| 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 ... | 2013 | 24169102 |
| 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 ... | 2013 | 24101972 |
| 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 ... | 2013 | 24032035 |
| 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. ... | 2013 | 24013080 |
| 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 ... | 2014 | 24001818 |
| 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 ... | 2013 | 23989878 |
| 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 ... | 2013 | 23938447 |
| interactions and competition processes among tree species in young experimental mixed forests, assessed with chlorophyll fluorescence and leaf morphology. | chlorophyll a fluorescence (chlf) and leaf morphology were assessed in two sites in europe (kaltenborn, germany, and satakunta, finland) within a forest diversity experiment. trees at satakunta, planted in 1999, form a stratified canopy, while in kaltenborn the trees are 7 years old, with no apparent canopy connection among broadleaf species. the following chlf parameters from measured ojip transient curves were examined: f(v)/f(m) (a proxy for maximum quantum yield); ψeo (a proxy for efficiency ... | 2014 | 23926925 |
| 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 ... | 2013 | 23899411 |
| 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 ... | 2013 | 23776177 |
| 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 ... | 2013 | 23770903 |
| 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 ... | 2013 | 23735814 |
| 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 ... | 2013 | 23732291 |
| cultivable actinomycetes from rhizosphere of birch (betula pendula) growing on a coal mine dump in silets, ukraine. | five actinomycete strains were isolated from the rhizosphere of birch, one of a few native tree forms capable of thriving on the upper level of a coal mine dump near the village of silets (lvivska region, ukraine). no such strains were isolated from surrounding gangue, or from nearby grass calamagrostis epigeios. using 16s rdna sequencing and analysis of cell wall aminoacids, four of these strains were shown to belong to genus streptomyces and one to be amycolatopsis. the isolates were able to p ... | 2014 | 23686352 |
| 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 ... | 2013 | 23681117 |
| 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 ... | 2013 | 23630329 |
| 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 ... | 2013 | 23566373 |
| 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 ... | 2013 | 23496144 |
| 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, ... | 2013 | 23487987 |
| 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 ... | 2013 | 23425688 |
| 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 ... | 2013 | 23376521 |
| 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 ... | 2012 | 23203108 |
| 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 ... | 2013 | 23163340 |
| study of the betulin enriched birch bark extracts effects on human carcinoma cells and ear inflammation. | | 2012 | 23158079 |
| 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 ... | 2012 | 23065107 |
| 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 ... | 2012 | 22864237 |
| 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 ... | 2012 | 22844709 |
| 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. | 2012 | 22808999 |
| 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], ... | 2012 | 22807401 |
| 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 ... | 2012 | 22789654 |
| 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 ... | 2013 | 22612878 |
| 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 ... | 2013 | 22607385 |
| [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 ... | 2012 | 22568184 |
| 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 ... | 2012 | 22548444 |
| 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 ... | 2012 | 22480759 |
| 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 ... | 2012 | 22474938 |
| 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 ... | 2012 | 22396147 |
| 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 ... | 2012 | 22363070 |
| 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 ... | 2012 | 22360995 |
| 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 ... | 2012 | 22348028 |
| 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 ... | 2012 | 22345325 |
| 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 ... | 2012 | 22284170 |
| population- and ecosystem-level effects of predation on microbial-feeding nematodes. | we studied the role of nematode predation in the functioning of detrital food webs assembled in microcosms. the microcosms contained defaunated humus and litter materials, a diverse microbial community with bacteria, fungi and protozoa, and a birch (betula pendula) seedling infected with mycorrhizal fungi. different levels of top-down control upon microbivorous nematodes were set up by assembling food webs either without predators, or in combinations with a specialist and a non-specialist predat ... | 1999 | 28308090 |
| the charcoal effect in boreal forests: mechanisms and ecological consequences. | wildfire is the principal disturbance regime in northern boreal forests, where it has important rejuvenating effects on soil properties and encourages tree seedling regeneration and growth. one possible agent of this rejuvenation is fire-produced charcoal, which adsorbs secondary metabolites such as humus phenolics produced by ericaceous vegetation in the absence of fire, which retard nutrient cycling and tree seedling growth. we investigated short-term ecological effects of charcoal on the bore ... | 1998 | 28308435 |
| regenerating temperate forest mesocosms in elevated co2: belowground growth and nitrogen cycling. | the response of temperate forest ecosystems to elevated atmospheric co2 concentrations is important because these ecosystems represent a significant component of the global carbon cycle. two important but not well understood processes which elevated co2 may substantially alter in these systems are regeneration and nitrogen cycling. if elevated co2 leads to changes in species composition in regenerating forest communities then the structure and function of these ecosystems may be affected. in mos ... | 1997 | 28307286 |
| herbivore-induced resistance in betula pendula: the role of plant vascular architecture. | we studied the role of plant vascular architecture in the determination of the spatial extent of herbivore induced responses within betula pendula roth saplings. the induced responses were measured in bioassays in terms of the relative growth rate of larvae of a geometrid moth, epirrita autumnata. we hypothesised that the level of induced resistance of a certain leaf would be determined by the degree of vascular connectivity between the leaf in question and a damaged leaf, as suggested by recent ... | 1996 | 28307807 |
| elevated co2 reduces field decomposition rates of betula pendula (roth.) leaf litter. | the effect of elevated atmospheric co2 and nutrient supply on elemental composition and decomposition rates of tree leaf litter was studied using litters derived from birch (betula pendula roth.) plants grown under two levels of atmospheric co2 (ambient and ambient +250 ppm) and two nutrient regimes in solar domes. co2 and nutrient treatments affected the chemical composition of leaves, both independently and interactively. the elevated co2 and unfertilized soil regime significantly enhanced lig ... | 1996 | 28307453 |
| allozyme variation in populations, full-sib families and selfed lines in betula pendula roth. | changes in genetic variability in populations (stand origins), full-sib (fs) families and three generations of selfed lines of betula pendula were observed based on 15 allozyme loci. growth vigour, measured as stem volume, and its relationship with heterozygosity was studied to determine the effect of inbreeding. pooled fs families showed a higher percentage of polymorphic loci (p) and allelic numbers per locus (a) than those of natural populations, but no difference in heterozygosity. there was ... | 1996 | 24166635 |
| effects of bilberry (vaccinium myrtillus l.) litter on seed germination and early seedling growth of four boreal tree species. | laboratory and greenhouse bioassays were used to test for inhibitory effects of senescent and decomposed leaves and aqueous extract from bilberry (vaccinium myrtillus l.) against seed germination and seedling growth of aspen (populus tremula l.), birch (betula pendula roth.), scots pine (pinus sylvestris l.), and norway spruce [picea abies (l.) karst.]. aqueous extracts from bilberry leaves were inhibitory to aspen seed germination and seedling growth and also induced root damage and growth abno ... | 1996 | 24227618 |
| effect of birch (betula pendula) bark and food protein level on root voles (microtus oeconomus): ii. detoxification capacity. | the effect of protein and birch bark powder (bbp) content of forage on detoxification capacity of root voles (microtus oeconomus) was studied. young voles were fed with eight different diets for two weeks. individuals on low (3%) protein diets had significantly lighter livers and kidneys than those on moderate (6%) or high (12%) protein diets. birch bark powder addition did not have significant effect on organ weight. detoxification was significantly induced, apparently due to secondary compound ... | 1996 | 24227580 |
| effect of birch (betula pendula) bark and food protein level on root voles (microtus oeconomus): i. food consumption, growth, and mortality. | the effect of protein and birch bark powder (bbp) content of forage on food consumption and growth of root voles (microtus oeconomus) was studied by feeding young voles with eight different diets for two weeks. voles ate more when the protein content of forage was moderate (6%) or low (3%), and when bbp was added to the diets, as compared to a high (12%) protein diet without bbp addition. on high and moderate protein diets voles gained weight, whereas on low protein diets they lost weight. addit ... | 1996 | 24227579 |
| xylem dysfunction during winter and recovery of hydraulic conductivity in diffuse-porous and ring-porous trees. | xylem embolism in winter and spring as well as the occurrence of positive xylem pressure were monitored in several diffuse-porous and one ring-porous tree species (fraxinus excelsior). in acer pseudoplatanus and betula pendula embolism reversal was associated with positive (above-atmospheric) xylem pressures that frequently occurred during a 2-month period prior to leaf expansion. in acer high stem pressures were occasionally triggered on sunny days after a night frost. the other species investi ... | 1996 | 28307135 |
| growth performance of hybrid families by crossing selfed lines of betula pendula roth. | hybrid breeding is an effective approach in many agricultural crops. in allogamous tree species severe inbreeding depression and long reproductive cycles generally prohibit its use. however, three generations of selfing in silver birch (betula pendula roth) were obtained by forcing trees to flowering under greenhouse conditions. hybrids were produced by crossing first-, second and third-generation selfed lines. the effects of different levels of parental inbreeding on the growth performance of h ... | 1996 | 24166273 |
| the influence of ozone and nutrition on δ(13)c in betula pendula. | in the cellulose of stems and leaves, δ(13)c was investigated in a birch clone (betula pendula), which was exposed throughout the growing season to either <3 (control) or 90/40 nl o3 1(-1) (day/night). each regime was split into plants under high or low nutrient supply. δ(13)c was increased (becoming less negative), in stems rather than leaves, by both high nutrition (+2‰) and o3 stress (+1‰). whereas high nutrition raised the wateruse efficiency (wue) while lowering the co2 concentration in the ... | 1995 | 28306987 |
| the effect of elevated carbon dioxide and fertilization on primary and secondary metabolites in birch,betula pendula (roth). | seedlings of european white birch (betula pendula roth) were grown in growth chambers for one growth season under four carbon dioxide regimes (350, 700, 1050 and 1400 ppm) and at three fertilization levels (0, 100 and 500 kg ha(-1) monthly). the soluble carbohydrates and secondary phenolics in the leaves and stems were analysed. it was found that fertilizer addition reduced the amounts of glucose and fructose while sucrose remained almost unaffected. the sugar content of leaves increased at 700 ... | 1994 | 28313886 |
| do birch-feeding caterpillars make the right feeding choices? | the effects of leaf quality on caterpillar performance are frequently investigated, as are the feeding preferences of caterpillars, but rarely are the two considered together to see how preferences match performance. i looked at the preferences and performance of the specialist feeder achlya flavicornis and the generalist spilosoma luteum on betula pendula leaves which were artificially damaged, mined or left undamaged, and on leaves of different ages. often feeding preferences were not for the ... | 1991 | 28313843 |
| phenolic biosynthesis, leaf damage, and insect herbivory in birch (betula pendula). | the effect of both caterpillar herbivory and artificial damage on phenylalanine ammonia lysase (pal) activity of birch foliage was measured, using an intact cell assay. after artificial damage there was a small increase in pal activity in damaged leaves but no change in adjacent undamaged ones. insect grazing produced a larger increase in pal activity, and the enzyme activity was also increased in adjacent undamaged leaves. artificial damage increased the phenolic levels of the damaged leaves. i ... | 1989 | 24271442 |
| the inhibition of phenolic biosynthesis in damaged and undamaged birch foliage and its effect on insect herbivores. | 1. the leaves of betula pendula roth trees were damaged artificially, or by insect-grazing. both induced an increase in phenolic levels in damaged leaves, larger in the case of insect attack.-2. some of the damaged trees were sprayed with an inhibitor of phenolic biosynthesis, (aminoxy) acetic acid, which led to a reduction in phenolic levels in both undamaged and damaged leaves. hence both the effects of damage per se and damage-induced changes in foliage phenolic levels on insect feeding prefe ... | 1988 | 28312381 |
| chemical defense in birch. platyphylloside: a phenol frombetula pendula inhibiting digestibility. | extracts of scandinavian birch (betula pendula roth) buds and internodes of varying twig diameters have been investigated for their inhibitory effect on ruminant digestibility in vitro. the predominant inhibitory effect was observed in extracts containing the phenol platyphylloside, 5-hydroxy-1,7-bis-(4-hydroxy-phenyl)-3-heptan-one-3-o-β-d-glucopyranoside. isolation of the pure compound and incubation with rumen inocula showed that digestibility was negatively related to the concentration. signi ... | 1988 | 24276001 |
| effects of different types of damage on the chemistry of birch foliage, and the responses of birch feeding insects. | 1. we collected insect-grazed, mined, and holepunched leaves of betula pendula roth, and assessed their palatability to four species of birch-feeding lepidopteran caterpillars (apocheima pilosaria d. & s., erranis defolaria clerck, epirrita dilutata d. & s., and euproctis similis fuessly) in laboratory preference tests. the palatability of hole-punched leaves of different ages was also determined, using apocheima pilosaria only. 2. the total phenolic content and protein-precipitating ability of ... | 1987 | 28312484 |
| a parenchymatic medium solidifier for plant in vitro culture. | a new material for the solidification of liquid culture media was prepared from plant parenchyma tissues by mechanical subdivision, solute extration and dessication from ethanol. it is suitable for in vitro culture and propagation of callus as well as shoot tip cultures. the following plant materials have been grown by means of the new medium solidifier: shoot cultures of betula pendula roth, gerbera jamesonii h. bolus ex hook and floribunda rose "triumph", callus tissues of daucus carota l. and ... | 1987 | 24248936 |
| effects of terrestrial isopods on the decomposition of woodland leaf litter. | the indirect contribution terrestrial isopods make to decomposition processes by stimulating microbial activites has been quantified in laboratory experiments. the extent to which microbial metabolism is enhanced as a result of the passage of betula pendula leaf litter through the alimentary system of isopods was measured for both freshly fallen and decayed leaves. faeces derived from 1 g freshly fallen litter lost 75 mg g(-1) d.w. more than did intact leaves, as a result of enhanced microbial m ... | 1987 | 28312524 |
| leaf growth of betula and acer in simulated shadelight. | leaves of birch (betula pendula roth) and sycamore (acer pseudoplatanus l.) were initiated and grown either in a simulated shadelight (80 μmol m(-2) s(-1), r/fr ratio 0.28)/dark photoenvironment or a white light (250 μmol m(-2) s(-1), r/fr>1)/dark photoenvironment. until the leaves were more than 50% expanded, growth rates (measured every 24 h) were the same for both species in both environments. after this time, growth rate slowed and this correlated well with a decrease in wall extensibility ( ... | 1986 | 28311620 |
| chemical defense in birch: inhibition of digestibility in ruminants by phenolic extracts. | the biological activity of phenolic extracts originating from winter twigs of birch (betula pendula roth.) was measured using the ruminant in vitro method and the nylon bag technique. different extracts were prepared by extraction with organic solvents, removing phenols of corresponding solubility. the extract of birch twigs (diameter <1.5 mm) contained about 19% phenol equivalents, corresponding to 6% of twig dry matter (dm). coarse birch twigs (diameter 1.5-5 mm) contained about 3% in the dm p ... | 1985 | 28310902 |
| seasonal variation of phenols, crude protein and cell wall content of birch (betula pendula roth.) in relation to ruminant in vitro digestibility. | birch twigs of diameter ≦1.5 mm exhibit seasonal trends in ruminant in vitro organic matter digestibility (ivomd), and in the contents of crude protein, cell walls (neutral detergent fibre, ndf), and phenolic compounds. the ivomd is low in winter twigs, increases in spring, and reaches a maximum in early summer. crude protein behaves similarly. on the other hand, the proportion of hydrophilic phenols and cell walls (cellulose, hemicellulose, and lignin) to dry weight decreases dramatically in sp ... | 1985 | 28310434 |
| cytokinins in the spring sap of curly birch (betula pendula f. carelica) and the non-curly form. | the different forms of cytokinins in the spring sap fo curly (f. carelica) and non-curly birch (betula pendula) were determined by two preparation methods, with (1) or without (2) acid hydrolysis, and were fractionated using a column of sephadex lh-20 eluted with 35 % ethanol. the levels of cytokinins in the fractions were estimated with theamaranthus caudatus explant bioassay and the total cytokinin contents were calculated on amino nitrogen, total sugar and sap volume bases. using method 1, th ... | 1985 | 23195929 |
| rapid wound-induced resistance in white birch (betula pubescens) foliage to the geometrid epirrita autumnata: a comparison of trees and moths within and outside the outbreak range of the moth. | two strains of a geometrid defoliator, epirrita autumnata, were used in bioassays to test existence and relative efficacy of rapid, wound-induced foliage resistance in two provenances of the white birch. one birch and one moth strain originated in the outbreak range of the moth and another outside it. both birch provenances responded to manual leaf damage by changes in foliage quality which significantly retarded growth of the insects, reducing their pupal weights and protracting larval periods. ... | 1985 | 28310669 |
| the role of coprophagy in the feeding strategies of terrestrial isopods. | the hypothesis that faeces recycling in isopods evolved as an adaption to facilitate maintenance of an adequate copper balance in terrestrial environments is examined. experimental observations on the consumption, absorption and growth rates of porcellio scaber fed betula pendula leaf litter varying in copper content and extent of microbial decay are reported. preventing the isopods from reingesting their faeces caused a reduction in the growth rates of experimental animals fed their natural low ... | 1982 | 28311744 |
| root growth and water relations of oak and birch seedlings. | first year seedlings of english oak (quercus cobur) and silver birch (betula pendula) were subjected to pressure-volume analysis to investigate the water potential components and cell wall properties of single leaves. it was hoped that this rapid-drying technique would differentiate between reductions in plant solute potential resulting from dehydration and the effects of solute accumulation.comparison of results from these experiments with those of slow drying treatments (over a number of days) ... | 1981 | 28310018 |
| the influence of plant water stress on stomatal control of gas exchange at different levels of atmospheric humidity. | leaves of well-watered and mildly water-stressed seedlings of betula pendula roth. and gmelina aroborea l. were subjected to a range of vapour pressure deficits (vpd) between 10 and 24 kpa. the stomatal conductance of birch seedlings decreased as vpd was increased and at least in mildly-stressed seedlings this response seemed to be closely linked to the water status of the air rather than to the bulk water status of the plant. mild water stressing enhanced the degree of the stomatal humidity-res ... | 1980 | 28310617 |
| the influence of water stress on the photosynthetic performance and stomatal behaviour of tree seedlings subjected to variation in temperature and irradiance. | seedlings of betula pendula roth. and gmelina arborea l. were subjected to variation in temperature and irradiance. the influence of a mild water-stressing treatment on the photosynthetic performance and stomatal behaviour of these plants was assessed. for both species, the shape of the relationships between irradiance and photosynthesis and temperature and photosynthesis resembled those reported for other species. the effect of water stress was to reduce the rate of photosynthesis, particularly ... | 1980 | 28310929 |
| water permeability of betula periderm. | the water permeability of periderm membranes stripped from mature trees of betula pendula roth was investigated. the diffusion of water was studied using the system water/membrane/water, and transpiration was measured using the system water/membrane/water vapor. betula periderm consists of successive periderm layers each made up of about 5 heavily suberized cell layers and a varying number of cell layers that are little suberized, if at all. it is shown that these layers act as resistances in se ... | 1980 | 24311086 |
| the decomposition of branch-wood in the canopy and floor of a mixed deciduous woodland. | the pattern of decomposition of branch-wood greater than 2 cm diameter is described for a one hectare site at meathop wood, cumbria, based on studies carried out as part of the ibp between 1967 and 1972. three phases of decomposition are recognised. following the death of branches in the canopy and their colonisation by fungi, decomposition proceeded at an average annual loss rate of about 8.4%. wood at branch-fall had on average lost about 40% of its original dry weight. on the forest floor the ... | 1976 | 28309258 |
| naturally-occurring growth regulators in leaf washings of picea sitchensis (bong.) carr and betula pendula roth. | leaf washings were collected during and immediately after periods of rainfall ('natural') from picea sitchensis (bong.) carr and betula pendula roth., growing in the field. they contained acidic and non-acidic ethyl acetate-soluble growth regulating factors, including a gibberellin-like compound and an inhibitor resembling abscisic acid (aba). similar ranges of growth regulators were obtained when needles of picea sitchensis were intermittently sprayed with a fine water mist ('artificial') in gl ... | 1974 | 24458991 |