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rapid and long-term effects of water deficit on gas exchange and hydraulic conductance of silver birch trees grown under varying atmospheric humidity.effects of water deficit on plant water status, gas exchange and hydraulic conductance were investigated in betula pendula under artificially manipulated air humidity in eastern estonia. the study was aimed to broaden an understanding of the ability of trees to acclimate with the increasing atmospheric humidity predicted for northern europe. rapidly-induced water deficit was imposed by dehydrating cut branches in open-air conditions; long-term water deficit was generated by seasonal drought.201424655599
contrasting responses of silver birch voc emissions to short- and long-term herbivory.there is a need to incorporate the effects of herbivore damage into future models of plant volatile organic compound (voc) emissions at leaf or canopy levels. short-term (a few seconds to 48 h) changes in shoot voc emissions of silver birch (betula pendula roth) in response to feeding by geometrid moths (erannis defoliaria hübner) were monitored online by proton transfer reaction time-of-flight mass spectrometry (ptr-tof-ms). in addition, two separate field experiments were established to study ...201424627262
arsenic (as), antimony (sb), and lead (pb) availability from au-mine technosols: a case study of transfer to natural vegetation cover in temperate climates.soils from old au-mine tailings (la petite faye, france) were investigated in relation to the natural vegetation cover to evaluate the risk of metals and metalloids (pb, as, sb) mobilizing and their potential transfer to native plants (graminea, betula pendula, pteridium aquilinum, equisetum telmateia). the soils are classified as technosols with high contamination levels of as, pb, and sb. the single selective extractions tested to evaluate available fraction (cacl2, acetic acid, a-rhizo, and d ...201424474610
effect of betulin-containing extract from birch tree bark on α-amylase activity in vitro and on weight gain of broiler chickens in vivo.in vitro effect of betulin-containing extract from betula pendula roth. bark on alpha-amylase activity was studied, the kinetic mechanism of interaction was proposed and in vivo effect of betulin-containing extract on weight gain and meat quality of broiler chickens was evaluated. the highest level of inhibitory activity (20%) was detected in extract concentration of 1,000 mg/l. increased extract concentration did not lead to increased enzyme inhibition. using dixon and cornish-bowden coordinate ...201424445672
effect of air pollutant no₂ on betula pendula, ostrya carpinifolia and carpinus betulus pollen fertility and human allergenicity.pollen of betula pendula, ostrya carpinifolia and carpinus betulus was exposed in vitro to two levels of no2 (about 0.034 and 0.067 ppm) - both below current atmospheric hour-limit value acceptable for human health protection in europe (0.11 ppm for no2). experiments were performed under artificial solar light with temperature and relative humidity continuously monitored. the viability, germination and total soluble proteins of all the pollen samples exposed to no2 decreased significantly when c ...201424361564
mitochondrial toxin betulinic acid induces in vitro eryptosis in human red blood cells through membrane permeabilization.betulinic acid (ba), a compound isolated from the bark of white birch (betula pubescens), was reported to induce apoptosis in many types of cancer through mitochondrial dysfunction with low side effects in normal cells. because of these features, ba is regarded as a potential anti-cancer agent. however, the effect of ba on the induction of cell death in human erythrocytes remains unknown. given that ba is a mitochondrial toxin and mitochondria are the central cell death regulator, we hypothesize ...201424241250
overexpression of bpap1 induces early flowering and produces dwarfism in betula platyphylla × betula pendula.the involvement of apetala1 (ap1) in the flowering transition has been the focus of much research. here, we produced betula platyphylla × betula pendula (birch) lines that overexpressed bpap1 using agrobacterium-mediated transformation; we obtained five independent 35s::bpap1 transgenic lines. polymerase chain reaction (pcr), southern, northern and western analyses were used to identify the transformants. as determined by quantitative real-time pcr (qrt-pcr), bpap1 expression in roots, shoots, l ...201424200078
rapid gc/ms determination of botanical precursors of eurasian propolis.in this work, ether extracts of propolises from 11 countries of europe and asia together with extracts of the buds of their principal plant precursors were prepared and investigated by gas chromatography-mass spectrometry. for the first time, chemical compositions of the exudates of aspen, white birch and silver birch buds were determined. basing on the data on the content of individual components and their groups, the method of rapid examination of plant precursors of propolis was developed. th ...201424001818
genetic and metal analyses of fragmented populations of betula papyrifera (marsh) in a mining reclaimed region: identification of population-diagnostic molecular marker.white birch (betula papyrifera) is an open pollinate species that is, dominant in the northern ontario after land reclamation. in fact, this species represents 65% of all trees in the region. we hypothesized that the exchange of genetic information between fragmented populations by range-wide paternal introgression is possible in wind-pollinated species such as b. papyrifera. on the other hand, the effects of heavy metal contamination from the mining activities on plant growth and population dyn ...201425535559
shotgun bisulfite sequencing of the betula platyphylla genome reveals the tree's dna methylation patterning.dna methylation plays a critical role in the regulation of gene expression. most studies of dna methylation have been performed in herbaceous plants, and little is known about the methylation patterns in tree genomes. in the present study, we generated a map of methylated cytosines at single base pair resolution for betula platyphylla (white birch) by bisulfite sequencing combined with transcriptomics to analyze dna methylation and its effects on gene expression. we obtained a detailed view of t ...201425514241
phenolic compounds and expression of 4cl genes in silver birch clones and pt4cl1a lines.a small multigene family encodes 4-coumarate:coa ligases (4cls) catalyzing the coa ligation of hydroxycinnamic acids, a branch point step directing metabolites to a flavonoid or monolignol pathway. in the present study, we examined the effect of antisense populus tremuloides 4cl (pt4cl1) to the lignin and soluble phenolic compound composition of silver birch (betula pendula) pt4cl1a lines in comparison with non-transgenic silver birch clones. the endogenous expression of silver birch 4cl genes w ...201425502441
soil application of biochar produced from biomass grown on trace element contaminated land.trace element (te) contamination of soils is a worldwide problem. however, although not considered safe anymore for food production without clean-up, many of these soils may still be used to produce biomass for non-food purposes such as biochar. exploring the suitability of such biochar for the amendment of low-fertility soil, we investigated growth and metal accumulation of ryegrass (lolium perenne, var. calibra) as well as soil microbial abundance on a non-contaminated soil after amendment wit ...201425163600
effects of elevated co2 on litter chemistry and subsequent invertebrate detritivore feeding responses.elevated atmospheric co2 can change foliar tissue chemistry. this alters leaf litter palatability to macroinvertebrate detritivores with consequences for decomposition, nutrient turnover, and food-web structure. currently there is no consensus on the link between co2 enrichment, litter chemistry, and macroinvertebrate-mediated leaf decomposition. to identify any unifying mechanisms, we presented eight invertebrate species from aquatic and terrestrial ecosystems with litter from alnus glutinosa ( ...201424465985
combining microtomy and confocal laser scanning microscopy for structural analyses of plant-fungus associations.the serious problem of extended tissue thickness in the analysis of plant-fungus associations was overcome using a new method that combines physical and optical sectioning of the resin-embedded sample by microtomy and confocal microscopy. improved tissue infiltration of the fungal-specific, high molecular weight fluorescent probe wheat germ agglutinin conjugated to alexa fluor® 633 resulted in high fungus-specific fluorescence even in deeper tissue sections. if autofluorescence was insufficient, ...201424249491
influence of partial cutting on parasitism of endemic spruce budworm (lepidoptera: tortricidae) populations.silvicultural treatments such as thinning have been suggested as management tools against the spruce budworm, choristoneura fumiferana (clemens) (lepidoptera: tortricidae). among other things, parasitoids are also proposed to be influenced by silvicultural procedures, but the effect of thinning on spruce budworm's natural enemies has not been tested yet. in this study, the influence of partial cutting on parasitism of endemic spruce budworm populations has been investigated in mature balsam fir- ...201424780195
medicinal plant extracts can variously modify biofilm formation in escherichia coli.low concentrations of black tea and water extracts from medicinal plants arctostaphylos uva-ursi, vaccinium vitis-idaea, tilia cordata, betula pendula and zea mays stimulated biofilm formation in escherichia coli bw25113 up to three times. similar effect was observed for tannic acid and low concentrations of quercetin. in contrast, the extract from urtica dioica reduced biofilm production. pretreatment with plant extracts variously modified antibiotic effects on specific biofilm formation (sbf). ...201424500005
suitability of different pollen as alternative food for the predatory mite amblyseius swirskii (acari, phytoseiidae).the predacious mite amblyseius swirskii athias-henriot is used as a biological control agent against various pests in greenhouses. pollen offered as supplementary food is reported to improve their fast establishment and performance. however, the nutritional suitability of different pollens for a. swirskii is not sufficiently known yet. pollens of 21 plant species were offered to the mites as exclusive food during preimaginal development. preimaginal mortality and developmental time have been ass ...201323670826
elevated co2 enrichment induces a differential biomass response in a mixed species temperate forest plantation.in a free-air carbon dioxide (co(2)) enrichment study (bangorface), alnus glutinosa, betula pendula and fagus sylvatica were planted in areas of one-, two- and three-species mixtures (n = 4). the trees were exposed to ambient or elevated co(2) (580 μmol mol(-1)) for 4 yr, and aboveground growth characteristics were measured. in monoculture, the mean effect of co(2) enrichment on aboveground woody biomass was + 29, + 22 and + 16% for a. glutinosa, f. sylvatica and b. pendula, respectively. when t ...201323356474
effects of tree species richness and composition on moose winter browsing damage and foraging selectivity: an experimental study.the optimal foraging theory, the nutrient balance hypothesis, and the plant association theories predict that foraging decisions and resulting tree damage by large mammalian browsers may be influenced by the species richness and species composition of forest stands. this may lead to either associational susceptibility (increased damage on a focal plant in a mixed stand) or associational resistance (reduced damage in a mixed stand). better understanding of the mechanisms and the relative importan ...201323363076
from soil to leaves--aluminum fractionation by single step extraction procedures in polluted and protected areas.the paper presents the fractionation of aluminum in the samples of soil and plants of different species using a selective single-step extraction method. the study was conducted in the area located near a chemical plant, which for many years served as a post-crystallization leachate disposal site storing chemical waste (sector i), and in the area around the site: in wielkopolski national park, rogalin landscape park and toward the infiltration ponds at the "dębina" groundwater well-field for the ...201323651943
influence of experience on intake and feeding behavior of dairy sheep when offered forages from woody plants in a multiple-choice situation.a satisfactory intake of novel low-quality forages by ruminants may require previous experience with this feed. therefore, this study tested in sheep whether experience with forages from woody plants had an influence on feed intake, feeding behavior, and nutrient supply when offered in a multiple-choice arrangement. two sheep experiments were conducted, 1 in syria (mediterranean region; exp. 1) and the other in switzerland (central europe; exp. 2), that investigated 5 and 6 woody test plants, re ...201323989878
photosynthetic response of early and late leaves of white birch (betula platyphylla var. japonica) grown under free-air ozone exposure.betula platyphylla var. japonica (white birch) has heterophyllous leaves (i.e., early and late leaves) and is a typical pioneer tree species in northern japan. seedlings of white birch were exposed to ozone during two growing seasons, and measurements were carried out in the second year. early leaves did not show an ozone-induced reduction in photosynthesis because of lower stomatal conductance resulting in higher avoidance capacity for ozone-induced stress. also, an ozone-related increase in le ...201323938447
betula pendula roth leaves: gastroprotective effects of an hplc-fingerprinted methanolic extract.in this study, a methanolic extract of betula pendula leaves (ble) was investigated for its gastroprotective effects against 90% ethanol-induced ulcer in rats. oral pretreatment of rats with ble (100, 200 and 400 mg kg(- 1)) significantly reduced the incidence of gastric lesions induced by ethanol administration as compared with misoprostol (0.50 mg kg(- 1)). furthermore, ble inhibited the increase in malondialdehyde (mda) and prevented depletion of total sulhydryl and non-protein sulhydryl grou ...201323163340
can spatial data substitute temporal data in phenological modelling? a survey using birch flowering.in addition to the evaluation of long-term series, the analysis of spatial gradients, such as urbanization gradients, may be helpful in assessing phenological responses to global warming. but are phenological responses of birch (betula pendula roth) assessed by temperature variations comparable over time and space and can spatially calibrated models predict long-term phenological data adequately? we calibrated and tested linear regression models and the process-based dormphot model on phenologic ...201324169102
do elevations in temperature, co2, and nutrient availability modify belowground carbon gain and root morphology in artificially defoliated silver birch seedlings?climate warming increases the risk of insect defoliation in boreal forests. losses in photosynthetically active surfaces cause reduction in net primary productivity and often compromise carbon reserves of trees. the concurrent effects of climate change and removal of foliage on root growth responses and carbohydrate dynamics are poorly understood, especially in tree seedlings. we investigated if exposures to different combinations of elevated temperature, co2, and nutrient availability modify be ...201324101972
morphological plasticity of ectomycorrhizal short roots in betula sp and picea abies forests across climate and forest succession gradients: its role in changing environments.morphological plasticity of ectomycorrhizal (ecm) short roots (known also as first and second order roots with primary development) allows trees to adjust their water and nutrient uptake to local environmental conditions. the morphological traits (mts) of short-living ecm roots, such as specific root length (srl) and area, root tip frequency per mass unit (rtf), root tissue density, as well as mean diameter, length, and mass of the root tips, are good indicators of acclimation. we investigated t ...201324032035
transcriptomic analysis of incised leaf-shape determination in birch.plant researchers have focused much attention on leaf shape because of its importance in the identification. to evaluate the impact of intraspecies leaf-shape variation on the transcriptome, a series of betula pendula 'dalecarlica' and b. pendula saplings were generated through tissue culture. the leaf shapes and transcriptomes of b. pendula 'dalecarlica' clones were compared with those of b. pendula clones. the leaf shape of b. pendula 'dalecarlica' was incised and that of b. pendula was ovate. ...201324013080
co 2 elevation improves photosynthetic performance in progressive warming environment in white birch seedlings.white birch (betula paperifera mash) seedlings were exposed to progressively warming in greenhouses under ambient and elevated co 2 concentrations for 5 months to explore boreal tree species' potential capacity to acclimate to global climate warming and co 2 elevation. in situ foliar gas exchange, in vivo carboxylation characteristics and chlorophyll fluorescence were measured at temperatures of 26 (o)c and 37 (o)c. elevated co 2 significantly increased net photosynthetic rate (pn) at both measu ...201324555025
daily dynamics of leaf and soil-to-branch hydraulic conductance in silver birch (betula pendula) measured in situ.daily dynamics of leaf (k(l)) and soil-to-branch hydraulic conductance (ks-b) was investigated in silver birch (betula pendula roth.) using evaporative flux method in situ: water potential drop was measured with a pressure chamber and evaporative flux was estimated as sap flux density measured with sap flow gauges. canopy position had a significant (p < 0.001) effect on both k(l) and k(s-b). upper-canopy leaves exhibited 1.7 and soil-to-branch pathway 2.3 times higher hydraulic efficiency than t ...201323681117
nutrient status: a missing factor in phenological and pollen research?phenology ranks among the best ecosystem processes for fingerprinting climate change since temperature explains a high percentage of the interannual or spatial variation in phenological onset dates. however, roles of other environmental variables, such as foliar nutrient concentrations, are far from adequately understood. this observational study examined the effects of air temperature and 11 nutrients on spring phenology of betula pendula roth (birch) along an urban-rural gradient in munich, ge ...201323630329
visualizing water-filled versus embolized status of xylem conduits by desktop x-ray microtomography.the hydraulic conductivity of the stem is a major factor limiting the capability of trees to transport water from the soil to transpiring leaves. during drought conditions, the conducting capacity of xylem can be reduced by some conduits being filled with gas, i.e. embolized. in order to understand the dynamics of embolism formation and repair, considerable attention has been given to developing reliable and accurate methods for quantifying the phenomenon. in the past decade, non-destructive ima ...201323566373
combination treatment of elevated uvb radiation, co2 and temperature has little effect on silver birch (betula pendula) growth and phytochemistry.elevations of carbon dioxide, temperature and ultraviolet-b (ubv) radiation in the growth environment may have a high impact on the accumulation of carbon in plants, and the different factors may work in opposite directions or induce additive effects. to detect the changes in the growth and phytochemistry of silver birch (betula pendula) seedlings, six genotypes were exposed to combinations of ambient or elevated levels of co2 , temperature and uvb radiation in top-closed chambers for 7 weeks. t ...201323496144
metal uptake and allocation in trees grown on contaminated land: implications for biomass production.phytostabilization aims to reduce environmental and health risks arising from contaminated soil. to be economically attractive, plants used for phytostabilization should produce valuable biomass. this study investigated the biomass production and metal allocation to foliage and wood of willow (salix viminalis l.), poplar (populus monviso), birch (betula pendula), and oak (quercus robur) on five different soils contaminated with trace elements (te), with varying high concentrations of cu, zn, cd, ...201323487987
carbohydrate concentrations and freezing stress resistance of silver birch buds grown under elevated temperature and ozone.the effects of slightly elevated temperature (+0.8 °c), ozone (o3) concentration (1.3 × ambient o3 concentration) and their combination on over-wintering buds of betula pendula roth were studied after two growing seasons of exposure in the field. carbohydrate concentrations, freezing stress resistance (fsr), bud dry weight to fresh weight ratio, and transcript levels of cytochrome oxidase (cox), alternative oxidase (aox) and dehydrin (lti36) genes were studied in two clones (clones 12 and 25) in ...201323425688
forest floor leachate fluxes under six different tree species on a metal contaminated site.trees play an important role in the biogeochemical cycling of metals, although the influence of different tree species on the mobilization of metals is not yet clear. this study examined effects of six tree species on fluxes of cd, zn, doc, h(+) and base cations in forest floor leachates on a metal polluted site in belgium. forest floor leachates were sampled with zero-tension lysimeters in a 12-year-old post-agricultural forest on a sandy soil. the tree species included were silver birch (betul ...201323376521
establishing correspondence in wood: the challenge and some solutions?establishing correspondence between the upper portion of a white birch sapling, a suspected weapon, and a potential source from a stand of trees was posed to one of us (gmc). a bending force shattered the sapling, precluding physical matching. three white birch saplings were taken from the same stand of trees in a similar manner. correspondence was achieved by measuring the width of the annual rings along four radii from a disk cut above and below the break. the regression coefficient of the dat ...201323899411
inhaled birch pollen extract induces airway hyperresponsiveness via oxidative stress but independently of pollen-intrinsic nadph oxidase activity, or the tlr4-trif pathway.oxidative stress in allergic asthma may result from oxidase activity or proinflammatory molecules in pollens. signaling via tlr4 and its adaptor toll-il-1r domain-containing adapter inducing ifn-β (trif) has been implicated in reactive oxygen species-mediated acute lung injury and in th2 immune responses. we investigated the contributions of oxidative stress and tlr4/trif signaling to experimental asthma induced by birch pollen exposure exclusively via the airways. mice were exposed to native or ...201323776177
litter supply as a driver of microbial activity and community structure on decomposing leaves: a test in experimental streams.succession of newly created landscapes induces profound changes in plant litter supplied to streams. grasses dominate inputs into open-land streams, whereas tree litter is predominant in forested streams. we set out to elucidate whether the activity and structure of microbial communities on decomposing leaves are determined by litter quality (i.e., grass or tree leaves colonized) or whether changes during riparian succession affecting litter standing stocks on the stream bed play an overriding r ...201323770903
effects of species-specific leaf characteristics and reduced water availability on fine particle capture efficiency of trees.trees can improve air quality by capturing particles in their foliage. we determined the particle capture efficiencies of coniferous pinus sylvestris and three broadleaved species: betula pendula, betula pubescens and tilia vulgaris in a wind tunnel using nacl particles. the importance of leaf surface structure, physiology and moderate soil drought on the particle capture efficiencies of the trees were determined. the results confirm earlier findings of more efficient particle capture by conifer ...201323735814
transcriptomic analysis of purple leaf determination in birch.'purple rain', a purple cultivar of betula pendula, has dark purple leaves throughout the vegetative period. in this study, b. pendula 'purple rain' was found to have a higher anthocyanidin level compared with b. pendula, transcriptome analysis revealed numerous changes in gene expression that could be attributed to color change, including the upregulation of 2467 unigenes and the downregulation of 2299 unigenes in 'purple rain'. furthermore, anthocyanidin synthesis and transcriptional regulatio ...201323732291
biochemical and growth acclimation of birch to night temperatures: genotypic similarities and differences.the responses of plants to environmental factors are connected to the time of day. in this study, silver birch (betula pendula) was grown in growth chambers at five different night temperatures (6-22 °c), using gradual changes during the evening and morning hours. despite the increased night respiration and unaffected daytime net photosynthesis (per square metre), the carbon uptake (biomass) of birch did not decrease, probably due to enhanced biochemical processes on warmer nights and the advant ...201322612878
photosynthetic downregulation in leaves of the japanese white birch grown under elevated co(2) concentration does not change their temperature-dependent susceptibility to photoinhibition.to determine the effects of elevated co(2) concentration ([co(2)]) on the temperature-dependent photosynthetic properties, we measured gas exchange and chlorophyll fluorescence at various leaf temperatures (15, 20, 25, 30, 35 and 40°c) in 1-year-old seedlings of the japanese white birch (betula platyphylla var. japonica), grown in a phytotron under natural daylight at two [co(2)] levels (ambient: 400 µmol mol(-1) and elevated: 800 µmol mol(-1)) and limited n availability (90 mg n plant(-1)). pla ...201322607385
[molecular aspects of allergy to plant products. part ii. pathogenesis-related proteins (prs), apple allergenicity governed by mal d 1 gene].of the plant allergens listed in the official allergen database of the international union of immunological societies, approximately 25% belong to the group of pathogenesis-related proteins (prs). they have been classified into 17 pr families based on similarities in their amino acid sequence, enzymatic activities, or other functional properties. plant-derived allergens have been identified with sequence similarities to pr families 2, 3, 4, 5, 8, 10, and 14. the main birch allergen in northern e ...201222568184
genotypic variation in yellow autumn leaf colours explains aphid load in silver birch.• it has been suggested that autumn-migrating insects drive the evolution of autumn leaf colours. however, evidence of genetic variation in autumn leaf colours in natural tree populations and the link between the genetic variation and herbivore abundances has been lacking. • here, we measured the size of the whole aphid community and the development of green-yellow leaf colours in six replicate trees of 19 silver birch (betula pendula) genotypes at the beginning, in the middle and at the end of ...201222548444
betula pendula leaves: polyphenolic characterization and potential innovative use in skin whitening products.the research of new tyrosinase inhibitors is currently important for the development of skin whitening agents; particularly, birch leaves extracts are included in many skin cosmetic products. in this study, the potential ability of betula pendula leaves ethanolic extract (be) was evaluated on mushroom tyrosinase activity. results showed that be was capable to inhibit dose-dependently l-dopa oxidation catalyzed by tyrosinase. the inhibition kinetics, analyzed by lineweaver-burk plots, showed a no ...201222480759
sesquiterpenes from the inner bark of the silver birch and the paper birch.the compositions of the mixtures of sesquiterpenoids, largely hydrocarbons that were found in the inner bark of the silver birch, betula pendula roth and the paper birch, betulapapyrifera marshall, grown in new zealand were analyzed by spme-gcms. the major components of the volatile oil from the inner bark of b. pendula were trans alpha-bergamotene (31%) and alpha-santalene (19%). this composition was quite different from that of the oil from the branches, buds and leaves of the same species fro ...201222474938
the effects of defoliation-induced delayed changes in silver birch foliar chemistry on gypsy moth fitness, immune response, and resistance to baculovirus infection.we tested the effects of defoliation-induced changes in silver birch, betula pendula, foliar chemistry (delayed induced resistance, dir) on the fitness and immune defense of the gypsy moth, lymantria dispar. we measured larval developmental time, pupal weight, rate of survival to the adult stage, and five characteristics of larval immune defense: (1) encapsulation response; (2) phenoloxidase activity; (3) hemocyte concentration and (4) lysozyme-like activity in the hemolymph; and (5) resistance ...201222396147
interactive effects of elevated ozone and temperature on carbon allocation of silver birch (betula pendula) genotypes in an open-air field exposure.in the present experiment, the single and combined effects of elevated temperature and ozone (o(3)) on four silver birch genotypes (gt12, gt14, gt15 and gt25) were studied in an open-air field exposure design. above- and below-ground biomass accumulation, stem growth and soil respiration were measured in 2008. in addition, a (13)c-labelling experiment was conducted with gt15 trees. after the second exposure season, elevated temperature increased silver birch above- and below-ground growth and so ...201222363070
inhibition of corneal inflammation following keratoplasty by birch leaf extract.the objective of this study was to determine the effect of birch leaf (betula pendula) extract (bpe) on corneal inflammation following keratoplasty in the rat model. t cells were stimulated in vitro in the presence of bpe. proliferation, activation phenotype and the number of apoptotic/necrotic cells in cell culture were analyzed by flow cytometry. corneal transplantation was performed between fisher and lewis rats. recipient rats were either treated with cyclosporine a at a low dosage (low-dose ...201222360995
characterization of profilin polymorphism in pollen with a focus on multifunctionality.profilin, a multigene family involved in actin dynamics, is a multiple partners-interacting protein, as regard of the presence of at least of three binding domains encompassing actin, phosphoinositide lipids, and poly-l-proline interacting patches. in addition, pollen profilins are important allergens in several species like olea europaea l. (ole e 2), betula pendula (bet v 2), phleum pratense (phl p 12), zea mays (zea m 12) and corylus avellana (cor a 2). in spite of the biological and clinical ...201222348028
the effects of soil and air temperature on co2 exchange and net biomass accumulation in norway spruce, scots pine and silver birch seedlings.soil temperature is proposed to affect the photosynthetic rate and carbon allocation in boreal trees through sink limitation. the aim of this study was to investigate the effect of temperature on co(2) exchange, biomass partitioning and ectomycorrhizal (ecm) fungi of boreal tree species. we measured carbon allocation, above- and below-ground co(2) exchange and the species composition of associated ecm fungi in the rhizosphere of scots pine (pinus sylvestris l.), norway spruce (picea abies k.) an ...201222345325
assessment of suitability of tree species for the production of biomass on trace element contaminated soils.to alleviate the demand on fertile agricultural land for production of bioenergy, we investigated the possibility of producing biomass for bioenergy on trace element (te) contaminated land. soil samples and plant tissues (leaves, wood and bark) of adult willow (salix sp.), poplar (populus sp.), and birch (betula pendula) trees were collected from five contaminated sites in france and germany and analysed for zn, cd, pb, cu, ca, and k. cadmium concentration in tree leaves were correlated with tre ...201222284170
betulin complex in γ-cyclodextrin derivatives: properties and antineoplasic activities in in vitro and in vivo tumor models.given the present high incidence of melanoma and skin cancer, interest in potential drugs of plant origin has increased significantly. pentacyclic lupane-type triterpenes are widely distributed in plants, offering numerous pharmacological benefits. betulin is an important compound in the bark of betula pendula roth and has important therapeutic properties, including antitumor activities. its biological effect is limited by its poor water solubility, which can be improved by cyclodextrin complexa ...201223203108
study of the betulin enriched birch bark extracts effects on human carcinoma cells and ear inflammation. 201223158079
phenolic compounds of the inner bark of betula pendula: seasonal and genetic variation and induction by wounding.the contents of individual phenolic compounds in the inner bark of silver birch (betula pendula roth) were analyzed by hplc-dad. samples from 21 mature trees originating from three micropropagated parent trees were collected six times over a 1-year period. significant seasonal variation in the quantities of ten compounds and four chromatographically unresolved compound pairs was found. a majority of the compounds also exhibited significant quantitative variation among birch clones. there were no ...201223065107
extraction of betulin, trimyristin, eugenol and carnosic acid using water-organic solvent mixtures.a solvent system consisting of ethyl acetate, ethyl alcohol and water, in the volume ratio of 4.5:4.5:1, was developed and used to extract, at room temperature, betulin from white birch bark and antioxidants from spices (rosemary, thyme, sage, and oregano) and white oak chips. in addition, under reflux conditions, trimyristin was extracted from nutmeg using the same solvent system, and eugenol from olives was extracted using a mixture of salt water and ethyl acetate. the protocol demonstrates th ...201222864237
influence of betulinic acid on lymphocyte subsets and humoral immune response in mice.betulinic acid is a pentacyclic triterpene found in many plant species, among others, in the bark of white birch betula alba. betulinic acid was reported to display a wide range of biological effects, including antiviral, antiparasitic, antibacterial, anticancer and anti-inflammatory activities. the effects of betulinic acid (50, 5, 0.5 mg/kg) administered orally five times at 24 hours intervals to non-immunized and red blood cells (srbc)-immunized mice were determined. the present study examine ...201222844709
evaluation and differentiation of the betulaceae birch bark species and their bioactive triterpene content using analytical ft-vibrational spectroscopy and gc-ms.aiming to obtain the highest triterpene content in the extraction products, nine bark samples from the forest abundant flora of apuseni mountains, romania were raman spectroscopically evaluated. three different natural extracts from betula pendula roth birch bark have been obtained and characterized using fourier transform vibrational spectra.201222808999
new validated high-performance liquid chromatographic method for simultaneous analysis of ten flavonoid aglycones in plant extracts using a c18 fused-core column and acetonitrile-tetrahydrofuran gradient.an hplc method of high resolution has been developed and validated for the simultaneous determination of ten prominent flavonoid aglycones in plant materials using a fused-core c18-silica column (ascentis® express, 4.6 mm × 150 mm, 2.7 μm). the separation was accomplished with an acetonitrile-tetrahydrofuran gradient elution at a flow rate of 1 ml/min and temperature of 30°c. uv spectrophotometric detection was employed at 370 nm for flavonols (quercetin [qu], myricetin [my], isorhamnetin [is], ...201222807401
analysis of arsenic and antimony distribution within plants growing at an old mine site in ouche (cantal, france) and identification of species suitable for site revegetation.one of the objectives of this study was to assess the contamination levels in the tailings of an old antimony mine site located in ouche (cantal, france). throughout the 1.3 ha site, homogenous concentrations of antimony and arsenic, a by-product of the operation, were found along 0-0.5 m-deep profiles. maximum concentrations for antimony and arsenic were 5780 mg kg(-1) dry tailings and 852 mg kg(-1) dry tailings, respectively. despite the presence of the contaminants and the low ph and organic ...201222789654
shortening tobacco life cycle accelerates functional gene identification in genomic research.definitive allocation of function requires the introduction of genetic mutations and analysis of their phenotypic consequences. novel, rapid and convenient techniques or materials are very important and useful to accelerate gene identification in functional genomics research. here, over-expression of pmft (prunus mume), a novel ft orthologue, and ptft (populus tremula) lead to shortening of the tobacco life cycle. a series of novel short life cycle stable tobacco lines (30-50 days) were develope ...201223107371
tree species diversity interacts with elevated co2 to induce a greater root system response.as a consequence of land-use change and the burning of fossil fuels, atmospheric concentrations of co2 are increasing and altering the dynamics of the carbon cycle in forest ecosystems. in a number of studies using single tree species, fine root biomass has been shown to be strongly increased by elevated co2 . however, natural forests are often intimate mixtures of a number of co-occurring species. to investigate the interaction between tree mixture and elevated co2 , alnus glutinosa, betula pen ...201223504733
nutrient supply has greater influence than sink strength on photosynthetic adaptation to co2 elevation in white birch seedlings.to study the effects of source-sink ratio and nutrient supply on photosynthetic acclimation to co(2) elevation, we subjected white birch seedlings to two levels of nutrient supply (high vs. low) and co(2) concentrations (ambient vs. doubled [co(2)]) for two months and then shaded the lower canopy on half of the seedlings to reduce source/sink ratio for an additional month. the co(2) elevation significantly increased p(n) and iwue at both nutrient levels but the increase was greater in the high t ...201223415328
plant species differences in particulate matter accumulation on leaf surfaces.particulate matter (pm) accumulation on leaves of 22 trees and 25 shrubs was examined in test fields in norway and poland. leaf pm in different particle size fractions (pm(10), pm(2.5), pm(0.2)) differed among the species, by 10- to 15-folds at both test sites. pinus mugo and pinus sylvestris, taxus media and taxus baccata, stephanandra incisa and betula pendula were efficient species in capturing pm. less efficient species were acer platanoides, prunus avium and tilia cordata. differences among ...201222554531
metal resistance in populations of red maple (acer rubrum l.) and white birch (betula papyrifera marsh.) from a metal-contaminated region and neighbouring non-contaminated regions.metal resistance in populations of acer rubrum and betula papyrifera in the industrially contaminated region of sudbury, ontario, was compared with resistance in populations from neighbouring uncontaminated regions. in two one-season experiments, seedlings were grown outdoors on contaminated (mainly cu, ni) and uncontaminated substrates. sudbury populations of both species responded less to contamination than populations from uncontaminated regions. in a. rubrum this difference was small. for bo ...201222336730
medicinal plants extracts affect virulence factors expression and biofilm formation by the uropathogenic escherichia coli.medicinal plants are an important source for the therapeutic remedies of various diseases including urinary tract infections. this prompted us to perform research in this area. we decided to focus on medicinal plants species used in urinary tract infections prevention. the aim of our study was to determine the influence of betula pendula, equisetum arvense, herniaria glabra, galium odoratum, urtica dioica, and vaccinium vitis-idaea extracts on bacterial survival and virulence factors involved in ...201222915095
procyanidin xylosides from the bark of betula pendula.a procyanidin dimer xyloside, catechin-(4α→8)-7-o-β-xylopyranosyl-catechin, was isolated from the inner bark of betula pendula and its structure was determined using 1d and 2d nmr, cd and high-resolution esims. interestingly, the 7-o-β-xylopyranose unit was found to be present in the lower terminal unit of the dimer. in addition to this procyanidin dimer xyloside, an entire series of oligomeric and polymeric procyanidin xylosides was detected. their structures were investigated by hydrophilic in ...201222273040
species-specific effect of uv-b radiation on the temporal pattern of leaf growth.recent molecular and physiological studies have demonstrated that ultraviolet-b radiation (uv-b) can affect some of the processes involved in leaf growth, but the phases of leaf growth affected have not been clearly delimited. we used functional growth analysis to assess the effects of uv-b radiation on the time course of leaf growth in seedlings of two birch species (betula pendula and betula pubescens). our aim was to identify the phase(s) of leaf development affected by uv-b radiation. in a g ...201222224454
[the influence of the triterpenoid from the weeping birch (betula pendula) on the changed reactivity of an organism exposed to action of the dust-radiating factor].the obtained data testify about immunmodulating properties of the given medicine. influence of "be phytomedicine on organism, which undergoes dust-radiation factor leads to positive dynamics in humoral and cellular parts of immunity, also to increasing immunological reactivity of an organism.201122279741
host species and strain combination determine growth reduction of spruce and birch seedlings colonized by root-associated dark septate endophytes.interactions of betula pendula and picea abies with dark septate endophytes of the phialocephala fortinii-acephala applanata species complex (pac) were studied. pac are ubiquitous fungal root symbionts of many woody plant species but their ecological role is largely unknown. sterile birch and spruce seedlings in monoculture and mixed culture were exposed to four pac strains, added either singularly or paired in all possible combinations at 18°c and 23°c. plant and fungal biomass was determined a ...201122212126
survey of microfungi in the landschaftspark duisburg-nord (germany).during an excursion in the landschaftspark duisburg-nord in 2009 and 2010 we were able to collect and identify more than 100 specimens of microfungi on different parts of cultivated and wild plant species. we found parasitic and saprophytic microfungi on trees, bushes and herbaceous plants. some of them have been observed only rarely until now. most of the collected microfungi species belong to the classes of ascomycetes, basidiomycetes and deuteromycetes - for example leptosphaeria modesta (des ...201122702187
Liberomyces gen. nov. with two new species of endophytic coelomycetes from broad-leaved trees.During a study of endophytic and saprotrophic fungi in the sapwood and phloem of broad-leaved trees (Salix alba, Quercus robur, Ulmus laevis, Alnus glutinosa, Betula pendula), fungi belonging to an anamorphic coelomycetous genus not attributable to a described taxon were detected and isolated in pure culture. The new genus Liberomyces with two species, L. saliciphilus and L. macrosporus, is described. Both species have subglobose conidiomata containing holoblastic sympodial conidiogenous cells. ...201121937729
N(2) fixation and cycling in Alnus glutinosa, Betula pendula and Fagus sylvatica woodland exposed to free air CO(2) enrichment.We measured the effect of elevated atmospheric CO(2) on atmospheric nitrogen (N(2)) fixation in the tree species Alnus glutinosa growing in monoculture or in mixture with the non-N(2)-fixing tree species Betula pendula and Fagus sylvatica. We addressed the hypotheses that (1) N(2) fixation in A. glutinosa will increase in response to increased atmospheric CO(2) concentrations, when growing in monoculture, (2) the impact of elevated CO(2) on N(2) fixation in A. glutinosa is the same in mixture an ...201122179329
boron nutrition affects the carbon metabolism of silver birch seedlings.boron (b) is an essential micronutrient whose deficiency is common both in agriculture and in silviculture. boron deficiency impairs the growth of plants and affects many metabolic processes like carbohydrate metabolism. boron deficiency and also excess b may decrease the sink demand by decreasing the growth and sugar transport which may lead to the accumulation of carbohydrates and down-regulation of photosynthesis. in this study, we investigated the effects of b nutrition on the soluble and st ...201122084021
temporal variation in epidermal flavonoids due to altered solar uv radiation is moderated by the leaf position in betula pendula.the physiological mechanisms controlling plant responses to dynamic changes in ambient solar ultraviolet (uv) radiation are not fully understood: this information is important to further comprehend plant adaptation to their natural habitats. we used the fluorimeter dualex to estimate in vivo the epidermal flavonoid contents by measuring epidermal uv absorbance (a(375) ) in betula pendula roth (silver birch) leaves of different ages under altered uv. seedlings were grown in a greenhouse for 15 da ...201121883252
[karelian birch (betula pendula roth. var. carelica merkl.) as a model for studying genetic and epigenetic variation related to the formation of patterned wood].the results of long-term pioneering studies on in vitro micropropagation of karelian birch patterned forms and simultaneous cytological analysis of plants multiplied using different periods of in vitro culturing are published for the first time. the patterned wood character has been shown to be correlated with the degree of mixoploidy of its somatic tissue, which is higher in the plants obtained from callus cultures during the first years of culturing. subsequent intracellular selection leads to ...201121954616
inter- and intra-specific variation in stem phloem phenolics of paper birch (betula papyrifera) and european white birch (betula pendula).outbreaks of bronze birch borer (bbb) (agrilus anxius), a wood-boring beetle endemic to north america, have been associated with widespread mortality of birch (betula spp.). there is substantial inter- and intra-specific variation in birch resistance to bbb. species endemic to north america, such as paper birch (b. papyrifera), have coevolved with bbb and are more resistant than european and asian birch species, such as european white birch (b. pendula), which lack an evolutionary history with b ...201122012323
vertical profiles reveal impact of ozone and temperature on carbon assimilation of betula pendula and populus tremula.rising temperature and tropospheric ozone (o(3)) concentrations are likely to affect carbon assimilation processes and thus the carbon sink strength of trees. in this study, we investigated the joint action of elevated ozone and temperature on silver birch (betula pendula) and european aspen (populus tremula) saplings in field conditions by combining free-air ozone exposure (1.2 × ambient) and infrared heaters (ambient +1.2&emsp14;°c). at leaf level measurements, elevated ozone decreased leaf ne ...201121856655
interspecific variation in resistance of asian, european, and north american birches (betula spp.) to bronze birch borer (coleoptera: buprestidae).bronze birch borer (agrilus anxius gory) is the key pest of birches (betula spp.) in north america, several of which have been recommended for ornamental landscapes based on anecdotal reports of borer resistance that had not been confirmed experimentally. in a 20-yr common garden experiment initiated in 1979 in ohio, north american birch species, including paper birch (betula papyrifera marshall), 'whitespire' gray birch (betula populifolia marshall), and river birch (betula nigra l.), were muc ...201122251643
chilling of dormant buds hyperinduces flowering locus t and recruits ga-inducible 1,3-beta-glucanases to reopen signal conduits and release dormancy in populus.in trees, production of intercellular signals and accessibility of signal conduits jointly govern dormancy cycling at the shoot apex. we identified 10 putative cell wall 1,3-ß-glucanase genes (glucan hydrolase family 17 [gh17]) in populus that could turn over 1,3-ß-glucan (callose) at pores and plasmodesmata (pd) and investigated their regulation in relation to ft and cenl1 expression. the 10 genes encode orthologs of arabidopsis thaliana bg_ppap, a pd-associated glycosylphosphatidylinositol (gp ...201121282527
quantification of lignin-carbohydrate linkages with high-resolution nmr spectroscopy.a quantitative approach to characterize lignin-carbohydrate complex (lcc) linkages using a combination of quantitative ¹³c nmr and hsqc 2d nmr techniques has been developed. crude milled wood lignin (mwlc), lcc extracted from mwlc with acetic acid (lcc-acoh) and cellulolytic enzyme lignin (cel) preparations were isolated from loblolly pine (pinus taeda) and white birch (betula pendula) woods and characterized using this methodology on a routine 300 mhz nmr spectrometer and on a 950 mhz spectrome ...201121298285
proteomic profiling of birch (betula verrucosa) pollen extracts from different origins.pollen of the european white birch is a major source of spring pollinosis in europe. pollen-allergy diagnosis and treatment by specific immunotherapy commonly rely on extracts of natural origin. to gain insight into the protein content and its variability, we evaluated the profile of allergenic and non-allergenic proteins in extracts of pollen from different origins by ms-based proteomics. aqueous extracts prepared from commercially available swedish birch pollen, pollen collected from austrian ...201121360672
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 ...201121401617
impact of light quality on leaf and shoot hydraulic properties: a case study in silver birch (betula pendula).responses of leaf and shoot hydraulic conductance to light quality were examined on shoots of silver birch (betula pendula), cut from lower ('shade position') and upper thirds of the crowns ('sun position') of trees growing in a natural temperate forest stand. hydraulic conductances of leaf blades (k(lb) ), petioles (k(p) ) and branches (i.e. leafless stem; k(b) ) were determined using a high pressure flow meter in steady state mode. the shoots were exposed to photosynthetic photon flux density ...201121414012
proteomic analysis of the major birch allergen bet v 1 predicts allergenicity for 15 birch species.pollen of the european and asian white birch (betula pendula and b. platyphylla) causes hay fever in humans. the allergenic potency of other birch species is largely unknown. to identify birch trees with a reduced allergenicity, we assessed the immunochemical characteristics of 15 species and two hybrids, representing four subgenera within the genus betula, while focusing on the major pollen allergen bet v 1. antigenic and allergenic profiles of pollen extracts from these species were evaluated ...201121459169
deer browsing and soil disturbance induce cascading effects on plant communities: a multilevel path analysis.understanding how large herbivores shape plant diversity patterns is an important challenge in community ecology, especially because many ungulate populations in the northern hemisphere have recently expanded. because species within plant communities can exhibit strong interactions (e.g., competition, facilitation), selective foraging by large herbivores is likely not only to affect the abundance of palatable species, but also to induce cascading effects across entire plant communities. to inves ...201121563575
an aqueous birch leaf extract of betula pendula inhibits the growth and cell division of inflammatory lymphocytes.ethnopharmacological relevance: leaf extracts of betula pendula have been traditionally used for the treatment of patients with rheumatoid arthritis (ra) or osteoarthritis. aim of the study: we investigated the anti-proliferative capacity of an aqueous leaf extract of betula pendula (bpe) on human primary lymphocytes in vitro, because activated lymphocytes play a major role in the initiation and maintenance of ra. materials and methods: lymphocyte proliferation and cell division was measured by ...201121619918
distribution and expression characteristics of triterpenoids and osc genes in white birch (betula platyphylla suk.).betulin and oleanolic acids (pentacyclic triterpenoid secondary metabolites) have broad pharmacological activities and can be potentially used for the development of anti-cancer and anti-aids drugs. in this study, we detected the accumulation and the distribution characteristics of betulin and oleanolic acid in various organs of white birch at different ages. we also determined the expression of 4 osc genes (lus, β-as, cas1 and cas2) involved in the triterpenoid synthesis pathways by real time r ...201121647548
ultraviolet-b-induced flavonoid accumulation in betula pendula leaves is dependent upon nitrate reductase-mediated nitric oxide signaling.nitric oxide (no) is an important signaling molecule involved in many physiological processes in plants. nitric oxide generation and flavonoid accumulation are two early reactions of plants to ultraviolet-b (uv-b) irradiation. however, the source of uv-b-triggered no generation and the role of no in uv-b-induced flavonoid accumulation are not fully understood. in order to evaluate the origin of uv-b-triggered no generation, we examined the responses of nitrate reductase (nr) activity and the exp ...201121813515
bird predation enhances tree seedling resistance to insect herbivores in contrasting forest habitats.according to the associational resistance hypothesis, neighbouring plants are expected to influence both the insect herbivore communities and their natural enemies. however, this has rarely been tested for the effects of canopy trees on herbivory of seedlings. one possible mechanism responsible for associational resistance is the indirect impact of natural enemies on insect herbivory, such as insectivorous birds. but it remains unclear to what extent such trophic cascades are influenced by the c ...201121811874
isolation, identification and sequence analysis of a thioredoxin h gene, a member of subgroup iii of h-type trxs from grape (vitis vinifera l. cv. askari).thioredoxins (trxs) are small ubiquitous proteins which play a regulatory role in a variety of cellular processes. in contrast to other organisms, plants have a great number of trx types, consisting of six well-defined groups: f, m, x, and y in chloroplasts, o in mitochondria, and h mainly in cytosol. a full-length cdna, designated vvcxxs2, encoding trx h polypeptide was isolated and cloned from grape (vitis vinifera l. cv. askari) berries organ by reverse transcription polymerase chain reaction ...201121732058
suppression of stat3 and hif-1 alpha mediates anti-angiogenic activity of betulinic acid in hypoxic pc-3 prostate cancer cells.signal transducer and activator of transcription 3 (stat3) is a transcription factor that regulates various cellular processes such as cell survival, angiogenesis and proliferation. in the present study, we examined that betulinic acid (ba), a triterpene from the bark of white birch, had the inhibitory effects on hypoxia-mediated activation of stat3 in androgen independent human prostate cancer pc-3 cells.201121731766
elevation of night-time temperature increases terpenoid emissions from betula pendula and populus tremula.volatile organic compounds (vocs) are expected to have an important role in plant adaptation to high temperatures. the impacts of increasing night-time temperature on daytime terpenoid emissions and related gene expression in silver birch (betula pendula) and european aspen (populus tremula) clones were studied. the plants were grown under five different night-time temperatures (6, 10, 14, 18, and 22 degrees c) while daytime temperature was kept at a constant 22 degrees c. voc emissions were col ...201020181662
flavonol quantification and stability of phenolics in fermented extracts from fresh betula pendula leaves.an hplc method, which allows reliable quantitation of flavonols and other phenolics in birch leaf extracts, was developed and validated. the method was applied to study the bioconversion of flavonols in fermented aqueous extracts. almost 100% of the flavonols were converted during the 12 months observation period. the generated phenolics as well as consecutive conversion products were identified by hplc-dad, lc-ms and gc-ms techniques.201020189738
the past, present and future tasks of hungarian dendrological research.hungarian dendrological research (research of living woody plants) has more than 200 years old history; the first general work by j+ínos kereszt+®ly grossinger was published in 1797. further basic works in our time yet are: forest botany by lajos fekete and s+índor m+íg+¦csy-dietz (1896); and the chorological work, distribution of trees and shrubs of sylvicultural importance in the region of hungarian state by lajos fekete and tibor blattny (1913). a few dendrologists and many botanists have hel ...201021565760
low soil temperature inhibits the effect of high nutrient supply on photosynthetic response to elevated carbon dioxide concentration in white birch seedlings.to investigate the interactive effects of soil temperature (t(soil)) and nutrient availability on the response of photosynthesis to elevated atmospheric carbon dioxide concentration ([co(2)]), white birch (betula papyrifera marsh.) seedlings were exposed to ambient (360 micromol mol(-1)) or elevated (720 micromol mol(-1)) [co(2)], three t(soil) (5, 15 and 25 degrees c initially, increased to 7, 17 and 27 degrees c, respectively, 1 month later) and three nutrient regimes (4/1.8/3.3, 80/35/66 and ...201020007132
determination of de novo and pool emissions of terpenes from four common boreal/alpine trees by 13co2 labelling and ptr-ms analysis.boreal forests emit a large amount of monoterpenes into the atmosphere. traditionally these emissions are assumed to originate as evaporation from large storage pools. thus, their diurnal cycle would depend mostly on temperature. however, there is indication that a significant part of the monoterpene emission would originate directly from de novo synthesis. by applying 13co2 fumigation and analyzing the isotope fractions with proton transfer reaction mass spectrometry (ptr-ms) and classical gc-m ...201020040067
acc oxidase genes expressed in the wood-forming tissues of loblolly pine (pinus taeda l.) include a pair of nearly identical paralogs (nips).1-aminocyclopropane-1-carboxylate (acc) oxidase catalyzes the final reaction of the ethylene biosynthetic pathway, converting the unusual cyclic amino acid, acc, into ethylene. past studies have shown a possible link between ethylene and compression wood formation in conifers, but the relationship has received no more than modest study at the gene expression level. in this study, a cdna clone encoding a putative acc oxidase, ptaco1, was isolated from a cdna library produced using mrna from ligni ...201020053371
foliar methyl salicylate emissions indicate prolonged aphid infestation on silver birch and black alder.it is well documented that when plants are damaged by insects they respond by emitting a range of volatile organic compounds (vocs). while there have been numerous reports concerning vocs induced by chewing herbivores, there are relatively few studies detailing the vocs induced by aphid feeding. the effects of aphid feeding on vocs emitted by boreal forest trees have been particularly neglected. herbivore-induced vocs have relevance to direct and indirect plant defence and atmospheric chemistry. ...201020097686
differential gene expression in senescing leaves of two silver birch genotypes in response to elevated co2 and tropospheric ozone.long-term effects of elevated co(2) and o(3) concentrations on gene expression in silver birch (betula pendula roth) leaves were studied during the end of the growing season. two birch genotypes, clones 4 and 80, with different ozone growth responses, were exposed to 2x ambient co(2) and/or o(3) in open-top chambers (otcs). microarray analyses were performed after 2 years of exposure, and the transcriptional profiles were compared to key physiological characteristics during leaf senescence. ther ...201020132521
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