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Concept: Birch


Allergenic pollen is produced by the flowers of a number of trees, grasses and weeds found throughout the UK. Exposure to such pollen grains can exacerbate pollen-related asthma and allergenic conditions such as allergic rhinitis (hay fever). Maps showing the location of these allergenic taxa have many applications: they can be used to provide advice on risk assessments; combined with health data to inform research on health impacts such as respiratory hospital admissions; combined with weather data to improve pollen forecasting systems; or as inputs to pollen emission models. In this study we present 1km resolution maps of 12 taxa of trees, grass and weeds found in the UK. We have selected the main species recorded by the UK pollen network. The taxa mapped in this study were: Alnus (alder), Fraxinus (ash), Betula (birch), Corylus (hazel), Quercus (oak), Pinus (pine) and Salix (willow), Poaceae (grass), Artemisia (mugwort), Plantago (plantain), Rumex (dock, sorrels) and Urtica (nettle). We also focus on one high population centre and present maps showing local level detail around the city of London. Our results show the different geographical distributions of the 12 taxa of trees, weeds and grass, which can be used to study plants in the UK associated with allergy and allergic asthma. These maps have been produced in order to study environmental exposure and human health, although there are many possible applications. This novel method not only provides maps of many different plant types, but also at high resolution across regions of the UK, and we uniquely present 12 key plant taxa using a consistent methodology. To consider the impact on human health due to exposure of the pollen grains, it is important to consider the timing of pollen release, and its dispersal, as well as the effect on air quality, which is also discussed here.

Concepts: Immune system, Asthma, Plant, Allergy, Atopy, Birch, Pollen, Betulaceae


The construction and application of a novel electrochemical detection system with an in situ plated lead film electrode for high performance liquid chromatography is described. The working electrode of interest was tested as potential sensor for the adsorptive stripping voltammetric determination of betulinic acid (BA). The high sensitivity of the proposed electrochemical detection results from the accumulation by adsorption of betulinic acid on the lead film surface before the proper electrode process. In a solution of sodium hydroxide, used as a supporting electrolyte for the proposed voltammetric method, the oxidation signal for betulinic acid was found to be proportional to the BA concentration in the range from 0.02 to 0.5 μg L(-1) with the limit of detection equal to 0.009 μg L(-1) (with preconcentration for 15 s). The voltammetric detection was successfully applied to the determination of BA in the birch bark (Betula verrucosa) extracts after high performance liquid chromatographic separation. The content of betulinic acid obtained by the proposed method was in close agreement with that obtained by high performance liquid chromatography coupled with photodiode array detector (HPLC-PAD). This appears to be the first application of electrochemical detection to the determination of pentacyclic triterpene.

Concepts: Protein, Electrochemistry, Chromatography, High performance liquid chromatography, Analytical chemistry, Electrolysis, Birch, Separation process


Plants have an accumulative response to heavy metals present in soils or deposited from airborne sources of emissions. Therefore, their tissues are very often used in studies of heavy metal contamination originating from different sources as a bioindicator of environmental pollution. This research was undertaken to examine accumulation capacities of Pb, Zn, Cd, Cu and Cr in washed and unwashed needles of Scots pine (Pinus sylvestris L.) and leaves of silver birch (Betula pendula Roth) growing in a contaminated area. We collected needles of Scots pine and leaves of silver birch in an area around a sedimentation pond and metallurgic plant processing Pb and Zn ores near Olkusz, Poland. Concentrations of heavy metals, which have been linked with exposure to emissions, were determined from foliar samples collected at 33 sites. These sites were established at various distances (0.5-3.6 km) from the pond and metallurgic plant so as to identify the predominant accumulative response of plants. Spatial gradients for Pb and Zn were calculated using an ordinary kriging interpolation algorithm. A spatial pattern was identified by a GIS method to visualize maps over the Pb-Zn ore mining area. The accumulation of Zn (R(2) = 0.74, p < 0.05) and Pb (R(2) = 0.85, p < 0.01) in plant tissues correlated with soil concentrations. This tendency was not found in the case of Cu, Cd and Cr.

Concepts: Zinc, Lead, Birch, Heavy metal music, Scots Pine, Pine, Pinus classification, Betula pendula


Silver birch (Betula pendula) is a pioneer boreal tree that can be induced to flower within 1 year. Its rapid life cycle, small (440-Mb) genome, and advanced germplasm resources make birch an attractive model for forest biotechnology. We assembled and chromosomally anchored the nuclear genome of an inbred B. pendula individual. Gene duplicates from the paleohexaploid event were enriched for transcriptional regulation, whereas tandem duplicates were overrepresented by environmental responses. Population resequencing of 80 individuals showed effective population size crashes at major points of climatic upheaval. Selective sweeps were enriched among polyploid duplicates encoding key developmental and physiological triggering functions, suggesting that local adaptation has tuned the timing of and cross-talk between fundamental plant processes. Variation around the tightly-linked light response genes PHYC and FRS10 correlated with latitude and longitude and temperature, and with precipitation for PHYC. Similar associations characterized the growth-promoting cytokinin response regulator ARR1, and the wood development genes KAK and MED5A.

Concepts: DNA, Gene, Genetics, Genome, Genomics, Population genetics, Birch, Latitude


Pollen allergies have been rapidly increasing over the last decades. Many allergenic proteins and non-allergenic adjuvant compounds of pollen are involved in the plant defense against environmental or microbial stress. The first aim of this study was to analyze and compare the colonizing microbes on allergenic pollen. The second aim was to investigate detectable correlations between pollen microbiota and parameters of air pollution or pollen allergenicity. To reach these aims, bacterial and fungal DNA was isolated from pollen samples of timothy grass (Phleum pratense, n = 20) and birch trees (Betula pendula, n = 55). With this isolated DNA, a terminal restriction fragment length polymorphism analysis was performed. One result was that the microbial diversity on birch tree and timothy grass pollen samples (Shannon/Simpson diversity indices) was partly significantly correlated to allergenicity parameters (Bet v 1/Phl p 5, pollen-associated lipid mediators). Furthermore, the microbial diversity on birch pollen samples was correlated to on-site air pollution (nitrogen dioxide (NO2), ammonia (NH3), and ozone (O3)). What is more, a significant negative correlation was observed between the microbial diversity on birch pollen and the measured NO2 concentrations on the corresponding trees. Our results showed that the microbial composition of pollen was correlated to environmental exposure parameters alongside with a differential expression of allergen and pollen-associated lipid mediators. This might translate into altered allergenicity of pollen due to environmental and microbial stress.

Concepts: Bacteria, Metabolism, Asthma, Nitrogen, Allergen, Birch, Timothy-grass, Phleum


Migraine is a common primary headache disorder. The mechanisms underlying the onset of a migraine attack are not completely understood. Environmental changes and a number of other factors could induce migraine attacks. The aim of this study was to investigate the relationship between the frequency of migraine attacks and allergens. Migraine patients without aura, and healthy individuals similar in age and gender without a history of headache and allergy were prospectively included in the study. The duration of migraine, the frequency of migraine attacks, the medication history, and the symptoms during attacks were questioned. Migraine disability assessment score (MIDAS) and visual analog scale (VAS) scores were obtained. Allergen extracts including dust, fungi, insect, animal epithelium, pollens, and food allergens were applied for allergy tests. 49 migraine patients and 49 healthy individuals were enrolled in the study. There was no significant difference in terms of age and gender. The median migraine disease duration, the number of attacks in a month, and the duration of attacks were, respectively, 5.5 years (1-44), 4 (1-10) day/month, and 24 (4-72) h. The mean MIDAS grade was 2.45 ± 0.14 (1-4), and mean VAS score was 7.89 ± 0.27 (4-10). The positivity of allergy tests was 55.1 % (27/49) in the migraine group and 32.7 % (16/49) in the control group (p < 0.05). The allergy tests were positive for house dust, red birch, hazel tree, olive tree, nettle, and wheat. The frequency of migraine attacks was higher in allergy-test-positive patients than in negative ones in the migraine group (p = 0.001). The migraine patients who had frequent attacks should be examined for allergies.

Concepts: Asthma, Atopy, Arithmetic mean, Birch, Food allergy, Headache, Allergen immunotherapy, Ragweed


Latitudinal patterns in herbivory, i.e. variations in plant losses to animals with latitude, are generally explained by temperature gradients. However, earlier studies suggest that geographical variation in abundance and diversity of gall-makers may be driven by precipitation rather than by temperature. To test the above hypothesis, we examined communities of eriophyoid mites (Acari: Eriophyoidea) on leaves of Betula pendula and B. pubescens in boreal forests in Northern Europe. We sampled ten sites for each of five latitudinal gradients from 2008-2011, counted galls of six morphological types and identified mites extracted from these galls. DNA analysis revealed cryptic species within two of six morphologically defined mite species, and these cryptic species induced different types of galls. When data from all types of galls and from two birch species were pooled, the percentage of galled leaves did not change with latitude. However, we discovered pronounced variation in latitudinal changes between birch species. Infestation by eriophyoid mites increased towards the north in B. pendula and decreased in B. pubescens, while diversity of galls decreased towards the north in B. pendula and did not change in B. pubescens. The percentage of galled leaves did not differ among geographical gradients and study years, but was 20% lower in late summer relative to early summer, indicating premature abscission of infested leaves. Our data suggest that precipitation has little effect on abundance and diversity of eriophyoid mites, and that climate warming may impose opposite effects on infestation of two birch species by galling mites, favouring B. pendula near the northern tree limit.

Concepts: DNA, Species, Earth, Climate, Birch, Arachnid, Mite, Oak


Indoor pollen concentrations are an underestimated human health issue. In this study, we measured hourly indoor birch pollen concentrations on eight days in April 2015 with portable pollen traps in five rooms of a university building at Freising, Germany. These data were compared to the respective outdoor values right in front of the rooms and to background pollen data. The rooms were characterised by different aspects and window ventilation schemes. Meteorological data were equally measured directly in front of the windows. Outdoor concentration could be partly explained with phenological data of 56 birches in the surrounding showing concurrent high numbers of trees attaining flowering stages. Indoor pollen concentrations were lower than outdoor concentrations: Mean indoor/outdoor (I/O) ratio was highest in a room with fully opened window and additional mechanical ventilation (0.75), followed by rooms with fully opened windows (0.35, 0.12) and lowest in neighbouring rooms with tilted window (0.19) or windows only opened for short ventilation (0.07). Hourly I/O ratios depended on meteorology and increased with outside temperature and wind speed oriented perpendicular to the window opening. Indoor concentrations additionally depended on the previously measured concentrations, indicating accumulation of pollen inside the rooms even after the full flowering period. This article is protected by copyright. All rights reserved.

Concepts: Birch, Meteorology, All rights reserved, Wind, Copyright, Euclid's Elements, Atmospheric chemistry, Oral allergy syndrome


Pollen morphology of three parental Quercus species (Q. robur L., Q. petraea (Matt) Liebl, Q. pubescens Willd.) and two spontaneous hybrids of these species (Q. ×calvescens Vuk. = Q. petraea × Q. pubescens and Q. ×rosacea Bechst. = Q. robur × Q. petraea) was investigated in this study. The pollen originated from 18 natural oak sites and 67 individuals (oak trees). Each individual was represented by 30 pollen grains. In total, 2010 pollen grains were measured. They were analysed for nine quantitative and four qualitative features. Pollen size and shape were important features to diagnosing Quercus parental species and hybrids. On the basis of exine ornamentation, it was possible to identify only Q. pubescens, while the remaining species and hybrids did not differ significantly with respect to this feature. The determination of the diagnostic value of endoaperture features requires further palynological studies. On the basis of pollen size and shape Q. robur × Q. petraea was clearly separated. Grouping of 67 oak trees on the basis of pollen grain features has shown that individuals from different as well as same taxa occurred in the same groups. Likewise, with respect to natural sites, oak trees originating from the same places as well as from geographically distant ones, grouped together. Pollen morphological features allow to distinguish a part of the studied Quercus taxa. Therefore, it can be used as an auxiliary feature in the taxonomy.

Concepts: Species, Plant, Birch, Flowering plant, Pollen, Oak, Quercus, Fagaceae


The strong link between stomatal frequency and CO2 in woody plants is key for understanding past CO2 dynamics, predicting future change, and evaluating the significant role of vegetation in the hydrological cycle. Experimental validation is required to evaluate the long-term adaptive leaf response of C3 plants to CO2 conditions; however, studies to date have only focused on short-term single-season experiments and may not capture (1) the full ontogeny of leaves to experimental CO2 exposure or (2) the true adjustment of structural stomatal properties to CO2, which we postulate is likely to occur over several growing seasons. We conducted controlled growth chamber experiments at 150 ppmv, 450 ppmv and 800 ppmv CO2 with woody C3 shrub Betula nana (dwarf birch) over two successive annual growing seasons and evaluated the structural stomatal response to atmospheric CO2 conditions. We find that while some adjustment of leaf morphological and stomatal parameters occurred in the first growing season where plants are exposed to experimental CO2 conditions, amplified adjustment of non-plastic stomatal properties such as stomatal conductance occurred in the second year of experimental CO2 exposure. We postulate that the species response limit to CO2 of B. nana may occur around 400-450 ppmv. Our findings strongly support the necessity for multi-annual experiments in C3 perennials in order to evaluate the effects of environmental conditions and provide a likely explanation of the contradictory results between historical and palaeobotanical records and experimental data.

Concepts: Photosynthesis, Plant, Hydrology, Water cycle, Birch, Betula nana, Betula, Leaf