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At least 19 recordsLinked to original sources
PubMed2006

Effects of elevated carbon dioxide and ozone on foliar proanthocyanidins in Betula platyphylla, Betula ermanii, and Fagus crenata seedlings.

Proanthocyanidins (PAs) or condensed tannins are a major group of phenolic compounds in the leaves of birch trees and many other woody and herbaceous plants. These compounds constitute a significant allocation of carbon in leaves and are involved in plant responses to environmental stress factors, such as pathogens or herbivores. In some plants, PA concentrations are affected by atmospheric carbon dioxide (CO(2)) and ozone (O(3)) levels that may influence, for example, species fitness, community structure, or ecosystem nutrient cycling. Therefore, a study on the quantitative response of PAs to elevated concentrations of carbon dioxide (CO(2)) and ozone (O(3)) was undertaken in seedlings of Betula platyphylla, Betula ermanii, and Fagus crenata. Seedlings were exposed to ambient or elevated O(3) and CO(2) levels during two growing seasons in the Kanto district in Japan. Ten open-top chambers were used for five different treatments with two replicates: filtered air (FA), ambient air (ambient O(3), 43 ppb; ambient CO(2), 377 ppm), elevated O(3) (1.5 x ambient O(3), 66 ppb), elevated CO(2) (1.5 x ambient CO(2), 544 ppm), and elevated O(3) and CO(2) combined. In addition, seedlings growing in natural conditions outside of chambers were studied. Leaf samples were analyzed for total PA concentrations by butanol-HCl assay and for polymeric PA concentrations by normal-phase high-performance liquid chromatography. Total PA concentrations in leaves of all species were similarly affected by different treatments. They were significantly higher in seedlings treated with elevated CO(2) and O(3) combined, and in seedlings growing outside chambers compared with the FA controls. F. crenata contained only traces of polymeric PAs, but significant species x treatment interaction was observed in the polymeric PA concentrations in B. ermanii and B. platyphylla. In B. platyphylla, leaves treated with elevated CO(2) + O(3) differed significantly from all other treatments. It was suggested that the strongest effect of elevated CO(2) and O(3) combined on leaf PA contents resulted from the additive effect of these environmental factors on phenolic biosynthesis.

Adaptation, Biological↗
PubMed1997

Variation in ozone sensitivity among clones of Betula pendula and Betula pubescens.

Forty clones of Betula pendula and 6 clones of Betula pubescens, originating from southern and central Finland, were ranked in order of ozone sensitivity according to visible injuries, growth and leaf senescense under low ozone exposure. The plants were fumigated in natural climatic conditions using an open-air exposure system during two growing seasons. Control plants were grown under ambient air, and the elevated-ozone exposures were 1.6x the ambient in 1994 and 1.7x the ambient in 1995. The differences in ozone sensitivity among clones were large. Ozone tolerance was related to thicker leaves and higher stomatal density as compared to sensitive clones. Ultrastructural ozone-induced symptoms were found in chloroplasts of sensitive clones. Increased number of visibly injured leaves on fumigated plants was correlated with reduced leaf formation, foliage area, shoot dry wt and number of stomata, and increased yellowing of leaves. The results suggest that a considerable proportion of birch trees, showing high sensitivity to ozone, are at risk if ambient ozone exposures increase.

Journal Article↗
PubMed2003

Characteristics of pollinosis caused by Betula in patients from Ourense (Galicia, Spain).

UNLABELLED: A retrospective study was performed to describe the features of the pollinosis caused by Betula in the area of Ourense, Spain. The pollen count was carried out with a Lanzoni volumetric Hirts spore trap (1993-2000). The Betula pollen represented 5% over the annual total (annual mean quantity: 965 grains). It was present in the air from March to mid-May. The highest peaks took place in April (maximum values mean: 131 grains/m3). The medical records of 222 patients (mean age 25.66 years) diagnosed with pollinosis (1998-2000), who lived at less than 30 km. from the spore trap, were reviewed. In all of them, the skin-prick test (SPT) was carried out with pollen allergens. The percentages of positive SPT were: Lolium perenne, 91.89% (16.6% monosensitized); Plantago lanceolata, 71.17% (1.26% monosensitized); Betula alba, 41.89% (10.75% monosensitized); Platanus hybrida, 34.95%; Olea europea, 10.36%; and Parietaria judaica, 6.3%. The mean age of Betula monosensitized patients was 44.7 years. The majority of them had symptoms in March-April, 40% had asthma symptoms, 80% had lived in Central Europe, and 30% of them presented an oral allergy syndrome to fruits. There were 41.93% of the patients with positive SPT to Betula pollen who had asthma symptoms, in comparison with 23.25% of the patients with negative SPT to Betula (p = 0.0034). There were 20.28% of the patients with positive SPT to Betula pollen, who had lived in Central Europe, in comparison with 4.27% of the patients with negative SPT to Betula, p: 0.00049. The relative risk of sensitization was 2.05. CONCLUSIONS: Betula pollen was the second cause of clinical pollinosis in our patients, after grass, being responsible of the symptoms in the early spring, in a small number of the patients in their forties. The presence of asthma was higher in Betula sensitized patients, and the residence in Central Europe was a sensitization risk factor.

Adult↗
PubMed2004

[Biomass and yield of Betula platyphylla population in Mila Mount of Tibet].

Mila Mount in Southeast Tibet is the west boundary of the horizontal distribution of Betula platyphylla. It is also the highest altitude area in China and the world, where Betula platyphylla is distributed. Based on the investigation of regional sample plots and the analysis of analytic trees, this paper compared the biomass and yield of Betula platyphylla population at different slope orientation and different altitude. The results showed that the growth of Betula platyphylla was greatly interfered by human activities. The yearly productivity of Betula platyphylla grown in Mila Mount was 363.1-2,072.94 kg x hm(-2), and the biomass was 7,625.00-33,167.00 kg x hm(-2), indicating that the biomass of Betula platyphylla was quite different for different population. The productivity and biomass of Betula platyphylla coppice after cutting were lower than those of seedling forest, and there existed youth broken-down in the coppice. The zonal changes of water resources had no significant effect on the water allocation and the biomass of Betula platyphylla.

Altitude↗
PubMed2002

[Geostatistical analysis of the pattern of Betula ermanii population in Changbai Mountain].

The distribution pattern and spatial correlation of Betula ermanii population in Changbai Mountain were studied using the theory of geostatistics. According to the data, these mivariograms of Betula ermanii volume were calculated, the models of semivariograms were simulated, and Kriging interpolation was also done to draw the Kriging map. The results showed that at the elevation of 1650-1700 m, the semivariograms of Betula ermanii volume could be described as spherical model, the spatial distribution pattern was the aggregated type, and the population was in a trend of declining. At the elevation of 1750-2000 m, the semivariograms of Betula ermanii volume could be described as linear model, the spatial distribution pattern was the random type, the population was stable. At the elevation of 2000-2150 m, the semivariograms of Betula ermanii volume could be described as spherical model, the spatial distribution pattern was the aggregated type, and the population was in a tend of increasing. Betula ermanii population in Changbai Mountain was in a trend of moving upper, especially Betula ermanii population in the ecotone.

Altitude↗
PubMed2006

Effect of Betula platyphylla var. japonica on proteoglycan release, type II collagen degradation, and matrix metalloproteinase expression in rabbit articular cartilage explants.

Articular cartilage is a potential target for drugs designed to inhibit the activity of matrix metalloproteinases (MMPs) to stop or slow the destruction of proteoglycan and collagen in the cartilage extracellular matrix. The purpose of this study was to investigate the effects of Betula platyphylla var. japonica on inhibiting the release of glycosaminoglycan (GAG), the degradation of collagen, and MMP expression and activity in rabbit articular cartilage explants. Interleukin-1alpha (IL-1alpha) rapidly induced GAG, but collagen was much less readily released from cartilage explants. Betula platyphylla var. japonica significantly inhibited GAG and collagen release in a concentration-dependent manner. Betula platyphylla var. japonica dose-dependently inhibited MMP-3 and MMP-13 expression and activities from IL-1alpha-treated cartilage explant culture when tested at concentrations ranging from 0.02 to 0.2 mg/ml. Betula platyphylla var. japonica had no harmful effect on chondrocyte viability or cartilage morphology in cartilage explants. Histological analysis indicated that Betula platyphylla var. japonica reduced the degradation of the cartilage matrix compared with that of IL-1alpha-treated cartilage explants. These results indicate that Betula platyphylla var. japonica inhibits the degradation of proteoglycan and collagen through the down regulation of MMP-3 and MMP-13 expression and activities without affecting the viability or morphology of IL-1alpha-stimulated rabbit articular cartilage explants.

Animals↗
PubMedDate not supplied

Fungal decomposition of Abies needle and Betula leaf litter.

The effect of litter type and incubation temperature on the ability of fungi to decompose leaf litter of subalpine trees was examined by a pure-culture test. Mass loss of Abies needle and Betula leaf litter and utilization patterns of lignin and carbohydrates were investigated under two temperature conditions (20 C and 10 C) and compared for 29 species in basidiomycetes, ascomycetes and zygomycetes. The decomposing ability was generally higher in basidiomycetes than in ascomycetes and zygomycetes. Mass loss (% original mass) of litter was higher in Betula than in Abies and higher at 20 C than at 10 C. The 29 fungi were divided into lignocellulose decomposers, cellulose decomposers and sugar fungi based on their substrate utilization in Abies and Betula litter. Mass loss of lignin and carbohydrates by lignocellulose and cellulose decomposers was higher in Betula than in Abies. Mass loss of carbohydrates was higher at 20 C than at 10 C, but the temperature did not influence mass loss of lignin, indicating lignin decomposition by fungi was less sensitive to temperature than carbohydrate decomposition. Lignin/carbohydrate loss ratio (L/C) of Collybia spp. that caused selective delignification was lower at 20 C than at 10 C. These results indicate that the decomposability of litter, lignin and carbohydrate was different between Abies and Betula and that temperature affected not only the rate at which fungi decompose litter but also the ability of fungi to use lignin and carbohydrates.

Abies↗
PubMed1987

Efficiency of a new bioaerosol sampler in sampling Betula pollen for antigen analyses.

A new bioaerosol sampler consisting of Liu-type atmospheric aerosol sampling inlet, coarse particle inertial impactor, two-stage high-efficiency virtual impactor (aerodynamic particle sizes respectively in diameter: greater than or equal to 8 microns, 8-2.5 microns, and 2.5 microns; sampling on filters) and a liquid-cooled condenser was designed, fabricated and field-tested in sampling birch (Betula) pollen grains and smaller particles containing Betula antigens. Both microscopical (pollen counts) and immunochemical (enzyme-linked immunosorbent assay) analyses of each stage were carried out. The new sampler was significantly more efficient than Burkard trap e.g. in sampling particles of Betula pollen size (ca. 25 microns in diameter). This was prominent during pollen peak periods (e.g. May 19th, 1985, in the virtual impactor 9482 and in the Burkard trap 2540 Betula p.g. X m-3 of air). Betula antigens were detected also in filter stages where no intact pollen grains were found; in the condenser unit the antigen concentrations instead were very low.

Aerosols↗
PubMed2001

Comparative analysis of pollen counts of Corylus, Alnus and Betula in Szczecin, Warsaw and Lublin (2000-2001).

The aim of the study was to compare the airborne concentrations of allergenic pollen produced by three early flowering tree taxa (Corylus, Alnus, Betula) in the cities of Warsaw (central Poland), Lublin (eastern Poland) and Szczecin (western Poland) during the years 2000-2001. Measurements were performed by the volumetric method. Pollen seasons were defined as the periods in which 95% of the total catch occurred. The highest concentration and annual pollen count of Corylus was measured in Lublin in both seasons, while the highest annual pollen counts of Alnus and Betula were noted in Warsaw, where the annual pollen count of Betula in 2001 was four times higher than in 2000 and equalled 5,376 grains in m3 per 24 h. Significant differences in the pollen count of the examined taxa were observed between two seasons: the pollen count of Corylus was higher in 2000 than in 2001, while for Alnus and Betula the opposite was the case. The longest pollen seasons were observed at low annual pollen counts for the pollen of Corylus. Results of the study reveal significant differences between the seasons and the cities. The differences concern the dates of the appearance of pollen grains in the air, the duration of the presence of sporomorphs and the maximum concentrations in particular seasons. The pollen counts of alder, birch and hazel trees are determined by the weather, diversity of local flora and specific rhythm of pollination of particular taxa.

Air Pollution↗
PubMed2000

Is homeopathic 'immunotherapy' effective? A double-blind, placebo-controlled trial with the isopathic remedy Betula 30c for patients with birch pollen allergy.

The objective of the study was to examine the effect of the homeopathic remedy Betula 30c vs. placebo for patients with birch pollen allergy. A double-blind, randomized, placebo-controlled trial was carried out. Tablets were given for 4 weeks during the birch pollen season. The setting was Oslo, Norway, May 1995. Patients were aged between 18 and 50 y; 32 patients received Betula 30c tablets and 34 patients received placebo tablets. The main outcome measure was the total score of 17 different allergy symptoms. Daily total scores were calculated, as well as differences and ratios between the run-in and the following time periods. Point estimates of the median difference between the experimental and placebo groups, with their 95% confidence intervals, were the main measure of effect. No statistically significant difference between the groups was found during the first and last period of May. However, from 8 to 18 May, a clinically interesting difference was revealed between the groups, those receiving Betula 30c having fewer and less serious symptoms. For some days these differences were statistically significant. Surprisingly, this group reported more aggravation from the tablets than did the placebo group. With a statistical power of 70% for a defined clinically interesting difference (25%), the present results indicate that treatment with Betula 30c during the pollen season deserves further attention.

Adult↗
PubMed2001

Prophylactic and acute treatment with the homeopathic medicine, Betula 30c for birch pollen allergy: a double-blind, randomized, placebo-controlled study of consistency of VAS responses.

A study of the consistency of responses by allergic patients in repeated studies of the homeopathic remedy Betula 30c or placebo against birch pollen allergy, was made. A randomized, double-blind, placebo-controlled trial was performed including participants with a known allergy to birch pollen. Allergy symptoms were assessed on a visual analogue scale (VAS) by patients or parents each day during a 20-day period during two different pollen seasons. The work was carried out in Oslo, Norway during May 1995, 1996 and 1997. There were 51 patients ranging in age from 7 to 50y. The homeopathic remedy Betula 30c or placebo was given as tablets, both as a prophylactic agent, once a week for 4 weeks before the pollen season started, and as an acute remedy during the pollen season. The mean value of the symptom scores on the visual analogue scale, for all registration days from each patient was the main outcome. The patient groups that received either placebo or Betula 30c for two successive years showed a consistent response (r=0.75, P=0.01 and r=0.70, P=0.003, respectively). No such correlation was found in the two groups that changed remedy from one year to another (either from placebo to Betula or vice versa). Subjective assessment of allergic symptoms to birch pollen differed more from one year to another when different regimens (placebo or homeopathic) had been administered these two seasons, than when the same treatment had been given.

Adult↗
PubMed2004

Fungi associated with shoots of silver birch (Betula pendula) in Scotland.

The fungi associated with diseased and healthy shoots of young, planted Betula pendula were studied at five sites in Scotland where crown die-back of birch is occurring. At each site, 30 diseased and 30 healthy shoots were sampled twice, with 1 yr-old shoots collected in May 2002, and 4-5-month-old shoots collected in September/October 2002. Overall, 34 different fungal species were recorded, with 92 % and 60 % of all diseased and healthy shoot pieces, respectively, colonised by at least one fungal species. The main colonisers of both diseased and healthy shoots were Melanconium bicolor, Discula betulina and Godronia urceolus, and the fungi most frequently found on diseased shoots only included Marssonina betulae and Fusarium avenaceum. The pathogenicity of these fungi was tested on seedlings of B. pendula and B. pubescens. Melanconium bicolor required a wound for lesion development on both birch species and caused larger lesions on B. pubescens than on B. pendula. Discula betulina caused lesions on stems and shoots of both birch species, including non-wounded current shoots. Marssonina betulae caused lesions and die-back of wounded and non-wounded current shoots of B. pendula seedlings. This fungus was not pathogenic on B. pubescens. Fusarium avenaceum caused restricted lesions on the main stems of both birch species. Godronia urceolus was not pathogenic on either birch species. Further work needs to focus on the role of these fungi in causing crown die-back of young, planted B. pendula in Scotland.

Betula↗
PubMed2004

Tree growth and competition in a Betula platyphylla-Larix cajanderi post-fire forest in central Kamchatka.

BACKGROUND AND AIMS: Fire is the dominant disturbance in central Kamchatka boreal forests, yet patterns and mechanisms of stand recovery have not been investigated. METHODS: Measurements were made of 1433 stems > or =1.3 m height and annual radial increments of 225 randomly selected trees in a 0.4-ha plot of a 53-year-old fire-origin mixed-species stand to examine the spatio-temporal variation in establishment, growth, size inequality and the mode of competition among individual trees. Growth variations were related to tree size, age and local interference with neighbours. KEY RESULTS: Betula platyphylla formed the main canopy following a fire in 1947, with Larix cajanderi and Pinus pumila progressively reinvading the lower tree and shrub stratum. Most B. platyphylla originated from sprouts in small patches (polycormons) during the first 15 post-fire years. Betula platyphylla had normal distributions of diameter and age classes, but negatively skewed height distribution, as expected from shade-intolerant, pioneer species. Larix cajanderi had fewer tall and many short individuals. The smaller and younger B. platyphylla grew disproportionately more in diameter than larger trees from 1950 to 1975, and hence stem size inequalities decreased. The reverse trend was observed from 1995 to 2000: larger trees grew more, indicating an increasing asymmetry of competition for light. Betula platyphylla had steady diameter growth in the first 25 post-fire years, after which the growth declined in smaller trees. Neighbourhood analysis showed that the decline resulted from increased competition from taller neighbours. CONCLUSIONS: The observed growth patterns suggest that mode of interactions altered during stand development from early stages of weak competition for soil resources released by fire to later stages of asymmetric competition for light. Asymmetric crown competition started later than reported in other studies, which can be attributed to the lower stem density leaving much space for individual growth, greater relative importance of below-ground competition in this site of nutrient-poor volcanic soil, and the vegetative origin of B. platyphylla. Larix cajanderi growing under B. platyphylla had steady diameter growth during the first 20 years, after which growth declined. It is suggested that early succession fits the tolerance model of succession, while inhibition dominates in later stages.

Betula↗
PubMed2004

[Position of Betula ermanii population ecotone in Changbai Mountains].

The vegetation on the northern slope of Changbai Mountains forms a vertical zone due to the vertical differentiation of moisture and heat conditions. Ecotones are obviously existed between different vegetation zones, but it is difficult to decide their positions. In the area from 1400 m to 2200 m elevation, we adopted the methods of gradient sampling, fractal analysis, population pattern analysis, and interspecific competition index analysis to describe Betula ermanii population ecotone. The results showed that there was a forest ecotone between Betula ermanii and Picea-Abies forest near elevation 1650 m, and there was a forest line ecotone between Betula ermanii and alpine tundra near elevation 2080 m.

Abies↗
PubMed2000

Betulenols from Betula species.

The essential oils from buds of five Betula species growing in Turkey were investigated by GC-MS. A major component in the essential oils was shown to be 14-hydroxy-beta-caryophyllene (6). The structure of beta-betulenal (12) which was isolated from Betula essential oils was also confirmed by synthesis. Chemical reactions yielded 14-acetoxy-beta-caryophyllene (15), 14-hydroxy-isocaryophyllene (10) and its acetate (14), giving evidence to the natural occurrence in Betula species of the formerly known alpha-betulenol acetate (3), beta-betulenol (2) and beta-betulenol acetate (4), respectively. Compounds 6, 9, 10, 12, and 15 were evaluated for antimicrobial activity.

Anti-Bacterial Agents↗
PubMed1993

Variations in leaf morphometry and nitrogen concentration in Betula pendula Roth., Corylus avellana L. and Lonicera xylosteum L.

Relations between leaf dry weight to leaf area (LWA), leaf nitrogen concentration and irradiance inside a natural canopy were studied in Betula pendula Roth., Corylus avellana L. and Lonicera xylosteum L. In all species, LWA increased with increasing irradiance. Relative variability in LWA was smaller in Betula pendula than in the other two species. In Corylus avellana, LWA also depended on total plant height. Foliar nitrogen concentration (on a dry weight basis) increased with increasing irradiance and LWA in Betula pendula, but decreased in the other two species. The interspecific variation in response to light availability and in nitrogen partitioning may be caused by different light demands or different life forms (trees versus shrubs), or both, of the species examined, and must be considered in contemporary canopy models.

Journal Article↗