Analysis of mating system in two Pinus cembra L. populations of the Ukrainian Carpathians

Volume 51 (1), 2008, pages 11-18Back Analysis of mating system in two Pinus cembra L. populations of the Ukrainian Carpathians     D.V. PolitovLaboratory of Population Genetics, Vavilov Institute of General Genetics, Russian Academy of Sciences Y.V. PirkoInstitute of Cell Biology and Genetic Engineering, Ukraine N.N. PirkoInstitute of Cell Biology and Genetic Engineering, Ukraine E.A. MudrikDonetsk Botanical Gardens, Ukraine I.I. KorshikovDonetsk Botanical Gardens, Ukraine  contact authors by Editorial Office  SUMMARY  In natural pine populations, a mixed mating system is typical, characterized by the proportions of selfed and outcrossed seeds. Swiss stone pine (Pinus cembra L.) is one of the least studied European conifers in this respect. The mating system of six polymorphic allozyme loci were studied in haploid megagametophytes and diploid open-pollinated embryos in two stands located in the East Carpathians. In the 'Gorgany' population (24 trees, 198 seeds) the mean singlelocus estimated outcrossing rate (ts) was 0.731, and the multilocus estimate (tm) was 0.773. In the 'Yayko' population the outcrossing rate was lower (27 trees, 213 seeds, ts=0.645, tm=0.700), suggesting 23-30% of seeds are self-pollinated. Correlation of outcrossing rate estimates among loci was less than 1, (0.300 in 'Gorgany' and 0.469 in 'Yayko') indicating biparental inbreeding occurred. Differences between tm and ts (0.042 in 'Gorgany' and 0.056 in 'Yayko') can also be influenced by consanguineous mating, indicated by the presence of spatial and genetic family structure. In small isolated populations of Pinus cembra, which are typical for the Carpathian part of the species' range, inbreeding depression may negatively affect seed quality. The high proportion of selfed seeds observed here can be expected in any seedlot of this species and should be taken into account while planning gene conservation or reforestation measures. Maternal trees in these populations showed no heterozygote deficiency at these allozyme loci, and instead showed increased proportions of heterozygotes (inbreeding coefficient FIS = -0.200 in 'Gorgany' and -0.142 in 'Yayko'). Balancing selection may explain heterozygosity levels up to and above equilibrium proportions.</table

Diversity and Vitality of Tree Species in the Street Plantations of Kryvyi Rih City

The important factor of improving the ecological-esthetical role of green plantations in the city environment is a reasoned selection of tree species for greening city territories. That is why there is a necessity to study the state of green plantations in industrial cities. The aim of the work was to study the diversity of dendroflora in city plantations in green plantations of Saksagansky district of Kryvyi Rih city and to reveal decorative species of tree plantations, most resistant to conditions of the urbanized environment. The studies were conducted by the method of inventory of green plantations with defining their type, forest valuation parameters and vitality level. It was established, that the studied territories contain 49 types of tree plants that include 17 families and present 23 genera. By the number of specimens there prevail Aesculus hippocastanum L.(13,4% of the whole number of trees), Populus bolleana Louche (7,8%), Populus nigra L. (6,6%), Ulmus laevis Pall. (6,4%), Tilia cordata Mill. (6,0 %), Robinia pseudoacacia L.(4,1%). The most number of types, characterized with 7-8 points of vitality originates from the Circumboreal floristic region (almost 39% of all species that received highest vitality indices). Fast-growing species prevail in plantations of the studied region, they are 67%. The share participation of middle-growing and slow-growing species is essentially less (23% and 10% respectively). The decrease of vitality of tree plants with age depends on their growth intensity. The decrease of vitality of tree plants is most Fast in slow-growing species (in the age after 30 years), and in middle- and Fast-growing species after 40-50 years. So, slow-growing tree plants must not be involved into the composition of linear street plantations of the Right-bank Pridneprovie, because they are less long-lived under these conditions. The highest vitality is typical for plants in age categories 21-30 and 31-40 years (27,4% and 22,9% respectively). The most number of trees with the lowest vitality level was revealed among young plants under 10 years old. Species of genera Fraxinus L., Acer L., Populus L., Robinia L.,Ulmus L can be recommended as the most vital among street plantation