tree host range and world distribution of the extomycorrhizal fungus pisolithus tinctorius.the natural occurrence of pisolithus tinctorius has been confirmed in 33 countries of the world and in 38 states in the united states. this ectomycorrhizal fungus is found associated with various tree species in nurseries, urban areas, orchards, forests, and strip-mined spoils. experiments have proved that this fungal symbiont forms ectomycorrhizae with abies procera, betula pendula, carya illnoensis, 11 species of eucalyptus, 30 species of pinus, pseudotsuga menziesii var. meniziesii, 2 species ...1977856419
sequence of a cdna encoding nitrite reductase from the tree betula pendula and identification of conserved protein regions.the sequence of an mrna encoding nitrite reductase (nir, ec from the tree betula pendula was determined. a cdna library constructed from leaf poly(a)+ mrna was screened with an oligonucleotide probe deduced from nir sequences from spinach and maize. a 2.5 kb cdna was isolated that hybridized to an mrna, the steady-state level of which increased markedly upon induction with nitrate. the nucleotide sequence of the cdna contains a reading frame encoding a protein of 583 amino acids that r ...19921347145
distribution of allergens and allergen-coding mrnas in various tissues of white birch.the distribution of allergenic proteins was investigated in various tissues of white birch, betula verrucosa (pollen, leaves and male inflorescences containing immature pollen). in addition, callus and suspension culture cells were investigated for expression of ige-binding proteins. furthermore, rna was extracted from all these tissues and subjected to in vitro translation in a cell-free wheat germ system. bet v i, the major birch pollen allergen, could be extracted easily from pollen, and in l ...19921406724
[immunological study of the hla class ii antigen associated with birch pollen allergy].pollinosis is known as a hereditary disease. recently, association of hla antigens and pollinosis caused by several pollen allergens has been reported. furthermore, hla antigens are considered to have a very important role in the development of pollinosis. we performed an hla population study and tested the lymphocyte proliferative response (lpr) to birch pollen allergens with birch pollen allergic patients and healthy control subjects. the results of the hla population study indicated that hla- ...19921602355
pcr based cloning and sequencing of isogenes encoding the tree pollen major allergen car b i from carpinus betulus, hornbeam.cloning of the gene encoding the major allergen, car b i, from carpinus betulus (hornbeam) pollen was performed using the polymerase chain reaction (pcr) to specifically amplify the gene of interest using single stranded cdna as template. specific primers, deduced from the aminoterminal sequence of the purified protein, were tailored to facilitate direct expression of plasmic clones, and the large fraction of positive clones obtained, revealed the presence of isogenic variation. three clones wer ...19921603091
sequence of a cdna encoding the bi-specific nad(p)h-nitrate reductase from the tree betula pendula and identification of conserved protein regions.nitrate reductase (nr) assays revealed a bispecific nad(p)h-nr (ec to be the only nitrate-reducing enzyme in leaves of hydroponically grown birches. to obtain the primary structure of the nad(p)h-nr, leaf poly(a)+ mrna was used to construct a cdna library in the lambda gt11 phage. recombinant clones were screened with heterologous gene probes encoding nadh-nr from tobacco and squash. a 3.0 kb cdna was isolated which hybridized to a 3.2 kb mrna whose level was significantly higher in pl ...19911675424
identification of profilin as a novel pollen allergen; ige autoreactivity in sensitized individuals.a complementary dna encoding a pollen allergen from white birch (betula verrucosa) that was isolated from a pollen complementary dna library with serum immunoglobulin e from a birch pollen-allergic individual revealed significant sequence homology to profilins. the recombinant protein showed high affinity to poly-l-proline. immunoglobulin e antibodies from allergic individuals bound to natural and recombinant birch profilin and also to human profilin. in addition, birch and human profilin induce ...19911857985
a low molecular weight allergen of white birch (betula verrucosa) is highly homologous to human profilin.cloning of allergens has contributed substantially to the understanding of mechanisms in allergic diseases by providing information about the sequence and hence biological functions of allergens. the major birch pollen allergen, bet v i [breiteneder h, et al: embo j 1989;8:1935-1938] and the white-faced hornet venom allergen (antigen 5) [si yun fang k, et al: proc. natl. acad. sc. usa 1988;85:895-899] were shown to be highly homologous to pathogenesis-related proteins of plants. in the case of t ...19911937902
the gene coding for the major birch pollen allergen betv1, is highly homologous to a pea disease resistance response gene.pollen of the white birch (betula verrucosa) is one of the main causes of type i allergic reactions (allergic rhinoconjunctivitis, allergic bronchial asthma) in middle and northern europe, north america and the ussr. type i allergies are a major threat to public health in these countries, since 10-15% of the population suffer from these diseases. betvi, an allergenic protein with an mr of 17 kd is a constituent of the pollen of white birch and is responsible for ige binding in more than 95% of b ...19892571499
[a new rapid test for the detection of ige antibodies in inhalation allergies].we compared the results of the skin-prick-test, phadezym-rast and ige-quick, developed by quidel, obtained from 75 patients suffering from an inhalant allergy and 25 controls. the ige-quick is a qualitative eia dipstick test designed for the rapid visual detection of allergen-specific ige. the ige-quick contained nine test pads coated with one of the following purified allergens: betula pendula, phleum pratense, secale cereale, artemisia vulgare, felis domestica, canis familiare, d. pteronyssinu ...19892742661
isolation and characterization of messenger rna from male inflorescences and pollen of the white birch (betula verrucosa).a glycoprotein with a molecular weight (mw) of 17 kilodaltons (kd), bet v i, represents the major allergen of the white birch (betula verrucosa, bv) and plays an important role in tree-pollen-induced type i allergic reactions. in order to characterize the major and also some minor allergens of bv, we investigated the ige-binding properties of these allergens using immunoblot techniques. normal and patients' sera were employed for this study. furthermore, rna from male inflorescences and from pol ...19883170006
visualization of birch pollen allergens using ige-containing sera from human atopic individuals in immunogold labelling experiments.pollen from birch trees (betula pendula) was fixed in paraformaldehyde with or without the addition of 0.5% cetylpyridinium chloride, dehydrated and embedded in lowicryl k4m in the cold. ultrathin sections were incubated using the following sequence of antibodies and antisera: ige-containing serum from an atopic human individual allergic to birch pollen allergens, rabbit anti-human ige antibodies, and colloidal gold-labelled goat anti-rabbit antibodies. controls were performed by replacing the s ...19863486858
[hemostatic system function as affected by thromboplastic agents from higher plants].it has been determined that the thromboplastic agents from the inflorescence of the birch betula pendula roth, blossoms of the willow salix daphnoides vill., seeds of the pea pisum sativum l. provoke protective reaction of the animal's anticoagulation system, though weaker expressed than the reaction of thromboplastin from brain. the mechanisms of action of thromboplastic agents of plant origin is similar to the mechanism of action of tissue thromboplastin.19863708030
[cherry leaf-roll virus from birch (betula pendula roth)]. 19725068493
[triterpenes of betula pendula roth and betula pubescens ehrh. comparative study of the bark]. 19665220364
[cytokinins of parasitic origin. i. cytokinin activity in leaves of betula pendula roth caused by an infecion by stigmella argentipedella zeller (lep.)]. 19705537265
electron microscopic localization of concanavalin a receptor sites in pollen surface material after fixation with glutaraldehyde-cetylpyridinium chloride.pollen from birch trees (betula pendula) was fixed in glutaraldehyde containing 0.5% cetylpyridinium chloride (cpc), incubated with concanavalin a (con a)-ferritin, postfixed in osmium, dehydrated, and embedded in epon. on ultrathin sections, ferritin particles were observed closely associated with the electron-dense material precipitated by cpc on the surface of the pollen grains. controls for cpc, which were fixed in glutaraldehyde alone, showed no electron-dense material on the surface. in co ...19846430993
immunoelectron-microscopic localization of diffusible birch-pollen antigens in ultrathin sections using the protein-a/gold technique.pollen grains from betula pendula were fixed in a mixture of p-formaldehyde and cetylpyridinium chloride (cpc) for the precipitation of soluble pollen glycoproteins. after dehydration and embedding at low temperatures in the water-soluble resin, lowicryl k4m, ultrathin sections of the pollen grains were incubated using specific antibodies against birch-pollen extract and protein-a/gold complexes. antigen activity was found in the cpc-precipitated surface material and within the exine (bacular ca ...19846520024
differentiation--a consequence of idiotype-environment interaction.the present paper deals with a model of idiotype-environment interaction and its application to a tissue culture experiment with birch (betula pendula roth.). the data of the experiment are characterized with respect to the physiological reactions and are discussed in the light of the model. the main results of the paper are: with respect to the environmental action one has to discriminate between the environment inside and outside the cell (external and internal environment). the environmental ...19846743790
discovery of betulinic acid as a selective inhibitor of human melanoma that functions by induction of a result of bioassay-guided fractionation, betulinic acid, a pentacyclic triterpene, was identified as a melanoma-specific cytotoxic agent. in follow-up studies conducted with athymic mice carrying human melanomas, tumour growth was completely inhibited without toxicity. as judged by a variety of cellular responses, antitumour activity was mediated by the induction of apoptosis. betulinic acid is inexpensive and available in abundant supply from common natural sources, notably the bark of whi ...19957489361
[molecular and functional characterization of allergens: fundamental and practical aspects].well-defined allergens are a prerequisite for the exact diagnosis and immunotherapy of type i (ige-mediated) allergic diseases. the allergens have to be available in highly purified form and in sufficient quantities. by applying molecular cloning methods this goal can be achieved with respect to both characterization and reproducibility of allergen preparations. moreover, this technique leads to the deduction of primary structures of allergens, which allows computer-aided comparisons with alread ...19937507286
heterogeneity of pollen proteins within individual betula pendula determine the variation of antigenic water soluble proteins in white birch (betula pendula) pollen, extracts of pollen from different sides of individual trees were analyzed by isoelectric focusing (ief), crossed immunoelectrophoresis, and crossed radioimmunoelectrophoresis. ige-antibody-binding patterns were also studied in samples analyzed by ief by probing with serum pooled from patients with birch pollen allergy, followed by radiolabelled anti-ige. antigenic proteins and allergens per uni ...19957580310
the choice of reducing substrate is altered by replacement of an alanine by a proline in the fad domain of a bispecific nad(p)h-nitrate reductase from birch.differences in the amino acid sequence between the bispecific nad(p)h-nitrate reductase of birch (betula pendula roth) and the monospecific nadh-nitrate reductases of a variety of other higher plants have been found at the dinucleotide-binding site in the fad domain. to pinpoint amino acid residues that determine the choice of reducing substrate, we introduced mutations into the cdna coding for birch nitrate reductase. these mutations were aimed at replacing certain amino acids of the nad(p)h-bi ...19957784504
association between hla-drb3*0101 and immunoglobulin-e responsiveness to bet v i.the relationship between hla-drb3 antigens and specific ige responsiveness to highly purified major allergen from white birch (betula verrucosa), bet v i, was studied in 43 patients, who were skin-prick test positive to birch pollen extract. specific ige to bet v i was measured using an assay based on the principle of the magic lite method. hla-dr and -dq typings were performed by standard restriction fragment-length polymorphism techniques and hla-drb3 typing by the use of polymerase chain reac ...19947910161
characterization of a birch (betula pendula roth.) embryogenic gene, bp8.we have isolated the birch homologue (bp8) for the carrot embryogenic gene dc8 by heterologous hybridization. the birch bp8 gene encodes a putative protein of 53 kda, showing 52% sequence identity with the dc8 gene at the amino acid level. the putative bp8 protein contains 20 repeats of 11 amino acids and thus belongs to the group of lea proteins isolated from such plants as carrot, cotton and wheat. northern hybridization of mrna isolated from birch cells representing different stages of somati ...19938219076
characterization of recombinant bet vi, the major pollen allergen of betula verrucosa (white birch), produced by fed-batch fermentation.the gene encoding the major allergen, bet v i, from betula verrucosa (white birch) pollen was cloned by application of the polymerase chain reaction with double-stranded cdna as template and specific primers based on the published nucleotide sequence of the gene. the gene was inserted into plasmid pkk223-3 and expressed in escherichia coli k-12 strain jm105 grown to high cell density in a fermenter using a fed-batch procedure. ample material was provided for a thorough characterization of the ep ...19938219778
saponins in the leaves of birch? hemolytic dammarane triterpenoid esters of betula pendula.three hemolytic dammarane triterpenes, esterified with malonate at c-3 and acetate at c-12, were isolated from the leaves of betula pendula. their structures were elucidated by chemical and spectroscopic means. former reports on the presence of saponins in birch leaf extracts could not be confirmed. the hemolytic activity of the extracts, which was ascribed to saponins, is caused by the dammarane esters instead. a fraction containing a mixture of the dammarane esters did not exhibit diuretic act ...19938441786
preseasonal intranasal immunotherapy in birch-alder allergic rhinitis. a double-blind study.a double-blind, placebo-controlled study was carried out to test the clinical efficacy and safety of local nasal immunotherapy (lnit) in powder form. twenty-two patients suffering from allergic rhinitis strictly associated with early spring symptoms, with positive skin prick tests and rast for birch-alder, all responders to a specific nasal provocation test (npt), received randomly active or placebo treatment for 4 months. immunotherapy consisted of administration of a set of capsules containing ...19968836333
characterization of purified recombinant bet v 1 with authentic n-terminus, cloned in fusion with maltose-binding protein.a gene encoding the pollen major allergen bet v 1 from betula verrucosa (white birch) has been cloned and expressed in escherichia coli as a fusion with maltose-binding protein and a factor xa proteolytic cleavage site. a generally applicable cloning strategy based on polymerase chain reaction was designed to position the factor xa proteolytic site so that the authentic amino terminus of bet v 1 was generated after cleavage. fusion protein was isolated by amylose affinity chromatography and enzy ...19968936599
crystallization and preliminary x-ray investigation at 2.0 a resolution of bet v 1, a birch pollen protein causing ige-mediated allergy.the 17 kda protein from betula verrucosa (white birch) pollen, bet v 1, is the clinically most important birch pollen allergen causing immediate type i ige-mediated allergy. the three-dimensional structure of bet v 1 and its ige-binding epitopes are at present not known. in addition, the biological function of bet v 1 in birch pollen is not fully established. in this work, bet v 1 has been expressed in escherichia coli as a recombinant protein, purified and crystallized. the space group of recom ...19968953655
[standardization of the birch leaf].dried leaves of betula pendula roth (14 batches) and b. pubescens ehrh. (3 batches) present a similar flavonoid pattern. the mean levels of the principal flavonoid compounds were respectively: total flavonoids 3.29 and 2.77%, hyperoside 0.80 and 0.77%, avicularin (two forms) 0.57 and 0.26%, galactosyl-3 myricetol 0.37 and 0.18%, glucuronyl-3 quercetol 0.25 and 0.36%, quercitrin 0.14 and 0.12%. the flavonoid levels were higher in young leaves and lower in old leaves of b. pendula. 14 batches of c ...19968953799
isolation and characterization of cdna for a plant mitochondrial phosphate translocator (mpt1): ozone stress induces mpt1 mrna accumulation in birch (betula pendula roth).we have isolated by ddrt-pcr (differential-display reverse-transcription polymerase chain reaction) and cdna library screening a 1.3 kb cdna corresponding to a strongly ozone-inducible transcript from birch (betula pendula roth). nucleotide sequence analysis suggests that it encodes a mitochondrial phosphate translocator protein (pic), the first one isolated from plants. the isolated birch mitochondrial phosphate translocator cdna (designated mpt1) contains an open reading frame of 1092 bases en ...19979349251
effects of air pollution and other environmental factors on birch pollen determine the effects of anthropogenic pollution on water-soluble proteins and specifically allergens in birch (betula pendula and b. pubescens) pollen, we analyzed extracts of pollen from the pollution gradient around a factory complex (emitting sulfur oxides and heavy metals) by sodium dodecyl sulfate (sds)--polyacrylamide gel electrophoresis (page) and ige immunoblotting. in addition, tree density-associated shading of the tree habitat, and quantity and quality of proteins and allergens in ...19979450140
effect of abscisic acid, cold hardening, and photoperiod on recovery of cryopreserved in vitro shoot tips of silver birchrecovery of cryopreserved in vitro shoot tips of silver birch (betula pendula roth) was doubled by incorporating abscisic acid (aba) in the culture medium during cold hardening of the mother shoots. the average recovery of shoot tips was over 40% after cold hardening for 28 days at +5 degreesc under an 8/16 light/dark photoperiod on medium containing 10(-4) m aba. aba was effective in combination with low temperature and short daylength only, although large genotypical differences were noted. ab ...19989500934
visualization and quantification of birch-pollen allergens directly on air-sampling filters.a new technique is presented to detect and quantify birch (betula pendula)-pollen allergens directly on air-sampling filters. it is based on the use of specific antibodies, enzymatic reactions, and measurement by chemiluminescence or densitometry. the major pollen antigens are the most important birch allergens. the antibodies used recognize birch-pollen antigens which thus correspond to allergens. calibration was done with a standardized extract of birch pollen for skin prick testing. the corre ...19989689341
the griess assay: suitable for a bio-guided fractionation of anti-inflammatory plant extracts?in the field of inflammation research the inducible nitric oxide synthase (inos) became an important pharmacological target, since overproduction of nitric oxide (no) after induction of this enzyme seems to be associated with numerous pathological conditions. no released from cells can be detected and quantified photometrically as its stable product nitrite by a simple colorimetric reaction (griess reaction). the aim of our study was to investigate whether this method might be suitable for the b ...19989690344
[dispersal of pollen and the variation in number of patients prescribed medicine for allergies in otaru].the number of patients prescribed medicine for allergies increased in may and september. therefore, we suspected that the cause for the increase was pollen. many kinds of pollen occur in otaru, such as alder in april, japanese black pine, white birch, acacia, larch in may, oak in june, and mugwort in september. the total number of pollen count of white birch was about 9 times that of mugwort, but the total number of patients prescribed celestamine in the season of white birch pollen was about 0. ...199910198596
quantification of birch and grass pollen allergens in indoor air.birch and grass pollen grains as well as pollen-derived small particles appear as potent allergens in the outdoor air during spring and summer. the occurrence of pollen allergens in indoor air, however, has not been studied in depth due to lack of suitable sampling and analytical methods. herein, a recently reported "direct on sampling filter estimation" (dosafe) technique (acevedo et al., 1998) has been validated for quantification of pollen allergens in indoor air using two school rooms and tw ...199910390933
[a relationship between birch pollen and meteorological factors during the past four years and pollen survey in sapporo in 1997].it is well known that grass pollinosis has been the most representative pollinosis in hokkaido prefecture, japan, however, it is also well known that birch (japanese white birch, betula platyphylla var. japonica) pollinosis is gradually increasing, which is marked especially in sapporo and its neighborhood. we analyzed a relationship between the birch pollen count and meteorological factors statistically. moreover, the principal airborne pollen counts in sapporo in 1997 were assessed and compare ...199910481357
host-driven population dynamics in an herbivorous insect.understanding the nature and relative importance of endogenous (density-dependent) and exogenous (density-independent) effects on population dynamics remains a central problem in ecology. evaluation of these forces has been constrained by the lack of long time series of population densities and largely limited to populations chosen for their unique dynamics (e.g., outbreak insects). especially in herbivore populations, the relative contributions of bottom-up and top-down effects (resources and n ...199910485895
microbial activities related to c and n cycling and microbial community structure in the rhizospheres of pinus sylvestris, picea abies and betula pendula seedlings in an organic and mineral soil.the aim of this study was to determine whether scots pine (pinus sylvestris l.), norway spruce (picea abies (l.) karst.) and silver birch (betula pendula roth) seedlings have a selective influence on the soil microbial community structure and activity and whether this varies in different soils. seedlings of pine, spruce and birch were planted into pots of two soil types: an organic soil and a mineral soil. pots without seedlings were also included. after one growing season, microbial biomass c ( ...199910508943
new bet v 1 isoforms including a naturally occurring truncated form of the protein derived from austrian birch v 1, the major pollen allergen from white birch, displays a considerable degree of heterogeneity. until now, all molecular and immunological characterization studies of bet v 1 isoforms have been performed with commercially available pollen of swedish origin. in regard to clinical studies with austrian birch pollen allergic individuals, knowledge about the isoform repertoire in austrian birch pollen was necessary. cdnas coding for bet v 1 isoforms from austrian birch pollen were cloned by pc ...199910509815
[the mechanisms of the anti-ulcer action of plant drug agents].the mechanisms of the gastroprotective effect of well-known drugs (plantaglucid, befungin, plantain juice), extractions of birch bark (betula pendula roth,) and burdock seeds (arctium tomentosum mill.) on various links of gastric ulcer pathogenesis were compared. phytopreparations were found to have a variety of effects on gastric secretion in rats. differences in their action on the smooth muscles of the stomach and intestine were detected.199910513334
ammonium and methylamine transport by the ectomycorrhizal fungus paxillus involutus and ectomycorrhizas.using [(14)c]methylamine as an analogue of ammonium, the kinetics and the energetics of nh(4)(+) transport were studied in the ectomycorrhizal fungus, paxillus involutus (batsch) fr. the apparent half-saturation constant (k(m)) and the maximum uptake rate (v(max)) for the carrier-mediated transport derived from the eadie-hofstee transformation were 180 µm and 380 nmol (mg dry wt)(-1) min(-1,) respectively. both ph dependence and inhibition by protonophores indicate that methylamine transport in ...199910568844
short communication: subcellular localization of ozone-induced hydrogen peroxide production in birch (betula pendula) leaf cells.the atmospheric air pollutant ozone (o3) is one of the environmental stresses that induce formation of reactive oxygen species (ros) in plants. previously, the toxicity of o3 has been believed to be a result of ros formation from o3-degradation. recently, however, it has been shown that o3 induces active ros production, which suggests that o3-responses may be mechanistically similar to pathogen-induced responses and that o3-damage could be a result of deleterious firing by the ros of pathways no ...199910571895
humus bacteria of norway spruce stands: plant growth promoting properties and birch, red fescue and alder colonizing capacity.we studied the potential of the humus layer of the norway spruce stands to supply beneficial rhizobacteria to birch (betula pendula), alder (alnus incana) and fescue grass (festuca rubra), representatives of pioneer vegetation after clear-cutting of the coniferous forest. axenically grown seedlings of these species were inoculated with the acid spruce humus, ph 3.7-5.3. actinorhizal propagules, capable of nodulating alder, were present in high density (10(3) g(-1)) in humus of long-term limed pl ...200010640667
effects of resource availability on carbon allocation and developmental instability in cloned birch seedlings.abundant nitrogen improves seedling growth and establishment. vigorous growth brings about changes in rates and patterns of plant development and changes in the relationship between primary and secondary metabolism, which may make seedlings more susceptible to herbivores and pathogens than are slow-growing seedlings. we studied how nitrogen fertilization and manual defoliation of source leaves affect growth, carbon allocation, and developmental instability in cloned seedlings of white birch (bet ...200010648201
substrate preference profiles of proteases released by allergenic pollens.pollens are important triggers for allergic asthma and seasonal rhinitis. we have recently reported that proteases released by major allergenic pollens can injure airway epithelial cells in vitro. disruption of epithelial integrity by proteases released following deposition of pollens on mucosal surfaces could promote sensitization and induce inflammation.200010718856
[cytogenetic characteristics of seed progeny of trees under condition of antropogenic contamination in voronezh town].it has been shown that in seed progeny of quercus robur l., pinus sylvestris l. and betula pendula roth. some cytogenetical characteristics vary under conditions of contamination. such changes may be common or specific type. thus, the frequency of pathological mitosis increases under such conditions in all the investigated species of trees. inhibition of mitosis was found in the progeny of the pine, and variability in the number of nucleoli was detected in the pine and oak. however, in some case ...200010752126
chemometrics: an important tool for the modern chemist, an example from wood-processing chemistrythis study briefly outlines the idea of principal component analysis and cross-correlation calculations (applied chemometrics) and presents an illustrative example from wood-processing chemistry. the applicability of chemometric data analysis was demonstrated by investigating the various structural changes that take place in dissolved and degraded lignin ("kraft lignin") during laboratory-scale kraft pulping of scots pine (pinus sylvestris) and silver birch (betula pendula). the structural data ...200010761150
functional analysis of a nitrite reductase promoter from birch in transgenic tobacco.nitrate assimilation is a highly regulated process in higher plants, and the regulatory cues governing gene expression in this pathway include both external and internal factors. in birch (betula pendula roth) the expression of nitrate reductase (nr) and nitrite reductase (nir) genes is co-regulated by light and nitrate at the transcriptional level. in order to identify cis-acting dna-elements involved in light and nitrate induction of the birch nir gene, a 0.9 kb 5' flanking region of the nir g ...200010814817
antimicrobial effects of finnish plant extracts containing flavonoids and other phenolic compounds.plant phenolics, especially dietary flavonoids, are currently of growing interest owing to their supposed functional properties in promoting human health. antimicrobial screening of 13 phenolic substances and 29 extracts prepared from finnish plant materials against selected microbes was conducted in this study. the tests were carried out using diffusion methods with four to nine microbial species (aspergillus niger, bacillus subtilis, candida albicans, escherichia coli, micrococcus luteus, pseu ...200010857921
effects of aluminium on the growth and mineral composition of betula pendula roth.aluminium (al) is rhizotoxic and is often present in acidic soils at activities high enough to inhibit root elongation. the objectives of the present study were to assess the level of al tolerance in different races of betula pendula roth (silver birch) and to investigate how growth and nutrient acquisition were affected by al. a solution culture technique was employed which simulated natural soil solutions. aluminium at low concentrations (2 and 5 mg l(-1)), enhanced the growth of two races of ...200010948233
strategies of a bark beetle, pityogenes bidentatus, in an olfactory landscape.volatiles from leaves or bark of nonhost birch (betula pendula) and norway spruce (picea abies) dramatically reduced the attraction of the bark beetle, pityogenes bidentatus (coleoptera: scolytidae), to their aggregation pheromone components (cis-verbenol and grandisol) in the field. in addition, odors from both the needles and bark of the host scots pine (pinus sylvestris) similarly inhibited attraction. monoterpenes of pine and spruce (alpha-pinene, beta-pinene, terpinolene, and 3-carene) as w ...200011151671
[radionuclide accumulation in fruit bodies of macromycetes].coefficients of 137cs accumulation and 90sr were determined in macromycetes of different trophic groups (137cs in 43 species and 90sr in 19 species) in the conditions of droughty year (1992). their variability in forest formations was determined in the period from 1992 to 1998. in the year with increased atmospheric humidity (1998), two-fold rise of 137cs accumulation in fruit bodies was registered on average. the pollution of boletus edulis correlates with photosynthetically active part of betu ...200011155341
clonal differences in copper and zinc tolerance of birch in metal-supplemented soils.metal tolerance of a range of birch clones (betula pendula and betula pubescens) originating from metal-contaminated sites in england, wales, belgium and finland were tested in soils supplemented with several concentrations of copper (cu) or zinc (zn) (500, 2000, 5000 mg kg-1 dry wt. soil of cuso(4).5h2o or znso(4).7h2o) for 4 months and with sub-toxic metal supplements (500 mg cuso4, 2000 mg znso4) for 6 months. when grown at high concentrations of metals, severe toxicity symptoms (growth inhib ...200111202657
manganese toxicity as indicated by visible foliar symptoms of japanese white birch (betula platyphylla var. japonica).for the purpose of a field diagnosis of mn toxicity, we showed the possibility of using visible foliar symptoms of japanese white birch (betula platyphylla var. japonica hara) as indicator. to examine the relationship between the expression of visible symptoms and leaf mn concentrations, white birch seedlings were grown under four different mn levels: 1 mg mn l-1 as control, 10, 50 and 100 mg mn l-1. foliar symptoms of mn toxicity for white birch were: (1) chlorosis at entire young leaves in the ...200111202719
ozone exposure thresholds and foliar injury on forest plants in switzerland.canton ticino in southern switzerland is exposed to some of the highest concentrations of tropospheric ozone in europe. during recent field surveys in canton ticino, foliar symptoms identical to those caused by ozone have been documented on native tree and shrub species. in europe, the critical ozone level for forest trees has been defined at an aot40 of 10 ppm.h o3 (10 ppm.h accumulated exposure of ozone over a threshold of 40 ppb) during daylight hours over a six-month growing season. the obje ...200111202736
temperature response of leaf photosynthetic capacity in seedlings from seven temperate tree species.seedlings of seven temperate tree species (acer pseudoplatanus l., betula pendula roth, fagus sylvatica l., fraxinus excelsior l., juglans regia l., quercus petraea matt. liebl. and quercus robur l.) were grown in a nursery under neutral filters transmitting 45% of incident global irradiance. during the second or third year of growth, leaf photosynthetic capacity (i.e., maximal carboxylation rate, vcmax, maximal photosynthetic electron transport rate, jmax, and dark respiration, rd) was estimate ...200111276416
testing a process-based model of tree seedling growth by manipulating.a model was developed that simulated photosynthesis, growth and allocation in tree seedlings. the model was parameterized with data from experiments on seedlings of sycamore (acer pseudoplatanus l.), sitka spruce (picea sitchensis (bong) carr.) and young birch trees (betula pendula roth.). in these experiments, co2 concentration ([co2]) and nutrient addition rate were varied. parameters quantifying nutrient uptake, translocation and starch synthesis were fitted, based on data from control treatm ...200011305461
three mads-box genes similar to apetala1 and fruitfull from silver birch (betula pendula).despite intensive research on genetic regulation of flower development there are still only a few studies on the early phases of this process in perennial plants like trees. the aim of this study has been to identify genes that regulate early stages of inflorescence development in silver birch (betula pendula roth) and to follow the expression of these genes during development of the unisexual birch inflorescences. here we describe the cloning and characterization of 3 cdnas representing mads-bo ...200111319020
seasonal variation in the content of hydrolysable tannins in leaves of betula pubescens.the contents of 13 hydrolysable tannins in the leaves of white birch (betula pubescens l.) trees were analysed at twelve stages throughout the growing season. all individual galloylglucoses, from 1-o-galloyl-beta-d-glucopyranose to 1,2,3,4,6-penta-o-galloyl-beta-d-glucopyranose, accumulated in young leaves, while ellagitannins showed significantly variable seasonal trends. the major ellagitannin during the whole growing season was pedunculagin while 2,3-(s)-hhdp-glucopyranose. the end product of ...200111336256
do pollen donors with fastest-growing pollen tubes sire the best offspring in an anemophilous tree, betula pendula (betulaceae)?the relationship between pollen and progeny performance has been a subject of many studies but the evidence for pollen-tube growth rate as an indicator of progeny fitness is equivocal. we used an anemophilous tree, betula pendula, to examine the relationship between pollen-tube growth rate and seed and seedling performance. we crossed nine maternal plants with pollen from six pollen donors in a clonal b. pendula seed orchard, measured the pollen-tube growth rates for every cross, and analyzed th ...200111353710
variation of gas exchange within native plant species of switzerland and relationships with ozone injury: an open-top experiment.gas exchange and ozone-induced foliar injury were intensively measured during a 6-day period in mid-august 1998 on leaves of acer pseudoplatanus, betula pendula, corylus avellana, fagus sylvatica, fraxinus excelsior, morus nigra, prunus avium, prunus serotina, rhamnus cathartica, and viburnum lantana at a forest nursery site in canton ticino, switzerland. plants were grown in four open plots (aa), four open-top chambers receiving carbon-filtered (cf) air, and four receiving non-filtered (nf) air ...200111383335
why plants grow poorly on very acid soils: are ecologists missing the obvious?factors associated with soil acidity are considered to be limiting for plants in many parts of the world. this work was undertaken to investigate the role of the toxicity of hydrogen (h(+)) which seems to have been underconsidered by ecologists as an explanation of the reduced plant growth observed in very acid soils. racial differences are reported in plant growth response to increasing acidity in the grass holcus lanatus l. (yorkshire-fog) and the tree betula pendula roth (silver birch). soils ...200111413215
exploitation of pollen by mycorrhizal mycelial systems with special reference to nutrient recycling in boreal forests.very large quantities of pollen are released annually by wind-pollinated trees, which dominate northern forest ecosystems. since pollen is enriched in both nitrogen and phosphorus, this recurrent pulse of deposition constitutes a significant potential source of these elements in what are known to be severely nutrient-limited systems. here, we demonstrate for the first time, to our knowledge, that an ectomycorrhizal fungus, paxillus involutus, is able to scavenge effectively for nitrogen and phos ...200111429131
[the pollen survey and dynamic statistics of patients with allergic rhinitis in hakodate].we have investigated the pollen survey (1994-1998) and dynamic statistics of patients with allergic rhinitis (1999-2000) in hakodate, which is located southern part of hokkaido. we have noted the pollen dispersion of cryptomeria japonica, cupressaceae, white birch, gramineae and artemisia. especially, a lot of dispersion of cryptomeria japonica has been noted in april. concerning the dynamic statistics of patients with allergic rhinitis, we have investigated the 192 patients with allergic rhinit ...200111436334
free radical scavenging activities measured by electron spin resonance spectroscopy and b16 cell antiproliferative behaviors of seven an effort to discover new antioxidant natural compounds, seven plants that grow in france (most of them in the limousin countryside) were screened. among these plants, was the extensively studied vitis vinifera as reference. for each plant, sequential percolation was realized with five solvents of increasing polarities (hexane, chloroform, ethyl acetate, methanol, and water). free radical scavenging activities were examined in different systems using electron spin resonance (esr) spectroscopy ...200111453770
effects of long-term open-field ozone exposure on leaf phenolics of european silver birch (betula pendula roth).the response of phenolic compounds as a result of long-term low open-field ozone exposure was studied in ozone-sensitive and ozone-tolerant clones of european silver birch (betula pendula roth). the saplings were exposed to 1.5-1.6 times the ambient (elevated) ozone and ambient air (as control) over three growing seasons from may 1996 until august 1998. quantification by modified folin-ciocalteau assay showed a 16.2% increase in total phenolics in elevated ozone plants as compared to that in con ...200111471939
phosphoenolpyruvate carboxylase in mistletoe leaves: regulation of gene expression, protein content, and covalent modification.seasonal changes in the activity of phosphoenolpyruvate carboxylase (pepcase, ec, a key enzyme in the interaction of carbohydrate and nitrogen metabolism, were studied in leaves of the c3 semiparasitic mistletoe, viscum album, growing on different host trees. maximum extractable pepcase activities were higher in leaves of mistletoes growing on betula pendula and alnus glutinosa hosts compared with those on the conifers, abies alba and larix decidua. independent of host, maximum extract ...200111473691
identification of processes governing long-term accumulation of 137cs by forest trees following the chernobyl accident.the regularities of 137cs distribution in trees (pinus sylvestris and betula pendula) growing in different types of forest ecosystems were investigated. high levels of heterogeneity of 137cs activity concentrations in different parts of the trees, resulting from their varied metabolism have been shown. the data obtained demonstrate a non-uniform character of 137cs distribution along the trunks, which can be explained by radionuclide fixation by the xylem vessel walls and by geometry changes alon ...200111484781
phenolics in selected european hardwood species by liquid chromatography-electrospray ionisation mass spectrometry.the phenols in beech (fagus sylvatica), birch (betula pendula) and ash (fraxinus excelsior) wood dusts were compared using a mass spectrometer fitted with an electrospray ionisation interface with liquid chromatographic separation. hardwood dust is a carcinogen, and an analysis of the polyphenol profile is a useful method for identifying the dust source in workplace air. the mass spectrometer was operated in both the negative and positive ion modes. phenolic compounds were identified by comparin ...200111592645
a natural experiment on plant acclimation: lifetime stomatal frequency response of an individual tree to annual atmospheric co2 increase.carbon dioxide (co2) has been increasing in atmospheric concentration since the industrial revolution. a decreasing number of stomata on leaves of land plants still provides the only morphological evidence that this man-made increase has already affected the biosphere. the current rate of co2 responsiveness in individual long-lived species cannot be accurately determined from field studies or by controlled-environment experiments. however, the required long-term data sets can be obtained from co ...199611607712
uv-b absorbance and uv-b absorbing compounds (para-coumaric acid) in pollen and sporopollenin: the perspective to track historic uv-b levels.uv-b absorbance and uv-b absorbing compounds (uacs) of the pollen of vicia faba, betula pendula, helleborus foetidus and pinus sylvestris were studied. sequential extraction demonstrated considerable uv-b absorbance both in the soluble (acid methanol) and insoluble sporopollenin (acetolysis resistant residue) fractions of uacs, while the wall-bound fraction of uacs was small. the uv-b absorbance of the soluble and sporopollenin fraction of pollen of vicia faba plants exposed to enhanced uv-b (10 ...200111693361
nitrate reductase activity in some subarctic species and uv influence in the foliage of betula pendula roth. seedlings.nitrate reductase (nr) activity was studied in the foliage of five subarctic species: mature trees of european white birch (betula pubescens erch. s.s.), scots pine (pinus sylvestris l.), norway spruce (picea abies l. karst), ericaceous shrub bilberry (vaccinium myrtillus l.), naturally growing in a forest, and seed-grown silver birch (betula pendula roth.) seedlings in an ultraviolet (uv) exclusion field experiment at the pallas-ounastunturi national park in finnish lapland (68 degrees n). mean ...200211846159
microbial transformations of two lupane-type triterpenes and anti-tumor-promoting effects of the transformation products.microbial transformation of betulin (1), a lupane-type triterpene obtained from the bark extract of white birch (betula platyphylla sukatshev var. japonica), and its chemical oxidation product, betulonic acid (2), by the fungus chaetomium longirostre yielded 4,28-dihydroxy-3,4-seco-lup-20(29)-en-3-oic acid (3) and 4-hydroxy-3,4-seco-lup-20(29)-ene-3,28-dioic acid (4) from 1, and 4,7beta,17-trihydroxy-3,4-seco-28-norlup-20(29)-en-3-oic acid (5) and 7 beta,15 alpha-dihydoxy-3-oxolup-20(29)-en-28-o ...200211908965
the impact of wood ice cream sticks' origin on the aroma of exposed ice cream mixes.the effect of volatile compounds in white birch sticks obtained from four different geographical locations on the aroma of ice cream mix was investigated. sensory evaluation, (specifically, a series of warmed-up paired comparisons) was conducted on stick-exposed ice cream mixes to determine whether aroma differences in those mixes could be detected. batches of ice cream mix were exposed to the sticks and aged for 6 d at 4 degrees c and then assessed by the panelists by pairwise comparison. findi ...200211913694
the major birch allergen, bet v 1, shows affinity for a broad spectrum of physiological v 1 is a 17-kda protein abundantly present in the pollen of the white birch tree and is the primary cause of birch pollen allergy in humans. its three-dimensional structure is remarkable in that a solvent-accessible cavity traverses the core of the molecule. the biological function of bet v 1 is unknown, although it is homologous to a family of pathogenesis-related proteins in plants. in this study we first show that bet v 1 in the native state is able to bind the fluorescent probe 8-anilino ...200211953433
foliar phenolic composition of european white birch during bud unfolding and leaf development.we studied the between-tree and within-tree variation in the composition and content of foliar low-molecular-weight phenolics (lmwp) of european white birch (betula pendula roth) during the unfolding of vegetative buds and during early leaf development. in buds, the major groups of phenolic compounds were hydrolysable tannins and flavonoid aglycones, whereas, later during leaf development, the flavonoid glycosides accounted for most of the total lmwp. the content of total lmwp, as well as indivi ...200212060268
the inhibition of ammonium uptake in excised birch (betula pendula) roots by northern sweden, plants growing in association with the clonal dwarf shrub empetrum hermaphroditum usually exhibit limited growth and are n-depleted. previous studies suggest that this negative effect by e. hermaphroditum may be explained, at least in part, by the release of phenolic compounds, particularly the dihydrostilbene, batatasin-iii from foliage to soil. in the present work, we investigated whether batatasin-iii has the potential to interfere with nh4+ uptake in birch (betula pendula ...200112060282
ascorbate transport from the apoplast to the symplast in intact leaves.infiltration of reduced ascorbate (asc) into the leaves of betula pendula roth and subsequent measurement of its loss therein after incubation allowed us to follow ascorbate transport from apoplast to symplast in intact leaves. all of the ascorbate extracted from the native apoplast was in fully oxidized form, dehydroascorbate (dha). when 5 mm of asc was infiltrated into the leaves, its intense decay occurred, but only 55% of asc lost was recovered in apoplast as dha. when asc was added to the f ...200112060283
distribution of hydrolysable tannins in the foliage of finnish birch species.on the basis of qualitative and quantitative analysis with liquid chromatography--electrospray ionisation mass spectrometry, the foliage of dwarf birch (betula nana l.), silver birch (b. pendula roth) and mountain birch (b. pubescens ssp. czerepanovii (orlova) hämet-ahti) were found, for the first time, to contain the same individual hts that were described earlier for white birch (b. pubescens ehrh.). in addition, one previously unidentified ellagitannin was preliminarily identified from the le ...200212064722
mercury levels in lichens from different host trees around a chlor-alkali plant in new brunswick, canada.mercury concentrations were determined in the epiphytic lichen hypogymnia physodes along five transects starting from a chlor-alkali plant located at dalhousie, new brunswick, a landfill site and a nearby electricity generating station. lichen samples were collected from white birch (betula papyrifera) and spruce (picea sp.) or balsam fir (abies balsamea). average lichen background mercury values were 0.088+/-0.005 microg/g from white birch and 0.148+/-0.046 microg/g from spruce trees, with a de ...200212109479
hydrogen peroxide activates cell death and defense gene expression in birch.the function of hydrogen peroxide (h(2)o(2)) as a signal molecule regulating gene expression and cell death induced by external stresses was studied in birch (betula pendula). ozone (o(3)), pseudomonas syringae pv syringae (pss), and wounding all induced cell death of various extents in birch leaves. this was temporally preceded and closely accompanied by h(2)o(2) accumulation at, and especially surrounding, the lesion sites. o(3) and pss, along with an artificial h(2)o(2) producing system gluco ...200212376624
maintenance and impacts of an inoculated mer/luc-tagged pseudomonas fluorescens on microbial communities in birch rhizospheres developed on humus and peat.antagonistic bacteria represent promising biocontrol agents for improving forest production in seedling nurseries or forest soils. the fate of an introduced mer/luc-tagged antagonistic pseudomonas fluorescens 31k3 was monitored in the rhizosphere of silver birch (betula pendula) seedlings grown in microcosms containing forest humus or nursery peat. the inoculated strain (10(8) cfu g(-1) soil) was unable to establish in significant numbers in either soil type and turned nonculturable in humus. de ...200312447585
effects of long-term, elevated ultraviolet-b radiation on phytochemicals in the bark of silver birch (betula pendula).long-term outdoor experiments were conducted to investigate the effects of elevated ultraviolet-b (uv-b, 280-320 nm) radiation on secondary metabolites (phenolics and terpenoids) and the main soluble sugars (sucrose, raffinose and glucose) in the bark of silver birch (betula pendula roth) saplings. saplings were exposed to a constant 50% increase in erythemal uv irradiance (uv-b(cie); based on the cie (international commission on illumination) erythemal action spectrum) and a small increase in u ...200212464579
leaching of nitrogen and phosphorus during production of forest seedlings in containers.little information is available concerning the contamination risk caused by forest seedling nurseries to local surface and ground waters compared with agricultural and horticultural production. leaching of nitrogen (n) and phosphorus (p) through peat growing medium in containers and nutrient uptake of seedlings were monitored in production of silver birch (betula pendula roth), norway spruce [picea abies (l.) karst], and scots pine (pinus sylvestris l.) seedlings. about half of the applied nutri ...200212469836
postglacial recolonization and cpdna variation of silver birch, betula pendula.chloroplast pcr-rflp markers were used to reconstruct the history of the silver birch, betula pendula roth, in europe since the last glacial maximum (lgm). in birch, fossil pollen maps do not reveal a clear chronological sequence of postglacial spread. if anything, the pollen record suggests that most of europe was recolonized by birches as early as 10000 bp, probably from populations that remained close to the ice sheets during the lgm. the geographical distribution of haplotypes supports a sce ...200312492888
biochemical acclimation patterns of betula pendula and pinus sylvestris seedlings to elevated carbon dioxide concentrations.acclimation of photosynthesis to increasing atmospheric carbon dioxide concentration ([co2]; 350 to 2,000 micromol mol-1) was followed in silver birch (betula pendula roth.) and scots pine (pinus sylvestris l.) seedlings for two years. chlorophyll fluorescence and concentrations of rubisco, chlorophyll, total soluble protein and nitrogen were monitored together with steady-state gas exchange at three co2 concentrations (ambient [co2] (345 +/- 20 micromol mol-1), the growth [co2] and 1950 +/- 55 ...200312533303
dna sequence variation in bpmads2 gene in two populations of betula pendula.the pistillata (pi) homologue, bpmads2, was isolated from silver birch (betula pendula roth) and used to study nucleotide polymorphism. two regions (together about 2450 bp) comprising mainly untranslated sequences were sequenced from 10 individuals from each of two populations in finland. the nucleotide polymorphism was low in the bpmads2 locus, especially in the coding region. the synonymous site overall nucleotide diversity (pis) was 0.0043 and the nonsynonymous nucleotide diversity (pia) was ...200312535088
adaptive significance of c partitioning and regulation of specific leaf area in betula pendula.carbon allocation and regulation of specific leaf area (sigma) define key processes underlying the adaptation of plants to varying habitats. in this study, the general principles governing adaptation and a dynamic optimality model of plant adaptation are reviewed. the central new elements of this model are: (i) differential root carbon costs for maintaining a defined nutrient status; (ii) a simple formula for optimal sigma at steady-state as a function of nitrogen (n) status and irradiance; and ...200312566268
genotype-environment interactions in pollen competitive ability in an anemophilous tree, betula pendula roth.this study describes genotype-environment interactions in pollen competitive ability expressed as pollen-tube growth rate and seed-siring success in betula pendula roth. a factorial crossing design was applied using the same maternal and paternal clones in two different environmental conditions, in a b. pendula seed orchard established in a greenhouse and at an outdoor clone collection. both single donor and two-donor pollinations were employed. female inflorescences were collected after a fixed ...200212582552
influence of elevated co2 and o3 on betula pendula roth crown structure.elevated co(2) and ozone effects were studied singly and in combination on the crown structure of two betula pendula clones. measurements were made at the end of the second fumigation period in an open-top-chamber experiment with 9-year-old trees. shoot ramification (number of long and short daughter shoots), shoot length, and number of metamers, leaves and buds were measured at four positions in every tree. as a result of increased temperature, trees in chambers had longer shoots and more frequ ...200312646500
microbial impacts on plant-herbivore interactions: the indirect effects of a birch pathogen on a birch aphid.the role of indirect interactions in structuring communities is becoming increasingly recognised. plant fungi can bring about changes in plant chemistry which may affect insect herbivores that share the same plant, and hence the two may interact indirectly. this study investigated the indirect effects of a fungal pathogen ( marssonina betulae) of silver birch ( betula pendula) on an aphid ( euceraphis betulae), and the processes underpinning the interaction. there was a strong positive associati ...200312647147
accumulation of flavonoids and related compounds in birch induced by uv-b irradiance.a growth chamber experiment was conducted to examine the effects of uv-b exposure (4.9 kj m(-2) day(-1) of biologically effective uv-b, 280-320 nm) on shoot growth and secondary metabolite production in betula pendula (roth) and b. resinifera (britt.) seedlings originating from environments in finland, germany and alaska differing in solar uv-b radiation and climate. neither shoot growth nor the composition of secondary metabolites was affected by uv-b irradiance, but the treatment induced signi ...199812651299
long-term photosynthetic acclimation to increased atmospheric co(2) concentration in young birch (betula pendula) study the long-term response of photosynthesis to elevated atmospheric co(2) concentration in silver birch (betula pendula roth.), 18 trees were grown in the field in open-top chambers supplied with 350 or 700 &mgr;mol mol(-1) co(2) for four consecutive growing seasons. maximum photosynthetic rates, stomatal conductance and co(2) response curves were measured over the fourth growing season with a portable photosynthesis system. the photosynthesis model developed by farquhar et al. (1980) was ...199812651355
stomatal conductance, growth and root signaling in betula pendula seedlings subjected to partial soil drying.seedlings of betula pendula roth were grown with their root systems separated between two soil compartments. four treatments were imposed: (i) adequate irrigation in both compartments (ww, controls); (ii) adequate irrigation in one compartment and drought in the other compartment (wd); (iii) drought in both compartments (dd); and (iv) half of the root system severed and the remainder kept well-watered (root excision, re). predawn leaf water potential, stomatal conductance, soil-to-leaf specific ...199812651411
effects of dormancy and environmental factors on timing of bud burst in betula pendula.we tested three theories predicting the timing of bud burst in mature birch (betula pendula roth) trees utilizing a 60-year phenological time series together with meteorological temperature observations. predictions of the timing of bud burst based on light conditions in addition to temperature were more accurate than predictions based on dormancy development and temperature (prediction standard error of 2.4 days versus 4.3 days). the signal from light conditions, represented by fixed calendar d ...199812651420
genetic transformation of silver birch (betula pendula) by particle bombardment.we used in vitro callus and shoot cultures as target material for genetic transformation of silver birch (betula pendula roth) by particle bombardment. cultivation of in vitro shoot cultures before particle bombardment and a long selection period, combined with a high concentration of selective agent after bombardment, led to the production of transformed plantlets that were stable, and no escapes were found among the tree lines produced. clonal variation in transformation efficiency was found i ...200012651425
photosynthetic utilization efficiency of absorbed photosynthetically active radiation by scots pine and birch forest stands in the southern taiga.absorption and utilization of photosynthetically active radiation (par) were investigated in scots pine (pinus sylvestris l.) and birch (betula pendula roth.) stands that were 41 years old at the end of the experimental period. canopy depth of the scots pine stand was about half that of the birch stand (6.5 versus 11.0 m), but absorption of par was similar in the two stands. the scots pine forest canopy, with a leaf area index of 8.9, absorbed 90% of the incoming par (apar), whereas the birch fo ...200012651489
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