| use of thermal imaging to determine leaf conductance along a canopy gradient in european beech (fagus sylvatica). | using an infrared camera, we measured the leaf temperature across different canopy positions of a 23-m-tall deciduous forest tree (fagus sylvatica l.) including typical sun and shade leaves as well as intermediate leaf forms, which differed significantly in specific leaf area (sla). we calculated a temperature index (i(g)) and a crop water stress index (cwsi) using the surface temperatures of wet and dry reference leaves. additional indices were computed using air temperature plus 5 °c (i(g) + 5 ... | 2012 | 22427372 |
| effect of flooding on c metabolism of flood-tolerant (quercus robur) and non-tolerant (fagus sylvatica) tree species. | flooding is assumed to cause an energy crisis in plants because-due to a lack of o(2)-mitochondrial respiration is replaced by alcoholic fermentation which yields considerably less energy equivalents. in the present study, the effect of flooding on the carbon metabolism of flooding-tolerant pedunculate oak (quercus robur l.) and flooding-sensitive european beech (fagus sylvatica l.) seedlings was characterized. whereas soluble carbohydrate concentrations dropped in roots of f. sylvatica, they we ... | 2012 | 22367762 |
| wide variation in spatial genetic structure between natural populations of the european beech (fagus sylvatica) and its implications for sgs comparability. | identification and quantification of spatial genetic structure (sgs) within populations remains a central element of understanding population structure at the local scale. understanding such structure can inform on aspects of the species' biology, such as establishment patterns and gene dispersal distance, in addition to sampling design for genetic resource management and conservation. however, recent work has identified that variation in factors such as sampling methodology, population characte ... | 2012 | 22354112 |
| throughfall deposition and canopy exchange processes along a vertical gradient within the canopy of beech (fagus sylvatica l.) and norway spruce (picea abies (l.) karst). | to assess the impact of air pollution on forest ecosystems, the canopy is usually considered as a constant single layer in interaction with the atmosphere and incident rain, which could influence the measurement accuracy. in this study the variation of througfall deposition and derived dry deposition and canopy exchange were studied along a vertical gradient in the canopy of one european beech (fagus sylvatica l.) tree and two norway spruce (picea abies (l.) karst) trees. throughfall and net thr ... | 2012 | 22325986 |
| comparison of leaf gas exchange and stable isotope signature of water-soluble compounds along canopy gradients of co-occurring douglas-fir and european beech. | combined δ(13) c and δ(18) o analyses of water-soluble leaf and twig phloem material were used to determine intrinsic water-use efficiency (iwue) and variability of stomatal conductance at different crown positions in adult european beech (fagus sylvatica) and douglas-fir (pseudotsuga menziesii) trees. simultaneous gas exchange measurements allowed evaluation of the differences in calculating iwue from leaf or phloem water-soluble compounds, and comparison with a semi-quantitative dual isotope m ... | 2012 | 22292498 |
| effects of drought on mesophyll conductance and photosynthetic limitations at different tree canopy layers. | in recent years, many studies have focused on the limiting role of mesophyll conductance (gm ) to photosynthesis (an ) under water stress, but no studies have examined the effect of drought on gm through the forest canopy. we investigated limitations to an on leaves at different heights in a mixed adult stand of sessile oak (quercus petraea) and beech (fagus sylvatica) trees during a moderately dry summer. moderate drought decreased an of top and lowest beech canopy leaves much more than in leav ... | 2013 | 23527762 |
| current near-to-nature forest management effects on functional trait composition of saproxylic beetles in beech forests. | with the aim of wood production with negligible negative effects on biodiversity and ecosystem processes, a silvicultural practice of selective logging with natural regeneration has been implemented in european beech forests (fagus sylvatica) during the last decades. despite this near-to-nature strategy, species richness of various taxa is lower in these forests than in unmanaged forests. to develop guidelines to minimize the fundamental weaknesses in the current practice, we linked functional t ... | 2013 | 23432190 |
| assessment of spatial discordance of primary and effective seed dispersal of european beech (fagus sylvatica l.) by ecological and genetic methods. | spatial discordance between primary and effective dispersal in plant populations indicates that postdispersal processes erase the seed rain signal in recruitment patterns. five different models were used to test the spatial concordance of the primary and effective dispersal patterns in a european beech (fagus sylvatica) population from central spain. an ecological method was based on classical inverse modelling (sss), using the number of seed/seedlings as input data. genetic models were based on ... | 2013 | 23379310 |
| reconstruction of a beech population bottleneck using archival demographic information and bayesian analysis of genetic data. | range expansion and contraction has occurred in the history of most species and can seriously impact patterns of genetic diversity. historical data about range change are rare and generally appropriate for studies at large scales, whereas the individual pollen and seed dispersal events that form the basis of geneflow and colonization generally occur at a local scale. in this study, we investigated range change in fagus sylvatica on mont ventoux, france, using historical data from 1838 to the pre ... | 2011 | 22097929 |
| genotypic variability and phenotypic plasticity of cavitation resistance in fagus sylvatica l. across europe. | xylem cavitation resistance is a key physiological trait correlated with species tolerance to extreme drought stresses. little is known about the genetic variability and phenotypic plasticity of this trait in natural tree populations. here we measured the cavitation resistance of 17 fagus sylvatica populations representative of the full range of the species in europe. the trees were grown in three field trials under contrasting climatic conditions. our findings suggest that the genotypic variabi ... | 2011 | 21989814 |
| phosphite protects fagus sylvatica seedlings towards phytophthora plurivora via local toxicity, priming and facilitation of pathogen recognition. | phytophthora plurivora causes severe damage on fagus sylvatica and is responsible for the extensive decline of european beech throughout europe. unfortunately, no effective treatment against this disease is available. phosphite (phi) is known to protect plants against phytophthora species; however, its mode of action towards p. plurivora is still unknown. to discover the effect of phi on root infection, leaves were sprayed with phi and roots were subsequently inoculated with p. plurivora zoospor ... | 2014 | 24489973 |
| converting probabilistic tree species range shift projections into meaningful classes for management. | the paper deals with the management problem how to decide on tree species suitability under changing environmental conditions. it presents an algorithm that classifies the output of a range shift model for major tree species in europe into multiple classes that can be linked to qualities characterizing the ecological niche of the species. the classes: i) core distribution area, ii) extended distribution area, iii) occasional occurrence area, and iv) no occurrence area are first theoretically dev ... | 2014 | 24486469 |
| fine-root carbon and nitrogen concentration of european beech (fagus sylvatica l.) in italy prealps: possible implications of coppice conversion to high forest. | fine-root systems represent a very sensitive plant compartment to environmental changes. gaining further knowledge about their dynamics would improve soil carbon input understanding. this paper investigates c and n concentrations in fine roots in relation to different stand characteristics resulting from conversion of coppiced forests to high forests. in order to evaluate possible interferences due to different vegetative stages of vegetation, fine-root sampling was repeated six times in each st ... | 2013 | 23785374 |
| clues for regulatory processes in fungal uptake and transfer of minerals to the basidiospore. | several fungal species are notorious for the preferential acquisition of toxicants such as ascdhgpbu in their wild-grown basidiomes, but it is not known how, or whether at all, mineral uptake is regulated. in this study, basidiomes of kuehneromyces mutabilis, pleurotus ostreatus, and hypholoma fasciculare were grown on fagus sylvatica logs embedded in sand, uranium-overburden soil, and garden soil (sio) at a lab scale to raise the accessible mineral resources 30 to >1,000 times over those availa ... | 2013 | 23761201 |
| spatial patterns of ectomycorrhizal assemblages in a monospecific forest in relation to host tree genotype. | ectomycorrhizas (ecm) are important for soil exploration and thereby may shape belowground interactions of roots. we investigated the composition and spatial structures of ecm assemblages in relation to host genotype in an old-growth, monospecific beech (fagus sylvatica) forest. we hypothesized that neighboring roots of different beech individuals are colonized by similar ecm assemblages if host genotype had no influence on the fungal colonization and that the similarity would decrease with incr ... | 2013 | 23630537 |
| interspecific temporal and spatial differences in the acquisition of litter-derived nitrogen by ectomycorrhizal fungal assemblages. | the spatiotemporal dynamics of, and interspecific differences in, the acquisition of litter-derived nitrogen (n) by natural assemblages of ectomycorrhizal root tips are poorly understood. small cylindrical mesh bags containing (15)n-labelled beech (fagus sylvatica) leaf litter that permit hyphal but not root ingrowth were inserted vertically into the top soil layer of an old-growth beech forest. the lateral transfer of (15)n into the circumjacent soil, roots, microbes and ectomycorrhizas was mea ... | 2013 | 23594339 |
| differences in soil fungal communities between european beech (fagus sylvatica l.) dominated forests are related to soil and understory vegetation. | fungi are important members of soil microbial communities with a crucial role in biogeochemical processes. although soil fungi are known to be highly diverse, little is known about factors influencing variations in their diversity and community structure among forests dominated by the same tree species but spread over different regions and under different managements. we analyzed the soil fungal diversity and community composition of managed and unmanaged european beech dominated forests located ... | 2012 | 23094057 |
| assessing ozone and nitrogen impact on net primary productivity with a generalised non-linear model. | some studies suggest that in europe the majority of forest growth increment can be accounted for n deposition and very little by elevated co(2). high ozone (o(3)) concentrations cause reductions in carbon fixation in native plants by offsetting the effects of elevated co(2) or n deposition. the cause-effect relationships between primary productivity (npp) of quercus cerris, q. ilex and fagus sylvatica plant species and climate and pollutants (o(3) and n deposition) in italy have been investigate ... | 2013 | 23078996 |
| resistance of european tree species to drought stress in mixed versus pure forests: evidence of stress release by inter-specific facilitation. | while previous studies focused on tree growth in pure stands, we reveal that tree resistance and resilience to drought stress can be modified distinctly through species mixing. our study is based on tree ring measurement on cores from increment boring of 559 trees of norway spruce (picea abies [l.] karst.), european beech (fagus sylvatica [l.]) and sessile oak (quercus petraea (matt.) liebl.) in south germany, with half sampled in pure, respectively, mixed stands. indices for resistance, recover ... | 2013 | 23062025 |
| ground-level ozone differentially affects nitrogen acquisition and allocation in mature european beech (fagus sylvatica) and norway spruce (picea abies) trees. | impacts of elevated ground-level ozone (o(3)) on nitrogen (n) uptake and allocation were studied on mature european beech (fagus sylvatica l.) and norway spruce (picea abies [l.] karst.) in a forest stand, hypothesizing that: (i) chronically elevated o(3) limits nutrient uptake, and (ii) beech responds more sensitively to elevated o(3) than spruce, as previously found for juvenile trees. tree canopies were exposed to twice-ambient o(3) concentrations (2 × o(3)) by a free-air fumigation system, w ... | 2012 | 23042769 |
| the composition of phyllosphere fungal assemblages of european beech (fagus sylvatica) varies significantly along an elevation gradient. | little is known about the potential effect of climate warming on phyllosphere fungi, despite their important impact on the dynamics and diversity of plant communities. the structure of phyllosphere fungal assemblages along elevation gradients may provide information about this potential effect, because elevation gradients correspond to temperature gradients over short geographic distances. we thus investigated variations in the composition of fungal assemblages inhabiting the phyllosphere of eur ... | 2012 | 22934891 |
| effect of tree size and competition on tension wood production over time in beech plantations and assessing relative gravitropic response with a biomechanical model. | gravitropic movements are unexpected mechanical processes that could disturb tree design allometries derived from the physics of nonliving bodies. we investigated whether the scaling law of gravitropic performance (power of -2 of stem diameter) derived from integrative biomechanical modeling is disturbed by ontogeny or environment, then discuss the silvicultural and dendroecological consequences. | 2012 | 22922395 |
| fagus sylvatica trunk epicormics in relation to primary and secondary growth. | european beech epicormics have received far less attention than epicormics of other species, especially sessile oak. however, previous work on beech has demonstrated that there is a negative effect of radial growth on trunk sprouting, while more recent investigations on sessile oak proved a strong positive influence of the presence of epicormics. the aims of this study were, first, to make a general quantification of the epicormics present along beech stems and, secondly, to test the effects of ... | 2012 | 22887022 |
| phenological mismatch strongly affects individual fitness but not population demography in a woodland passerine. | populations are shifting their phenology in response to climate change, but these shifts are often asynchronous among interacting species. resulting phenological mismatches can drive simultaneous changes in natural selection and population demography, but the links between these interacting processes are poorly understood. here we analyse 37 years of data from an individual-based study of great tits (parus major) in the netherlands and use mixed-effects models to separate the within- and across- ... | 2013 | 22862682 |
| seasonal dynamics of arboreal spider diversity in a temperate forest. | measuring and estimating biodiversity patterns is a fundamental task of the scientist working to support conservation and inform management decisions. most biodiversity studies in temperate regions were often carried out over a very short period of time (e.g., a single season) and it is often-at least tacitly-assumed that these short-term findings are representative of long-term general patterns. however, should the studied biodiversity pattern in fact contain significant temporal dynamics, perh ... | 2012 | 22837825 |
| sapflow+: a four-needle heat-pulse sap flow sensor enabling nonempirical sap flux density and water content measurements. | • to our knowledge, to date, no nonempirical method exists to measure reverse, low or high sap flux density. moreover, existing sap flow methods require destructive wood core measurements to determine sapwood water content, necessary to convert heat velocity to sap flux density, not only damaging the tree, but also neglecting seasonal variability in sapwood water content. • here, we present a nonempirical heat-pulse-based method and coupled sensor which measure temperature changes around a linea ... | 2012 | 22816502 |
| multivariate analysis of physiological parameters reveals a consistent o3 response pattern in leaves of adult european beech (fagus sylvatica). | • increasing atmospheric concentrations of phytotoxic ozone (o(3) ) can constrain growth and carbon sink strength of forest trees, potentially exacerbating global radiative forcing. despite progress in the conceptual understanding of the impact of o(3) on plants, it is still difficult to detect response patterns at the leaf level. • here, we employed principal component analysis (pca) to analyse a database containing physiological leaf-level parameters of 60-yr-old fagus sylvatica (european beec ... | 2012 | 22775349 |
| influence of litter chemistry and stoichiometry on glucan depolymerization during decomposition of beech (fagus sylvatica l.) litter. | glucans like cellulose and starch are a major source of carbon for decomposer food webs, especially during early- and intermediate-stages of decomposition. litter quality has previously been suggested to notably influence decomposition processes as it determines the decomposability of organic material and the nutrient availability to the decomposer community. to study the impact of chemical and elemental composition of resources on glucan decomposition, a laboratory experiment was carried out us ... | 2012 | 22761539 |
| stoichiometric controls of nitrogen and phosphorus cycling in decomposing beech leaf litter. | resource stoichiometry (c:n:p) is an important determinant of litter decomposition. however, the effect of elemental stoichiometry on the gross rates of microbial n and p cycling processes during litter decomposition is unknown. in a mesocosm experiment, beech (fagus sylvatica l.) litter with natural differences in elemental stoichiometry (c:n:p) was incubated under constant environmental conditions. after three and six months, we measured various aspects of nitrogen and phosphorus cycling. we f ... | 2012 | 22690628 |
| novel, cyclic heat dissipation method for the correction of natural temperature gradients in sap flow measurements. part 2. laboratory validation. | sap flow measurements conducted with thermal dissipation probes (tdps) are vulnerable to natural temperature gradient (ntg) bias. few studies, however, attempted to explain the dynamics underlying the ntg formation and its influence on the sensors' signal. this study focused on understanding how the tdp signals are affected by negative and positive temperature influences from ntg and tested the novel cyclic heat dissipation (chd) method to filter out the ntg bias. a series of three experiments w ... | 2012 | 22659459 |
| sensitivity of beech trees to global environmental changes at most north-eastern latitude of their occurrence in europe. | the present study aimed to detect sensitivity of beech trees (fagus sylvatica l.) to meteorological parameters and air pollution by acidifying species as well as to surface ozone outside their north-eastern distribution range. data set since 1981 of preila emep station enabled to establish that hot summers, cold dormant, and dry and cold first-half of vegetation periods resulted in beech tree growth reduction. these meteorological parameters explained 57% variation in beech tree ring widths. aci ... | 2012 | 22649321 |
| metatranscriptomics reveals the diversity of genes expressed by eukaryotes in forest soils. | eukaryotic organisms play essential roles in the biology and fertility of soils. for example the micro and mesofauna contribute to the fragmentation and homogenization of plant organic matter, while its hydrolysis is primarily performed by the fungi. to get a global picture of the activities carried out by soil eukaryotes we sequenced 2×10,000 cdnas synthesized from polyadenylated mrna directly extracted from soils sampled in beech (fagus sylvatica) and spruce (picea abies) forests. taxonomic af ... | 2012 | 22238585 |
| greater accumulation of litter in spruce (picea abies) compared to beech (fagus sylvatica) stands is not a consequence of the inherent recalcitrance of needles. | replacement of beech by spruce is associated with changes in soil acidity, soil structure and humus form, which are commonly ascribed to the recalcitrance of spruce needles. it is of practical relevance to know how much beech must be admixed to pure spruce stands in order to increase litter decomposition and associated nutrient cycling. we addressed the impact of tree species mixture within forest stands and within litter on mass loss and nutritional release from litter. | 2017 | 25834285 |
| multiplexed microsatellite markers for genetic studies of beech. | european beech (fagus sylvatica l.) is one of the economically most important broadleaved tree species in europe and has become a model for studying climate change effects on forests. multiplex pcr of microsatellites is a fast and cost-effective technique allowing high-throughput genotyping. here we present the procedure used to develop two multiplex kits (8-plexes) for european beech. we paid particular attention to quality control throughout all steps of the multiplex kits development (null al ... | 2012 | 22145937 |
| phenols in leaves and bark of fagus sylvatica as determinants of insect occurrences. | beech forests play an important role in temperate and north mediterranean ecosystems in greece since they occupy infertile montane soils. in the last glacial maximum, fagus sylvatica (beech) was confined to southern europe where it was dominant and in the last thousand years has expanded its range to dominate central europe. we sampled four different beech forest types. we found 298 insect species associated with beech trees and dead beech wood. while f. sylvatica and quercus (oak) are confamili ... | 2011 | 21686149 |
| a new conceptual model for the fate of lignin in decomposing plant litter. | lignin is a main component of plant litter. its degradation is thought to be critical for litter decomposition rates and the build-up of soil organic matter. we studied the relationships between lignin degradation and the production of dissolved organic carbon (doc) and of co2 during litter decomposition. needle or leaf litter of five species (norway spruce, scots pine, mountain ash, european beech, sycamore maple) and of different decomposition stage (freshly fallen and up to 27 months of field ... | 2011 | 21661566 |
| soil respiration rates and δ13c(co2) in natural beech forest (fagus sylvatica l.) in relation to stand structure. | soil respiration rates were studied as a function of soil type, texture and light intensity at five selected natural beech forest stands with contrasting geology: stands on silicate bedrock at kladje and bricka in pohorje, a stand on quartz sandstone at vrhovo and two stands on a carbonate bedrock in the karstic-dinaric area in kocevski rog, snezna jama and rajhenav, slovenia, during the growing season in 2005-2006. soil respiration exhibited pronounced seasonal and spatial variations in the stu ... | 2011 | 21644135 |
| patterns of lignin degradation and oxidative enzyme secretion by different wood- and litter-colonizing basidiomycetes and ascomycetes grown on beech-wood. | the degradation of lignocellulose and the secretion of extracellular oxidoreductases were investigated in beech-wood (fagus sylvatica) microcosms using 11 representative fungi of four different ecophysiological and taxonomic groups causing: (1) classic white rot of wood (e.g. phlebia radiata), (2) 'nonspecific' wood rot (e.g. agrocybe aegerita), (3) white rot of leaf litter (stropharia rugosoannulata) or (4) soft rot of wood (e.g. xylaria polymorpha). all strong white rotters produced manganese- ... | 2011 | 21631549 |
| do interactions between plant and soil biota change with elevation? a study on fagus sylvatica. | theoretical models predict weakening of negative biotic interactions and strengthening of positive interactions with increasing abiotic stress. however, most empirical tests have been restricted to plant-plant interactions. no empirical study has examined theoretical predictions of interactions between plants and below-ground micro-organisms, although soil biota strongly regulates plant community composition and dynamics. we examined variability in soil biota effects on tree regeneration across ... | 2011 | 21525055 |
| leaf traits, shoot growth and seed production in mature fagus sylvatica trees after 8 years of co2 enrichment. | masting, i.e. synchronous but highly variable interannual seed production, is a strong sink for carbon and nutrients. it may, therefore, compete with vegetative growth. it is currently unknown whether increased atmospheric co(2) concentrations will affect the carbon balance (or that of other nutrients) between reproduction and vegetative growth of forest species. in this study, reproduction and vegetative growth of shoots of mature beech (fagus sylvatica) trees grown at ambient and elevated atmo ... | 2011 | 21493641 |
| gene expression profiling in wounded and systemic leaves of fagus sylvatica reveals up-regulation of ethylene and jasmonic acid signalling. | wounding is a crucial threat to plants because of the physical damage caused and the possible entry of pathogens. little is known about the wound reaction in forest trees. therefore, leaves of young beech trees were wounded and the transcriptional response of wounded leaves and leaves directly above and below was analysed. a total of 123 genes exhibited significant regulation. the magnitude of regulation was slightly weaker in the downward leaves but the regulation pattern resembles that of the ... | 2011 | 21489095 |
| is iron phloem mobile during senescence in trees? a reinvestigation of rissmüller's finding of 1874. | as long as 130 years ago rissmüller reported substantial retranslocation of iron (fe) from beech leaves (fagus sylvatica l.) shortly before leaf fall. this rather limited report on fe retranslocation via the phloem in plants was the reason for this research to study changes in fe content in individual beech leaves in more detail during the vegetative period. besides fe, other micronutrients and particularly ca and k, well known to differ substantially in phloem mobility, were analysed as mineral ... | 2011 | 21486699 |
| development and verification of a water and sugar transport model using measured stem diameter variations. | in trees, water and sugars are transported by xylem and phloem conduits which are hydraulically linked. a simultaneous study of both flows is interesting, since they concurrently influence important processes such as stomatal regulation and growth. a few mathematical models have already been developed to investigate the influence of both hydraulically coupled flows. however, none of these models has so far been tested using real measured field data. in the present study, a comprehensive whole-tr ... | 2010 | 20176887 |
| impacts of drought on mineral macro- and microelements in provenances of beech (fagus sylvatica l.) seedlings. | beech seedlings originating from 11 german provenances with different climatic conditions were grown in pots and cultivated in a greenhouse. the composition of macro- and microelements in roots, axes and leaves was measured after half of the seedlings were subjected to a simulated summer drought. the recently described sensitivity of these provenances to drought was compared with drought-mediated changes in the elemental and ionic composition in organs of the seedlings; in addition, partitioning ... | 2011 | 21450981 |
| growth and posture control strategies in fagus sylvatica and acer pseudoplatanus saplings in response to canopy disturbance. | forest tree saplings that grow in the understorey undergo frequent changes in their light environment to which they must adapt to ensure their survival and growth. crown architecture, which plays a critical role in light capture and mechanical stability, is a major component of sapling adaptation to canopy disturbance. shade-adapted saplings typically have plagiotropic stems and branches. after canopy opening, they need to develop more erect shoots in order to exploit the new light conditions. t ... | 2011 | 21444338 |
| spatial vs. temporal effects on demographic and genetic structures: the roles of dispersal, masting and differential mortality on patterns of recruitment in fagus sylvatica. | trees' long lifespan, long-distance dispersal abilities and high year-to-year variability in fecundity are thought to have pervasive consequences for the demographic and genetic structure of recruited seedlings. however, we still lack experimental studies quantifying the respective roles of spatial processes such as restricted seed and pollen dispersal and temporal processes such as mast seeding on patterns of regeneration. dynamics of european beech (fagus sylvatica) seedling recruitment was mo ... | 2011 | 21426434 |
| microbial processes and community composition in the rhizosphere of european beech - the influence of plant c exudates. | plant roots strongly influence c and n availability in the rhizosphere via rhizodeposition and uptake of nutrients. this study aimed at investigating the effect of resource availability on microbial processes and community structure in the rhizosphere. we analyzed c and n availability, as well as microbial processes and microbial community composition in rhizosphere soil of european beech and compared it to the bulk soil. additionally, we performed a girdling experiment in order to disrupt root ... | 2011 | 21412402 |
| the long way down--are carbon and oxygen isotope signals in the tree ring uncoupled from canopy physiological processes? | the carbon (δ(13)c) and oxygen (δ(18)o) stable isotope composition is widely used to obtain information on the linkages between environmental drivers and tree physiology over various time scales. the tree-ring archive can especially be exploited to reconstruct inter- and intra-annual variation of both climate and physiology. there is, however, a lack of information on the processes potentially affecting δ(13)c and δ(18)o on their way from assimilation in the leaf to the tree ring. as a consequen ... | 2011 | 21957095 |
| to what extent is altitudinal variation of functional traits driven by genetic adaptation in european oak and beech? | the phenotypic responses of functional traits in natural populations are driven by genetic diversity and phenotypic plasticity. these two mechanisms enable trees to cope with rapid climate change. we studied two european temperate tree species (sessile oak and european beech), focusing on (i) in situ variations of leaf functional traits (morphological and physiological) along two altitudinal gradients and (ii) the extent to which these variations were under environmental and/or genetic control u ... | 2011 | 21908436 |
| comparison of pollen gene flow among four european beech (fagus sylvatica l.) populations characterized by different management regimes. | the study of the dispersal capability of a species can provide essential information for the management and conservation of its genetic variability. comparison of gene flow rates among populations characterized by different management and evolutionary histories allows one to decipher the role of factors such as isolation and tree density on gene movements. we used two paternity analysis approaches and different strategies to handle the possible presence of genotyping errors to obtain robust esti ... | 2012 | 21897442 |
| tree and stand growth of mature norway spruce and european beech under long-term ozone fumigation. | in a 50- to 70-year-old mixed stand of norway spruce (picea abies (l.) karst.) and european beech (fagus sylvatica l.) in germany, tree cohorts have been exposed to double ambient ozone (2xo(3)) from 2000 through 2007 and can be compared with trees in the same stand under the ambient ozone regime (1xo(3)). annual diameter growth, allocation pattern, stem form, and stem volume were quantified at the individual tree and stand level. ozone fumigation induced a shift in the resource allocation into ... | 2010 | 19713019 |
| belowground effects of enhanced tropospheric ozone and drought in a beech/spruce forest (fagus sylvatica l./picea abies [l.] karst). | the effects of experimentally elevated o(3) on soil respiration rates, standing fine-root biomass, fine-root production and delta(13)c signature of newly produced fine roots were investigated in an adult european beech/norway spruce forest in germany during two subsequent years with contrasting rainfall patterns. during humid 2002, soil respiration rate was enhanced under elevated o(3) under beech and spruce, and was related to o(3)-stimulated fine-root production only in beech. during dry 2003, ... | 2010 | 19682778 |
| rhizospheric no interacts with the acquisition of reduced n sources by the roots of european beech (fagus sylvatica l.). | the gas phase of the soil plays an important role in plant growth and development. we investigated the effect of rhizospheric no as a signalling compound for n uptake of beech roots. following exposure to no, ammonium and glutamine uptake into roots were determined using (15)n-labelling, and gene expression of selected transporters was analysed by quantitative real-time pcr. uptake of both n sources increased significantly with elevated no concentration. however, with one exception, this increas ... | 2009 | 19660460 |
| consistent patterns in leaf lamina and leaf vein carbon isotope composition across ten herbs and tree species. | wide-spread post-photosynthetic fractionation processes deplete metabolites and plant compartments in (13)c relative to assimilates to varying degrees. fragmentation fractionation and exchange of metabolites with distinct isotopic signatures across organ boundaries further modify the patterns of plant isotopic composition. heterotrophic organs tend to become isotopically heavier than the putative source material as a result of respiratory metabolism. in addition fractionation may occur during me ... | 2009 | 19603469 |
| modelling tree roots in mixed forest stands by inhomogeneous marked gibbs point processes. | the aim of the paper is to apply point processes to root data modelling. we propose a new approach to parametric inference when the data are inhomogeneous replicated marked point patterns. we generalize geyer's saturation point process to a model, which combines inhomogeneity, marks and interaction between the marked points. furthermore, the inhomogeneity influences the definition of the neighbourhood of points. using the maximum pseudolikelihood method, this model is then fitted to root data fr ... | 2009 | 19572316 |
| fine root dynamics of mature european beech (fagus sylvatica l.) as influenced by elevated ozone concentrations. | fine root dynamics (diameter < 1 mm) in mature fagus sylvatica, with the canopies exposed to ambient or twice-ambient ozone concentrations, were investigated throughout 2004. the focus was on the seasonal timing and extent of fine root dynamics (growth, mortality) in relation to the soil environment (water content, temperature). under ambient ozone concentrations, a significant relationship was found between fine root turnover and soil environmental changes indicating accelerated fine root turno ... | 2009 | 19515468 |
| seasonal time-course of gradients of photosynthetic capacity and mesophyll conductance to co2 across a beech (fagus sylvatica l.) canopy. | leaf photosynthesis is known to acclimate to the actual irradiance received by the different layers of a canopy. this acclimation is usually described in terms of changes in leaf structure, and in photosynthetic capacity. photosynthetic capacity is likely to be affected by mesophyll conductance to co(2) which has seldom been assessed in tree species, and whose plasticity in response to local irradiance is still poorly known. structural [n and chlorophyll content, leaf mass to area ratio (lma)] a ... | 2009 | 19457983 |
| non-reducing sugar levels in beech (fagus sylvatica) seeds as related to withstanding desiccation and storage. | levels of sucrose and raffinose family oligosaccharides (rfos) (raffinose and stachyose) were determined in beech (fagus sylvatica l.) seeds during development, maturation, desiccation and storage. an increase in rfos and a marked decrease in the s:(r+st) ratio (i.e. mass ratio of sucrose to the sum of rfos) were observed at the time of desiccation tolerance (dt) acquisition by seeds. in seeds stored at -10 degrees c through 1, 4, 7, and 12 years, changes in sucrose, raffinose and stachyose leve ... | 2009 | 19359065 |
| beech carbon productivity as driver of ectomycorrhizal abundance and diversity. | we tested the hypothesis that carbon productivity of beech (fagus sylvatica) controls ectomycorrhizal colonization, diversity and community structures. carbon productivity was limited by long-term shading or by girdling. the trees were grown in compost soil to avoid nutrient deficiencies. despite severe limitation in photosynthesis and biomass production by shading, the concentrations of carbohydrates in roots were unaffected by the light level. shade-acclimated plants were only 10% and sun-accl ... | 2009 | 19344334 |
| leaf and twig delta13c during growth in relation to biochemical composition and respired co2. | in deciduous trees, the delta(13)c values of leaves are known to diverge during growth from those of woody organs. the main purpose of this study is to determine whether the divergence in delta(13)c between leaves and current-year twigs of fagus sylvatica (l.) is influenced by changes (i) in the relative contents of organic matter fractions and (ii) in the delta(13)c of respired co(2). the delta(13)c values of bulk matter, extractive-free matter, lignin, holocellulose, starch, soluble sugars, wa ... | 2009 | 19324695 |
| dilution-to-extinction cultivation of leaf-inhabiting endophytic fungi in beech (fagus sylvatica l.)--different cultivation techniques influence fungal biodiversity assessment. | two cultivation-based isolation techniques - the incubation of leaf fragments (fragment plating) and dilution-to-extinction culturing on malt extract agar - were compared for recovery of foliar endophytic fungi from fagus sylvatica near greifswald, north-east germany. morphological-anatomical characters of vegetative and sporulating cultures and its sequences were used to assign morphotypes and taxonomic information to the isolates. data analysis included species-accumulation curves, richness es ... | 2009 | 19233268 |
| interception of spray drift by border structures. part 2: field experiments. | this research studied the effect of drift-intercepting structures surrounding the field borders, like artificial screens and natural hedges, which are not yet a part of the drift mitigation measures for field crop sprayers in belgium. drift-interception experiments were performed in a grassland (lolium perenne) with various interception structures: artificial screens with heights of 1, 1.5 and 2 m and screen open areas of 16, 36 and 63% and a row of fagus sylvatica trees with a height of 1.5 m a ... | 2008 | 19226820 |
| summer drought impedes beech seedling performance more in a sub-mediterranean forest understory than in small gaps. | refugia of mixed beech forest persist in the central mountains of the iberian peninsula at the south-western limit of european beech (fagus sylvatica l.) distribution. the lack of beech regeneration is a concern in this region that has experienced reduced rainfall and higher temperatures over the past 30 years. beech is considered especially susceptible to climate change because of its conservative shade-tolerant growth strategy; hence seedling responses to drought stress in gaps and in the unde ... | 2009 | 19203950 |
| variability in radial sap flux density patterns and sapwood area among seven co-occurring temperate broad-leaved tree species. | forest transpiration estimates are frequently based on xylem sap flux measurements in the outer sections of the hydro-active stem sapwood. we used granier's constant-heating technique with heating probes at various xylem depths to analyze radial patterns of sap flux density in the sapwood of seven broad-leaved tree species differing in wood density and xylem structure. study aims were to (1) compare radial sap flux density profiles between diffuse- and ring-porous trees and (2) analyze the relat ... | 2008 | 19193565 |
| mechanical behaviour analyses of sap ascent in vascular plants. | a pure mechanical anisotropic model of a tree trunk has been developed based on the 3d finite element method. it simulates the microscopic structure of vessels in the trunk of a european beech (fagus sylvatica) in order to study and analyse its mechanical behaviour with different configurations of pressures in the conduits of xylem and phloem. the dependence of the strains at the inner bark was studied when sap pressure changed. the comparison with previously published experimental data leads to ... | 2010 | 21886343 |
| seasonal changes of c and n non-structural compounds in the stem sapwood of adult sessile oak and beech trees. | we assessed the pools of non-structural nitrogen compounds (nsnc) through a year, thereby addressing the question of whether mature sessile oak [quercus petraea (matt.) liebl.] and beech (fagus sylvatica l.), which differ in wood anatomy and growth patterns, exhibit contrasting seasonal dynamics of nsnc pools as previously shown for non-structural carbohydrate (nsc) pools. seasonal fluctuations of nsnc (amino acids and soluble proteins) and nsc (starch and soluble sugars) pools were analyzed in ... | 2011 | 21856656 |
| the diel imprint of leaf metabolism on the δ13 c signal of soil respiration under control and drought conditions. | recent (13) co(2) canopy pulse chase labeling studies revealed that photosynthesis influences the carbon isotopic composition of soil respired co(2) (δ(13) c(sr)) even on a diel timescale. however, the driving mechanisms underlying these short-term responses remain unclear, in particular under drought conditions. the gas exchange of co(2) isotopes of canopy and soil was monitored in drought/nondrought-stressed beech (fagus sylvatica) saplings after (13) co(2) canopy pulse labeling. a combined ca ... | 2011 | 21851360 |
| soil matrix tracer contamination and canopy recycling did not impair ¹³co₂ plant-soil pulse labelling experiments. | when conducting (13)co(2) plant-soil pulse labelling experiments, tracer material might cause unwanted side effects which potentially affect δ(13)c measurements of soil respiration (δ(13)c(sr)) and the subsequent data interpretation. first, when the soil matrix is not isolated from the atmosphere, contamination of the soil matrix with tracer material occurs leading to a physical back-diffusion from soil pores. second, when using canopy chambers continuously, (13)co(2) is permanently re-introduce ... | 2011 | 21756196 |
| the presence of amino acids affects inorganic n uptake in non-mycorrhizal seedlings of european beech (fagus sylvatica). | to investigate the impact of organic n compounds for inorganic nitrogen uptake in the rhizosphere, we fed ammonium nitrate with or without amino acids (i.e., glutamine or arginine) to the roots of non-mycorrhizal beech (fagus sylvatica l.) seedlings under controlled conditions at different levels of n availability. uptake of individual n sources was determined from ¹⁵n (inorganic n) and ¹⁵n ¹³c (organic n) accumulation in the roots. in addition, gene fragments encoding proteins involved in n upt ... | 2010 | 20595637 |
| use of sap flow measurements to validate stomatal functions for mature beech (fagus sylvatica) in view of ozone uptake calculations. | for a quantitative estimate of the ozone effect on vegetation reliable models for ozone uptake through the stomata are needed. because of the analogy of ozone uptake and transpiration it is possible to utilize measurements of water loss such as sap flow for quantification of ozone uptake. this technique was applied in three beech (fagus sylvatica) stands in switzerland. a canopy conductance was calculated from sap flow velocity and normalized to values between 0 and 1. it represents mainly stoma ... | 2010 | 20580473 |
| calcium is a major determinant of xylem vulnerability to cavitation. | xylem vulnerability to cavitation is a key parameter in the drought tolerance of trees, but little is known about the control mechanisms involved. cavitation is thought to occur when an air bubble penetrates through a pit wall, and would hence be influenced by the wall's porosity. we first tested the role of wall-bound calcium in vulnerability to cavitation in fagus sylvatica. stems perfused with solutions of oxalic acid, egta, or sodium phosphate (napo(4)) were found to be more vulnerable to ca ... | 2010 | 20547703 |
| competition for nitrogen sources between european beech (fagus sylvatica) and sycamore maple (acer pseudoplatanus) seedlings. | to investigate the short-term consequences of direct competition between beech and sycamore maple on root n uptake and n composition, mycorrhizal seedlings of both tree species were incubated for 4 days (i.e. beech only, sycamore maple only or both together) in an artificial nutrient solution with low n availability. on the fourth day, n uptake experiments were conducted to study the effects of competition on inorganic and organic n uptake. for this purpose, multiple n sources were applied with ... | 2010 | 20522181 |
| resurrection kinetics of photosynthesis in desiccation-tolerant terrestrial green algae (chlorophyta) on tree bark. | the rough bark of orchard trees (malus) around darmstadt is predominantly covered in red to purple-brown layers (biofilms) of epiphytic terrestrial alga of trentepohlia umbrina. the smooth bark of forest trees (fagus sylvatica l. and acer sp.) in the same area is covered by bright green biofilms composed of the green algae desmococcus, apatococcus and trebouxia, with a few cells of coccomyxa and 'chlorella' trebouxioides between them. these algae are desiccation tolerant. after samples of bark w ... | 2010 | 20522179 |
| the influence of climate and fructification on the inter-annual variability of stem growth and net primary productivity in an old-growth, mixed beech forest. | the periodic production of large seed crops by trees (masting) and its interaction with stem growth has long been the objective of tree physiology research. however, very little is known about the effects of masting on stem growth and total net primary productivity (npp) at the stand scale. this study was conducted in an old-growth, mixed deciduous forest dominated by fagus sylvatica (l.) and covers the period from 2003 to 2007, which comprised wet, dry and regular years as well as two masts of ... | 2010 | 20453002 |
| early events in populus hybrid and fagus sylvatica leaves exposed to ozone. | this paper aims to investigate early responses to ozone in leaves of fagus sylvatica (beech) and populus maximowiczii x populus berolinensis (poplar). the experimental setup consisted of four open-air (oa) plots, four charcoal-filtered (cf) open-top chambers (otcs), and four nonfiltered (nf) otcs. qualitative and quantitative analyses were carried out on nonsymptomatic (cf) and symptomatic (nf and oa) leaves of both species. qualitative analyses were performed applying microscopic techniques: ev ... | 2010 | 20364237 |
| laccase catalyzed covalent coupling of fluorophenols increases lignocellulose surface hydrophobicity. | this work presents for the first time the mechanistic evidence of a laccase-catalyzed method of covalently grafting hydrophobicity enhancing fluorophenols onto fagus sylvatica veneers. coupling of fluorophenols onto complex lignin model compounds guaiacylglycerol beta-guaiacyl ether and syringylglycerol beta-guaiacyl ether was demonstrated by lc-ms and nmr. laccase-mediated coupling increased binding of 4-[4-(trifluoromethyl)phenoxy]phenol (4,4-f3mpp) and 4-(trifluoromethoxy)phenol (4-f3mp) to v ... | 2010 | 20044252 |
| ozone fumigation (twice ambient) reduces leaf infestation following natural and artificial inoculation by the endophytic fungus apiognomonia errabunda of adult european beech trees. | in 2006, a controlled infection study was performed in the 'kranzberger forst' to address the following questions: (1) will massive artificial inoculation with apiognomonia errabunda override the previously observed inhibitory effect of chronic ozone? (2) can biochemical or molecular markers be detected to account for the action of ozone? to this end six adult beech trees were chosen, three ozone fumigated (2x ozone) and three control trees (ambient = 1x ozone). spore-sprayed branches of sun and ... | 2010 | 19850384 |
| stable isotope signatures reflect competitiveness between trees under changed co2/o3 regimes. | here we synthesize key findings from a series of experiments to gain new insight on inter-plant competition between juvenile beech (fagus sylvatica) and spruce (picea abies) under the influence of increased o(3) and co(2) concentrations. competitiveness of plants was quantified and mechanistically interpreted as space-related resource investments and gains. stable isotopes were addressed as temporal integrators of plant performance, such as photosynthesis and its relation to water use and nitrog ... | 2010 | 19796853 |
| the effects of gap size on some microclimate variables during late summer and autumn in a temperate broadleaved deciduous forest. | the creation of gaps can strongly influence forest regeneration and habitat diversity within forest ecosystems. however, the precise characteristics of such effects depend, to a large extent, upon the way in which gaps modify microclimate and soil water content. hence, the aim of this study was to understand the effects of gap creation and variations in gap size on forest microclimate and soil water content. the study site, in north west england, was a mixed temperate broadleaved deciduous fores ... | 2010 | 19763632 |
| hydraulic properties of naturally regenerated beech saplings respond to canopy opening. | enhanced sapling growth in advance regeneration requires gaps in the canopy, but is often delayed after canopy opening, because acclimation of saplings to the new environment is gradual and may last for several years. canopy opening is expected to result in an increased transpiration because of a larger climatic demand and a higher stomatal conductance linked to the higher rates of photosynthesis. therefore, we focused on the changes in water relations and the hydraulic properties of beech (fagu ... | 2009 | 19744973 |
| seasonal patterns of carbon allocation to respiratory pools in 60-yr-old deciduous (fagus sylvatica) and evergreen (picea abies) trees assessed via whole-tree stable carbon isotope labeling. | • the co(2) efflux of adult trees is supplied by recent photosynthates and carbon (c) stores. the extent to which these c pools contribute to growth and maintenance respiration (r(g) and r(m), respectively) remains obscure. • recent photosynthates of adult beech (fagus sylvatica) and spruce (picea abies) trees were labeled by exposing whole-tree canopies to (13) c-depleted co(2). label was applied three times during the year (in spring, early summer and late summer) and changes in the stable c i ... | 2011 | 21395596 |
| ozone influence on native vegetation in the jizerske hory mts. of the czech republic: results based on ozone exposure and ozone-induced visible symptoms. | ozone levels in the jizerske hory mts. measured at 13 sites by diffusive samplers during the 2006 and 2007 vegetation seasons are presented. a significant ozone gradient (5.4 ppb in 2006 and 4.0 ppb in 2007) per 100 m difference in altitude between 370 and 1,100 m a.s.l. was recorded. high-resolution maps of phytotoxic potential were developed. the aot40 threshold (5 ppm h) was exceeded over the entire area with the highest levels exceeding this threshold by 12 times in the upper portions of the ... | 2011 | 21374050 |
| carbon exchange between ecosystems and atmosphere in the czech republic is affected by climate factors. | by comparing five ecosystem types in the czech republic over several years, we recorded the highest carbon sequestration potential in an evergreen norway spruce forest (100%) and an agroecosystem (65%), followed by european beech forest (25%) and a wetland ecosystem (20%). because of a massive ecosystem respiration, the final carbon gain of the grassland was negative. climate was shown to be an important factor of carbon uptake by ecosystems: by varying the growing season length (a 22-d longer s ... | 2011 | 21345558 |
| seasonal dynamics in the stable carbon isotope composition δ¹³c from non-leafy branch, trunk and coarse root co₂ efflux of adult deciduous (fagus sylvatica) and evergreen (picea abies) trees. | respiration is a substantial driver of carbon (c) flux in forest ecosystems and stable c isotopes provide an excellent tool for its investigation. we studied seasonal dynamics in δ¹³c of co₂ efflux (δ¹³c(e)) from non-leafy branches, upper and lower trunks and coarse roots of adult trees, comparing deciduous fagus sylvatica (european beech) with evergreen picea abies (norway spruce). in both species, we observed strong and similar seasonal dynamics in the δ¹³c(e) of above-ground plant components, ... | 2011 | 21054435 |
| insights into xylem vulnerability to cavitation in fagus sylvatica l.: phenotypic and environmental sources of variability. | xylem vulnerability to cavitation is a key parameter in understanding drought resistance of trees. we determined the xylem water pressure causing 50% loss of hydraulic conductivity (p(50)), a proxy of vulnerability to cavitation, and we evaluated the variability of this trait at tree and population levels for fagus sylvatica. we checked for the effects of light on vulnerability to cavitation of stem segments together with a time series variation of p(50). full sunlight-exposed stem segments were ... | 2010 | 20935319 |
| expanding leaves of mature deciduous forest trees rapidly become autotrophic. | emerging leaves in evergreen tree species are supplied with carbon (c) from the previous year's foliage. in deciduous trees, no older leaves are present, and the early phase of leaf development must rely on c reserves from other tissues. how soon developing leaves become autotrophic and switch from being c sinks to sources has rarely been studied in mature forest trees, and simultaneous comparisons of species are scarce. using a canopy crane and a simple (13)co(2)-pulse-labelling technique, we d ... | 2010 | 20688879 |
| transcriptional signatures in leaves of adult european beech trees (fagus sylvatica l.) in an experimentally enhanced free air ozone setting. | tropospheric ozone causes severe oxidative stress in plants. to investigate the transcriptional responsiveness of adult trees to ozone, fully-expanded sun and shade leaves of mature beech trees were harvested at four time points over the entire vegetation period in 2005 and 2006. microarray analyses were conducted on leaves from trees grown in the field under ambient and twice-ambient ozone concentrations at kranzberger forst (bavaria). beech trees changed their transcript levels in response to ... | 2010 | 19744757 |
| within-canopy and ozone fumigation effects on delta13c and delta18o in adult beech (fagus sylvatica) trees: relation to meteorological and gas exchange parameters. | in this study, the effects of different light intensities either in direct sunlight or in the shade crown of adult beech (fagus sylvatica l.) trees on delta13c and delta18o were determined under ambient (1 x o3) and twice-ambient (2 x o3) atmospheric ozone concentrations during two consecutive years (2003 and 2004). we analysed the isotopic composition in leaf bulk, leaf cellulose, phloem and xylem material and related the results to (a) meteorological data (air temperature, t and relative humid ... | 2009 | 19734546 |
| elevated aluminium concentration in acidified headwater streams lowers aquatic hyphomycete diversity and impairs leaf-litter breakdown. | aquatic hyphomycetes play an essential role in the decomposition of allochthonous organic matter which is a fundamental process driving the functioning of forested headwater streams. we studied the effect of anthropogenic acidification on aquatic hyphomycetes associated with decaying leaves of fagus sylvatica in six forested headwater streams (ph range, 4.3-7.1). non-metric multidimensional scaling revealed marked differences in aquatic hyphomycete assemblages between acidified and reference str ... | 2008 | 18202885 |
| genotypic variation and phenotypic plasticity in the drought response of fine roots of european beech. | how temperate trees respond to drier summers, as predicted by climate change models for parts of europe and eastern north america, will depend on the drought susceptibility of the root systems. we investigated the importance of the genetic constitution for the belowground drought response of european beech (fagus sylvatica l.), in four populations from regions differing in precipitation (520-970 mm year(-1)). saplings were grown at ample (10 vol.%; well-watered) or reduced (5 vol.%; drought trea ... | 2008 | 18055440 |
| tree stem phosphoenolpyruvate carboxylase (pepc): lack of biochemical and localization evidence for a c4-like photosynthesis system. | here, the kinetic properties and immunolocalization of phosphoenolpyruvate carboxylase (pepc) and ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) in young stems of fagus sylvatica were investigated. the aim of the study was to test the hypothesis that there is a c4-like photosynthesis system in the stems of this c3 tree species. the activity, optimal ph and l-malate sensitivity of pepc, and the michaelis-menten constant (km) for phosphoenolpyruvate (pep), were measured in protein extra ... | 2007 | 17997763 |
| qualitative and quantitative changes of beech wood degraded by wood-rotting basidiomycetes monitored by fourier transform infrared spectroscopic methods and multivariate data analysis. | beech wood (fagus sylvatica l.) veneers were cultivated with white and brown rot fungi for up to 10 weeks. fungal wood modification was traced with fourier transform near infrared (ft-nir) and fourier transform mid infrared (ft-mir) methods. partial least square regression (plsr) models to predict the total lignin content before and after fungal decay in the range between 17.0% and 26.6% were developed for ft-mir transmission spectra as well as for ft-nir reflectance spectra. weight loss of the ... | 2007 | 17466029 |
| monitoring of ozone risk for forests in the czech republic: preliminary results. | ozone (o3) is supposed to represent a significant risk for the health of forest ecosystems in central europe. so far, however, its impact on stands growing under natural conditions has not been clearly proved. a new project of the national agency for the research in agriculture is focused on the o3 effect on selected parameters of forest health. this paper presents the results of the first year of monitoring, 2005. in 2005, high o3 concentrations were measured, mainly in the spring. in the summe ... | 2007 | 17450283 |
| effects of chronic elevated ozone exposure on gas exchange responses of adult beech trees (fagus sylvatica) as related to the within-canopy light gradient. | the effects of elevated o3 on photosynthetic properties in adult beech trees (fagus sylvatica) were investigated in relation to leaf mass per area as a measure of the gradually changing, within-canopy light availability. leaves under elevated o3 showed decreased stomatal conductance at unchanged carboxylation capacity of rubisco, which was consistent with enhanced delta 13c of leaf organic matter, regardless of the light environment during growth. in parallel, increased energy demand for o3 deto ... | 2009 | 18976843 |
| impact of lambda-cyhalothrin on a macroinvertebrate assemblage in outdoor experimental channels: implications for ecosystem functioning. | in this study, the impact of a single pulse of the pyrethroid lambda-cyhalothrin was tested on a macroinvertebrate assemblage consisting of gammarus pulex, leuctra nigra, heptagenia sulphurea and ancylus fluviatilis in outdoor experimental stream channels. channels (4m long, 0.1m wide) were groundwater fed and had natural substratum. macroinvertebrates were exposed to 10.65 or 106.5 ng l(-1) lambda cyhalothrin for 90 min in the laboratory and after 24h introduced to the experimental stream chann ... | 2008 | 18945499 |
| simultaneous estimation of null alleles and inbreeding coefficients. | although microsatellites are a very efficient tool for many population genetics applications, they may occasionally produce "null" alleles, which, when present in high proportion, may affect estimates of key parameters such as inbreeding and relatedness coefficients or measures of genetic differentiation. in order to account for the presence of null alleles, it is first necessary to estimate their frequency within studied populations. however, the commonly used null allele frequency estimators a ... | 2008 | 18936113 |
| effects of drought and canopy ozone exposure on antioxidants in fine roots of mature european beech (fagus sylvatica). | we quantified ascorbate, glutathione and alpha-tocopherol in fine roots of mature fagus sylvatica l. under free-air canopy ozone (o(3)) exposure (twice ambient o(3) concentration, 2x[o(3)]) during two growing seasons that differed in the extent of summer drought (exceptional drought year 2003, average year 2004). this design allowed us to test whether o(3) exposure or drought, or both, affected root antioxidants during the growing season. in both years, root ascorbate and alpha-tocopherol showed ... | 2008 | 18316303 |
| changes of photosynthetic traits in beech saplings (fagus sylvatica) under severe drought stress and during recovery. | in the context of an increased risk of extreme drought events across europe during the next decades, the capacity of trees to recover and survive drought periods awaits further attention. in summer 2005, 4-year-old beech (fagus sylvatica l.) saplings were watered regularly or were kept for 4 weeks without irrigation in the field and then re-watered again. changes of plant water status, leaf gas exchange and chl a fluorescence parameters, as well as alterations in leaf pigment composition were fo ... | 2007 | 18251880 |
| [fungal endophytes in juncus imbricatus var chamissonis: identification of colonization patterns.]. | colonization patterns corresponding to individual endophytic species were observed in asymptomatic leaves and culms of juncus imbricatus var chamissonis, a perennial plant. the presence of the fungi within the host was demonstrated by light microscopy after the cleaning and staining of tissues. the main endophytic species, pleospora aff togwotiensis, was found colonizing the substomatal chamber and growing intercellularly between mesophyll cells. in a second colonization pattern, an unknown fung ... | 1997 | 17655388 |
| combining delta 13 c and delta 18 o analyses to unravel competition, co2 and o3 effects on the physiological performance of different-aged trees. | combined delta(13)c and delta(18)o analyses of leaf material were used to infer changes in photosynthetic capacity (a(max)) and stomatal conductance (g(l)) in fagus sylvatica and picea abies trees growing under natural and controlled conditions. correlation between g(l) and delta(18)o in leaf cellulose (delta(18)o(cel)) allowed us to apply a semi-quantitative model to infer g(l) from delta(18)o(cel) and also interpret variation in delta(13)c as reflecting variation in a(max). extraction of leaf ... | 2007 | 17617829 |