| the enrichment of (18)o in leaf water under natural conditions. | the enrichment of (18)o in the water of transpiring leaves under natural conditions is described. in the first series two, later three species at the same location and at the same time are compared (birch betula pubescens l., oak quercus robur ehrh., larch larix decidua mill., and spruce picea abies karst). all four show parallel enrichment properties. in addition two beeches (fagus silvatica l.) were observed, one at jülich, the other at the solling hills. they show similar (18)o/(16)o ratio fl ... | 1978 | 756054 |
| toxicity testing of leaves from oak (quercus robur) harvested in aust-agder county, norway. | | 1999 | 10493119 |
| evolution of phenolic compounds of spanish oak wood during natural seasoning. first results. | low molecular weight polyphenols and ellagitannins were analyzed by hplc, and the molecular weight distribution of ellagitannins was calculated by gpc, in oak heartwood of quercus robur l., quercus petraea liebl., quercus pyrenaica wild., and quercus faginea lam., grown in spain, before and after 1 year of seasoning, in bordeaux, france. during this process, the concentrations of low molecular weight polyphenols (acids and aldehydes, benzoic and cinnamic, and coumarins) increased, and those of e ... | 1999 | 10564039 |
| differential toxicity of leaf litter to dipteran larvae of mosquito developmental sites. | the relative toxicity of leaf litter to nematocerous dipteran larvae characteristic of mosquito developmental sites was investigated. culicidae, chironomidae, and simuliidae taxa originating from alpine hydrosystems were tested together with two laboratory nonindigenous culicid taxa. bioassays indicate that ingestion of 10-month-old decaying leaves from alnus glutinosa, populus nigra, and quercus robur by larvae is more deleterious for aedes aegypti, a. albopictus, culex pipiens, simulium varieg ... | 2000 | 10631052 |
| [cytogenetic characteristics of seed progeny of trees under condition of antropogenic contamination in voronezh town]. | it has been shown that in seed progeny of quercus robur l., pinus sylvestris l. and betula pendula roth. some cytogenetical characteristics vary under conditions of contamination. such changes may be common or specific type. thus, the frequency of pathological mitosis increases under such conditions in all the investigated species of trees. inhibition of mitosis was found in the progeny of the pine, and variability in the number of nucleoli was detected in the pine and oak. however, in some case ... | 2000 | 10752126 |
| analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry. | extractable tannins were analysed by liquid chromatography-electrospray ionisation mass spectrometry in two oak species, north american white oak (quercus alba) and european red oak (quercus robur). they mainly included various glucose gallic and ellagic acid esters. the structures were partially determined, and they included grandinin/roburin e, castalagin/vescalagin, gallic acid, valoneic acid bilactone, monogalloyl glucose, digalloyl glucose, trigalloyl glucose, ellagic acid rhamnose, quercit ... | 2000 | 10999626 |
| differential stress responses of antioxidative systems to drought in pendunculate oak (quercus robur) and maritime pine (pinus pinaster) grown under high co(2) concentrations. | maritime pine (pinus pinaster), a drought-avoiding species, contained 2--4-fold lower activities of superoxide dismutase, ascorbate peroxidase, catalase, dehydroascorbate reductase, and glutathione reductase than pendunculate oak (quercus robur), a drought-tolerant species. the levels of ascorbate, monodehydroascorbate radical reductase activity, and glutathione in pine needles were similar to those in oak leaves. in both species the development of drought stress, characterized by decreasing pre ... | 2001 | 11181722 |
| cushing's disease: a new approach to therapy in equine and canine patients. | forty-one cases of cushing's disease affecting both equine and canine patients were treated with an identical mixture of two homeopathically prepared remedies (acth 30c and quercus robur 30c), and the clinical improvements seen in the cases assessed. homeopathy has been described as a medicine that can only be prescribed on the basis of individual symptoms shown, fitting the remedy to the patient, not the disease. the aim of this study was to define whether a standardised approach, using homeopa ... | 2001 | 11212087 |
| temperature response of leaf photosynthetic capacity in seedlings from seven temperate tree species. | seedlings of seven temperate tree species (acer pseudoplatanus l., betula pendula roth, fagus sylvatica l., fraxinus excelsior l., juglans regia l., quercus petraea matt. liebl. and quercus robur l.) were grown in a nursery under neutral filters transmitting 45% of incident global irradiance. during the second or third year of growth, leaf photosynthetic capacity (i.e., maximal carboxylation rate, vcmax, maximal photosynthetic electron transport rate, jmax, and dark respiration, rd) was estimate ... | 2001 | 11276416 |
| photosynthetic capacity in relation to nitrogen in the canopy of a quercus robur, fraxinus angustifolia and tilia cordata flood plain forest. | we measured gas exchange and various leaf parameters of ash (fraxinus angustifolia vahl.) and oak (quercus robur l.) in the high canopy and of lime (tilia cordata mill.) in the lower canopy of a planted, 120-year-old floodplain forest in southern moravia, czech republic. the high-canopy leaves of f. angustifolia and q. robur had nitrogen concentrations on a leaf area basis (n(area)) that were twice those of low-canopy leaves of t. cordata. upper-canopy leaves of f. angustifolia had a photosynthe ... | 2000 | 11305457 |
| changes in low molecular weight phenolic compounds in spanish, french, and american oak woods during natural seasoning and toasting. | the evolution of low molecular weight polyphenols in spanish oak heartwood of quercus robur,quercus petraea, quercus pyrenaica, and quercus faginea was studied by hplc, in relation to the processing of wood in barrel cooperage. the polyphenolic composition of spanish woods subjected to natural seasoning for 3 years and to the toasting process was studied in relation to those of french oak of q. robur (limousin) and q. petraea (allier) and american oak of q. alba (missouri), which are habitually ... | 2001 | 11308327 |
| evolution of ellagitannins in spanish, french, and american oak woods during natural seasoning and toasting. | the evolution of tannins in spanish oak heartwood of quercus robur l., quercus petraea liebl.,quercus pyrenaica wild., and quercus faginea lam. was studied in relation to the processing of wood in barrel cooperage. their evolution was compared with that of french oak of q. robur (limousin, france) and q. petraea (allier, france) and american oak of quercus alba l. (missouri), which are habitually used in cooperage. two stages of process were researched: the seasoning of woods during 3 years in n ... | 2001 | 11513647 |
| genetic differentiation of oak populations within the quercus robur/quercus petraea complex in central and eastern europe. | genetic structure of 25 indigenous populations of sessile and pedunculate oaks (quercus petraea and q. robur), originating from three geographical regions: slovakia, bulgaria and the republic mari-el (russia), was investigated using isozyme markers. mean number of alleles per locus ranged between 1.8 and 2.6 in q. robur populations and from 2.0 to 3.0 in q. petraea populations; slightly higher expected heterozygosity values were found in q. robur compared to q. petraea. one locus, coding for a s ... | 2001 | 11554972 |
| lichens of the knyszyńska forest (ne poland). | during the period 1991-1999 the lichen species composition of 26 reserves of the knyszyńska forest were examined. 315 taxa, including 271 species were found. epiphytic lichens were predominant, while epilithic species were the least common. of the coniferous trees, pine (pinus sylvestis) was the habitat which supported most species (67), and common larch (larix decidua) the fewest (5). only two species were found on juniper (juniper communis). of deciduous trees, the largest number of species de ... | 2001 | 11780570 |
| rate of stomatal opening, shoot hydraulic conductance and photosynthetic characteristics in relation to leaf abscisic acid concentration in six temperate deciduous trees. | correlations between leaf abscisic acid concentration ([aba]), stomatal conductance (gs), rate of stomatal opening in response to an increase in leaf water potential (si), shoot hydraulic conductance (l) and photosynthetic characteristics were examined in saplings of six temperate deciduous tree species: acer platanoides l., padus avium mill., populus tremula l., quercus robur l., salix caprea l. and tilia cordata mill. species-specific values of foliar [aba] were negatively related to the mean ... | 2002 | 11874723 |
| [genetic differentiation of pedunculate oak quercus robur l. in the european part of russia based on rapd markers]. | using randomly amplified polymorphic dna markers (rapd), genetic variation and differentiation in four populations of pedunculate oak quercus robur l. were examined. the populations occupy a large part of the quercus robur range in the european russia (voronezh and novgorod oblasts; republics of mordovia and bashkortostan). with each of six random primers (a02, a09, a17, b01, b08, b11), 96 dna samples were analyzed by pcr. in all, 48 putative polymorphic rapd loci were detected. we failed to rev ... | 2002 | 11898612 |
| quantitative analysis of phytopathogenic ascomycota on leaves of pedunculate oaks (quercus robur l.) by real-time pcr. | leaves of oak trees are often infected by various pathogenic fungi. as it is difficult to remove such organisms quantitatively from the leaf surface and as it is often impossible to grow these organisms independently from their host, there are almost no molecular data available from these oak leaf specific pathogens. for the quantitative removal of the microorganisms a procedure was developed combining a wax and microorganism freezing method with a dna extraction technique. for the development o ... | 2002 | 12007821 |
| influence of odor from wood-decaying fungi on host selection behavior of deathwatch beetle, xestobium rufovillosum. | adult females of xestobium rufovillosum de geer demonstrated anemotactic orientation when exposed to an odor plume containing volatiles generated by wood-decaying fungi (coriolus versicolor, donkioporia expansa) and decayed oak wood (quercus petraea, quercus robur). they did not orient towards undecayed oak wood, beech (fagus sylvatica), or pine wood (pinus sylvestris). although all insects tested showed anemotactic orientation, responses were nonlinear with respect to insect age. adult females ... | 2002 | 12035923 |
| diversity of culturable bacterial populations associated to tuber borchii ectomycorrhizas and their activity on t. borchii mycelial growth. | isolation and physiological and molecular characterisation of culturable bacterial strains belonging to actinomycetes, pseudomonads and aerobic spore-forming bacteria were carried out on mycorrhizal root tips of quercus robur var. peduncolata infected by tuber borchii. cellular density of the three bacterial groups in ectomycorrhizal root tips was estimated to be 1.3+/-0.11 x 10(6) cfu g(-1) dry weight for total heterotrophic bacteria and 1.08+/-0.6 x 10(5) (mean+/-s.e.), 1.3+/-0.3 x 10(5) and 1 ... | 2002 | 12076812 |
| historical changes in lead concentrations in tree-rings of sycamore, oak and scots pine in north-west england. | lead concentrations in tree rings of sycamore (acer pseudoplatanus l.), oak (quercus robur l.) and scots pine (pinus sylvestris l.) sampled at a parkland in north-west england were measured in wood formed since the mid-1800s. concentrations of pb in scots pine and oak peaked in wood formed between 1900 and 1940, most likely because of pb accumulation in heartwood, indicating that oak and scots pine are unsuitable for monitoring temporal changes in pb deposition at the study site. in contrast, pb ... | 2002 | 12109483 |
| anticancer and antithrombin activity of russian plants. | a chromogenic bioassay was utilized to determine the antithrombin activity of the methylene chloride and methanol extracts prepared from forty-five plants of russia. mouse leukemia cells (l1210) were utilized to screen these extracts for activity against cancer. the results indicated that eight plant extracts demonstrated 90% or higher activity in the inhibition of thrombin. also, nine methanol extracts demonstrated activity of 90% or higher in the inhibition of mouse leukemia l1210 cells. the m ... | 2002 | 12127234 |
| responses of antioxidative systems to drought stress in pendunculate oak and maritime pine as modulated by elevated co2. | the aim of the present study was to investigate the effects of an enhanced co2 concentration alone or in combination with drought stress on antioxidative systems of a deciduous (oak; quercus robur) and an evergreen (pine; pinus pinaster) tree species. the seedlings were grown for one season in a greenhouse in tunnels supplied with 350 or 700 [mu]l l-1 co2. the experiment was repeated in a second year. antioxidants, protective enzymes, soluble protein, and pigments showed considerable fluctuation ... | 1996 | 12226191 |
| phenological behaviour of quercus in ourense (nw spain) and its relationship with the atmospheric pollen season. | knowing the beginning of the pollen season is of particular importance to people allergic to a given pollen. phenological studies in combination with aerobiological studies enable us to observe the relationship between the reproductive phenology of the species and their airborne pollen curves. they also enable us to study the relationship between the release of pollen from anthers and its presence in the atmosphere. the objectives of this study are (1) to determine chill and heat requirements fo ... | 2002 | 12242473 |
| comparison of different methods for lignin determination as a basis for calibration of near-infrared reflectance spectroscopy and implications of lignoproteins. | three commonly employed methods for lignin determination, i.e., the thioglycolic acid (tga), the acetylbromide (ab), and the acid detergent fiber (adf) method, were compared using leaves and xylem tissue from five species (nicotiana tabacum, populus x canescens, fagus sylvatica, quercus robur, and picea abies). in each case, cell walls were isolated before lignin determination. each of the three methods estimated a different lignin concentration in a given tissue, except for spruce wood. the "li ... | 2002 | 12564795 |
| seasonal variations in leaf area index, leaf chlorophyll, and water content; scaling-up to estimate fapar and carbon balance in a multilayer, multispecies temperate forest. | seasonal differences in phenology between coniferous and deciduous tree species need to be considered when developing models to estimate co(2) exchange in temperate forest ecosystems. because seasonal variations in co(2) flux in temperate forests are closely correlated with plant phenology, we quantified the phenology of forest species in a multilayered forest with patches of scots pine (pinus sylvestris l.) and oak (quercus robur l.) in brasschaat, belgium. a scaling-up modeling approach was de ... | 1999 | 12651323 |
| physiology-based phenology models for forest tree species in germany. | models of phenology are needed for the projection of effects of a changing climate on, for example, forest production, species competition, vegetation-atmosphere feedback and public health. a new phenology model for deciduous tree bud burst is developed and parameters are determined for a wide geographical range (germany) and several forest tree species. the new model is based on considerations of simple interactions between inhibitory and promotory agents that are assumed to control the develop ... | 2003 | 12698325 |
| heavy metals in the dump of an abandoned mine in galicia (nw spain) and in the spontaneously occurring vegetation. | the concentrations of different forms of heavy metals (fe, mn, zn, cu, cr, ni, cd and pb) were determined in a mine dump material rich in chalcopyrite. the concentrations were compared with those of the natural vegetation colonising the dump. samples taken from the dump are acid (ph(h(2)o) between 3.0 and 5.0), have carbon contents lower than 0.5%, n lower than 0.2%, effective cation exchange capacity between 0.74 and 4.96 cmol(+)kg(-1) and percent al saturation in the exchange complex higher th ... | 2003 | 12922070 |
| phytophthora pseudosyringae sp. nov., a new species causing root and collar rot of deciduous tree species in europe. | in several studies of oak decline in europe, a semi-papillate homothallic phytophthora taxon was consistently isolated, together with other phytophthora species, from rhizosphere soil samples. it was also found associated with necrotic fine roots and stem necroses of fagus sylvatica and alnus glutinosa. due to morphological and physiological similarities, the semi-papillate isolates were previously identified as p. syringae by various authors. the morphology, physiology and pathogenicity against ... | 2003 | 12967204 |
| volatile compounds in spanish, french, and american oak woods after natural seasoning and toasting. | the volatile composition (volatile phenols, phenolic aldehydes, furanic compounds, lactones, phenyl ketones, and other related compounds) of spanish oak heartwood of quercus robur, quercus petraea,quercus pyrenaica, and quercus faginea was studied by gas chromatography/mass spectrometry, in relation to the processing in barrels cooperage and in relation to the french oak of quercus robur (limousin) and quercus petraea (allier) and american oak of quercus alba (missouri), which are habitually use ... | 2003 | 13129296 |
| distribution of genomic regions differentiating oak species assessed by qtl detection. | pedunculate oak and sessile oak are two sympatric interfertile species that exhibit leaf morphological differences. we aimed to detect quantitative trait loci (qtls) of these traits in order to locate genomic regions involved in species differentiation. a total of 15 leaf morphological traits were assessed in a mixed forest stand composed of quercus petraea and q. robur and in a full-sib pedigree of q. robur. the progeny of the full-sib family were vegetatively propagated in two successive exper ... | 2004 | 14508500 |
| the timing of bud burst and its effect on tree growth. | a phenology model for estimating the timings of bud burst--one of the most influential phenological phases for the simulation of tree growth--is presented in this study. the model calculates the timings of the leafing of beech (fagus sylvatica l.) and oak (quercus robur l.) and the may shoot of norway spruce (picea abies l.) and scots pine (pinus sylvestris l.) on the basis of the daily maximum temperature. the data for parameterisation and validation of the model have been taken from 40 climate ... | 2004 | 14564495 |
| genus- and isolate-specific real-time pcr quantification of erwinia on leaf surfaces of english oaks (quercus robur l.). | in order to quantify pathogenic epiphytic bacteria on leaf surfaces of the important european forest tree quercus robur without time-intensive cultivation and separation of microorganisms, methods were developed to selectively quantify dna copy numbers of the genus erwinia in dna isolated from the leaf surface. by using the combination of the two different real-time pcr techniques sybr-green and taqman, methods were developed not only to allow quantification of the total dna copy number of erwin ... | 2003 | 14570272 |
| detecting differences in crown transparency assessments between countries using the image analysis system croco. | estimates of crown transparency calculated using the semi-automatic image analysis system croco were compared with the visual estimates of survey teams from 12 european countries. for each of five european species (norway spruce (picea abies (l.) karst.), silver fir (abies alba mill.), scots pine (pinus sylvestris l.), beech (fagus sylvatica l.), oak (quercus robur l.)) 15 trees were assessed. in 64% of the comparisons, croco estimates and the survey teams' scores differed significantly, while d ... | 2003 | 14632089 |
| volatile compounds in a spanish red wine aged in barrels made of spanish, french, and american oak wood. | a red rioja wine was aged in barrels made of spanish oak wood (quercus robur, quercus petraea,quercus pyrenaica, and quercus faginea) during 21 months. the concentrations of some volatile compounds [syringaldehyde, vanillin, eugenol, maltol, guaiacol, 4-ethylphenol, cis and trans isomers of beta-methyl-gamma-octalactone, 2-furfuraldehyde, 5-methyl-2-furfuraldehyde, 5-(hydroxymethyl)-2-furfuraldehyde, and furfuryl alcohol] were studied in these wines and compared with those of the same wine aged ... | 2003 | 14664527 |
| requirements for in vitro rooting of quercus robur and q. rubra shoots derived from mature trees. | stabilized shoot cultures initiated from crown material of six adult quercus robur l. trees and from basal epicormic shoots of a quercus rubra l. tree showed good in vitro rooting capacity. an initial five-day dark period generally improved the rooting response but was detrimental to plantlet quality. there were clonal differences in rooting capacity. the concentration and exposure time of the indolebutyric acid (iba) treatment were critical for root induction. in both species, best rooting effi ... | 1996 | 14871689 |
| auxin and ethylene regulation of diameter growth in trees. | recent studies on the phytohormonal regulation of seasonal cell-division activity in the cambium, primary-wall radial expansion of cambial derivatives, differentiation of xylem cells, and growth of the cortex in forest trees of the north temperate zone are reviewed. indol-3-ylacetic acid (iaa, auxin) has been characterized by combined gas chromatography-mass spectrometry (gc-ms) in the cambial region of abies balsamea, pinus densiflora, pinus sylvestris and quercus robur. all of the evidence sup ... | 1988 | 14972810 |
| [polyclonal antisera to birch pollen allergen for the air allergen screening]. | the cross reactivity of the pollen allergens of birch (betula pendula), hazel (corylus avelana), alder (alnus glutinosa), wormwood (artemisia absinthium), oak (quercus robur) and ashtree (fraxinus excelsior) was studied by the methods of the enzyme immunoassay and gel diffusion with the use of rabbit polyclonal antisera (pas) prepared against birch pollen allergen. pas was shown to be greatly related to all above-mentioned allergens with the exception of oak pollen allergen. pas was found capabl ... | 2004 | 15024987 |
| research on the impact of forest stand structure on atmospheric deposition. | dry and wet deposition onto thirty forest stands in relation to stand structure is studied by sampling throughfall and bulk precipitation. nine measurement sites are situated in pseudotsuga menziesii stands, ten in pinus sylvestris and eleven in quercus robur stands. all stands are situated within a radius of 1.2 km to assure a more or less equal air pollution load. in each stand, detailed forest structure inventories are made to determine aerodynamic roughness, collecting efficiency and surface ... | 1992 | 15092040 |
| antimicrobial and antioxidative enrichment of oak (quercus robur) bark by rotation planar extraction using extrachrom. | the multifunctional extrachrom instrument was used in the extraction of antimicrobial and radical scavenging components from oak (quercus robur l.) bark. milled and sieved oak bark was extracted with 80% (v/v) methanol solution in water on the extrachrom instrument using step-gradient in the preparative separation. extracts were tested using agar diffusion method on staphylococcus aureus, enterobacter aerogenes and candida albicans. some extracts showed moderate bactericidal, fungicidal, bacteri ... | 2004 | 15109795 |
| avoidance of nonhost plants by a bark beetle, pityogenes bidentatus, in a forest of odors. | the bark beetle, pityogenes bidentatus (coleoptera: scolytidae), searches in mixed conifer and deciduous forests of northern europe for suitable branches of its host, scots pine ( pinus sylvestris). we tested whether odors from several diverse nonhost trees and plants common in the habitat (e.g., mountain ash, sorbus aucuparia; oak, quercus robur; alder buckthorn, frangula alnus; blueberry, vaccinium myrtillus; raspberry, rubus idaeus; and grass, deschampsia flexuosa) would reduce the attraction ... | 2004 | 15146267 |
| phaeoacremonium rubrigenum--hyphomycete associated with bark beetles found in czechia. | phaeoacremonium is a recently described genus (crous et al. 1996) associated with decline diseases of woody hosts and with human infections. during a study of surface mycobiota of the oak bark beetles, the hyphomycetous microfungus phaeoacremonium rubrigenum was isolated from larvae of scolytus intricatus (coleoptera: scolytidae) and their galleries on quercus robur and also from an adult of leperisinus fraxini found under the bark of fraxinus excelsior. the species determination was confirmed b ... | 2004 | 15227778 |
| in vitro effects of three woody plant and sainfoin extracts on 3rd-stage larvae and adult worms of three gastrointestinal nematodes. | most studies on the effects of tanniferous plants on nematodes have examined forages but have neglected the woody plants. therefore, in vitro effects of extracts from 3 woody plants (rubus fructicosus, quercus robur, corylus avellana) have been tested on trichostrongyles and compared to sainfoin, a legume forage. because some in vivo results indicated that the effects of tannins differed depending on the parasitic species and/or stages, the effects were measured on 3rd-stage larvae (l3) and adul ... | 2004 | 15267113 |
| [cytogenetic characteristics of seed offspring of leafy tree plants from one-kilometer zone of novovoronezh nuclear power station]. | cytogenetic characteristics (mitotic activity, level and spectrum of pathological mitoses, nucleoly characteristics) of seed offspring of quercus robur l. and betula pendula roth from novovoronezh nuclear power station's 1-kilometer zone have been studied. it has been shown the change of time of passing though mitotic stages by cells, the increasing of bridges frequency occur in spectrum of mitotic aberrations (that shows activation of reparation systems), the change in nucleoly characteristics ... | 2004 | 15455676 |
| the effect of climate on the phenology, acorn crop and radial increment of pedunculate oak (quercus robur) in the middle volga region, tatarstan, russia. | our data, collected in the extreme east of europe, show that a significant biological effect of climate change has been experienced even in territories where temperature increase has been the lowest. this study documents the climatic response of pedunculate oak (quercus robur) growing near its north-eastern limits in europe. it demonstrates the potential of oak trees in old-growth forest to act as proxy climate indicators. many factors may influence the temporal stability of the growth-climate, ... | 2005 | 15538637 |
| characterization and discrimination of pollen by raman microscopy. | the chemical characterization and discrimination of allergy-relevant pollen (common ragweed (ambrosia artemisiifolia), white birch (betula pendula), english oak (quercus robur), and european linden (tilia cordata)) has been studied by raman microscopy. spectra were obtained at different excitation wavelengths (514, 633, and 780 nm) and various methods were examined to minimize the strong fluorescence background. the use of a he-ne laser (633 nm) for excitation yields high-quality single pollen r ... | 2004 | 15605236 |
| seasonal and interannual variability of photosynthetic capacity in relation to leaf nitrogen in a deciduous forest plantation in northern italy. | gas exchange was measured in a forest plantation dominated by fraxinus angustifolia vahl. and quercus robur l. in northern italy, over three growing seasons that differed in water availability (2001, 2002 and 2003). the objectives were to: (1) determine variability in the photosynthetic parameters v(cmax) (maximum carboxylation capacity) and j(max) (maximum rate of electron transport) in relation to species, leaf ontogeny and drought; and (2) assess the potential of the photosynthesis-nitrogen r ... | 2005 | 15631983 |
| effects of management on understory diversity in the forest ecosystems of northern spain. | pine plantations are an alternative to marginal agriculture in many countries, and are often presented as an option that improves biodiversity. however, these plantations can have adverse environmental effects if improperly managed. to evaluate the effect of forest management practices on biodiversity, the diversity, species richness, dominance and frequency of understory woody plant species in different forests of the basque country (northern spain) were compared. plantations of exotic conifers ... | 2004 | 15726282 |
| soil respiration in a mixed temperate forest and its contribution to total ecosystem respiration. | soil respiration (sr) was measured with an infrared gas analyzer in nine plots representative of the heterogeneous vegetation in a mixed coniferous-deciduous forest in the belgian campine region. selected plots included the two most representative overstory species (pinus sylvestris l. and quercus robur l.) in combination with the most representative understory species of the forest. a model that includes temperature and water as the main controlling variables was fitted to the data. we found la ... | 2005 | 15741145 |
| new, rare or remarkable microfungi in the italian alps (carnic alps)--part i--ascomycotina. | during our observations in the se part of the carnic alps in the year 2003 we were able to collect and identify 35 ascomycetes on trees and dead wood. among these one can find numerous ascomycetes of different orders e.g. pyrenomycetes, loculoascomycetes and discomycetes. some species like botryosphaeria ribis grosenlucher & duggar on ribes alpinum l., dothiora pyrenophora (fr.) fr. on sorbus aucuparia l., gemmamyces piceae (borth.) casago. on picea excelsa (lam.) link, glomerella montana (sacc. ... | 2004 | 15756826 |
| contrasting net primary productivity and carbon distribution between neighboring stands of quercus robur and pinus sylvestris. | standing biomass, net primary production (npp) and soil carbon (c) pools were studied in a 67-year-old pedunculate oak (quercus robur l.) stand and a neighboring 74-year- old scots pine (pinus sylvestris l.) stand in the belgian campine region. despite a 14% lower tree density and a lower tree height in the oak stand, standing biomass was slightly higher than in the pine stand (177 and 169 mg ha(-1) in oaks and pines, respectively), indicating that individual oak trees contained more biomass tha ... | 2005 | 15805090 |
| in situ net mineralization rates in a heterogeneous mixed deciduous forest receiving elevated n deposition. | in situ net mineralization was studied at 6 locations (e, eb, ec, f1, f2, f3) of a heterogeneous mixed deciduous forest ("de gulkeputten") with oak (quercus robur l., quercus rubra) and birch (betula pendula) as dominant species. net nitrogen mineralization was determined by means of a sequential in situ incubation experiment using intact soil cores. for all incubations, the net mineralization rates of the organic (f+h) layer varied between -0.4 and 2.0 g n m(-2) month(-1), while the net nitrifi ... | 2001 | 15952425 |
| meteorological factors and air pollution in lithuanian forests: possible effects on tree condition. | this study investigates changes in tree condition and environmental factors in lithuania during the active growing season in 1991-2001. the average crown defoliation and the proportion of healthy trees of pinus sylvestris, picea abies, betula sp., fraxinus excelsior, alnus incana, alnus glutinosa, populus tremula, and quercus robur, meteorological (average temperature, amount of precipitation, hydrothermal coefficient) and air pollution data (acidity of precipitation, concentrations of so2, no2 ... | 2005 | 16005769 |
| enzymology of gallotannin and ellagitannin biosynthesis. | gallotannins and ellagitannins, the two subclasses of hydrolyzable tannins, are derivatives of 1,2,3,4,6-penta-o-galloyl-beta-d-glucopyranose. enzyme studies with extracts from oak leaves (quercus robur, syn. quercus pedunculata; quercus rubra) and from staghorn sumac (rhus typhina) revealed that this pivotal intermediate is synthesized from beta-glucogallin (1-o-galloyl-beta-d-glucopyranose) by a series of strictly position-specific galloylation steps, affording so-called 'simple' gallotannins, ... | 2005 | 16153405 |
| the chemistry of soils, rocks and plant bioindicators in three ecosystems of the holy cross mountains, poland. | in june of 2000, biogeochemical study was carried out in three ecosystems of the holy cross mountains (south-central poland). this paper presents element concentrations and stable sulfur (and in one site lead) isotope ratios in rocks, detailed soil profiles, and plant bioindicators including epiphytic lichen hypogymnia physodes (l.) nyl., mosses (pleurozium schreberi (brid.) mitt., hypnum cupressiforme hedw. s. str., hylocomium splendens (hedw.) b.s.g.), scots pine (pinus sylvestris l.), common ... | 2005 | 16308778 |
| influence of the species and geographical location on volatile composition of spanish oak wood (quercus petraea liebl. and quercus robur l.). | the influence of the species and geographical origin on the volatile composition of wood samples from 80 spanish oaks (55 quercus petraea liebl. and 25 quercus robur l.) has been studied. oak volatile components were isolated by simultaneous distillation-extraction and analyzed by gas chromatography-mass spectrometry. cis- and trans-beta-methyl-gamma-octalactones were the main constituents, the cis stereoisomer being predominant. other important volatile components were furfural, 5-methylfurfura ... | 2006 | 16608231 |
| sensory-directed identification of taste-active ellagitannins in american (quercus alba l.) and european oak wood (quercus robur l.) and quantitative analysis in bourbon whiskey and oak-matured red wines. | aimed at increasing our knowledge on the sensory-active nonvolatiles migrating from oak wood into alcoholic beverages upon cooperaging, an aqueous ethanolic extract prepared from oak wood chips (quercus alba l.) was screened for its key taste compounds by application of the taste dilution analysis. purification of the compounds perceived with the highest sensory impacts, followed by liquid chromatography/mass spectrometry as well as one-dimensional and two-dimensional nmr experiments, revealed t ... | 2006 | 16637699 |
| genetic variability of fragmented stands of pedunculate oak (quercus robur) in finland. | the genetic structure of 33 natural quercus robur stands in finland was studied using 13 allozyme loci to analyze the effects of fragmentation in a wind-pollinated tree species. the present fragmented and discontinuous distribution of oak is a result of both short-term human impact and long-term climatic and geological change, including post-glacial land uplift. in accordance with general expectations, genetic diversity in small populations was lower than that in large populations, and different ... | 2006 | 16850227 |
| functional traits and plasticity in response to light in seedlings of four iberian forest tree species. | we investigated the differential roles of physiological and morphological features on seedling survivorship along an experimental irradiance gradient in four dominant species of cool temperate-mediterranean forests (quercus robur l., quercus pyrenaica willd., pinus sylvestris l. and pinus pinaster ait.). the lowest photochemical efficiency (f(v)/f(m) in dark-adapted leaves) was reached in deep shade (1% of full sunlight) in all species except q. robur, which had the lowest photochemical efficien ... | 2006 | 16877327 |
| assessment of oak forest condition based on leaf biochemical variables and chlorophyll fluorescence. | pedunculate oak forests (quercus robur l.) in the ticino regional park, italy, are declining as a result of insect attacks, summer droughts and air pollution. the assessment and monitoring of forest condition can provide a basis for managing and conserving forest ecosystems and thereby avoid loss of valuable natural resources. currently, most forest assessments are limited to ground-based visual evaluations that are local and subjective. it is therefore difficult to compare data collected by dif ... | 2006 | 16877333 |
| tree species effects on decomposition and forest floor dynamics in a common garden. | we studied the effects of tree species on leaf litter decomposition and forest floor dynamics in a common garden experiment of 14 tree species (abies alba, acer platanoides, acer pseudoplatanus, betula pendula, carpinus betulus, fagus sylvatica, larix decidua, picea abies, pinus nigra, pinus sylvestris, pseudotsuga menziesii, quercus robur, quercus rubra, and tilia cordata) in southwestern poland. we used three simultaneous litter bag experiments to tease apart species effects on decomposition v ... | 2006 | 16995629 |
| influence of geographical origin and botanical species on the content of extractives in american, french, and east european oak woods. | the chemical composition of east european (republic of moldova, ukraine, and romania) oaks was investigated profoundly for the first time in the present study and compared with american and french counterparts. taking into account the high natural variability of oak extractives contents, the wide-ranging sampling was performed for all oak origins: 276 french oaks, 102 east european oaks of both species (quercus robur l. and quercus petraea liebl.), and 56 american oaks (quercus alba). these oaks ... | 2006 | 17032018 |
| chemical characterization of oak heartwood from spanish forests of quercus pyrenaica (wild.). ellagitannins, low molecular weight phenolic, and volatile compounds. | the need for new sources of quality wood supply for cooperage has led to looking into the possibility of utilizing quercus pyrenaica wild. oak, a species native to the iberian peninsula, as an alternative to other european (quercus robur and qurecus petraea) and american (quercus alba) oaks. the low molecular weight phenolic composition, ellagitannins, and volatile compounds (including a wide range of compound families such as volatile phenols, furanic compounds, lactones, phenyl ketones, other ... | 2006 | 17032045 |
| irradiance-induced plasticity in the hydraulic properties of saplings of different temperate broad-leaved forest tree species. | we assessed the irradiance-related plasticity of hydraulic architecture in saplings of betula pendula roth., a pioneer species; acer pseudoplatanus l., fraxinus excelsior l. and quercus robur l., which are post-pioneer light-requiring species; and quercus petraea matt. liebl. and fagus sylvatica l. plants were grown in pots in 36%, 16% and 4% of full sunlight. hydraulic conductance was measured with a high-pressure flow-meter in entire, in situ root systems and in excised shoots. leaf-specific w ... | 2006 | 17169890 |
| daldinia decipiens and entonaema cinnabarina as fungal symbionts of xiphydria wood wasps. | the identity of symbiotic fungi associated with the xiphydria spp. wood wasps was investigated using dna analysis. the fungi were isolated from the mycangia of adult females of x. camelus, x. prolongata and x. longicollis reared from colonized logs of alnus glutinosa, salix alba and quercus robur, respectively. sequences of rdna and beta-tubulin were obtained. phylogenetic analysis based on the nj method showed that the isolates from x. camelus clustered with daldinia decipiens, whereas those of ... | 2007 | 17188483 |
| a noninvasive optical system for the measurement of xylem and phloem sap flow in woody plants of small stem size. | over the past 70 years, heat has been widely used as a tracer for estimating the flow of water in woody and herbaceous plants. however, most commercially available techniques for monitoring whole plant water use are invasive and the measurements are potentially flawed because of wounding of the xylem tissue. the study of photosynthate transport in the phloem remains in its infancy, and little information about phloem transport rates is available owing to the fragility of the vascular tissue. the ... | 2007 | 17241960 |
| variation in cold hardiness and carbohydrate concentration from dormancy induction to bud burst among provenances of three european oak species. | although cold hardiness is known to be a major determinant of tree species distribution, its dynamics and the factors that regulate it remain poorly understood. variation in cold hardiness and carbohydrate concentration, from dormancy induction until bud burst, were investigated in populations of two deciduous (quercus robur l. and quercus pubescens willd.) and one evergreen (quercus ilex l.) european oak. mean cold hardiness values in january were -56, -45 and -27 degrees c for q. robur, q. pub ... | 2007 | 17331900 |
| the trophic structure of bark-living oribatid mite communities analysed with stable isotopes ((15)n, (13)c) indicates strong niche differentiation. | the aim of the present study was to identify food sources of bark-living oribatid mites to investigate if trophic niche differentiation contributes to the diversity of bark living oribatida. we measured the natural variation in stable isotope ratios ((15)n/(14)n, (13)c/(12)c) in oribatid mites from the bark of oak (quercus robur), beech (fagus sylvatica), spruce (picea abies) and pine (pinus sylvestris) trees and their potential food sources, i.e., the covering vegetation of the bark (bryophytes ... | 2007 | 17333459 |
| mistletoe lectin is not the only cytotoxic component in fermented preparations of viscum album from white fir (abies pectinata). | preparations of mistletoe (viscum album) are the form of cancer treatment that is most frequently used in the complementary medicine. previous work has shown that these preparations are able to exert cytotoxic effects on carcinoma cells, the extent of which might be influenced by the host tree species and by the content of mistletoe lectin. | 2007 | 17493268 |
| synthesis and establishment of tuber melanosporum vitt. ectomycorrhizae on two nothofagus species in chile. | axenically germinated seedlings of two species of southern beech (nothofagus obliqua, n. glauca) from chile were inoculated with spores of the périgord black truffle (tuber melanosporum). ectomycorrhizal development was monitored for 6 months in the greenhouse and compared to the performance of the natural host species quercus ilex and quercus robur. seedling survival and mycorrhization showed major differences in both nothofagus species: t. melanosporum readily formed ectomycorrhizae with seedl ... | 2007 | 17598134 |
| cloning and characterization of two different types of geranyl diphosphate synthases from norway spruce (picea abies). | geranyl diphosphate (gpp), the universal precursor of monoterpenes, is formed from isopentenyl diphosphate and dimethylallyl diphosphate by the action of geranyl diphosphate synthase, one of the key branchpoint enzymes of terpene biosynthesis. three types of gpp synthase can be distinguished in plants based on sequence similarity and subunit architecture, but until now individual species have been reported to contain only one of these types. here we show that the conifer, norway spruce (picea ab ... | 2008 | 17673268 |
| visible leaf injury in young trees of fagus sylvatica l. and quercus robur l. in relation to ozone uptake and ozone exposure. an open-top chambers experiment in south alpine environmental conditions. | an open-top chambers experiment on fagus sylvatica and quercus robur seedlings was conducted in order to compare the performance of an exposure-based (aot40) and a flux-based approaches in predicting the appearance of ozone visible injuries on leaves. three different ozone treatments (charcoal-filtered; non-filtered; and open plots) and two soil moisture treatments (watered and non-watered plots) were performed. a jarvisian stomatal conductance model was drawn up and parameterised for both speci ... | 2008 | 17688979 |
| resource selection by female moths in a heterogeneous environment: what is a poor girl to do? | 1. according to the preference-performance hypothesis, female insects select resources that maximize offspring performance. to achieve high fitness, leaf miner females should then adjust their oviposition behaviour in response to leaf attributes signalling high host quality. 2. here we investigate resource selection in tischeria ekebladella, a leaf-mining moth of the pedunculate oak (quercus robur), in relation to two alternative hypotheses: (1) females select their resources with respect to the ... | 2007 | 17714263 |
| energy potential of waste from 10 forest species in the north of spain (cantabria). | in this work, the waste from 10 forest species of cantabria have been characterized from the point of view of energy. the studied species were the waste of: eucalyptus globulus, eucalyptus nitens, the hybrid e. globulusxe. nitens, eucalyptus viminalis, eucalyptus smithii, eucalyptus regnans, eucalyptus gunni, fagus sylvatica, quercus robur and pinus radiata. the leaves were the tree part with the greatest ncv (net calorific value) in all the species. the best results were obtained for the leaves ... | 2008 | 18215515 |
| heavy metal transfers between trophic compartments in different ecosystems in galicia (northwest spain): essential elements. | in the present study, we determined the concentrations of cu, fe, mn, and zn in soil and several trophic compartments at a total of 16 sampling stations. the trophic compartments studied were primary producers, represented by two species of terrestrial mosses (pseudoescleropodium purum and hypnum cupressiforme) and oak trees (quercus robur or q. pyrenaica); primary consumers, represented by the wood mouse (apodemus sylvaticus) and the yellow necked mouse (a. flavicollis); secondary consumers, re ... | 2008 | 18350242 |
| comparative measurements of transpiration and canopy conductance in two mixed deciduous woodlands differing in structure and species composition. | transpiration of two heterogeneous broad-leaved woodlands in southern england was monitored by the sap flux technique throughout the 2006 growing season. grimsbury wood, which had a leaf area index (lai) of 3.9, was dominated by oak (quercus robur l.) and birch (betula pubescens l.) and had a continuous hazel (corylus avellana l.) understory. wytham woods, which had an lai of 3.6, was dominated by ash (fraxinus excelsior l.) and sycamore (acer pseudoplatanus l.) and had only a sparse understory. ... | 2008 | 18381276 |
| spatial population structure of a specialist leaf-mining moth. | 1. the spatial structure of natural populations may profoundly influence their dynamics. depending on the frequency of movements among local populations and the consequent balance between local and regional population processes, earlier work has attempted to classify metapopulations into clear-cut categories, ranging from patchy populations to sets of remnant populations. in an alternative, dichotomous scheme, local populations have been classified as self-sustaining populations generating a sur ... | 2008 | 18422557 |
| evidence from population genetics that the ectomycorrhizal basidiomycete laccaria amethystina is an actual multihost symbiont. | it is commonly assumed that ectomycorrhizal (ecm) fungi associated with temperate forest tree roots are not host-specific. because this assumption relies on species delineations based on fruitbodies morphology or ribosomal dna sequences, host-specific, cryptic biological species cannot be ruled out. to demonstrate that laccaria amethystina has true generalist abilities, we sampled 510 fruitbodies on three french sites situated 150-450 km away from each other. at each site, populations from monos ... | 2008 | 18489549 |
| phytophthora gallica sp. nov., a new species from rhizosphere soil of declining oak and reed stands in france and germany. | a non-papillate, slow-growing phytophthora species, which could not be assigned to any existing taxon, was isolated from rhizosphere soil of a declining oak in northeast france, and from the rhizosphere of phragmites australis at lake constance in south-west germany in 1998 and 2004, respectively. we describe this species, previously informally designated phytophthora taxon 'g', as phytophthora gallica sp. nov. morphology, growth rates, and pathogenicity against cuttings of riparian tree species ... | 2008 | 18693002 |
| comparison of forest edge effects on throughfall deposition in different forest types. | this study examined the influence of distance to the forest edge, forest type, and time on cl-, so4(2-), no3(-), and nh4+ throughfall deposition in forest edges. the forests were dominated by pedunculate oak, silver birch, or corsican/austrian pine, and were situated in two regions of flanders (belgium). along transects, throughfall deposition was monitored at distances of 0-128 m from the forest edge. a repeated-measures analysis demonstrated that time, forest type, and distance to the forest e ... | 2008 | 18783861 |
| prediction and mapping of the impact of winter temperature on the development of phytophthora cinnamomi-induced cankers on red and pedunculate oak in france. | abstract phytophthora cinnamomi is the causal agent of a perennial canker that develops on the lower bole on northern red oak and pedunculate oak. the disease has a limited range in europe, being reported only in southwest france. this limited distribution is probably linked to the susceptibility of p. cinnamomi to frost. a model was developed in previous work to estimate the impact of temperatures of <0 degrees c on the winter survival of p. cinnamomi in trunk cortical tissues and on the subseq ... | 2004 | 18943102 |
| range of phytoplasma concentrations in various plant hosts as determined by competitive polymerase chain reaction. | abstract for competitive polymerase chain reaction (pcr), an internal standard dna template was developed that consisted of a highly conserved, internally deleted 16s rdna fragment of an aster yellows phytoplasma. the internal standard was calibrated using a quantified culture of acholeplasma laidlawii. serial dilutions of the internal standard and fixed amounts of target templates from infected plants were coamplified with the same primers, and the products obtained were quantified using an enz ... | 2000 | 18944479 |
| validation of the stomatal flux approach for the assessment of ozone visible injury in young forest trees. results from the top (transboundary ozone pollution) experiment at curno, italy. | this paper summarises some of the main results of a two-year experiment carried out in an open-top chambers facility in northern italy. seedlings of populus nigra, fagus sylvatica, quercus robur and fraxinus excelsior have been subjected to different ozone treatments (charcoal-filtered and non-filtered air) and soil moisture regimes (irrigated and non-irrigated plots). stomatal conductance models were applied and parameterised under south alpine environmental conditions and stomatal ozone fluxes ... | 2009 | 19019512 |
| pollen allergenic potential nature of some trees species: a multidisciplinary approach using aerobiological, immunochemical and hospital admissions data. | trees are considered producers of allergenic pollen. the aims of this work were to characterize the aerobiology of the platanus, acer, salix, quercus, betula and populus pollen, linking it with monthly emergency hospital admissions and to identify the different reactivity levels in sensitized patients. this information would be of great importance to evaluate the convenience of changing the inventory of pollen producer trees related to the risk of allergenic reactions. the study was conducted in ... | 2009 | 19147130 |
| comparative study of antioxidant properties and total phenolic content of 30 plant extracts of industrial interest using dpph, abts, frap, sod, and orac assays. | aqueous extracts of 30 plants were investigated for their antioxidant properties using dpph and abts radical scavenging capacity assay, oxygen radical absorbance capacity (orac) assay, superoxide dismutase (sod) assay, and ferric reducing antioxidant potential (frap) assay. total phenolic content was also determined by the folin-ciocalteu method. antioxidant properties and total phenolic content differed significantly among selected plants. it was found that oak (quercus robur), pine (pinus mari ... | 2009 | 19199445 |
| complex climate controls on 20th century oak growth in central-west germany. | we analyze interannual to multi-decadal growth variations of 555 oak trees from central-west germany. a network of 13 pedunculate oak (quercus robur l.) and 33 sessile oak (quercus petraea (matt.) liebl.) site chronologies is compared with gridded temperature, precipitation, cloud-cover, vapor pressure and drought (i.e., palmer drought severity index, pdsi) fluctuations. a hierarchic cluster analysis identifies three groups for each oak species differentiated by ecologic settings. when high prec ... | 2009 | 19203931 |
| determination of screw and nail withdrawal resistance of some important wood species. | in this study, screw and nail withdrawal resistance of fir (abies nordmanniana), oak (quercus robur l.) black pine (pinus nigra arnold) and stone pine (pinus pinea l.) wood were determined and compared. the data represent the testing of withdrawal resistance of three types of screws as smart, serrated and conventional and common nails. the specimens were prepared according to ts 6094 standards. the dimensions of the specimens were 5x5x15cm and for all of the directions. moreover, the specimens w ... | 2008 | 19325775 |
| terpenoid emissions from quercus robur. a case study of galicia (nw spain). | isoprene and monoterpenes emission fluxes emitted by quercus robur seedlings were measured at a leaf scale in the field. isoprene emissions were always predominant over the monoterpene ones, alpha-pinene, beta-pinene and camphene being the most abundant emitted monoterpenes. emission fluxes were normalised at standard conditions of temperature and photosynthetically active radiation, par, (30 degrees c and 1000 micromol m(-2) s(-1) respectively) using temperature and light dependent algorithms. ... | 2009 | 19513459 |
| in vitro anticancer potential of tree extracts from the walloon region forest. | forty-eight extracts from 16 common belgian trees from the walloon region forest were evaluated for in vitro growth inhibitory activity against the human lovo colon cancer, pc3 prostate cancer, and u373 glioblastoma cell lines. our study was performed with the aim of selecting plant candidates in order to later isolate new anticancer compounds from an easily affordable tree material. extracts from alnus glutinosa (stem bark), carpinus betulus (leaves and stem bark), castanea sativa (stem bark), ... | 2009 | 19579185 |
| fine root decomposition rates do not mirror those of leaf litter among temperate tree species. | elucidating the function of and patterns among plant traits above ground has been a major research focus, while the patterns and functioning of belowground traits remain less well understood. even less well known is whether species differences in leaf traits and their associated biogeochemical effects are mirrored by differences in root traits and their effects. we studied fine root decomposition and n dynamics in a common garden study of 11 temperate european and north american tree species (ab ... | 2010 | 19882174 |
| changing climate and the phenological response of great tit and collared flycatcher populations in floodplain forest ecosystems in central europe. | this study is based on 47 years of observations (1961-2007) on two common bird species, the great tit (parus major) and the collared flycatcher (ficedula albicollis), and a dominant tree species in their habitat, the english oak (quercus robur). the study took place at four research sites in the czech republic located in full-grown, multi-aged floodplain forests with no forestry management. an increase in air temperature over the evaluated period clearly influenced the length of phenological pha ... | 2010 | 20099374 |
| biodiversity and new records of microfungi in the ruhrarea (north rhine westfalia), germany. | during our investigations of the microflora in nrw (duisburg, düsseldorf and essen incl. the greenhouse of the botanical garden) in 2007 and 2008, we were able to collect and identify about 55 species on trees, bushes and ornamental plants as parasites and saprophytes. some of these species are new for germany or have been only rarely found until now. most of the species belong the ascomycotina, basidiomycotina and deuteromycotina for example arthrocladiella mougeotii (lév.) vassilkov. on lycium ... | 2009 | 20222564 |
| ectomycorrhizal identity determines respiration and concentrations of nitrogen and non-structural carbohydrates in root tips: a test using pinus sylvestris and quercus robur saplings. | fine roots play a significant role in plant and ecosystem respiration (rs); therefore, understanding factors controlling that process is important both to advancing understanding and potentially in modelling carbon (c) budgets. however, very little is known about the extent to which ectomycorrhizal (ecm) identity may influence rs or the underlying chemistry that may determine those rates. in order to test these relationships, we examined rs, measured as o(2) consumption, of first-order ecm root ... | 2010 | 20304781 |
| changes in leaf phenology of three european oak species in response to experimental climate change. | *because the phenology of trees is strongly driven by environmental factors such as temperature, climate change has already altered the vegetative and reproductive phenology of many species, especially in the temperate zone. here, we aimed to determine whether projected levels of warming for the upcoming decades will lead to linear changes in the phenology of trees or to more complex responses. *we report the results of a 3-yr common garden experiment designed to study the phenological response ... | 2010 | 20406403 |
| [mycobiota of quercus robur l. from the oak forest in the zhytomyr region]. | different organs of 155 samples of conditionally healthy and sick oaks were examined for mycological contamination. the isolated microscopic fungi belonged to 129 species of different taxonomic groups. the pathogenic complex was represented by 30 fungi species, however most of these species were isolated in single cases. roots, wood, bast and bark were not affected by the phytopathogenic fungi species that can cause the death of the trees. mycobiota of branches and sprouts was similar to that of ... | 2009 | 20458934 |
| population differentiation of sessile oak at the altitudinal front of migration in the french pyrenees. | to assess the effects of altitude on the level and structure of genetic diversity, a genetic survey was conducted in 12 populations of sessile oak (quercus petraea) located between 130 and 1660 m in two parallel valleys on the northern side of the pyrenees mountains. genetic diversity was monitored at 16 nuclear microsatellite loci and 5 chloroplast dna (cpdna) markers. the cpdna survey suggested that extant populations in both valleys shared the same source populations from the plain. there was ... | 2010 | 20561196 |
| can we predict indirect interactions from quantitative food webs?--an experimental approach. | 1. shared enemies may link the dynamics of their prey. recently, quantitative food webs have been used to infer that herbivorous insect species attacked by the same major parasitoid species will affect each other negatively through apparent competition. nonetheless, theoretical work predicts several alternative outcomes, including positive effects. 2. in this paper, we use an experimental approach to link food web patterns to realized population dynamics. first, we construct a quantitative food ... | 2011 | 20796204 |
| regeneration of transgenic plants by agrobacterium-mediated transformation of somatic embryos of juvenile and mature quercus robur. | a protocol was developed for genetic transformation of somatic embryos derived from juvenile and mature quercus robur trees. optimal transformation conditions were evaluated on the basis of the results of transient gus expression assays with five oak embryogenic lines and a strain of agrobacterium tumefaciens (eha105) harbouring a p35sgusint plasmid containing a nptii and a uida (gus) genes. for stable transformation, embryo clumps at globular/torpedo stages (4-10 mg) were inoculated with eha105 ... | 2010 | 20972795 |
| fungus symbionts colonizing the galleries of the ambrosia beetle platypus quercivorus. | isolations were made to determine the fungal symbionts colonizing platypus quercivorus beetle galleries of dead or dying quercus laurifolia, castanopsis cuspidata, quercus serrata, quercus crispula, and quercus robur. for these studies, logs from oak wilt-killed trees were collected from kyoto prefecture, japan. fungi were isolated from the: (1) entrances of beetle galleries, (2) vertical galleries, (3) lateral galleries, and (4) the larval cradle of p. quercivorus in each host tree. among the f ... | 2011 | 21384214 |
| how reliable is the double-ended pressure sleeve technique for assessing xylem vulnerability to cavitation in woody angiosperms? | the reliability of a double-ended pressure sleeve technique was evaluated on three woody angiosperm species with contrasting maximum vessel lengths. vulnerability curves (vcs) were constructed by varying sample length and the size of the pressure sleeves. vcs were compared against curves obtained with reference techniques. for the two diffuse-porous species, betula pendula and prunus persica, vcs built with shoot segments shorter than maximum vessel length strongly overestimated species vulnerab ... | 2011 | 21401617 |
| ectomycorrhizal fungal communities of native and non-native pinus and quercus species in a common garden of 35-year-old trees. | non-native tree species have been widely planted or have become naturalized in most forested landscapes. it is not clear if native trees species collectively differ in ectomycorrhizal fungal (emf) diversity and communities from that of non-native tree species. alternatively, emf species community similarity may be more determined by host plant phylogeny than by whether the plant is native or non-native. we examined these unknowns by comparing two genera, native and non-native quercus robur and q ... | 2011 | 21573837 |