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Abstract

Grass pollen is the main cause of pollen allergy in Europe, and-given its marked allergenic potential and elevated airborne concentrations-constitutes a major public health risk. This study sought to identify the grass species triggering allergies during the highest-risk periods, and to measure the contribution of each species to airborne grass pollen concentrations. This type of research is particularly useful with a view to optimising the prevention and diagnosis of pollen allergies and developing the most effective immunological treatments. To that end, a total of 28 species potentially responsible for allergies were analysed. In order to assess the potential contribution of these species to overall airborne pollen concentrations, an index was designed (Pollen Contribution Index) based on the following parameters for each species: flowering phenology, pollen grain size (polar and equatorial axes), abundance of the species in the area and pollen production. The species contributing most to airborne pollen concentrations were, in order: Dactylis glomerata subsp. hispanica, Lolium rigidum, Trisetum paniceum and Arrhenatherum album. These species all shared certain features: small grain size (and thus greater buoyancy in air), high pollen production and considerable abundance. This Index was applied to a case study in a Mediterranean-climate area of the central Iberian Peninsula, but could equally be applied to other areas and other allergenic pollens. Findings showed that a small number of species were responsible for most airborne grass pollen.

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... Grasses are significant not only in ecological and socioeconomic terms, but also in terms of public health. Their pollen is a major cause of hay fever in Europe and elsewhere (García-Mozo 2017; Larsson et al. 2016;Zeb et al. 2018), due to the elevated allergenic potential of grass pollen proteins (Scaparrotta et al. 2013;Westritschnig et al. 2008), the abundance and widespread distribution of grass species (Nyffeler 2003;Rivas-Martínez et al. 2002;Watson and Dallwitz 1992) and the high rates of pollen emission into the atmosphere (Aboulaich et al. 2009;Romero-Morte et al. 2018). In Europe, between 20 and 35% of the population suffer from grass pollen allergy, although allergy rates differ between countries (D'Amato et al. 2007;De Weger et al. 2013;García-Mozo 2017;Larsson et al. 2016). ...
... However, a larger number of species make a moderate or small contribution in the course of the grass pollen season, among them Bromus rubens, Avena sterilis and Hordeum murinum subsp. leporinum (also members of the subfamily Pooideae) (Romero- Morte et al. 2018). ...
... The boxplot analyses showed phenological values per species and per site. However, for the analyses per species (relationship between phenology of species and the meteorological variables) a single average phenological value was calculated for each species using a principal factor analysis to reduce dimensionality of the phenological data (Romero-Morte et al. 2018). This procedure allowed a weighted average value for each species to be computed over all sites. ...
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Grasses are a taxonomic group of considerable environmental importance, playing a major ecological role as well as making a significant contribution to the world’s economy, since they include valuable crop and pasture species. Grass pollen allergens are also among the main causes of respiratory allergies worldwide. The interpretation of airborne grass pollen concentrations is a particularly complex task, given the marked diversity of pollen-emitting species and the influence of weather-related variables. This paper examines the influence of meteorological variables on flowering in the species contributing most to airborne grass pollen concentrations. This study was carried out in the surroundings of the city of Toledo (Spain), a Mediterranean city located in the center of the Iberian Peninsula. Temperature was the variable most influencing flowering onset, which was also affected by relative humidity, rainfall and hours of sunlight. The flowering period of grass species that flower at the start of spring (Bromus rubens and Hordeum leporinum) began earlier in years with higher mean winter temperatures, while the species that flower from mid to late spring (Trisetaria panicea and Dactylis glomerata subsp. hispanica), the flowering period began earlier in years with higher cumulative rainfall in winter and spring, which were also the years with the highest mean temperatures. Research into the influence of weather-related variables on grass phenology can shed important light on variations in airborne pollen concentrations, which determine the potential period of exposure for allergy sufferers.
... Для оценки потенциального вклада пыльцы Poaceae в аэробиологическую ситуацию пунктов наблюдения использовали стандартизированный индекс вклада пыльцы. Он основан на следующих параметрах: сроках цветения, размере пыльцевых зерен (полярная ось и экваториальный диаметр), обилии видов в регионе и продукции пыльцы [33]. ...
... Спектр указанных аллергенов однообразен во всех изученных зонах, но в южных регионах доминируют сорго, свинорой и ежовник. Они отвечают требованиям стандартизированного индекса вклада пыльцы [33,35]. ...
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More than 12,000 species belong to the Poaceae family globally; 300 species grow in Kyrgyzstan, anemophilous and releasing a huge amount of pollen into the atmosphere. Poaceae pollen is currently considered the leading airborne biological pollutant (PM10) and the leading cause of pollen allergy worldwide. She is one of the top global aeroallergens. Poaceae pollen has common features: small size, homogeneous morphology, high pollen production and abundance of species. The aim of this work was to study the effect of environmental pollutants on the pollen of Poaceae plants, the classification of identified teratomorphoses and assessment of their specific contribution to the aerobiological situation. The study of Poaceae pollen from various observation points of Kyrgyzstan using scanning electron microscopy revealed teratomorphoses of varying degrees of complexity: 1) deformation; 2) perforation; 3) fragmentation; 4) complex changes in the sculptural elements of the exine surface; 5) combined teratomorphosis, including several types with the transformation of one modification into another. This article summarizes the results of studies reflecting the effects of environmental pollutants on Poaceae pollen, and ultimately on the severity of symptoms and the prevalence of pollinosis.
... To fully understand the ecology of grasses, a population-based approach is often needed (Bolnick et al. 2003;Watkinson and Ormerod 2001). Spatial and temporal observations of flowering of multiple populations are often used to understand demographic elements in the study of grasses in agriculture (Rossignol et al. 2014;Smith 1944), ecology (Eagles 1972;Lindner and Garcia 1997) and aerobiology (Rojo et al. 2017;Romero-Morte et al. 2018). Combining this approach with a stochastic Markov chain modelling approach (Balzter 2000) and a model grass species may provide deeper multifaceted understanding with respect to underlying flowering processes. ...
... Therefore, peak flowering of populations will likely be more connected with pollen release, than the average full flowering. If pollen has the potential to disperse evenly during the flowering progression, then peak flowering will also explain maximum pollen release potential (Frenguelli et al. 2010;Romero-Morte et al. 2018). This study therefore suggests that the daily or bi-daily resolution of Dactylis phenology is needed to illustrate the narrow window of maximum pollen release potential that occurs during the peak flowering of Dactylis glomerata populations. ...
Article
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Understanding the relationship between flowering patterns and pollen dispersal is important in climate change modelling, pollen forecasting, forestry and agriculture. Enhanced understanding of this connection can be gained through detailed spatial and temporal flowering observations on a population level, combined with modelling simulating the dynamics. Species with large distribution ranges, long flowering seasons, high pollen production and naturally large populations can be used to illustrate these dynamics. Revealing and simulating species-specific demographic and stochastic elements in the flowering process will likely be important in determining when pollen release is likely to happen in flowering plants. Spatial and temporal dynamics of eight populations of Dactylis glomerata were collected over the course of two years to determine high-resolution demographic elements. Stochastic elements were accounted for using Markov chain approaches in order to evaluate tiller-specific contribution to overall population dynamics. Tiller-specific developmental dynamics were evaluated using three different RV matrix correlation coefficients. We found that the demographic patterns in population development were the same for all populations with key phenological events differing only by a few days over the course of the seasons. Many tillers transitioned very quickly from non-flowering to full flowering, a process that can be replicated with Markov chain modelling. Our novel approach demonstrates the identification and quantifi-cation of stochastic elements in the flowering process of D. glomerata, an element likely to be found in many flowering plants. The stochastic modelling approach can be used to develop detailed pollen release models for Dactylis, other grass species and probably other flowering plants.
... The pollen of grass species pollinated by wind can represent a significant health risk because of its high allergenic potential [13]. These grass species are considered the main cause to pollen allergies in many parts of the world [14][15][16]. Airborne pollen concentrations have traditionally been used to establish potential exposure to airborne allergens. Nevertheless, research has shown that allergy symptoms may arise even at low pollen concentrations [17]. ...
Article
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When the landfill use comes to end, important subsequent steps include aftercare, safety assurance, and ecological regeneration. Landfill revegetation is cost-effective and eco-friendly approach in the management of landfill areas, which serves the purpose of stabilization and provides a pleasant landscape. There are various vegetation types that can be planted, yet grass species are often used for low-cost reasons. Plants can be important sources of air pollution, particularly by grass pollen. The main goal of our study was to identify plant species that produce allergenic pollen. Long-term vegetation monitoring took place on three sites in the growing seasons of years 2008-2018. Studied objects were landfills located in the Czech Republic. The vegetation was assessed using a floristic survey of identified plant species. Plant species that produced allergens were recorded. During the monitoring, 298 plant species were determined. Plant species with allergenic pollen have a considerable share in the landfill vegetation. Thus, landfills are potential sources of various kinds of allergenic pollen. Moreover, our results indicated that there are three periods of pollen production: early spring, late spring, and early summer; late summer; and autumn. The second period is typical for the production of highly allergenic pollen by grasses. Most detected plant species with allergenic pollen are common for all monitored sites, which demonstrates that the vegetation of landfills is a significant source of allergenic pollen.
... The pollen of B. tulda falls into category 3, which includes small pollen having sizes ranging from 33.1-43.9 µm [56], conferring higher buoyancy. Although most grass pollen are known to be air-borne and allergenic, no such observations have been reported for bamboo [57]. ...
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Citation: Chakraborty, S.; Biswas, P.; Dutta, S.; Basak, M.; Guha, S.; Chatterjee, U.; Das, M. Studies on Reproductive Development and Breeding Habit of the Commercially Important Bamboo Bambusa tulda Roxb. Plants 2021, 10, 2375. https:// Abstract: Compared to other grasses, flowering in bamboo is quite divergent, yet complex with respect to time to flower, number of individual culms in a population that have been induced at a time (sporadic vs. gregarious), nature of monocarpy, morphology of inflorescences (solitary spikelet vs. pseudospikelet), biology of pollen and nature of genetic compatibility. Wide diversity exists even across species and genotypes. However, due to the rarity of flowering and inaccessibility, few studies have been done to systematically analyse diverse aspects of the reproductive behaviour of bamboo. In this study, four recurrently occurring, sporadic flowering populations of Bambusa tulda have been closely observed over the last seven years. Detailed inflorescence and floral morphology and development of reproductive organs have been studied. Pollen viability was assessed by staining and in vitro germination. Self and cross pollination experiments were performed in a plantation site to assess the genetic nature of pollen-pistil interaction. The study identifies interesting reproductive features, that are not common in other grasses. A few important observations include the early appearance of a solitary spikelet vs. late appearance of a pseudospikelet in the flowering cycle, low rate of pollen germination, protandry, self-incompatibility and higher rate of seed setting by the pseudospikelet as compared to the solitary spikelet. The findings will not only be useful to understand the reproductive behaviour of this non-woody timber plant, but will also be useful for forest management and sustainable use of bamboo bioresources.
... At the local scale, several studies were devoted to this important point and developed methodologies to identify the origin of pollutants concentrations, such as ref. [28] for the identification of local sources of olive pollen, ref. [29] for the quantification of the impact of landuse and wind direction on local pollen concentrations and ref. [30],which proposed a new index to classify the several kinds of measured pollen grains. ...
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This study is dedicated to improving the daily release of ragweed pollen emission in the context of deterministic regional modelling for analysis and forecast. First, correlations are calculated between daily modelled meteorological variables (wind speed, temperature, humidity, precipitation, surface fluxes) and daily pollen counts at nine stations in Hungary, Croatia and France between 2005 and 2011. The 2 m temperature is the most correlated parameter, followed by convective velocity and incoming shortwave radiation, while precipitation rate and 2 m specific humidity act as limiting factors. Using these results, a ragweed pollen daily release formulation is proposed. This formulation is implemented in the CHIMERE chemistry-transport model and tested during the whole year of 2010. Results are compared to observations, and it is shown that the new formulation provides a more realistic day-to-day variability: the spatio-temporal correlation between surface measurements and modelled concentrations is 0.77, greater than two other known emission schemes.
... Стандартизированный индекс вклада пыльцы базируется на следующих показателях: сроки цветения, размер пыльцевых зерен (полярная ось и экваториальный диаметр), обилие видов в регионе и продукция пыльцы [27]. ...
Article
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It is known that 30–40% of people in the world population are sensitized to pollen. This phenomenon is exacerbated in contaminated and urbanized areas. Wormwood is one of the main herbaceous allergenic plants, and its pollen is among the ten global aeroallergens. An allergy to it is a common phenomenon on a global scale. The role of pollen the etiology of pollinosis is usually in tandem with wormwood pollen established in Russia, Central Asia and Kazakhstan, Europe and America. The purpose of this article was to develop a pollen strategy for wormwood and pollen as the leading aeroallergen and assessment of their standardized contribution to the aerobiological situation. The SEM images of the studied pollen of wormwood do not show pronounced changes in the structure and sculpture, since it is tolerant to the effects of pollutants. Different types of deformation and modification of sculptural elements were revealed in pollen from the haze family, since their pollen selectively reacts to various pollutants. The strategy for pollen from wormwood and haze pollen is that, due to its strong, prickly exine, and lipophilicity, weed pollen is a very good biological accumulator of all types of gaseous or solid pollutants. In general, this accumulation depends on the physicochemical processes at the surface or cytoplasmic level, independent of the physiological state of pollen. Many biological agents, such as bacteria and fungal spores, can accumulate on the surface layer of the pollen shell and be used for bioindication.
... Other factors that have been suggested to affect the distribution and dispersion of pollen grains include the location and height of flowers, the period of pollination, the number and characteristics of pollen grains released, and the habitat and meteorological conditions. According to Romero-Morte et al. [14], a small number of species were responsible for majority of the airborne grass pollen and critical factors affecting the contribution were flowering phenology, pollen size, abundance of the species and pollen production in Toledo, Spain. It has been suggested that the pollen dispersal capacity of several species of grasses is limited, because the size of pollen grain is relatively large and because pollen grains are released close to the ground [15]. ...
Article
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Introduction: It is important to study potential differences in pollen concentrations between sampling heights because of diverse outdoor and indoor activity of humans (exposure) at different height levels in urban environments. Previous studies have investigated the effect of height on pollen concentrations based on just one or a few sampling points. We studied the effect of sampling height on grass pollen concentrations in several urban environments with different levels of urbanity. Methods: This study was conducted in the Helsinki Metropolitan Area, Finland, in 2013 during the pollen season of grasses. Pollen grains were monitored in eight different points in the morning and afternoon. Rotorod-type samplers were attached on sampling poles at the heights of 1.5 meters and 4 meters. Results: Grass pollen concentrations were on average higher at the height of 1.5 meters (Helsinki mean 5.24 grains / m3; Espoo mean 75.71 grains / m3) compared to the height of 4 meters (Helsinki mean 3.84 grains / m3; Espoo mean 37.42 grains / m3) with a difference of 1.40 grains / m3 (95% CI -0.21 to 3.01) in Helsinki, and 38.29 grains / m3 (7.52 to 69.07) in Espoo, although not always statistically significant. This was detected both in the morning and in the afternoon. However, in the most urban sites the levels were lower at 1.5 meters compared to 4 meters, whereas in the least urban sites the concentrations were higher at 1.5 meters. In linear regression models with interaction terms, the modifying effect of urbanity on concentration-height relation was statistically significant in both cities. The effect of urbanity on pollen concentrations at both heights was stronger in less urban Espoo. Conclusions: The present study provides evidence that height affects the abundance and distribution of grass pollen in urban environments, but this effect depends on the level of urbanity.
... The interest increased since recent studies revealed the effects of the interaction between the inorganic pollutants and aeroallergens on allergies and respiratory diseases (Sénéchal et al., 2015;Reinmuth-Selzle et al., 2017;Cole-Hunter et al., 2018). Moreover, monitoring of biological particulate matter also provides relevant information for agronomic or ecological purposes (Jarosz et al., 2005;Fernandez-Gonzalez et al., 2013;Charalampopoulos et al., 2018;Romero-Morte et al., 2018). ...
Article
The effect of height on pollen concentration is not well documented and little is known about the near-ground vertical profile of airborne pollen. This is important as most measuring stations are on roofs, but patient exposure is at ground level. Our study used a big data approach to estimate the near-ground vertical profile of pollen concentrations based on a global study of paired stations located at different heights. We analyzed paired sampling stations located at different heights between 1.5 and 50 m above ground level (AGL). This provided pollen data from 59 Hirst-type volumetric traps from 25 different areas, mainly in Europe, but also covering North America and Australia, resulting in about 2,000,000 daily pollen concentrations analyzed. The daily ratio of the amounts of pollen from different heights per location was used, and the values of the lower station were divided by the higher station. The lower station of paired traps recorded more pollen than the higher trap. However, while the effect of height on pollen concentration was clear, it was also limited (average ratio 1.3, range 0.7-2.2). The standard deviation of the pollen ratio was highly variable when the lower station was located close to the ground level (below 10 m AGL). We show that pollen concentrations measured at >10 m are representative for background near-ground levels.
... The satellite sensors capture the annual variability and the phenological dynamics of vegetation by land surface phenology (LSP) (de Beurs and Henebry, 2004). The phenology of the vegetation and the pollen grain emissions to the air have been widely studied, showing a close relationship (Romero-Morte et al., 2018;Tormo-Molina et al., 2015;Velasco-Jiménez et al., 2015). Satellite-derived sources, such as the Normalized Difference Vegetation Index (NDVI), have been used to capture the phenology of different types of vegetation (oak and grass) in the Mediterranean environment . ...
Article
Techniques of remote sensing are being used to develop phenological studies. Our goal is to study the correlation among the Normalized Difference Vegetation Index (NDVI)related with oak trees included in three set data polygons (15, 25 and 50 km to aerobiological sampling point as NDVI-15, 25 and 50), and oak (Quercus)daily average pollen counts from 1994 to 2013. The study was developed in the SW Mediterranean region with continuous pollen recording within the mean pollen season of each studied year. These pollen concentrations were compared with NDVI values in the locations containing the vegetation under a study based on two cartographic sources: the Extremadura Forest Map (MFEx)of Spain and the Fifth National Forest Inventory (IFN5)from Portugal. The importance of this work is to propose the relationship among data related in space and time by Spearman and Granger causality tests. 9 out of 20 studied years have shown significant results with the Granger causality test between NDVI and pollen concentration, and in 12 years, significant values were obtained by Spearman test. The distances of influence on the contribution of Quercus pollen to the sampler showed statistically significant results depending on the year. Moreover, a predictive model by using Artificial Neural Network (ANN)was applied with better results in NDVI25 than for NDVI15 or NDVI50. The addition of NDVI25 with the lag of 5 days and some weather parameters in the model was applied with a RMSE of 4.26 (Spearman coefficient r = 0.77)between observed and predicted values. Based on these results, NDVI seems to be a useful parameter to predict airborne pollen.
... The analysis of the biotic content of the troposphere is very interesting from ecological, agronomic and medical points of view ( Oteros et al., 2019;Recio et al., 2018;Romero-Morte, Rojo, Rivero, Fernández- González, & Pérez-Badia, 2018). AeRobiology is the scientific field based on the study of abundance and dynamics of bioaerosols (pollen, spore, bacteria, virus …) in the air. ...
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1.Aerobiological databases are constantly increasing. Many of them contain long and extensive time series of data which are very difficult and tedious to manage. 2.The development of new real‐time automatic sampling devices also requires new tools to reduce time of calculations and data management. In this sense, the “AeRobiology” R package has been implemented to accelerate and facilitate these tasks. 3.This package was structured in three sections based on (1) the checking of the database, (2) calculation of the main aerobiological indexes and (3) visualization of the results. 4.The “AeRobiology” package contains numerous functions which, in conjunction, solve the main general tasks that scientists must assume for the analysis of the biological data. 5.The package is freely distributed under GNU General Public License (GPL) and can directly be installed from CRAN (http://cran.r-project.org/). The reference manual is available at https://cran.r-project.org/web/packages/AeRobiology. Contact: aerobiology.package@gmail.com. This article is protected by copyright. All rights reserved.
... Poaceae showed important differences between pollen traps (slope < 1, the highest pollen concentrations were collected by the trap located at lower height), and very variable data (low R 2 , Table 1). This different behavior according to the pollen type can be related to the dispersal capacity of the pollen grain and the local distribution of the main pollen sources [52,53]. Peel et al. [54] also found different daily patterns for grass pollen in several locations within a city, and even different intradiurnal emission patterns depending on the distribution of the pollen sources [40]. ...
Article
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Airborne pollen concentrations vary depending on the location of the pollen trap with respect to the pollen sources. Two Hirst-type pollen traps were analyzed within the city of Munich (Germany): one trap was located 2 m above ground level (AGL) and the other one at rooftop (35 m AGL), 4.2 km apart. In general, 1.4 ± 0.5 times higher pollen amounts were measured by the trap located at ground level, but this effect was less than expected considering the height difference between the traps. Pollen from woody trees such as Alnus, Betula, Corylus, Fraxinus, Picea, Pinus and Quercus showed a good agreement between the traps in terms of timing and intensity. Similar amounts of pollen were recorded in the two traps when pollen sources were more abundant outside of the city. In contrast, pollen concentrations from Cupressaceae/Taxaceae, Carpinus and Tilia were influenced by nearby pollen sources. The representativeness of both traps for herbaceous pollen depended on the dispersal capacity of the pollen grains, and in the case of Poaceae pollen, nearby pollen sources may influence the pollen content in the air. The timing of the pollen season was similar for both sites; however, the season for some pollen types ended later at ground level probably due to resuspension processes that would favor recirculation of pollen closer to ground level. We believe measurements from the higher station provides a picture of background pollen levels representative of a large area, to which local sources add additional and more variable pollen amounts.
... Not all grass species affect allergic people with the same strength. Romero-Morte et al. (2018) found that a small number of species were the important source of airborne grass pollen in central Iberian Peninsula. To this group belong Dactylis glomerata, Lolium rigidum, Arrenatherm album. ...
Article
In the face of the intensifying process of urbanization and the increased incidence of pollen allergies among urban residents, there is still a need to continuously monitor the airborne concentration of allergenic plant pollen. Urban green spaces (UGS) are a desirable element of the urban fabric and necessary for the proper functioning of cities, but they are a rich source of allergenic pollen that may pose a certain risk to people visiting them. The main aim of this study was to analyse the airborne allergenic pollen content in parks of different types relative to a reference point located on the roof of a building. Moreover, this study investigated the relationship between tree canopy volume and the number of recorded airborne pollen grains (SPIn- Seasonal Pollen Integral), and these parameters were compared with the potential impact of vegetation in the parks studied through the Index of Urban Green Zones Allergenicity (IUGZA). Aerobiological monitoring was carried out in Rzeszów, SE Poland in 2016. A volumetric Hirst-type device was used. The pollen seasons of many taxa largely overlapped at each site where the monitoring was carried out, but the concentration values clearly differed. Tree pollen concentration values were not dependent on total canopy volume, and the greatest disproportions were found for Acer, Betula, Quercus, and Tilia pollen. This may be due to the fact that a solitary tree produces more pollen than a tree growing near others of the same species. The downtown park, surrounded by densely built-up areas, exhibited the highest allergenic potential, and the concentration of pollen, in particular tree pollen, was highest there. It is undesirable to plant hedges of allergenic plants, as they are a rich local source of pollen. Aerobiological monitoring carried out in urban parks provides information about the real threat of allergenic pollen to park visitors.
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Grass pollen is the world’s most harmful outdoor aeroallergen. However, it is unknown how airborne pollen assemblages change across time and space. Human sensitivity varies between different species of grass that flower at different times, but it is not known whether temporal turnover in species composition match terrestrial flowering or whether species richness steadily accumulates over the grass pollen season. Here, using targeted, high-throughput sequencing, we demonstrate that all grass genera displayed discrete, temporally restricted peaks of incidence, which varied with latitude and longitude throughout Great Britain, revealing that the taxonomic composition of grass pollen exposure changes substantially across the grass pollen season.
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In Poland - already before the II World War, and then from the 50s, up to the end of 70s of the 20th century - mass afforestation of landscape was carried out, which involved implementation of roadside and by-water shelterbelts, windbreaks, woodlots, buffer zones, midfield forests and others, in urbanized, industrial and rural landscape. At that time around a quarter (ca. 25%!) of new such plantings were made using poplars (especially non-domestic species and hybrids). Woodlots and shelterbelts composed of poplar's various taxons are now an indispensable part of the cultural landscape of significant natural and compositional importance in Poland. Deliberately existing both in urban and rural areas they meet the strictly defined functions: technical (wind protection, anti-erosion, etc.), biocenotic, aesthetic and currently present certain landscape values. For this reason, they require maintenance and constant protection - they are characterized by limited vitality and durability, resulting from the biology of woody plants.
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The fruit trees and shrubs present practical (fructification) and significant ornamental values (beautiful and plentiful bloom). Following the example of other European countries, the fruit trees have been extensively planted since the end of 19th century in Poland, among other along roads as part of a country-wide roadside tree planting campaign. However ageing fruit tree alleys without renovation begin to vanish from the rural landscape in Poland. Currently, they may be seen mainly along low-traffic side roads, while the oldest, relic alleys in older parks. In Poland in recent years the number of roadside trees declines among others due to the modernization of local roads. Since 2012 authors of this publication have been observing and documenting existing fruit tree alleys scattered in the rural landscape in Poland. For comparative purposes, in 2018 observations were carried out in Moravia, a region where the tradition of using fruit alleys is exemplary continued - in the landscape, there are numerous old (historical) and contemporary plantings. As an example is "The Longest fruit tree alley in Europe" - an international Polish - Czech - Austrian natural and cultural heritage thematic route "Krakow - Moravia - Wien Greenways". In selected locations, the following have been examined: features of their spatial form (original tree spacing; row spacing; row distance from the road); tree measurements (breast height circumference; tree height, crown width). Analysis of individual sites allows establishing a level of preservation of the original layout and the estimated age of trees and the entire tree stand.
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Poaceae pollen is highly allergenic, with a marked contribution to the pollen worldwide allergy prevalence. Pollen counts are defined by the species present in the considered area, although year-to-year oscillations may be triggered by different parameters, among which are weather conditions. Due to the predominant role of Poaceae pollen in the allergenicity in urban green areas, the aim of this study was the analysis of pollen trends and the influence of meteorology to forecast relevant variations in airborne pollen levels. The study was carried out during the 1993–2020 period in Ourense, in NW Iberian Peninsula. We used a volumetric Lanzoni VPPS 2000 trap for recording Poaceae airborne pollen grains, and meteorological daily data were obtained from the Galician Institute for Meteorology and Oceanography. The main indexes of the pollen season and their trends were calculated. A correlation analysis and ‘C5.0 Decision Trees and Rule-Based Models’ data mining algorithm were applied to determine the influence of meteorological conditions on pollen levels. We detected atmospheric Poaceae pollen during 139 days on average, mainly from April to August. The mean pollen grains amount recorded during the pollen season was 4608 pollen grains, with the pollen maximum peak of 276 pollen/m³ on 27 June. We found no statistically significant trends and slight slopes for the seasonal indexes, similarly to previous Poaceae studies in the same region. The calculated C5.0 model offered defined results, indicating that the combination of mean temperature above 17.46 °C and sunlight exposure higher than 12.7 h is conductive to significantly high pollen levels. The obtained results make possible the identification of risk moments during the pollen season for the activation of protective measures for sensitized population to grass pollen.
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We tracked atmospheric phosphorus (P) in suspended particulate matter (PM) from a site in Beijing, China over a three-year period and found a new relationship between plants and atmospheric P. Concentrations of total phosphorus (TP) in the atmosphere during plant growing seasons were 2.5 times those observed in other months and levels of organic phosphorus (OP) were 3.9 times as high. TP and OP increases during growing seasons were much more significant in PM with diameters of over 2.5 μm (PM>2.5). PM collected during growing seasons included high levels of P but less nitrogen than that in primary biogenic aerosol particles (PBAPs) and differed from other emission sources such as combustion emissions and dust. A time series of OP concentrations in the atmosphere shows a time lag relative to Normalized Difference Vegetation Index (NDVI) data with high levels found during early growing periods and much lower levels found during flourishing periods. Thus, we find that plants contribute to atmospheric P and especially to OP rather than to PBAP levels.
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Airborne pollen are important aeroallergens affecting human health. Local airborne pollen compositions can pose health-risks for the sensitized population, but at present little is known about fine-scale pollen composition patterns. The overall objective of this study is to determine local variations in tree pollen composition with passive samplers and to identify the surrounding landscape characteristics that drive them. In February–May 2017, during the tree pollen season, airborne tree pollen were measured by passive sampling at 2 m height above ground-level in 14 sites in the Flanders and Brussels-Capital region (Belgium). Non-metric multidimensional scaling was used to investigate environmental gradients that determine the pollen composition and amounts. Land cover types were identified across spatial scales ranging between 20 m and 5 km. The passive samplers detected the same pollen taxa during the same time windows as the validated volumetric Burkard samplers. Using passive samplers, we were able to measure local airborne pollen compositions. Corylus and Platanus pollen were associated to urban areas; Populus, Juglans and Fraxinus pollen to agricultural areas; forests and wetlands were sources of Alnus and Quercus pollen. Salix, Populus and Betula pollen were also mainly associated to wetlands. The landscape context drives the airborne tree pollen composition at a meso-scale (1-5 km) rather than at finer scale (20-500 m). Thus, land cover types (e.g. forest, bush land, agricultural lands and wetlands) surrounding urban areas may increase exposure to allergenic pollen in the urban area, potentially affecting the health of a large proportion of the population.
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Halo-nitrophilous scrubs are characterised by their floristic richness in species of the family Amaranthaceae (include Chenopodiaceae) and the Mediterranean saltbush (Atriplex halimus L.) is one of the most characteristic species in the Mediterranean region. Pollen from Amaranthaceae is the main cause of pollinosis at the end of summer and autumn. In this study, the floral phenology of the species Atriplex halimus L., was studied relating it to the atmospheric concentration of Amaranthaceae pollen with the aim to know if it can serve as an indicator of the maximum pollen concentrations. Observations of the male floral phenology of Atriplex halimus were performed over the course of three years in the central Iberian Peninsula (Spain) and the aerobiological pollen data of Amaranthaceae were obtained using a Hirst-type volumetric trap. The results demonstrated that the flowering period of Atriplex halimus closely coincided with the peak pollen levels. Besides, the prevailing movements of air masses in relation to the distribution and abundance of the halo-nitrophilous scrub during the flowering period of Atriplex halimus were studied using a back-trajectory analysis. The results showed that distinct predominant wind patterns led to differences in the quantity of pollen recorded during the pollen season and in the behaviour of the evolution of airborne pollen concentrations.
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Grasses (Poaceae) pollen is a major cause for allergic diseases worldwide. Pollen monitoring in the atmosphere is of primary importance for symptoms interpretation and therapy planning. Microscopic pollen identification and counts do not allow the detection at species or genus level because of the stenopalynous nature of the family. Nevertheless, the assessment of the flowering phenology of different species would be important, because not all grass allergens are cross-reacting and allergic patients could be differentially sensitized. In this work, a phenological survey was carried out in five stations located on the urban territory of Perugia (Central Italy), from April to September 2015, recording the alternation between flowering phenophases of 19 grass species and estimating their contribution to the airborne pollen load of the area through the calculation of a Phenological Index. Moreover, pollen grains of the different species were collected and observed, confirming the impossibility to make a discrimination during microscope pollen counts. The prevailing grasses in terms of contribution to the pollen detection in the studied area resulted to be Dactylis glomerata and Lolium perenne during spring and early summer, and Cynodon dactylon during late summer. Data should be validated repeating the survey in successive years and possibly using biomolecular tools, but the obtained information could be relevant for diagnosis and treatment of grass pollen allergies.
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This study reports on the flowering phenology of 12 Poaceae species in different types of plant cover (scrub, riverbank and pasture), with a view to creating a phenological calendar for the major species contributing most to airborne pollen concentrations. The study has been carried out from March to June between 2000 and 2013. Seventeen sampling sites in the study area were selected by accessibility, and predominantly, grasses grow in different land covers for phenological monitoring. Airborne pollen was collected using a Hirst-type volumetric spore trap. Results showed that longer phenological ranges were recorded in the wettest year and shorter ranges in the driest year. Over the study period, certain species displayed changes in the timing of flowering phenology. In pastureland and scrubland, a slight phenological delay over the study period has been recorded. In pastureland, some species—i.e., Bromus madritensis, B. diandrus and B. hordeaceus, Hordeum leporinum and Stipa capensis—displayed a delay in the timing of phenophases over the study period, including B. hordeaceus and B. madritensis on riverbank. Dactylis glomerata and Trisetaria panicea in scrub have been the only species with a clear advance; B. diandrus and B. madritensis a clear flowering delay. Lolium rigidum, Dactylis glomerata, Aegilops geniculata, in scrub, riverbank and pasture, and Arrhenatherum album, only in scrub, full flowering coincided with pollen peak in some populations during several years.
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The objective of this study was to expand knowledge on the Poaceae and morphologically describe pollen grains of species occurring in the Azores Archipelago, Portugal. Pollen grains from each species under study were subjected to standard acetolysis, mounting of at least three permanent slides of each species for observations and measurement of pollen grains under light and scanning electron microscope. With regard to pollen morphology, all pollen grains were arranged as monads, with a single pore-type aperture – monoporate, featuring annulus and operculum; and outline in polar view circular, sub-circular and ovalate. Most species featured pollen size small, except for Agrostis stolonifera with pollen size very small, Brachypodium sylvaticum with pollen size medium, Zea mays with pollen size large. Species endemic to the archipelago show ornamentation pattern ranging between areolate-microechinate, microechinate, microrugulate-microechinate and verrucate-microechinate, most of which feature exine surface areolate-microechinate. Among endemic species, Rostraria azorica stood out for its oblate-spheroidal shape, whereas most species showed prolate-spheroidal shape.
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Key message The olive pollen production showed a variation related to temperature and rainfall during dormancy period. A correlation was found between the number of olive tree inflorescences and airborne pollen counts. Abstract Analysis of pollen production in crops such as the olive is of particular agronomical value, in that it can help to predict final harvest outcomes. Since olive pollen is a major cause of allergy in the Mediterranean region, this analysis can also provide health-related benefits. The present study analyzed flower and pollen production in ‘Cornicabra’ olive cultivar, charting its correlation with airborne pollen counts, with phenological findings such as onset of pre-flowering period, and with environmental factors such as temperature and rainfall, elevation and northern vs. southern exposure of floral structures on the tree crown. Findings confirmed spatiotemporal variations for most of the parameters studied. Mean pollen grain production per flower of olive tree was 1.10 × 105 ± 0.25 × 105. Variations in the production of flowering branches, inflorescences, flowers and pollen reflected internal regulation processes linked to alternate bearing as well as year-on-year variations in weather conditions. Temperature and rainfall during dormancy were the weather-related variables most influencing flower, inflorescence and flowering-branch production. Early attainment of chilling requirements during dormancy was associated with increased production, coinciding with earlier budburst. A correlation was found between the number of inflorescences—and thus overall flower production—and airborne pollen counts. Production parameters also varied as a function of olive grove location, although that variability was not clearly attributable to the elevation. The correlation between production parameters and northern vs. southern exposure on the olive tree crown was significant only for flowering branches, whose production varied depending on their location on the tree crown.
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Continuous measurements of total ozone (by Dobson spectrophotometers) across the contiguous United States began in the early 1960s. Here, we analyze temporal and spatial variability and trends in total ozone from the five US sites with long-term records. While similar long-term ozone changes are detected at all five sites, we find differences in the patterns of ozone variability on shorter timescales. In addition to standard evaluation techniques, STL-decomposition methods (Seasonal Trend decomposition of time series based on LOESS (LOcally wEighted Scatterplot Smoothing)) are used to address temporal variability and "fingerprints" of dynamical features in the Dobson data. Methods from statistical extreme value theory (EVT) are used to characterize days with high and low total ozone (termed EHOs and ELOs, respectively) at each station and to analyze temporal changes in the frequency of ozone extremes and their relationship to dynamical features such as the North Atlantic Oscillation (NAO) and El Niño–Southern Oscillation. A comparison of the fingerprints detected in the frequency distribution of the extremes with those for standard metrics (i.e., the mean) shows that more fingerprints are found for the extremes, particularly for the positive phase of the NAO, at all five US monitoring sites. Results from the STL decomposition support the findings of the EVT analysis. Finally, we analyze the relative influence of low- and high-ozone events on seasonal mean column ozone at each station. The results show that the influence of ELOs and EHOs on seasonal mean column ozone can be as much as ±5 %, about as large as the overall long-term decadal ozone trends.
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This pilot study aims to find whether C3 and C4 Poaceae species can be separated by their pollen grain size. One hundred and sixty Poaceae species were prepared for pollen grain size analyses using standard methods. The whole data set included 70 species from northern Pakistan, 35 species from Tanzania, 25 from South America and 30 from Germany. We measured four pollen grain parameters, i.e. pollen grain length, pollen grain width, pore diameter and annulus width. Results of the statistical tests and multivariate analyses performed on our specific data set confirmed that C3 polyploid and C4 polyploid species show trends of larger grain size than the respective diploid species. Results of our fresh Poaceae grains should be applied on fossil pollen embedded in environmental archives for reconstructing past climate, for detecting shifts between their C3/C4 Poaceae compositions and assessing the dynamics of grassland ecosystems.
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The importance of the olive tree phenology from agricultural and ecological point of view justifies the need to carry out phenological studies at local and regional scales. Furthermore, flowering phenology in the olive tree (Olea europaea L.) is an important indicator of climatic change in the Mediterranean region. In this paper, we study the effects of altitude and the exposure of crown-flowering branches on the flowering phenology of the olive tree. The study was carried out from 2009 to 2012 at eight sites of Cornicabra olive cultivar in central Spain (Toledo province, Castilla-La Mancha region), at altitudes between 440 and 875 m above sea level, since most olive groves in central Spain are to be found in this altitude range. Flowering phenology was also compared in two olive groves located at the same site and elevation; one in a flat area and the other on a north-facing hillside. Results revealed a significant correlation between altitude and flowering start-date: for each 100 m increase in altitude, flowering started 2.5 days later. Analysis of individual flowering branches of the same tree showed that preflowering and flowering started several days later on north-facing compared to south-facing branches. Olive trees growing on a north-facing hillside started the preflowering stage with some delay with respect to those growing in flat areas. Finally, taking onset of flowering as the variable, a hierarchical cluster analysis enabled olive-groves to be classified by flowering sequence across an altitudinal gradient.
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Airborne pollen transport at micro-, meso-gamma and meso-beta scales must be studied by atmospheric models, having special relevance in complex terrain. In these cases, the accuracy of these models is mainly determined by the spatial resolution of the underlying meteorological data set. This work examines how meteorological datasets determine results obtained from atmospheric transport models used to describe pollen transport in the atmosphere. We investigate the effect of the spatial resolution when computing backward trajectories with the HYSPLIT model. We have used meteorological datasets from the WRF model with 27, 9 and 3 km resolution and from the GDAS files with 1 degree resolution. This work allows characterizing atmospheric transport of Olea pollen in a region with complex flows. The results show that the complex terrain affects the trajectories and this effect varies with the different meteorological data sets. Overall, the change from GDAS to WRF-ARW inputs improves the analyses with the HYSPLIT model, thereby increasing the understanding the pollen episode. The results indicate that a spatial resolution of at least 9 km is needed to simulate atmospheric flows that are considerable affected by the relief of the landscape. The results suggest that the appropriate meteorological files should be considered when atmospheric models are used to characterize the atmospheric transport of pollen on micro-, meso-gamma and meso-beta scales. Furthermore, at these scales, the results are believed to be generally applicable for related areas such as the description of atmospheric transport of radionuclides or in the definition of nuclear-radioactivity emergency preparedness.
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Total pollen production per inflorescence was studied in the most important species of the Poaceae family in the city of Córdoba in order to further our knowledge of the partial contribution of each species of this family to the total amount of pollen released into the atmosphere.The contribution of grasses in a given area was estimated by counting the number of inflorescences in an area of one square meter. Four different representative areas of the city were selected. The number of pollen grains per anther and flowers per inflorescence was also estimated in order to obtain total pollen production per inflorescence.Pollen production per inflorescence ranged from 14,500 to more than 22,000,000 pollen grains, the amount being clearly higher in the perennial species. Pollen production per square meter was higher in the mountains near the city and lower in areas of abandoned crops.Only a few species are responsible for the majority of pollen produced. A phenological study is necessary in order to determine the temporal distribution of this pollen production and subsequent shedding.
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Self-fertility and inbreeding are important in limiting gene flow between populations and producing ecogenetic differentiation; in preserving gene combinations that confer high fitness in a local environment; in permitting fruit to be set after long-distance dispersal; and in reducing or eliminating the costs of sex. Cleistogamy - self-fertilization in an enclosed flower - intensifies these potential advantages of inbreeding, and may also be important in altering seed size, germinability, dispersibility and susceptibility to fire and herbivory. Cleistogamy is more common in grasses than in any other angiosperm family, being known in 321 species (c.5% of the family), 82 genera (19% of the total) and all of the major tribes and subfamilies. The origins and types of cleistogamy in grasses are examined by integrating ecological and systematic data, using evolutionary theory as a bridge. Potential evolutionary relationships between types of cleistogamy, habitats and life-history strategies are examined. There is discussion of current understanding of the heritability of cleistogamy in grasses and of additional genetic and demographic information needed to test various schemes and models that attempt to explain the evolution and maintenance of cleistogamy.-P.J.Jarvis
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The present study examines variations in the timing of flowering between populations of Iberian Poaceae species using pollen data from 12 sites in Spain. The spatial variation in pollen season start-date for any given year was around 1 month; year-on-year differences at any given site ranged around 1.5 months. The spatial variation in the pollen season peakdate was smaller, at around 15 days, while the year-on-year variation for the peak-date at a given site was never greater than 20 days. Two process-based models were developed, one to predict the start-date and the other the peak-date of the grass pollen season. These models take into account the effects of temperature, photoperiod and water availability on the timing of grass flowering in Spain. Apart from predicting the pollen-season start and peak dates, the models provide information on (i) the Poaceae response to weather-related factors, (ii) the period during which these factors affect grass growth, and (iii) the relationship between photoperiod, temperature and water availability for flowering grasses. Internal validation showed that themodels accounted for 45%of the variance in start-date and 68% of the variance in peak-date. External validation was performed for 2006 and 2007 at all sites: the root mean square error for the actual and predicted dates was around 4 days for the start-date and 6 for the peak-date. Analysis of the model estimates showed that a single model parameter set for all Spain, taking into account different bioclimatic factors, could be sufficient to account for the variability of the Poaceae pollen season across space and time.
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My objective is the examination of selective forces that affect pollen number. Relationships among other floral traits of animalpollinated plants, including pollen size, stigma area and depth, and the pollen-bearing area of the pollinator may affect pollen number and also provide a model to examine how change in one trait may elicit change in other traits. The model provides a conceptual framework for appreciating intra- and inter-specific differences in these traits. An equivalent model is presented for wind-pollinated plants. For these plants the distance between putative mates may be the most important factor affecting pollen number. I briefly consider how many pollen grains must reach a stigma to assure fruit set. I use pollen-ovule ratios (P/Os) to examine how breeding system, sexual system, pollen vector, and dispersal unit influence pollen grain number. I also compare the P/Os of plants with primary and secondary pollen presentation and those that provide only pollen as a reward with those that provide nectar as part or all of the reward. There is a substantial decrease in P/O from xenogamy to facultative xenogamy to autogamy. Relative to homoecious species the P/Os of species with most other sexual systems are higher. This suggests that there is a cost associated with changes in sexual system. The P/Os of wind-pollinated plants are substantially higher than those of animal-pollinated plants, and the available data suggest there is little difference in the pollination efficiency of the various animal vectors. The P/Os of plants whose pollen is dispersed in tetrads, polyads, or pollinia are substantially lower than those of species whose pollen is dispersed as monads. There was no difference in the P/Os of plants with primary and secondary pollen presentation. The P/Os of plants that provide only pollen as a reward were higher than those that provide nectar as a reward. All of these conclusions merit additional testing as they are based on samples that are relatively small and/or systematically biased.
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During the Quaternary, in particular during glacial times, different grassland ecosystems played a much larger role and had a significantly larger distribution. Little is known yet about past development, biodiversity and dynamics of grassland ecosystems. In this innovative study, we attempt to distinguish between different South American grassland types in space and time based on morphological pollen grain characteristics of Poaceae. For this purpose >60–80 Poaceae pollen grains of 20 grassland samples were measured using their length, width and pore diameter as well as annulus width. Samples were taken from five sites in wet Páramo vegetation from the Late Pleistocene to the Late Holocene in South Ecuador and from two sites in the south-eastern Brazilian highlands (Campos do Altitude) of the same period. Additionally, we investigated two samples from a Pampa site as well as six samples from one Campos grassland site in southern Brazil from the Late Pleistocene to the Late Holocene. Subsets of samples of the Campos grasslands and of the Páramo were investigated in order to retrieve more detailed information on patterns within these vegetation types. Multivariate data analysis of the complete data set shows changes in taxonomic composition along an elevational gradient in the Páramo grasslands. Our results reveal a highly dynamic development of the individual grassland types; they also provide interesting information on Poaceae taxa composition patterns, development and possibly changes in biodiversity within these ecosystems. Moreover, our data provide an indication about the origin and dynamics of the Campos ecosystems in the southern Brazilian highlands during the Late Pleistocene and the Holocene before and after the onset of human activities. KeywordsGrasslands–South America–Poaceae–Pollen grain morphology–Grain size–Pampa–Campos–Páramo–Campos de Altitude–Biodiversity
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Total pollen production per inflorescence and per square meter were studied in anemophilous species of the Poaceae family, to determine the relative contribution of each species to the total load of pollen released and to identify the species with the highest potential pollen emission. This was done by calculating the number of pollen grains per flower and per inflorescence and by estimating the density of inflorescences in an area of one square meter. Pollen production per inflorescence varied between 12,000 and 15million grains, often being higher in the perennial species. Mountainous, grassland, riverside, and littoral areas contributed similarly to the amount of pollen grain production per square meter. Species such as Gaudinia fragilis, Hordeum murinum, Lolium rigidum, and Trisetaria panicea, with high pollen records, were found in all the studied areas. Aerobiological analysis will be undertaken to determine the main pollen season of Poaceae species. The results obtained are of great importance for respiratory health management in this region.
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The present study sought to determine which of the common Poaceae species in the study area contribute most to the Poaceae pollen season curve, and to determine the phenological behaviour of the species studied. The different floral phenophases in thirty-three Poaceae species common in and around the city of Córdoba (SW Iberian Peninsula) were checked periodically over the period 2004–2006. Results showed that longer phenological ranges were recorded in the coolest and wettest year, and shorter ranges in the warmest and driest year. Moreover, ranges varied as a function of altitude: populations in lower-lying areas flowered earlier than those at higher altitudes. The results, taken in conjunction with the findings of preliminary research into potential pollen production, showed that probably only four of the Poaceae species studied—Dactylis glomerata, Lolium rigidum, Trisetaria panicea and Vulpia geniculata—were major contributors to the Poaceae airborne pollen curve. KeywordsPhenology–Poaceae–Pollen–Phenological phases
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Airborne pollen distribution in the city of Nicosia (Cyprus) was measured volumetrically during two consecutive years 2007-2008 on weekly basis using Lanzoni trap (Lanzoni VPPS 2000). A total of 7,880 pollen grains/m(3) belonging to 44 taxa, in 2007 were 3,593 pollen grains/m(3) and in 2008 it was 4,287 pollen grains/m(3), were determined. Out of these, 25 belonged to the arboreal and 19 to the non-arboreal taxa. At the end of 2 years, total pollen counts were 78.76% arboreal, 19.32% non-arboreal, and 1.92% unidentified taxa. The number of pollen in the arboreal plants followed the trend as Pinaceae (29.96%), Cupressaceae/Taxaceae (18.33%), Olea europaea L. (6.92%), and Quercus spp. (4.92%), and for non-arboreal representatives, these were Poaceae (8.46%), Chenopodiaceae/Amaranthaceae (2.61%), Plantago spp. (1.69%), and Parietaria spp. (1.51%). The distribution of pollen in the atmosphere of Nicosia followed the trend as March, April, May, and June.
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A study was made of airborne pollen counts in Cuenca (east-central Iberian Peninsula, Spain), using data obtained over a 3-year period (2008-2010). This is the first such study carried out in the World Heritage city of Cuenca, situated in the large region of Castilla-La Mancha. Air monitoring was performed using the sampling and analysis procedures recommended by the Spanish Aerobiology Network. Sampling commenced in mid- 2007, and provided the first recorded pollen-spectrum for the area. The greatest pollen-type diversity was recorded in spring, whilst the highest pollen counts (over 80 percent of the annual total) were observed between February and June. The lowest counts were found in September, November and December. The 10 leading taxa, in order of abundance, were: Cupressaceae, Quercus, Urticaceae, Pinus, Olea, Poaceae, Populus, Platanus, Chenopodiaceae-Amaranthaceae and Plantago. The pollen calendar was thus typically Mediterrean, and comprised the 27 pollen types reaching 10-day mean counts of over 1 grain/m(3) of air. Maximum concentration values during the day were recorded between 12:00-20:00, coinciding with the highest temperatures and lowest humidity levels. The pollen types responsible for most allergies in the city of Cuenca, ordered by the number of days on which risk levels were reached, were: Poaceae, Urticaceae, Cupressaceae, Olea, Platanus and Chenopodiaceae-Amaranthaceae.
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In allergic individuals, onset of symptoms is related to atmospheric pollen grain counts and aeroallergen concentrations. However, this relationship is not always clear. To analyze the correlation between grass pollen grain and aeroallergen concentrations in Ciudad Real, Spain, during the year 2004 and establish their association with symptoms in patients with allergic asthma, rhinitis, or both. Two different samplers were used to assess allergen exposure: a Burkard spore trap to collect pollen grains and a high-volume air sampler to collect airborne particles. Individual filters were extracted daily in phosphate-buffered serum and analyzed by enzyme-linked immunosorbent assay based on serum containing high titers of specific immunoglobulin (Ig) E to grasses. The study population comprised 27 grass-allergic patients whose symptoms and medication were recorded daily. Grass pollens were detected between April 28 and July 18. There was a positive correlation between pollen grain counts and symptoms (r = 0.62; P > .001). Grass aeroallergens were detected not only during the grass pollination period, but also before and after this period. There was also a very significant correlation between aeroallergen levels and symptoms (r = 0.76; P < .0001). The threshold level for grass pollen was 35 grains/m3. Grass-related allergenic activity is present throughout the year, demonstrating the existence of aeroallergens outside the pollen season. Symptoms in allergic patients may be related to airborne particle concentrations. This fact should be taken into account in the clinical follow-up and management of allergic patients.
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The present work analyses the airborne pollen dynamic of the atmosphere of Toledo (central Spain), a World Heritage Site and an important tourist city receiving over 2 millions of visitors every year. The airborne pollen spectrum, the annual dynamics of the most important taxa, the influence of meteorological variables and the risk of suffering pollen allergy are analysed. Results of the present work are compared to those obtained by similar studies in nearby regions. The average annual Pollen Index is 44,632 grains, where 70-90 percent is recorded during February-May. The pollen calendar includes 29 pollen types, in order of importance; Cupressaceae (23.3 percent of the total amount of pollen grains), Quercus (21.2 percent), and Poaceae and Olea (11.5 and 11.2 percent, respectively), are the main pollen producer taxa. From an allergological viewpoint, Toledo is a high-risk locality for the residents and tourist who visit the area, with a great number of days exceeding the allergy thresholds proposed by the Spanish Aerobiological Network (REA). The types triggering most allergic processes in Toledo citizens and tourists are Cupressaceae, Platanus, Olea, Poaceae, Urticaceae and Chenopodiaceae-Amaranthaceae. Allergic risk increases in 3 main periods: winter (January-March), with the main presence of the Cupressaceae type; spring, characterized by Poaceae, Olea, Platanus and Urticaceae pollen types; and, finally, late summer (August-September), characterized by Chenopodiaceae- Amaranthaceae pollen type, which are the main cause of allergies during these months.
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Allergy to taxonomically related species is a common phenomenon caused by the same immunological receptor cross-reacting to homologous allergens from different species. Knowledge of patterns of cross-reactivity is crucial for the selection of optimal products for diagnosis and for specific immunotherapy. The objective of this study was to investigate patterns of serum IgE cross-reactivity towards pollens from various grass species. With grass group 1 allergens as the representative group, amino acid sequence alignment, structural modelling and comparison of 3D surface characteristics were performed to exemplify the molecular basis of IgE cross-reactivity. IgE binding to extracts from ten different grass species was determined (total number of data pairs >19,000), and IgE inhibition experiments using Phleum pratense were performed. Analysis of surface topography for group 1 grass allergens demonstrated ample space for IgE binding epitopes in surface areas conserved among Pooideae grasses. Significant correlation was observed between the serum IgE response to P. pratense extract and extracts from the other Pooideae grasses analyzed. P. pratense extract was demonstrated to inhibit the binding of IgE to the allergens in all of the extracts included in the investigation, indicating patient IgE to be primarily directed towards common epitopes. Extensive IgE cross-reactivity was observed towards the allergens of the Pooideae grasses, meaning that the immune system does not appear to distinguish based on the IgE level between the different species of this subfamily. The data suggest equal effect upon use of any of the Pooideae species for diagnostic as well as therapeutic purposes.
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Background: The rich literature that characterizes the field of pollination biology has focused largely on animal-pollinated plants. At least 10 % of angiosperms are wind pollinated, and this mode of pollination has evolved on multiple occasions among unrelated lineages, and hence this discrepancy in research interest is surprising. Here, the evolution and functional ecology of pollination and mating in wind-pollinated plants are discussed, a theoretical framework for modelling the selection of wind pollination is outlined, and pollen capture and the occurrence of pollen limitation in diverse wind-pollinated herbs are investigated experimentally. Scope and conclusions: Wind pollination may commonly evolve to provide reproductive assurance when pollinators are scarce. Evidence is presented that pollen limitation in wind-pollinated plants may not be as common as it is in animal-pollinated species. The studies of pollen capture in wind-pollinated herbs demonstrate that pollen transfer efficiency is not substantially lower than in animal-pollinated plants as is often assumed. These findings challenge the explanation that the evolution of few ovules in wind-pollinated flowers is associated with low pollen loads. Floral and inflorescence architecture is crucial to pollination and mating because of the aerodynamics of wind pollination. Evidence is provided for the importance of plant height, floral position, and stamen and stigma characteristics in promoting effective pollen dispersal and capture. Finally, it is proposed that geitonogamous selfing may alleviate pollen limitation in many wind-pollinated plants with unisexual flowers.
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Allergic rhinitis (AR) is a prevalent allergic disease in Iberian countries, but there are no recent epidemiological studies that characterize this pathology according to clinical classification and aeroallergens sensitisation. This is a clinical study, representative of each country Descriptive, observational cross-sectional, population-based study carried-out in Portugal and Spain. 3397 consecutive patients (5 regions in Spain and 3 regions in Portugal) were selected for clinical observation and skin prick tests were carried out using the same panel of standardized aeroallergens. 3225 patients (aged 10-50 years old) completed the study (IC 95%, SE 15). Intermittent rhinitis makes up 36% of the entire sample. Of them, intermittent AR mild forms represented 82% in Spain and 92% in Portugal that is, 87% for Iberian countries. Persistent types of rhinitis showed exactly the same rate of severity in Portugal and Spain, 44% mild and 56% moderate/severe. Seasonal forms represent 37% while 63% were perennial. BA was present in 49% of AR patients. There were significant differences between aeroallergens according to the different regions considered. Mites and grass pollens are the most relevant aeroallergens in Spanish and Portuguese AR patients, while Alternaria showed higher positive rates among 10-20 year old patients. This study characterizes the AR patients in Iberian countries according to the ARIA classification. No correlation was observed between this classification and the conventional (seasonal/perennial). Our results also characterize the allergic cutaneous pattern of aeroallergen sensitisation using the same panel of standardized allergens and show differences between the different regions analysed.
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Mapping pollen concentrations is of great interest to study the health impact and ecological implications or for forestry or agronomical purposes. A deep knowledge about factors affecting airborne pollen is essential for predicting and understanding its dynamics. The present work sought to predict annual Quercus pollen over the Castilla and León region (Central and Northern Spain). Also to understand the relationship between airborne pollen and landscape. Records of Quercus and Quercus pyrenaica pollen types were collected at 13 monitoring sites over a period of 8 years. They were analyzed together with land use data applying the Concentric Ring Method (CRM), a technique that we developed to study the relationship between airborne particle concentrations and emission sources in the region.
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Ornamental trees in urban environment are a relevant cause of illness due to allergenic pollen airborne dispersed. The work presented here analyses the importance of ornamental tree distribution and investigates airborne pollen records using volumetric spore traps. Three localities in the southwest of Spain were studied: Don Benito (DB), Plasencia (PL), and Zafra (ZA), in the Extremadura region. Volumetric Hirst type spore traps recorded pollen levels continuously for three years. Ornamental street trees in the study area were identified, counted and mapped. Airborne pollen records were found to be related to the number of trees, the proximity of the trees to traps, the different pollination systems and wind direction. A total of 17635 trees, from all localities were counted, belonging to 67 species, 58% anemophilous, 22% entomophilous, and 20% both pollination systems. Five species represented more than 50% of the total number of ornamental trees: Platanus hispanica, Olea europaea, Ulmus minor, Acer negundo and Melia azedarach. The average total pollen concentration in g m⁻³ was 102 (DB), 93 (PL), and 99 (ZA)… Omitting the data for Quercus pollen, a statistically significant correlation between the number of trees at 0.5 km around the spore traps and the types of pollen recorded was found. Some measures to decrease the amount of potential allergenic airborne pollen in urban environments were identified, such as reducing trees with anemophilic pollination systems, eliminating male trees and employing suitable pruning practices. In any case, the closer the source of ornamental pollen, the greater the allergenic risks.
Article
Analysis of airborne pollen concentrations provides valuable information on plant phenology and is thus a useful tool in agriculture—for predicting harvests in crops such as the olive and for deciding when to apply phytosanitary treatments—as well as in medicine and the environmental sciences. Variations in airborne pollen concentrations, moreover, are indicators of changing plant life cycles. By modeling pollen time series, we can not only identify the variables influencing pollen levels but also predict future pollen concentrations. In this study, airborne pollen time series were modeled using a seasonal-trend decomposition procedure based on LOcally wEighted Scatterplot Smoothing (LOESS) smoothing (STL). The data series—daily Poaceae pollen concentrations over the period 2006–2014—was broken up into seasonal and residual (stochastic) components. The seasonal component was compared with data on Poaceae flowering phenology obtained by field sampling. Residuals were fitted to a model generated from daily temperature and rainfall values, and daily pollen concentrations, using partial least squares regression (PLSR). This method was then applied to predict daily pollen concentrations for 2014 (independent validation data) using results for the seasonal component of the time series and estimates of the residual component for the period 2006–2013. Correlation between predicted and observed values was r = 0.79 (correlation coefficient) for the pre-peak period (i.e., the period prior to the peak pollen concentration) and r = 0.63 for the post-peak period. Separate analysis of each of the components of the pollen data series enables the sources of variability to be identified more accurately than by analysis of the original non-decomposed data series, and for this reason, this procedure has proved to be a suitable technique for analyzing the main environmental factors influencing airborne pollen concentrations.
Article
Background: Grasses (Poaceae) are one of the largest plant families and are distributed worldwide. Grass pollen allergy is one of the most important pollen allergies affecting large parts of the population worldwide. The grass pollen season itself is special since it is caused by the flowering of various grass species that present unique profiles of allergenicity, which assumingly plays a significant role and impact on grass pollen sensitization profiles for the allergy sufferer. The aim of this study, conducted in Vienna, 2014, was to analyze the possible contribution of prevalent grass species to the grass pollen season and to the symptom load of grass allergy sufferers. Methods: This was the first study that combines phenological observations (i.e. grass species and their flowering periods) with aerobiological measurements (i.e. daily grass pollen concentrations) in concert with allergic symptoms from local users of the Patient's Hayfever Diary (symptom load index calculation). Results: Both the pollen concentrations and the symptom levels were higher in the first half of the main grass pollen season and therefore show the highest impact on pollen allergy sufferers. Of important note were the following species that are widely distributed in Vienna: Kentucky bluegrass (Poa pratensis), orchard grass (Dactylis glomerata), false oat-grass (Arrhenatherum elatius), fescue grass (Festuca sp.) and perennial rye-grass (Lolium perenne). Conclusion: Monitoring different grass species provided evidence for varying contribution in pollination across the main grass pollen season and highlighted the significance this impact may have on pollen allergy sufferers.
Article
Background: Local allergic rhinitis (LAR) is a phenotype of allergic rhinitis characterized by the presence of a localized immune response in the nasal mucosa of patients with negative skin prick test (SPT) results and undetectable serum specific IgE (sIgE). It unknown whether LAR is limited to areas with low or moderate aeroallergen exposure. Objective: To explore the presence of LAR and the clinical and immunological characteristics of this entity in geographic areas with high grass pollen loads. Methods: A cross-sectional observational study was carried out in 2 hospitals in central Spain (Madrid and Ciudad Real). Sixty-one patients with seasonal rhinitis and negative SPT results and undetectable serum sIgE were evaluated using a clinical questionnaire, determination of serum total IgE, and a nasal allergen provocation test (NAPT) with Phleum species. The response to NAPT was monitored using assessment of nasal symptoms, acoustic rhinometry, and determination of sIgE, tryptase, and eosinophil cationic protein in the nasal cavity. Results: Seasonal LAR was detected in 37 patients (61%) using the techniques described above. Eleven percent of patients with LAR were adolescents or children, and 14% reported onset of rhinitis in childhood. Most patients reported persistent-moderate seasonal nasal symptoms, and 41% reported worsening of the disease during the last 2 years. Conjunctivitis was the most common comorbidity, affecting 95% of cases. Conclusions: LAR to grass pollen is relevant in patients with seasonal symptoms indicative of allergic rhinitis but with a negative skin test result who live in areas with high allergenic pollen loads. This entity should be included the differential diagnosis of rhinitis.
Article
The interpretation of airborne pollen levels in cities based on the contribution of the surrounding flora and vegetation is a useful tool to estimate airborne allergen concentrations and, consequently, to determine the allergy risk for local residents. This study examined the pollen spectrum in a city in central Spain (Guadalajara) and analysed the vegetation landscape and land uses within a radius of 20km in an attempt to identify and locate the origin of airborne pollen and to determine the effect of meteorological variables on pollen emission and dispersal. The results showed that local wind direction was largely responsible for changes in the concentrations of different airborne pollen types. The land uses contributing most to airborne pollen counts were urban green spaces, though only 0.1% of the total surface area studied, and broadleaved forest which covered 5% of the study area. These two types of land use together accounted for 70% of the airborne pollen. Crops, scrubland and pastureland, though covering 80% of the total surface area, contributed only 18.6% to the total pollen count, and this contribution mainly consisted of pollen from Olea and herbaceous plants, including Poaceae, Urticaceae and Chenopodiaceae-Amaranthaceae. Pollen from ornamental species were mainly associated with easterly (Platanus), southerly (Cupressaceae) and westerly (Cupressaceae and Platanus) winds from the areas where the city's largest parks and gardens are located. Quercus pollen was mostly transported by winds blowing in from holm-oak stands on the eastern edge of the city. The highest Populus pollen counts were associated with easterly and westerly winds blowing in from areas containing rivers and streams. The airborne pollen counts generally rose with increasing temperature, solar radiation and hours of sunlight, all of which favour pollen release. In contrast, pollen counts declined with increased relative humidity and rainfall, which hinder airborne pollen transport.
Article
In single pollen grains, the polar axis should be defined in relation to the actual geometry of the surface of the monads. The ontogenetic definition, referring to the position in the tetrad, is inapplicable in practicc, and can lead to confusion.
Article
With the increasing ease of measuring multiple variables per object the importance of variable selection for data reduction and for improved interpretability is gaining importance. There are numerous suggested methods for variable selection in the literature of data analysis and statistics, and it is a challenge to stay updated on all the possibilities. We therefore present a review of available methods for variable selection within one of the many modeling approaches for high-throughput data, Partial Least Squares Regression. The aim of this paper is mainly to collect and shortly present the methods in such a way that the reader easily can get an understanding of the characteristics of the methods and to get a basis for selecting an appropriate method for own use. For each method we also give references to its use in the literature for further reading, and also to software availability.
Article
It is difficult to reliably distinguish Betula species solely on pollen morphological criteria. Size differences between the pollen of different Betula species have proved to provide a basis for their separation. Pollen grain size is affected by both sedimentary environment and laboratory treatment. Only grains from similar sediment lithologies that have had identical laboratory treatment can be considered comparable in size with each other. A simple size comparison between modern and fossil pollen is not advisable. In this paper previous methods for the separation of birch pollen types are reviewed and some new measurements of the Finnish birch species are presented and discussed.
Article
A study was made of the total pollen production per individual tree in ten anemophilous arboreal species (including wild, cultivated and ornamental species) of considerable aerobiological importance: Pinus pinaster, Ulmus minor, Juglans regia, Platanus hispanica, Quercus rotundifolia, Salix atrocinerea, Populus nigra, Acer negundo, Olea europaea and Fraxinus angustifolia.For each species three isolated well-shaped specimens of medium height were chosen, and the number of flowers per individual tree and the number of pollen grains per anther was estimated.The values of total pollen production varied between a little over 1000 million grains in Juglans regia and more than 500,000 million in one single tree in Quercus rotundifolia. For the production of pollen grains per anther, the values oscillated between 3000 grains in Juglans regia and 100,000 in Olea europaea. There is an exponential correlation between the size of the anthers and the number of pollen grains they contain. A linear correlation is also evident between the volume of the tree crown and the total production of inflorescences, flowers, anthers and pollen grains per individual tree. Based on this, a mean coefficient of the number of grains/meter of diameter of the tree crown is obtained which varies between 3.4 × 108 for Juglans regia and 550.9 × 108 for Quercus rotundifolia. The ratio between the number of anthers per inflorescence and the number of pollen grains per anther carries out a hyperbolic function; thus, the inflorescences with the most anthers have the anthers with the least pollen and viceversa. This ratio is also manifest between the number of grains per flower and the number of flowers per tree, as well as the number of grains per inflorescence and the number of inflorescences per tree.
Article
A suction trap has been made in which the spores entering a narrow orifice, directed into the wind, are impacted on a Vaseline-coated microscope slide moved across the orifice at 2 mm./hr. Estimates of spore content of the air can be made, with higher efficiency than by previous traps, at different times of day and thus be more closely correlated with variations in weather. Wind-tunnel tests with spores of Lycopodium clavatum showed maximal and minimal efficiencies of 93.8 and 62.4% respectively, with a suction rate of 10.0 1./min., in the range of wind speeds from 1.5 to 9.3 m./sec.
Article
The main aim of this work is to study the aerobiological behaviour of Poaceae pollen in three areas of central Spain (Aranjuez, Madrid and Toledo), all of which are similar from a geographical, climatic and biogeographical point of view, and they are located nearby one another. The samplings were carried out over a period of 4years (2005–2008) using Hirst-type spore traps. Grass pollen is responsible for most spring allergic reactions in the pollen-sensitive population in central Spain, and they are very abundant in the atmosphere of this part of Iberian Peninsula. The average amount of this pollen type, as a percentage of the annual total pollen amount, is 7.4% in Aranjuez, 9.2% in Madrid and 11.3% in Toledo. Poaceae pollen is present in the atmosphere over a long period of time (February–October), and its maximum concentrations are detected during May and June (weeks 16–25). The city of Toledo has the highest annual concentrations of grass pollen (average 5,797 grains) with a great number of days exceeding the allergy thresholds proposed by the Spanish Aerobiology Network (REA). Madrid and Aranjuez present similar annual concentrations of grass pollen with values of 2,961 grains and 2,751 grains, respectively. The correlation analysis between the daily levels of grass pollen and meteorological variables of temperature and rainfall show a significant correlation, positive with temperature (maximum, mean and minimum) and negative with rainfall. KeywordsAerobiology–Poaceae/grass pollen–Meteorological variables–Central Spain
Article
Grass pollen is a worldwide cause of respiratory allergy. Identifying the causative species is essential, for example for choosing the appropriate immunotherapy, because not all grass allergens are totally cross-reacting, and the pollen calendars provide only a gross estimate. Phenologic analyses allow identification of the pollen release for each individual grass. To assess, using phenologic analyses, the true flowering periods of grasses and to compare the data with the standard pollen calendar. Phenologic analyses were performed of the following grasses: black grass, sweet vernal grass, common wild oat, barren brome, cocksfoot, tall fescue, Yorkshire fog, ryegrass, Timothy grass, bulbous meadow-grass, Kentucky bluegrass, and Bermuda grass. Sampling was performed every 10 days, starting in April 2009, at 50 stations distributed across Italy. The flowering phase was assessed using a stereomicroscopy-based method for the detection of spreading stamens. The official pollen calendar was used for comparison. Relevant differences were found between grass pollen count and effective flowering of the grass species. Only some species contributed to the pollen peak, and a relevant pollen load for other species was also present out of the peak. Important Pooideae, such as Timothy grass, were not present during the pollen peak in northern and central Italy, and the same occurred with Bermuda grass. The various species of grasses release their pollen grains at different times during the pollen season, and this information is missing with pollen calendars. This may have a relevant effect on the choice of an appropriate immunotherapy.
Article
Phenological studies in combination with aerobiological studies enable one to observe the relationship between the release of pollen and its presence in the atmosphere. To obtain a suitable comparison between the daily variation of airborne pollen concentrations and flowering, it is necessary for the level of accuracy of both sets of data to be as similar as possible. To analyse the correlation between locally observed flowering data and pollen counts in pollen traps in order to set pollen information forecasts, pollen was sampled using a Burkard volumetric pollen trap working continuously from May 1993. For the phenological study we selected the main pollen sources of the six pollen types most abundant in our area: Cupressaceae, Platanus, Quercus, Plantago, Olea, and Poaceae with a total of 35 species. We selected seven sites to register flowering or pollination, two with semi-natural vegetation, the rest being urban sites. The sites were visited weekly from March to June in 2007, and from January to June in 2008 and 2009. Pollen shedding was checked at each visit, and recorded as the percentage of flowers or microsporangia in that state. There was an association between flowering phenology and airborne pollen records for some of the pollen types (Platanus, Quercus, Olea and Plantago). Nevertheless, for the other types (Cupressaceae and Poaceae) the flowering and airborne pollen peaks did not coincide, with up to 1 week difference in phase. Some arguments are put forward in explanation of this phenomenon. Phenological studies have shown that airborne pollen results from both local and distant sources, although the pollen peaks usually appear when local sources are shedding the greatest amounts of pollen. Resuspension phenomena are probably more important than long-distance transport in explaining the presence of airborne pollen outside the flowering period. This information could be used to improve pollen forecasts.
Article
Skin prick testing is the standard for diagnosing IgE-mediated allergies. A positive skin prick reaction, however, does not always correlate with clinical symptoms. A large database from a Global Asthma and Allergy European Network (GA(2)LEN) study with data on clinical relevance was used to determine the clinical relevance of sensitizations against the 18 most frequent inhalant allergens in Europe. The study population consisted of patients referred to one of the 17 allergy centres in 14 European countries (n = 3034, median age = 33 years). The aim of the study was to assess the clinical relevance of positive skin prick test reactions against inhalant allergens considering the predominating type of symptoms in a pan-European population of patients presenting with suspected allergic disease. Clinical relevance of skin prick tests was recorded with regard to patient history and optional additional tests. A putative correlation between sensitization and allergic disease was assessed using logistic regression analysis. While an overall rate of >or=60% clinically relevant sensitizations was observed in all countries, a differential distribution of clinically relevant sensitizations was demonstrated depending on type of allergen and country where the prick test was performed. Furthermore, a significant correlation between the presence of allergic disease and the number of sensitizations was demonstrated. This study strongly emphasizes the importance of evaluating the clinical relevance of positive skin prick tests and calls for further studies, which may, ultimately, help increase the positive predictive value of allergy testing.
Article
Skin prick testing is the standard for diagnosing IgE-mediated allergies. However, different allergen extracts and different testing procedures have been applied by European allergy centres. Thus, it has been difficult to compare results from different centres or studies across Europe. It was, therefore, crucial to standardize and harmonize procedures in allergy diagnosis and treatment within Europe. The Global Asthma and Allergy European Network (GA(2)LEN), with partners and collaborating centres across Europe, was in a unique position to take on this task. The current study is the first approach to implement a standardized procedure for skin prick testing in allergies against inhalant allergens with a standardized pan-European allergen panel. The study population consisted of patients who were referred to one of the 17 participating centres in 14 European countries (n = 3034, median age = 33 years). Skin prick testing and evaluation was performed with the same 18 allergens in a standardized procedure across all centres. The study clearly shows that many allergens previously regarded as untypical for some regions in Europe have been underestimated. This could partly be related to changes in mobility of patients, vegetation or climate in Europe. The results of this large pan-European study demonstrate for the first time sensitization patterns for different inhalant allergens in patients across Europe. The standardized skin prick test with the standardized allergen battery should be recommended for clinical use and research. Further EU-wide monitoring of sensitization patterns is urgently needed.
Article
Allergen-specific immunotherapy uses aqueous extracts of natural source materials as a basis for preparations to down regulate the allergic response. Recombinant DNA technology has enabled the cloning of many allergens, thus facilitating investigations aimed at improving efficacy and safety of immunotherapy. To determine the effectiveness of a mixture of 5 recombinant grass pollen allergens in reducing symptoms and need for symptomatic medication in patients allergic to grass pollen. A randomized, double-blind, placebo-controlled study of subcutaneous injection immunotherapy was performed in subjects with allergic rhinoconjunctivitis, with or without asthma. Primary endpoint was a symptom medication score compiled from separate symptom and medication scores. Secondary endpoints included a rhinitis quality of life questionnaire, conjunctival provocation, and specific antibody responses. The symptom medication score showed significant improvements in subjects receiving recombinant allergens as opposed to placebo, with reductions in both symptoms and medication usage. The rhinitis quality of life questionnaire revealed clinically relevant significant improvements in overall assessment and in 5 of 7 separate domains, and conjunctival provocation showed a clear trend in favor of active treatment. All treated subjects developed strong allergen-specific IgG(1) and IgG(4) antibody responses. Some patients were not sensitized to Ph l p 5 but nevertheless developed strong IgG antibody responses to that allergen. A recombinant allergen vaccine can be a effective and safe treatment to ameliorate symptoms of allergic rhinitis. The clinical benefit is associated with modification of the specific immune response with promotion of IgG(4) and reduction of IgE antibodies consistent with the induction of IL-10-producing regulatory T cells.
Article
The allergenic content of the atmosphere varies according to climate, geography and vegetation. Data on the presence and prevalence of allergenic airborne pollens, obtained from both aerobiological studies and allergological investigations, make it possible to design pollen calendars with the approximate flowering period of the plants in the sampling area. In this way, even though pollen production and dispersal from year to year depend on the patterns of preseason weather and on the conditions prevailing at the time of anthesis, it is usually possible to forecast the chances of encountering high atmospheric allergenic pollen concentrations in different areas. Aerobiological and allergological studies show that the pollen map of Europe is changing also as a result of cultural factors (for example, importation of plants such as birch and cypress for urban parklands), greater international travel (e.g. colonization by ragweed in France, northern Italy, Austria, Hungary etc.) and climate change. In this regard, the higher frequency of weather extremes, like thunderstorms, and increasing episodes of long range transport of allergenic pollen represent new challenges for researchers. Furthermore, in the last few years, experimental data on pollen and subpollen-particles structure, the pathogenetic role of pollen and the interaction between pollen and air pollutants, gave new insights into the mechanisms of respiratory allergic diseases.
Article
Asthma among children is a major public health problem worldwide. There are increasing number of studies suggesting a possible association between allergenic pollen and exacerbations of asthma. In the context of global climate change, a number of future climate and air pollution scenarios predict increases in concentrations of pollen, an extension of the pollen season, and an increase in the allergenicity of pollen. The goal of the present study is to evaluate the short-term effects of exposure to grass and weed pollen on emergency department visits and readmissions for asthma among children aged 0-9 years living in Montreal between April and October, 1994-2004. Time-series analyses were carried out using parametric log-linear overdispersed Poisson models that were adjusted for temporal variations, daily weather conditions (temperature, atmospheric pressure), and gaseous air pollutants (ozone and nitrogen dioxide). We have found positive associations between emergency department visits and concentrations of grass pollen 3 days after exposure. The effect of grass pollen was higher on emergency department readmissions as compared to initial visits. Weak negative associations were found between weed pollen (including ragweed pollen) and emergency department visits 2 days after exposure. The data indicate that among children, emergency department visits increased with increasing concentrations of grass pollen.
Article
Grass pollen is one of the most important allergen sources. The aim of this study was to compare the in vivo allergenic activity of two recently characterized major grass pollen allergens, Phl p 4 and Phl p 13, with three established major grass pollen allergens, Phl p 1, Phl p 2 and Phl p 5 as a basis for the formulation of a grass pollen allergy vaccine based on purified allergens. Eighty-two grass pollen allergic patients were skin prick tested with serial dilutions of approximately equimolar concentrations of the purified allergens in a double-blind study. Phl p 4 and Phl p 13 were identified as major grass pollen allergens according to IgE binding frequency (Phl p 4: 85%; Phl p 13: 56%), but exhibited a five to nine-fold lower allergenic skin reactivity compared to Phl p 1, Phl p 2 or Phl p 5. Our results indicate that Phl p 4 and Phl p 13 are not essential components for a therapeutic grass pollen vaccine and underpin the importance of evaluating the in vivo allergenic activity of individual allergens for the formulation of therapeutic vaccines based on purified allergens.