 78% in low mistletoe infection, 17% in medium and 3% in high infection. Of 1171 infections recorded on pines, 97% were on branches, 4% on the host trunk. The mistletoe individuals had an aggregated pattern of spatial distribution which was mainly explained by the host size. Infected trees are larger than uninfected ones, on average, and within the infected tree population, trees with mistletoe had higher number of dead branches than trees with none infection. Parasitized trees were more prevalent in low-density stands than in high-density stands. Mistletoes occurred mainly on the outer brunches within trees crowns.
Caspian forests (in the region it is called – Hyrcanian Forests) with an area of about 1.9 million ha are located in north of Iran, in southern coast of Caspian Sea. It is exclusive site for some valuable species like Populus caspica Bornm., Gleditsia caspica Desf., Parrotia persica Meyer. and Pterocaria fraxinifolia (Lam.) Spach., and the forests are dominated by Fagus orientalis Lipsky, Quercus castanifolia C. A. M., and Alnus glutinosa Gaertn. The mistletoe (Viscum album L.) effects on the area and weight of leaves of the two host tree species ( hornbeam Carpinus betulus L. and ironwood Parrotia persica Meyer.) were studied on a number of severely infected individuals and control trees in selected parts of Hyrcanian Forests. Almost 100 leaves from infested and non-infested branches of two host species were sampled in order to compare with control trees (non-infested trees growing near each host). Results showed, that area and weight of leaves taken from infested branches of ironwood were significantly lower (at 95% confidence level) than leaf area and weight in non-infested branches and control trees. The amount of K, Mn and Zn was higher in infested branches of both species compared to control trees. However, the amount of nitrogen in infected branches of ironwood was lower. The results suggest that V. album may have detrimental effect on leaf structure, physiology and chemical composition of strongly infested host trees.
The density and behavior of the Mistle Thrush in Niepołomice Forest (southern Poland) and adjacent open areas were studied during winter (December-February) in 1996/97, 1998/99 and 2000/01. Mistle Thrush densities differed significantly from winter to winter, and the abundance of thrushes decreased as the season progressed. Bird density and mistletoe clump density were correlated positively. Birds held territories or congregated in flocks. The latter were sighted in the forest only during winter 1996/97, when the largest density of birds was noted. Flock size decreased progressively during that winter, but at the same time, the number of territorial birds remained stable. This suggests that by the end of the winter 1996/97 some birds from the flocks had begun to hold territories. Flocks were also seen in open areas, and displayed a preference for foraging on pastureland. Each individual territory in the forest consisted of several clumps of mistletoe on a few adjacent trees, which were defended against both conspecifics and other species such as Pyrrhula pyrrhula, Turdus merula and Dendrocopos major. The aggressive encounter rate was correlated positively with bird density but negatively with the progress of winter (the latter was correlated negatively with the berry supply). Surprisingly, it was not correlated with mistletoe clump density or temperature. During abundant berry years, the density of birds may have been so large that defending the fruit against numerous neighbors would have been energetically less profitable than communal foraging.
Chloroform, butanolic and water fractions from the methanolic extracts of Lamium album L. and L. purpureum L. flowers and different organs of mistletoe (Viscum album L.), namely leaves, stalks and fruits were investigated for the free radical scavenging properties by using colour free radical DPPH • as a stain reagent for dot-blot assay on a T LC plate and two-dimensional thin-layer chromatography (2D-TLC) analysis (2D-TLC-DPPH test) as well as a dye reagent for the spectrophotometric assay. For each plant material, butanolic fractions showed the strongest activity, of which those of the Lamium species were nearly equal to that of the known antioxidant - BHA. According to 2D-TLC chromatography, the phenolic compounds present were responsible for the antiradical activity of the fractions.
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