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Somatic embryogenesis is an important biotechnological tool that has significant potential to be used in studies related to environmental stress. In this study, embryogenic cell masses of Abies alba and Picea abies were grown on media enriched with 50–500 µM cadmium (Cd2+) or lead (Pb2+). The effects of cadmium and lead were evaluated during the subsequent stages of somatic embryogenesis: proliferation, maturation, and germination. The following characteristics were evaluated: proliferation potential, cell viability, average number of somatic embryos obtained per 1 g of fresh weight, and morphology of the developed somatic embryos. The tested heavy metals significantly reduced the proliferation rate of A. alba and P. abies embryogenic cell masses. The highest tested cadmium concentration markedly slowed or stopped the growth of embryogenic cell masses in both species. Unexpectedly, the proliferation ratio remained fairly high for the P. abies cell lines treated with lead at all concentrations tested. During the maturation stage, the total number of somatic embryos declined under cadmium exposure. The formation of early precotyledonary and cotyledonary somatic embryos in both species was similarly reduced, although cadmium caused a higher death rate and was more toxic than lead. To the best of our knowledge, this is the first report to study the effects of heavy metals on A. alba embryogenic cell masses during the proliferation stage as well as on the maturation and germination processes of both species. This in vitro system can be used for testing the response of large sets of genotypes, and the best performing lines can be used in the future for in vivo performance tests of heavy metal-polluted soils.

Gomory, Dusan/0000-0002-9426-4247; Sevik, Hakan/0000-0003-1662-4830; Paule, Ladislav/0000-0002-5097-7472 WOS: 000417754100014 PubMed: 29238533 The eastern-Mediterranean Abies taxa, which include both widely distributed species and taxa with minuscule ranges, represent a good model to study the impacts of range size and fragmentation on the levels of genetic diversity and differentiation. To assess the patterns of genetic diversity and phylogenetic relationships among eastern-Mediterranean Abies taxa, genetic variation was assessed by eight nuclear microsatellite loci in 52 populations of Abies taxa with a focus on those distributed in Turkey and the Caucasus. Both at the population and the taxon level, the subspecies or regional populations of Abies nordmanniana s.l. exhibited generally higher allelic richness, private allelic richness, and expected heterozygosity compared with Abies cilicica s.l. Results of both the Structure analysis and distance-based approaches showed a strong differentiation of the two A.cilicica subspecies from the rest as well as from each other, whereas the subspecies of A.nordmanniana were distinct but less differentiated. ABC simulations were run for a set of scenarios of phylogeny and past demographic changes. For A. xolcayana, the simulation gave a poor support for the hypothesis of being a taxon resulting from a past hybridization, the same is true for Abies equi-trojani: both they represent evolutionary branches of Abies bornmuelleriana. Vedecka Grantova Agentura MSVVaS SR a SAV [VEGA 1/0269/16] Vedecka Grantova Agentura MSVVaS SR a SAV, Grant/Award Number: VEGA 1/0269/16

The study focuses on growth responses of Larix decidua provenances to climatic transfer based on a regional provenance experiment. This comprises a series of 5 trial plots situated in Germany and Slovakia, where 12 indigenous Sudetic and West-Carpathian larch provenances are planted. Transfer rates were defined as differences in altitudes or climatic variables between the site of plantation and the site of origin. 1st and 2nd-order polynomial regressions were used for the identification of overall trends of growth performance and responses to transfer. Sudetic provenances clearly outperformed the Carpathian ones on all test sites. When all provenances were considered jointly, height and breast-height diameter mostly showed significant monotonous geographical and climatic trends: the performance generally decreased with increasing altitude and precipitations and decreasing temperatures. The relationships between growth response and transfer rates (ecodistances) were mostly linear. However, when Sudetic and Carpathian provenances were considered separately, most significant response curves were unimodal. There is a very good correspondence between the responses in height and diameter growth within geographic groups, but the responses are not consistent between groups. Joint regression analysis showed that most provenances exhibited average stability. Stability indices are quite consistent between the response traits and did not show any association with the geographical position, climate of origin, or growth performance. The results indicate that populations in different climates remain adapted to a common optimum, the extent of local adaptation is quite limited. Possible explanations of this observation are briefly discussed.

Na plochách v Tatranskom národnom parku, ktoré boli postihnuté veternou kalamitou v roku 2004 a požiarom v roku 2005, sme študovali pôdne mikrobiálne spoločenstvo. Cieľom tejto práce je porovnať odozvu pôdnych mikroorganizmov na rozdielny manažment plôch a hodnotiť vývoj mikrobiálneho spoločenstva v priebehu rokov 2006-2013. Pôdne vzorky sme odoberali z A-horizontu pozdĺž 90 m dlhého tranzektu na 4 plochách (referenčná plocha, plocha s vyťaženou drevnou hmotou, plocha po požiari, plocha s nevyťaženou drevnou hmotou). V pôdnych vzorkách sme stanovovali bazálnu a potenciálnu respiráciu, mikrobiálnu biomasu, N-mineralizáciu, aktivitu katalázy, abundanciu a diverzitu funkčných skupín pôdnych mikroorganizmov použitím BIOLOG Eco platní. Vo všeobecnosti, najvyššiu aktivitu a biomasu pôdnych mikroorganizmov sme zaznamenali na ploche referenčnej a ploche po požiari. Nezistili sme významné rozdiely medzi plochou vyťaženou a nevyťaženou. Na všetkých kalamitných plochách sme v sledovanom období zaznamenali mierny trend nárastu hodnôt mikrobiálnej biomasy, potenciálnej respirácie a N-mineralizácie, čo poukazuje na proces postupnej obnovy mikrobiálneho spoločenstva na kalamitných plochách.

Field and indoor experiments demonstrated that conifer progenies possess a memory of temperature and photoperiod during female flowering and seed development, expressed in the timing of vegetative processes and frost hardiness, while these memory effects persist at least several years. To find out whether such carryover effects can also be provoked by climatic conditions during germination and early growth, we organized a nursery experiment where different Norway spruce and European larch provenances (10 and 12, respectively) were grown in two climatically contrasting nurseries and were reciprocally transplanted after the first year. Budburst phenology was scored 2 years after replanting. In Norway spruce, plants grown during the first year at the warm site consistently flushed later in both nurseries than those grown under cold climate, the difference ranged between 2.6 and 7.1 days for different provenances. In European larch, this was true only for plants scored in the warm nursery. In the cold nursery, the transferred material of low-altitude provenances flushed earlier but that of high-altitude provenances flushed later than the non-transferred plants of the same provenance. Plants also exhibited differences in budburst duration, which again were not consistent between species and provenances. The presented results give a strong indication for an epigenetic basis of the observed shifts in spring phenology, which may be important for nursery management, reforestation and afforestation.

The effect of soil amendment with the STOCKOSORB ®500 MICRO hydrophilic polymer on the photosynthetic traits in beech seedlings (Fagus sylvatica L.) during 50 days of dehydration was investigated. Dehydration was detected through osmotic potential (Ψ s ) in the assimilatory organs of beech seedlings. The addition of Stocko sorb positively affected the CO 2 assimilation rate (A) and instantaneous water use efficiency (A/T), for severely drought-treated seedlings. In comparison with irrigated plants, the values of A of non-irrigated plants with Stockoa sorb substrate decreased by 50%, and in non-irrigated plants with common substrate by 88%. The fast kinetics of chlorophyll a fluorescence indicated chronic photoinhibition under drought treatment without Stockosorb, while no significant changes in maximal quantum efficiency (F v /F m ) were recorded under drought treatment with Stockosorb. The actual quantum efficiency of PSII (Φ PSII ) markedly decreased in both treatments – with and without Stockosorb, though significant differences were found only between control treatments and drought treatment without Stockosorb. Moreover, the thermal energy dissipation (NPQ) was strongly limited under severe drought stress. The capacity to down regulate PSII functionality through non-photochemical quenching was maintained un der drought treatment with Stockosorb. The results indicate that an amendment with soil conditioner significantly improved the photosynthetic performance of drought-stressed beech seedlings.

The aim of the present study was to evaluate the adenosine triphospate (ATP), glucose-6-phosphate (glu-6P) and reduced form of nicotinamide adenine dinucleotide phosphate (NAD(P)H) cellular levels during the proliferation and maturation phases of Abies alba Mill. somatic embryos. For a better understanding of the dynamics of these parameters during the proliferation cycle, four embryonic cell lines were tested. During the maturation period, three independent experiments were conducted, focused on the effects of PEG-4000 (5 or 10% (w/v)) and abscisic acid (16, 32 or 64 μM) applied together (Experiments A and B) or with addition of gibberellic acid (Experiment C) on the dynamics of bio-energetic molecules and on the mean number of cotyledonary somatic embryos. Our results demonstrated that the cellular levels of bio-energetic molecules strongly depended on the composition of maturation media. Generally, the higher the number of cotyledonary embryos produced, the higher the level of ATP observed after a 2-week maturation period. The cellular level of ATP, glu-6P and NAD(P)H increased, particularly after the transition from the proliferation to the maturation phase when the differentiation and growth of somatic embryos occurred.

The unimodal species richness-altitude distribution pattern seems to be universal. To investigate the validity of this phenomenon in homogeneous substrate and vegetation conditions, we sampled beech-dominated forests in five volcanic mountain ranges in the Western Carpathians. European beech (Fagus sylvatica L.) formed monodominant closed-canopy stands at altitudes from 300 to 1,200 m. Along this gradient, the influence of beech on understory plant species richness was expected to be strong and uniform. The shape of the species richness-altitude relationship was analyzed for three datasets: herb layer, shrub layer, and both layers merged together. Contrary to prediction, the studied species richness-altitude relationship was inversely unimodal, with a minimum at intermediate altitudes. Quadratic regression models were statistically significant for all three datasets (P

Changes of soil microbial community caused by the heterogeneity of abiotic and biotic environment were studied in the reserve Dobroc, Slovakia. Data on vegetation, microclimate, soil properties and microbial activity were collected on two linear transects crossing both the core of the reserve and the buffer zone. In contrast to expectations, the variation of most environmental variables was comparable or even higher in the buffer zone than in the old-growth forest. Beta diversity was much higher in the natural forest, which coincided with differentiation patterns of trees and understory plants. Mantel correlations between microbial community indicators and environmental variables showed that soil chemistry and vegetation diversity were the most important determinants of microbial activity. Redundance analysis of microbial data identified potassium content, plant richness and influence of fir as the drivers of functional group composition. Inconsistency of correlations of microbial community characteristics with environmental variables indicates that different processes associated with the demography and functions of microbiota are driven by different environmental factors. Amount and variety of substrates available for decomposition seems to influence microbial community more than microclimate.

Somatic embryogenesis of Abies alba (Mill.) has significant potential to become an effective method for vegetative propagation of this species. To induce somatic embryogenesis in A. alba, the influence of the mother tree, sampling dates, and cold treatment storage of cones were examined. The initiation frequencies ranged from 1.7% to 16.6%. The sampling date and cone storage, but not the mother tree, had a significant effect on the initiation of embryogenic cultures. Storage of embryogenic cell lines was tested through cryopreservation for 6 yr. Four out of 12 cryostored embryogenic cell lines recovered, and the regeneration of cotyledonary embryos was obtained with two cell lines. The ability of embryogenic cell masses to produce somatic embryos and the mean number of cotyledonary embryos were higher when the maturation protocol was based on embryogenic suspensions dispersed on filter paper. The properly developed germinants were obtained only from maturation media where 32 μM abscisic acid was used, being 16.2% when polyethylene glycol (PEG) was not present and 1.8% when supplemented with 10% (w/v) PEG, respectively. The present study provides evidence that it is possible to cryopreserve A. alba embryogenic cultures while maintaining their maturing ability for the lengthy period (6 yr) needed for progeny testing of field-grown trees. Therefore, our findings are important for further studies and advanced breeding work of the species; however, the conversion of germinants into ex vitro conditions still remains a significant challenge.

Crossability relationships between six species of the Mediterranean, North American and Asian firs was tested using Abies alba and A. nordmanniana as female parents and A. alba, A. numidica, A. procera, A. grandis, and A. holophylla as pollen parents. An overwhelming majority of the crosses attempted was found to be compatible. In particular, it is true of the A. alba cross with A. numidica and those of A. nordmanniana with A. alba, A. numidica, A. procera, and A. holophylla. The crossing A. nordmanniana × A. grandis was the only exception producing empty seeds. Cytological study revealed the gametophytic incompatibility to be responsible for reproductive isolation of these species. At seedling level, all the interspecific crosses of A. nordmanniana surpassed in height growth self-pollinated control. The cross A. alba × A. numidica was comparable in this respect with control variants from open and self-pollination. Except for height growth, some characteristics of needle stomata are provided for individual crosses. The crosses A. nordmanniana with A. procera and A. holophylla represent unique interspecific combinations whose existence has not been reported yet. Based on needle stomata characteristics, the potential for increased resistance and drought tolerance of the hybrids with A. numidica involved as parental species is discussed.

The study focused on the temporal dynamics of soil water content (SWC) and soil microbial activity characterized by basal respiration and catalase activity in the litter (OL), fragmented (OF), and humus (OH) subhorizons of the forest floor and the mineral A-horizon, in relation to air temperature and rainfall. The study was conducted at three plots (old-growth Norway spruce (Picea abies Karst.) forest, even-aged mature commercial spruce stand, grassland dominated by Calamagrostis sp.) located in the Biosphere Reserve Polana (Slovakia, 19°28′E, 48°38′N) during four years. SWC as well as microbial activity differed among horizons as well as among plots. Generally, organic horizons in the old-growth forest exhibited higher microbial activity than in the managed forest, but no significant differences were observed for the A-horizon. On the other hand, the A-horizon showed higher catalase activity in the grassland than in both forest stands. The responses of SWC and microbial activity to air temperature and rainfall differed among horizons. SWC responded most sensitively to short-term temperature fluctuations in the OL horizon. In the underlying horizons, cumulative positive effects of high temperature (lasting 5–15 days) were reflected in the basal respiration. SWC responded rapidly to precipitations, but the effect lasted generally not more than 2 days. In contrast, catalase activity was negatively correlated with the precipitation amount; however, with increasing depth this relationship became less distinct.

Effective population size as a parameter closely correlating with the genetic and genotypic diversity of the seed orchard output is an important indicator of seed orchard functioning. It is determined by the variation of male and female gametic contributions of parental genotypes (including those outside the seed orchard), influenced by the variation in male and female gamete production, reproductive phenology, pollen dispersal within seed orchard and other factors. We assessed male and female fecundity, as well as temporal course of male and female flowering in two seed orchards of Pinus nigra ARNOLD and Fraxinus excelsior L./F. angustifolia VAHL. in Slovakia. In both cases, male and female gametic contributions of plus-tree clones were modeled on the basis of fecundity and flowering phenology, and were used to calculate status number as an estimator of effective population size. In the seed orchard of Pinus nigra, marker-aided verification of clonal fidelity revealed unexpectedly high proportion of misplaced ramets (29.9%) and alien genotypes (44.4%). Monitoring of reproductive processes in 2002 and 2003 showed high variation in both male and female fecundity, and pollen shedding preceding female receptivity in Pinus nigra. All these factors contributed to a very low relative status effective number, representing 8.6% to 38.6% of the population census (depending from the management option in relation to misplaced and alien genotypes). In the mixed seed orchard of Fraxinus excelsior and F. angustifolia, the proportion of misplaced and alien genotypes was much lower (22.4% and 12.3%, respectively). However, a high fecundity variation and protogyny resulted in a low relative status number (18.8% to 29.5% of the census number of clones) also in this seed orchard. Practical implications of these findings are shortly discussed and practical management options are proposed.

The effect of wood ash (WA) fertilisation on chemical and biological properties of forest floor layers was studied in a Norway spruce (Picea abies (L.) Karst.) stand in the central part of Slovakia at an altitude of 1300 m above sea level. In the forest floor, litter (OL), fragmented (OF), and humic (OH) horizons with average thickness of 1.5, 2, and 4 cm, respectively, could be distinguished. Three replicates of two wood ash treatments (3 and 6 t·ha−1) and a control were established in the autumn of 2012. Soil samples from OL, OF, OH and A-horizon were taken 0.5, 1, 6 and 12 months after the WA application. In soil samples chemical (pH, C and N content, C:N ratio, concentration of exchangeable Ca, Mg and K) and microbial properties (basal respiration, catalase activity, structure of microbial community based on BIOLOG assay) were determined. Our results showed that the changes in microbial and chemical properties do not occur simultaneously in particular horizons. WA application in autumn lead to a significant increase in pH, base cation concentration, and distinct losses in C and N content in the OL layer in the first month; however, at the beginning of the vegetation period, the most pronounced effect of WA was observed in OF and especially OH horizons; no changes were found in the A-horizon. Different properties of particular forest floor horizons led to a vertical stratification of the microbial community. Each forest floor horizon had particular properties, leading to a vertical stratification of the microbial community; deeper horizons had more homogenous functional groups.

Summary 1. Growth rates of European silver fi r( Abies alba Mill.) rapidly increased in the last century. At the same time, ring widths declined at the species southern distribution limits in the Mediterranean. Such diverse growth trends and responses have largely been attributed to regional climate conditions, but this was prior to considering the species’ post-glacial phylogeny. 2. A dendrochronological network composed of 1961 tree-ring width series (TRW) from 78 silver fir sites between 365 and 1400 m a.s.l. along the Carpathian Arc was compiled. Spatial differences in the species’ genetic diversity were investigated from genetic data of 69 silver fir populations in the region. Differences in growth variability and climate sensitivity were then related to post-glacial phylogeny and genetic diversity. 3. Significant differences in interannual and longer-term growth trends and climate responses across the Carpathian Arc were found to coincide with the geographical north–south separation of two post-glacial populations from effective refugia originating from the Apennine and Balkan peninsulas. Summer temperature was the main driver of growth in the western (Apennine) lineage, whereas ring widths in the Balkan population from the east were predominantly controlled by summer drought. Fir specimens that originated from the Balkan lineage exhibited higher genetic diversity and more regular growth dynamics and also appeared to be less sensitive to air pollution during the 1970s. 4. Synthesis. Although the phylogeny of forest trees has largely been neglected in most dendroecological studies, results here indicate the importance of different post-glacial histories for the growth sensitivity and adaptability to varying environmental factors. Decision-making under future climate warming scenarios (for building resilience through forest management) should therefore consider different phylogenetic origins.

Plants continue to flourish around the site of the Chernobyl Nuclear Power Plant disaster. The ability of plants to transcend the radio-contaminated environment was not anticipated and is not well understood. The aim of this study was to evaluate the proteome of flax (Linum usitatissimum L.) during seed filling by plants grown for a third generation near Chernobyl. For this purpose, seeds were harvested at 2, 4, and 6 weeks after flowering and at maturity, from plants grown in either non-radioactive or radio-contaminated experimental fields. Total proteins were extracted and the two-dimensional gel electrophoresis (2-DE) patterns analyzed. This approach established paired abundance profiles for 130 2-DE spots, e.g., profiles for the same spot across seed filling in non-radioactive and radio-contaminated experimental fields. Based on Analysis of Variance (ANOVA) followed by sequential Bonferroni correction, eight of the paired abundance profiles were discordant. Results from tandem mass spectrometry show that four 2-DE spots are discordant because they contain fragments of the cupin superfamily-proteins. Most of the fragments were derived from the N-terminal half of native cupins. Revisiting previously published data, it was found that cupin-fragments were also involved with discordance in paired abundance profiles of second generation flax seeds. Based on these observations we present an updated working model for the growth and reproductive success of flax in a radio-contaminated Chernobyl environment. This model suggests that the increased abundance of cupin fragments or isoforms and monomers contributes to the successful growth and reproduction of flax in a radio-contaminated environment.

The effect of 19 environmental variables on species richness of macrophytes was studied in 39 Slovak streams. The studied streams were poor in species; in total, 88 macrophyte taxa were found and the average number of macrophytes per sampling site was 4, ranging from 0 to15. The most frequently occurring macrophytes were filamentous algae (occurrence at 38.6% of sampling sites), followed by Rhynchostegium riparioides (28.4%) and Phalaris arundinacea (19.3%). The strongest environmental gradient in the sampling site detected by factor analysis (factor 1 explains more than 32% variability) is related to the portion of artificial banks, shading by woody vegetation along banks, flexuosity of stream course and the portion of natural land cover in the contact zone of the stream, and can be interpreted as a natural-anthropogenic gradient. The following variables had the highest correlations with species richness of macrophytes: shading by woody vegetation (r=−0.507), portions of artificial bank (r=0.488), flexuosity (r=−0.457) and distance from stream source (r=0.388).

Hybridization between divergent lineages of common ash Fraxinus excelsior L. was studied in Slovakia and adjacent regions of Hungary, the Czech Republic and Poland in the contact zone between two postglacial colonization routes originating from different glacial refugia. Thirty-eight common ash populations were studied using a combination of 6 maternally inherited chloroplast microsatellite markers and 7 biparentally inherited nuclear microsatellites (nSSR). Two predominant chloroplast lineages were identified, between which the boundary was very sharp. Populations containing a mixture of different haplotypes were found only in the immediate proximity of the boundary. Bayesian analysis of population structure based on nSSR loci revealed the existence of two clusters, which largely coincided with chloroplast lineages. Both haplotype frequencies and proportions of clusters identified by the Bayesian analysis exhibited a clinal transition over the hybrid zone, with cline widths of 36 km for chloroplast haplotype frequencies (reflecting gene flow by seeds) and 275 km for Bayesian clusters based on nSSR (reflecting gene flow by pollen and seeds). Chloroplast haplotype diversity increased along the boundary between lineages not only because of admixture, but also due to the presence of rare haplotypes. In contrast, diversity at nuclear loci did not exhibit any geographical trend.

Genetic exchange between divergent lineages of silver fir (Abies alba Mill.) was studied in the Ukrainian Carpathians where two expanding populations originating from different glacial refugia meet. The study included 33 silver fir populations from Ukraine, Romania and Slovakia which were investigated using the maternally inherited mitochondrial nad5-4 marker and biparentally inherited nuclear microsatellites. The boundary between mitochondrial lineages is very sharp; only six populations containing a mixture of different haplotypes were found. Bayesian analysis of population structure based on seven nSSR loci revealed the existence of two clusters which coincided fairly well with mitochondrial lineages. Both haplotype frequencies and proportions of clusters identified by the Bayesian analysis exhibited a clinal transition over the contact zone, with cline widths of 17.6 km for mitochondrial haplotype frequencies (reflecting gene flow by seeds) and 119.6 km for Bayesian clusters based on nSSR (reflecting gene flow by pollen). Allelic richness and gene diversity differ significantly between mitochondrial lineages, the Balkan group being more variable, but an increase in gene diversity towards the boundary between lineages was observed only within the Balkan lineage. The observed patterns are suggested to reflect the postglacial colonization and historical gene flow. They demonstrated that in silver fir as a wind-dispersed species, the colonization front is quite continuous, and the survival of migrant seeds in already established populations is low. The relative contribution of pollen-mediated gene flow to genetic exchange between divergent lineages associated with glacial refugia is much higher than in the case of seeds, but pollen dispersal distance is lower than suggested by earlier studies.

The effects of ectomycorrhizal (ECM) fungi, including Laccariabicolor (Maire) Orton, Laccaria laccata (Scop., Fr.) Berk. and Br., along with two strains of Pisolithus tinctorius (Pers.) Coker and Couch, on the proliferation and subsequent maturation of two embryogenic cell lines of Abies cephalonica Loud., designated lines 6 and 8, were investigated. In the presence of these ECM fungi, the proliferation of both embryogenic cell lines was inhibited. L. bicolor and P. tinctorius strain 2 resulted in the highest inhibition rates. On the other hand, cultivation of embryogenic cultures along with ECM fungi, termed a dual culture, increased radial growth of both P. tinctorius strains; whereas, L. bicolor and L. laccata did not grow as well in the presence of embryogenic cell masses. The dual culture during the proliferation period of embryogenic cells, however, enhanced the subsequent embryo formation and maturation of A. cephalonica; i.e. the capability of embryogenic cell lines to form somatic embryos as well as increasing the mean number of somatic embryos per 1 g fresh weight of embryogenic cell mass. However, levels of responses were highly dependent on the interaction between the specific embryogenic cell line and fungal strain.

In coniferous species, including Greek fir (Abies cephalonica Loud), the involvement of somatic embryo plants in breeding and reforestation programs is dependent on the success of long-term cryostorage of embryogenic cultures during clonal field testing. In the present study on Greek fir, we assayed the recovery, morphological characteristics and genetic fidelity of embryogenic cell lines 6 and 8 during proliferation and maturation after long-term cryostorage. Our results indicate successful recovery of both cell lines after 6 years in cryostorage. In the maturation phase, both cell lines were capable of producing somatic embryos although some differences were detected among experiments. However, these changes were more dependent on the differences in the components of the maturation media or in the experimental set-up than on the long-term cryostorage. During both proliferation and maturation phases, the morphological fidelity of the embryogenic cultures as well as of the somatic embryos were alike before and after cryopreservation. The genetic fidelity of the cryopreserved cell line 6 that was assayed by random amplified polymorphic DNA (i.e. RAPD) markers demonstrated some changes in the RAPD profiles. The results indicate possible genetic aberrations caused by long-term cryopreservation or somaclonal variation during the proliferation stage. However, in spite of these changes the embryogenic cultures did not lose their proliferation or maturation abilities.

Responses of Norway spruce populations to climatic transfer, in terms of growth and survival, were analyzed on the basis of a provenance experiment derived from the international provenance test IUFRO 1964/1968. The experiment comprises a series of five trial plots situated at contrasting elevations ranging from 484 to 1,275 m a.s.l., with 11 provenances represented at all trial plots that were used for the analysis. Transfer rates were defined as differences in altitudes or climatic variables between the site of plantation and the site of origin. Optimal transfer rates and optimal climates for individual provenances were derived from quadratic response functions. Spruce provenances generally responded positively by height and volume growth to transfer into lower altitudes, i.e., warmer conditions with less precipitations. The analysis at the level of provenances showed that optimal transfer rates were consistently negatively correlated with the underlying environmental variables and optimal climates were consequently nearly the same for all provenances irrespective of the response traits and ecodistance variables. Stability indices based on joint regression analysis indicate that provenances from higher altitudes, colder and wetter climates tend to be more stable, whereas provenances from lower altitudes, drier and warmer sites are more responsive to site quality. However, the differences in the stability are small and stability indices were generally close to 1. The results indicate that populations in different climates remain adapted to a common optimum and the extent of local adaptation is quite limited. Possible explanations of this observation are briefly discussed.

The genetic variation in fourteen Sorbus torminalis (L.) Crantz. populations distributed over the eastern and south-eastern part of its range was studied using seven nuclear microsatellite loci. The differentiation level was relatively high (FST = 0.228), as expected for a species with a fragmented range. The distance-based approach to the analysis of differentiation patterns (neighbour-joining tree based on pairwise coefficients of differentiation) did not reveal a clear geographical structure. On the other hand, model-based Bayesian methods (BAPS and STRUCTURE) gave geographically continuous clusters of populations. The occurrence of populations deviating strongly from the general pattern is attributed to founder effect. In spite of a generally high differentiation, a significant isolation-by-distance pattern was found, which might be a consequence of postglacial migration and gene flow among descendants of different refugia.

Reticulate evolution resulting from gene flow among diverged taxa was studied on the example of the Fagus sylvatica species complex in Europe and western Asia. F. sylvatica L. is one of the most widespread woody species of the Northern Hemisphere with two commonly recognized subspecies (namely, F. sylvatica subsp. sylvatica and F. sylvatica subsp. orientalis) and two putatively hybridogenous or intermediate taxa (F. moesiaca and F. taurica). Whereas the distribution of F. sylvatica subsp. sylvatica in Europe is almost continuous, the Asian range of F. sylvatica subsp. orientalis is fragmented into several larger regional populations. We studied genetic variation at 12 allozyme loci in 279 local subpopulations to assess whether previous contacts of regional populations left traces in their gene pools. Two approaches were used to infer potential reticulations: the reticulate network (Makarenkov and Legendre in J Comp Biol 11:195–212, 2004) and the neighbor-net network (Bryant and Moulton in Mol Biol Evol 21:255–265, 2004). A UPGMA dendrogram based on genetic distances between local populations revealed a high differentiation level within subsp. orientalis, whereby populations from Asia Minor, the Caucasus and the Alborz mts. were placed in different clusters. The reticulated network showed possible connections among adjacent populations, putatively resulting from previous contacts. The neighbor-net network also consisted of two major groups corresponding to F. sylvatica s. str. + F. moesiaca and F. orientalis including F. taurica. Regional populations of F. moesiaca are placed close to the basis of the European branch and are highly networked, indicating ambiguity in the phylogenetic signal. Similarly, three subgroups can be distinguished within the F. orientalis group and correspond well with broad regions of Asia Minor, the Caucasus and the Alborz. The Amanus regional population is intermediary between the subgroup of Asia Minor and the Caucasian subgroup. Crimean populations (i.e., putative hybrids) are placed near the basis of the subgraph. Two explanations of the observed reticulations are discussed: expansions and retreats of the range of beech associated with Pliocene and Pleistocene climatic fluctuations, resulting in contacts and exchanges of gene pools among regional populations, and sharing ancestral polymorphisms due to incomplete lineage sorting.

The study focuses on geographical patterns of genetic variation at allozyme loci common for four main tree species of Central Europe (Norway spruce, silver fir, common beech and sessile oak). Moving-window averaging of four indicators of allelic richness and diversity (proportion of polymorphic loci, mean number of alleles per locus, effective number of alleles and expected heterozygosity) with window size of 50 × 50 km was used to identify the patterns. Moreover, local genetic divergence was assessed using the G ST (Nei, Molecular population genetic and evolution, Amsterdam and Oxford, North-Holland, 1975) and D j (Gregorius and Roberds, Theor Appl Genet 71:826–834, 1986) statistics for common beech and silver fir, where raw genotype data were available. Spatial patterns of diversity and allelic richness were quite similar. Romanian Carpathians were identified as the most important hotspot of genetic diversity and evolutionary divergence in Central Europe. Implications for genetic conservation are briefly discussed.

The impact of secondary succession of grassland communities towards a Norway spruce forest on soil microbial community was studied on a belt transect established in the Pol’ana Mts., Central Europe. Data on understory vegetation, light availability, soil properties and microbial activity were collected on 147 plots distributed over regular grid. Moreover, distributions of functional groups of microorganisms were assessed using BIOLOG analysis on a subset of 27 plots. Mantel partial correlations between microbial community indicators and environmental variables showed that microbial activity generally decreased with increasing tree density and size, whereas it increased with increasing radiation at the soil surface, soil temperature, and cover and diversity of understory vegetation. Functional richness and diversity of microorganisms were positively correlated with solar radiation, but also with plant species richness and diversity. Abundance of several functional groups correlated closely with succession-related variables. Redundance analysis of microbial data provided slightly different outcomes. Forward selection yielded only two environmental variables significantly influencing the composition of the microbial community: tree influence potential and organic carbon content. Abundances of several functional microbial groups correlated with tree influence, documenting that microbial community changes are at least partially driven by the colonization of grassland by trees. Nevertheless, the relative importance of abiotic environment change and plant community succession on microbial community dynamics remains unresolved.

The effect of the amendment with alginite, an organic rock originating from the biomass of fossilized unicellular algae, on microbial activity of forest soils was tested using a pot experiment. Five variants of soil-alginite mixtures were tested in three replicates with two forest soils: a loose sandy soil and a sandy loam. Gravimetric moisture closely correlated with the dose of alginite in both soils. Basal respiration and catalase activity increased with the dose of alginite in the sandy soil, but not in the sandy loam, where the highest response was observed at intermediate doses of alginite. The correlations of microbial activity parameters with moisture in the sandy soil were also much closer than in the sandy loam. The amendment with alginite was thus effective in improving some of the selected microbial activity indicators, but the optimum dose of alginite strongly depends on soil texture.

This study analysed seasonal dynamics of macrophyte abundance in two perennial lowland regulated streams (Stream 1 and 2) in the Danube basin (Slovakia). Assessments of macrophyte abundance and environmental characteristics were accomplished 7 times during the vegetation period in 2005 within a 100 m long section. Statistically significant differences in total abundance of macrophytes as well as an abundance of macrophyte groups (hydrophytes, amphiphytes, helophytes) and Potamogeton nodosus were detected among months within the vegetation period. Abundance fluctuations for individual macrophyte groups and species were moderate in Stream 1 and much stronger in Stream 2. Only amphiphytes showed bimodal temporal distribution in Stream 1, but the abundance of this group was low, reflecting more or less random occurrence of species in vegetation period. Multiple linear regression revealed that water depths and air temperature are the most significant environmental variables affecting the seasonal pattern of total as well as dominating group abundance in Stream 1 and 2, respectively. In all cases, abundances are significantly influenced by the abundance of the respective group in the preceding month. Culmination time differed between streams for all macrophyte groups except helophytes. Total abundance culminated 0.57 month later in the Stream 1 compared to Stream 2.

Crop characteristics involving cone size, average number of seeds per cone, and seed germinability have been studied for three hybrid swarm populations of Pinus mugo and P. sylvestris, two pure P. mugo populations and one pure P. sylvestris population, in northern Slovakia. Generally, reproduction capability characteristics were significantly reduced in hybrid swarms in relation to the control populations. Although there were no consistent differences between hybrid swarms and control populations in the average number of seeds per cone or cone size, seed germination rates and full seed production in hybrid swarms were lower than for the control population of P. sylvestris and one of the pure populations of P. mugo. Based on these data a conclusion has been drawn postulating partial rather than full fertility of the hybrid swarm populations of P. mugo and P. sylvestris.

For promoting the maturation of two embryogenic cell lines of Abies cephalonica Loud., the effect of two sucrose concentrations (87.6 and 175.2 mM) applied alone (Control) or in combination with activated charcoal (AC) (1 week) or with polyethylene glycol (PEG1 and PEG4) (1 or 4 weeks) was studied. The effect of each maturation medium was tested with four concentrations of abscisic acid (4, 8, 16 and 32 μM ABA). AC supplement significantly increased the percentage of embryogenic cell masses (ECMs) with cotyledonary embryos but did not affect the average number of embryos per 1 g of ECMs fresh weight. The highest percentages of ECMs (77.5%) with cotyledonary somatic embryos and the highest average number of somatic embryos (36.5 ± 13.4) were found on media with PEG for 4 weeks. The maturation media with 87.6 mM sucrose significantly increased the number of ECMs able to form cotyledonary embryos (66.8%) when PEG was included in the maturation medium, but did not affect the average number of somatic embryos. Overall correlation between proliferation diameter during maturation phase and the number of ECMs with somatic embryos (r = −0.40) as well as all significant correlations within individual experimental variants were consistently negative after 8 weeks of maturation, meaning that proliferation growth hampers the formation of somatic embryos. The highest germination percentages 21.6% and 18.2% were obtained when somatic embryos were maturated on media with or without AC supplement, respectively. Lowest germination percentages, 9.1% and 4.4%, were obtained on maturation media with PEG4 and PEG1.

To induce somatic embryogenesis of Greek fir, Abies cephalonica Loud., the influence of different cultivation media, sampling dates, and cold treatment storage were examined. The initiation frequencies ranged from 1% to 25%. The sampling date had a significant effect on the initiation of embryogenic cultures and a high frequency was observed within a 5 week window. The effect of cone storage, composition of initiation media, and the medium by storage interaction also remained nonsignificant after 3 and 10 months of proliferation growth. At the maturation phase, the highest tested concentrations of abscisic acid (ABA), 16 and 32 µmol/L, increased both the capability of embryogenic cell masses (ECMs) to produce embryos and the mean number of embryos. Of the two tested carbohydrates, maltose-containing media produced more embryos altogether (1943, on the average of 22.3 embryos per gram fresh mass) and 76% of the ECMs were able to produce embryos when compared with the corresponding values (152, on the average 3.0 embryos per gram fresh mass) and 15.3%, respectively, on sucrose-containing medium. However, 93.5% of embryos on maltose-containing medium died during the germination phase, whereas the corresponding percentage on sucrose-containing medium was 78.2%.

Comparative study on fertilization process in Pinus sylvestris, Pinus mugo and in their putative hybrid swarm individuals was done involving pre-zygotic and post-zygotic stages. The amount of surviving ovules from open pollination reflecting the mode of interaction between pollen grains and nucellar tissue of an ovule averaged at 8.1 of sound ovules per conelet in Pinus sylvestris, 7.3 ovules in the hybrid swarm population and at 4.9 ovules in Pinus mugo. A strong correlation was observed between the number of surviving ovules and the proportion of germinating seeds in the compared species and hybrids. Normal course of embryogenesis in Pinus sylvestris and Pinus mugo contrasted with increased frequency of disturbances observed in the hybrid swarm individuals. The differential survival rates of the ovules and deviations from typical pattern of embryogenesis are discussed from the standpoint of cross-ability relationship between Pinus sylvestris and Pinus mugo.

Spatial genotypical diversity of Sesleria albicans Kit. ex Schultes was studied in a dry grassland community by isozyme analysis. The aim was to identify the genetical individuals within the studied population and to assess the species’ clonal growth parameters. Vegetative mobility and branching intensity were measured in field for the sake of the correct interpretation of the results. Five isozyme systems were analyzed and interpreted (MDH, MNR, 6-PGDH, SkDH, LAP). Altogether, 98 distinct isozyme profiles were identified within an area of 2 m2. Average genotype identity rapidly decreased with distance. Several very remote ramets (more than 1 m) belonging to the same genet were identified. The longest distance between ramets of the same genotype was 153 cm. With average annual rhizome increment of 13.59 mm assessed for the studied population the age of genet with the most remote ramets exceeded 56 years by a bi-directional growth and 112 years by a growth in single direction. Number of daughter tillers produced by a tiller per year was 0.67 (branching intensity, median) and the median of tiller life span was 2.5 years. The high genotypical diversity of S. albicans in the studied population could be a result of both, regular and continuous seed production with subsequent seedling recruitment and long life span of genets.

Fagus sylvatica L. is one of the most widespread broad-leaved trees in the temperate forests of the northern hemisphere. In addition to two subspecies, F. sylvatica ssp. sylvatica in Europe and F. sylvatica ssp. orientalis in south-western Asia, two further taxa were described: F. moesiaca (Maly) Czeczott in the south-western Balkans and F. taurica Popl. in Crimea. The opinions about the number and ranks of taxa within this complex are highly controversial. To assess the degree of genetic differentiation among them, and to reveal geographical patterns of genetic diversity and their relationships to history and biogeography of beech populations, genetic variation at 12 allozyme loci was studied in 279 populations in western Eurasia. A Bayesian analysis of population structure revealed the existence of two clusters, which fairly well coincided with F. sylvatica ssp. sylvatica and F. sylvatica ssp. orientalis, whereby the populations from the south-western Balkans and Crimea contained a mixture of these two gene pools. On the other hand, a neighbour-joining tree based on pairwise FST failed to separate the subspecies into well-defined distinct clades. Populations of F. sylvatica ssp. orientalis proved to be incomparably more differentiated than ssp. sylvatica (FST = 0.157 and 0.032, respectively). Asian populations also showed higher levels of allelic richness both on population and taxon levels than the European ones (the number of alleles after rarefaction was 3.40 and 4.27 in F. sylvatica ssp. sylvatica and ssp. orientalis, respectively). This indicates that the gene pool of F. sylvatica ssp. orientalis has not been depleted by reduced population sizes during the Pleistocene glaciations, as is the case of F. sylvatica ssp. sylvatica. Genetic similarities between isolated regional populations are explained by shared ancestral polymorphisms and/or range overlaps with subsequent hybridization in the past. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 154, 165–174.

European white oak species (Quercus subg. Lepidobalanus) are known to share a substantial part of the nuclear and cytoplasmic genome. In spite of this fact, they have preserved their integrity. We analyzed genetic variation at thirteen isozyme loci in nine Quercus robur, ten Q. petraea, two Q. pubescens and two mixed (two-species) populations in Slovakia to assess the extent of allele sharing. Moreover, a detailed morphometric study based on thirteen leaf traits was done in the mixed stands. A Bayesian analysis of population structure in the set of pure populations revealed the existence of three clusters, which coincided with the supposed taxonomical identity of populations. However, the distribution of posterior probabilities of data was bimodal with a second peak at six groups, what indicates a possible substructure in the gene pools of the investigated oak species. Moreover, gene admixture was close to 50% in all investigated populations. Morphometric analysis of the two mixed stands revealed a clear morphological separation of the studied oak species, sharply contrasting with a high degree of gene admixture. Differentiation is not uniformly distributed over the genome. High levels of differentiation (FST > 0.10) were observed at only three out of thirteen loci. The hypotheses explaining extensive allele sharing (shared ancestral polymorphisms vs. high levels of interspecific gene flow) are briefly discussed.

Although changes in land-use, climate, and the spread of introduced tree species have increased the global importance of tree invasions into grasslands, our ability to predict any particular invasion is limited. To elucidate mechanisms driving tree invasions of grasslands, we studied in detail how seed dispersal and fine-scale environment control the expansion of an introduced Picea abies Karst. (Norway spruce) population into Western Carpathian grassland. We mapped invading trees and measured tree size, fecundity, seed rain, seedling density, plant community composition, and light and soil environment within a 200 × 60 m belt across the invasion front. Maximum likelihood estimates of dispersal kernels suggested peak seed deposition directly underneath tree crowns where germination was poor, but mean dispersal distances were sufficiently large to generate overlapping seed shadows from multiple trees that saturated the invasion front with seeds further away from seed-dispersing trees. Partial Mantel tests indicated that germinant density was affected considerably less by seed rain than by moss cover (r = 0.54), overstory tree influence (r = −0.32), soil moisture (r = 0.21), grass cover (r = −0.15), and diffuse radiation (r = 0.13). However, these variables were not independent but formed complex multivariate gradients within the invasion front. Moss cover and soil moisture were negatively correlated with overstory tree influence and the resulting gradient clearly affected germinant density (partial Mantel r = 0.45). In contrast, positively correlated light and grass cover defined a gradient related weakly to germinant density (partial Mantel r = 0.05) as it integrated opposing effects of these variables on germinants. Seedlings had similar environmental associations, but except for the lasting positive effects of moss these tended to weaken with seedling size. Although a few seedlings may establish and survive in the more adverse environment of the outer edges of the invasion front, a significant population expansion may require a gradual build-up of the critical density of invading trees to reduce grass cover and facilitate germination on moist mossy seedbeds within uncolonized areas. Thus, Picea abies appears more likely to spread within temperate grasslands by gradual expansion of its population frontier rather than by advanced groups.

To characterize the spatial heterogeneity of selected soil microbiological characteristics in relation to soil moisture content within a natural beech stand, we collected soil samples at 50 m intervals along a 1,500 m long transect in a beech primeval forest at Vtacnik mountains (Slovakia) from organic layers (OL and OF horizons) and the mineral A horizon (depth 0-10 cm) in July 2004 and June 2005. Gravimetric soil moisture, basal and substrate-induced respiration, respiration in situ and soil catalase activity were measured. Statistically significant differences in soil variables were found among horizons and partially among sampling dates. Soil microbial activity was closely correlated with soil moisture, especially in the OL horizon. No clear spatial autocorrelation of the assessed soil variables was found, but a significant correlation between years occurred. Moisture and microbial activity parameters were positively correlated with canopy openness in the A horizon, whereas no or negative correlations were observed in the overlying organic horizons.

Genetic variation in 13 populations of a Balkan endemic, Serbian spruce (Picea omorika (Panc.) Purk.), was investigated using 16 isozyme loci. Serbian spruce is characterized by low levels of genetic variation (average proportion of polymorphic loci was 20.9% and average expected heterozygosity was 0.067). In most populations, a significant surplus of heterozygotes was observed, indicating a strong selection against inbreds. In the largest populations, fixation indices were positive, probably due to within-population differentiation and the associated Wahlund effect. Despite a strong overall differentiation (F ST =0.261), no geographical trends in the genetic variation could be identified. Genetic drift caused by small effective population sizes and a strong fragmentation is the most plausible explanation for such variation patterns. A Bayesian analysis of population structure revealed the existence of two clusters, which are supposed to be possible remnants of ancient differentiation within a large range of the predecessor of Serbian spruce, Picea omoricoides Weber. Ex situ conservation measures, namely establishing seed orchards from trees of mixed origin, are proposed as a necessary complement to in situ protection of natural stands.

The effects of air pollution on the genetic structure of Norway spruce, European silver fir and European beech were studied at four polluted sites in Slovakia, Romania and Czech Republic. In order to reduce potential effects of site heterogeneity on the health condition, pair-wise sampling of pollution-tolerant and sensitive trees was applied. Genotypes of sampled trees were determined at 21 isozyme gene loci of spruce, 18 loci of fir and 15 loci of beech. In comparison with Norway spruce, fewer genetic differences were revealed in beech and almost no differentiation between pollution-tolerant and sensitive trees was observed in fir. In adult stands of Norway spruce, sensitive trees exhibited higher genetic multiplicity and diversity. The decline of pollution-sensitive trees may result thus in a gradual genetic depletion of pollution-exposed populations of Norway spruce through the loss of less frequent alleles with potential adaptive significance to altered stressing regimes in the future. Comparison of the subsets of sensitive and tolerant Norway spruce individuals as determined by presence or absence of discolorations ("spruce yellowing") revealed different heterozygosity at 3 out of 11 polymorphic loci.

Effects of the variation in male and female fertilities of clones, flowering phenology, and spatial distribution of clones on the genetic structure of progenies of three Scots pine seed orchards were investigated using isozyme gene markers. A pronounced variation of male and female gametic contributions was found. Most clones appear to be phenologically synchronized, but up to 15% of early or late flowering clones were found in all seed orchards. The presence of ramets, which do not belong to any seed orchard clone, does not affect allelic or genotypic diversity of the seed orchard crop. Gene-pool genetic distances based on allelic frequencies between the parental and the progeny generations are not very high, but there are certain loci exhibiting a considerable differentiation. On the other hand, variance effective population sizes indicate a substantial drift of gene frequencies between seed orchard itself and its offspring. The necessity of a cautious use of the reproductive material originating from seed orchards is emphasized.

Three Alnus glutinosa populations from central Slovakia were investigated by means of isozyme analysis. The average expected heterozygosity ranged from 0.151 to 0.173. Despite significant differences in allele frequencies among populations, genetic differentiation was low (FST=0.022). Intrapopulation fixation indices indicate no or very slight deviation from panmictic expectations towards the heterozygote deficiency. No indications were found that the investigated populations have experienced recent bottlenecks in population size. A spatial autocorrelation analysis based on Moran’s I indicates the existence of a spatial genetic structuring in the population Kral’ova. Patch size was estimated to be 70–100 m, which is more than observed in other broadleaved tree species. This difference is explained by the linear shape of alder populations and a higher mobility of seeds.

A total of 1113 oak trees from 222 populations originating from eight countries (Austria, Bosnia-Herzegovina, Croatia, Hungary, Romania, Slovakia, Slovenia, Yugoslavia) were sampled in natural populations or in provenance tests. The sampled trees belong to four different species (Quercus robur, Quercus petraea, Quercus pubescens, Quercus frainetto) and to several putative subspecies. Variation at four chloroplast DNA (cpDNA) fragments was studied using restriction enzymes, resulting in the detection of 12 haplotypes. One haplotype was present in 36% of the trees, and six were found in 6–17% of the trees. The haplotypes are shared extensively between species and subspecies. They belong to three different lineages (A, C and E) and are phylogeographically structured in the region investigated. Haplotypes of lineage E dominate to the east of the Carpathian mountains in Romania, whereas the Carpathian Basin seems to have been colonised along several different colonisation routes, from the Balkan peninsula but also from Italy. The data support the possible role of climatic instability during the late glacial period in shaping this complex geographic structure. The presence of several secondary refugia could be inferred in the region, which have played a major role in the second step of recolonisation, at the onset of the Holocene period. # 2002 Elsevier Science B.V. All rights reserved.

This article presents a study of isozyme variation in Pinus peuce Griseb., a Balkan endemic. Among the enzyme systems studied, five were monomorphic and eight were polymorphic in at least one locus. The segregation analysis of the polymorphic loci were consistent with a Mendelian mode of inheritance. No significant deviation from the expected ratio was observed both at the individual and pooled segregation data levels. Segregation patterns were homogeneous across individuals. Two significant linkage groups were found in P. peuce: FEST-2:LAP-2 and 6PG-1:6PG-2, which correspond to the results obtained for other pine species.

International audience; At northern temperate latitudes trees haveadjusted their ranges substantially in response to changingclimates during the Holocene. Results from dispersalmodel simulations suggest that postglacial migration ratesmay have been over-estimated from fossil pollen data. As acontribution to this debate, we infer the migration rates ofAbies alba(Mill.), silver fir, as a case-study species, byusing a spatially explicit approach based on fossil pollenbut taking into account its modern genetic diversity pattern. Maximum estimates of migration rates from fossil pollendata alone are higher than 700 m yr-1during the Holocene.Considering the potential refugia as suggested from all thefossil data but restricting the area over which silver firexpanded from each glacial refugium using data on thecurrent haplotype distribution, the estimated maximummigration rates of silver fir are less than 250 m yr-1.Genetic information may allow for (1) the exclusion of thoserefugial areas where the species may have survived duringthe last glacial period but from which it did not spread orspread only very locally and (2) the delineation of the areas. over which the species spread from each glacial refugium.The estimated rates in the present study are generally con-sistent with rates suggested from modelling approaches.This study shows that integrating fossil pollen records canimprove simulations of dispersal processes and, thus, allowfor better predictions of future changes in tree species’ranges.

The effects of industrial pollution on allelic and genotypic structures of Norway spruce, European silver fir and European beech were investigated by means of isozyme analysis. In a mixed Norway spruce–silver fir forest stand in an area heavily polluted by sulphur dioxide and heavy metals in the region of Spis (eastern Slovakia), pairs of neighbouring damaged and apparently healthy trees were selected in two replicates (44 and 69 pairs in a heavily and moderately damaged stand, respectively). Pairwise sampling of trees with contrasting vitality was applied to reduce potential effects of site heterogeneity on the vitality of sampled trees. No significant differences in allelic and genotypic frequencies were found between sets of healthy and declining trees. There were differences in the single-locus heterozygosities, but these were not consistent between the replicates. However, the set of damaged trees exhibited higher levels of genetic multiplicity and diversity, possibly due to the deleterious effect of rare alleles under the conditions of air pollution. Consequently, following the decline of pollutant-sensitive trees, the remaining stand will be depleted of a part of alleles with unknown adaptive value to future selection pressures.

Seed zones for European beech (Fagus sylvatica L.) in the Czech Republic were proposed on the basis of isozyme polymorphism. Twenty beech populations distributed over the natural range of beech in the target area were analyzed using 12 isozyme loci. Analysis of genetic distances revealed the existence of geographical differentiation patterns. Allelic fre- quencies were estimated for a square network of 300 points, covering the territory of the Czech Republic, employing kriging as an optimum spatial interpolation method. Cluster analysis based on allelic profiles of the kriging points made it possible to divide the investigated area into eight seed zones. (© Inra/Elsevier, Paris.)

The aim of this study was the assessment of genetic diversity and differentiation patterns of European beech (Fagus sylvatica L.) populations within its natural range in Poland. These stands cover 5.2% of the forest area in Poland, and form the predominant forest tree communities throughout the Carpathians and Sudety Mountains, and the moraine landscape of the Pomeranian Lake District. Varying environmental conditions have resulted in a great number of ecotypes and populations which are characterized by various ecological requirements. Poland represents the northeastern limit of the beech’s natural distribution. Genetic diversity and differentiation was assessed using allozyme gene markers employing 9 enzyme systems: glutamate-oxaloacetate transaminase (GOT – EC 2.6.1.1), leucine aminopeptidase (LAP – EC 3.4.11.1), isocitrate dehydrogenase (IDH – EC 1.1.1.42), malate dehydrogenase (MDH – EC 1.1.1.37), menadione reductase (MNR – EC 1.6.99.2), phosphoglucomutase (PGM – EC 2.7.5.1), phosphoglucose isomerase (PGI – EC 5.3.1.9), peroxydase (PX – EC 1.11.17) and shikimate dehydrogenase (SKDH – EC 1.1.1.25). Beech populations occurring toward the northeast of the natural range were characterised by a decreasing the average number of alleles per locus and percentage of polymorphic loci. The highest genetic differentiation was found in the East Carpathians. The genetic differentiation levels of Polish beech populations are comparable to the other European countries.