Airborne pollen concentration in the region of Braga, Portugal, and its relationship with meteorological parameters

The variation in airborne pollen concentrationof the Braga region (Portugal) was studied inspringtime, during the flowering of Vitisvinifera. The data set was obtained for twoconsecutive years (1999 and 2000), using aCour-type sampler.During this period, thirty-six taxa wereobserved in a total of 3,200 pollengrains m^-3 of air (CPA). The main pollentypes observed were Olea, Poaceaea,nd Castanea, representing 74% of thepollen spectrum.The airborne pollen concentration (CPA) wassignificantly correlated with certainmeteorological parameters. Pollen concentrationwas positively correlated with temperature andwind direction (East and Northeast) andnegatively correlated with rainfall and numberof rainy days.     

Model for forecasting Olea europaea L. airborne pollen in South-West Andalusia, Spain

Data on predicted average and maximum airborne pollen concentrations and the dates on which these maximum values are expected are of undoubted value to allergists and allergy sufferers, as well as to agronomists. This paper reports on the development of predictive models for calculating total annual pollen output, on the basis of pollen and weather data compiled over the last 19 years (1982–2000) for Córdoba (Spain). Models were tested in order to predict the 2000 pollen season; in addition, and in view of the heavy rainfall recorded in spring 2000, the 1982–1998 data set was used to test the model for 1999. The results of the multiple regression analysis show that the variables exerting the greatest influence on the pollen index were rainfall in March and temperatures over the months prior to the flowering period. For prediction of maximum values and dates on which these values might be expected, the start of the pollen season was used as an additional independent variable. Temperature proved the best variable for this prediction. Results improved when the 5-day moving average was taken into account. Testing of the predictive model for 1999 and 2000 yielded fairly similar results. In both cases, the difference between expected and observed pollen data was no greater than 10%. However, significant differences were recorded between forecast and expected maximum and minimum values, owing to the influence of rainfall during the flowering period. Received: 25 October 2000 / Revised: 26 February 2001 / Accepted: 28 February 2001     

Production of total and stainable pollen grains in Olea europaea L

The production of the total and stainable number of pollen grains per flower and per inflorescence of 13 olive cultivars (Olea europaea L.) has been investigated. Grains stainability was evaluated by using the acetic carmine staining method whereas the production of pollen grains was calculated by using a Bürker haemocytometer. All pollen characteristics taken into account varied significantly among the cultivars. The number of flowers per inflorescence ranged from a maximum of 31.3 (‘Cipressino’) to a minimum of 13.0 (‘Leccino’), the number of pollen grains per anther ranged from 123?346 (‘Arbequina’) to 40?975 (‘Sant'Agostino’), and the pollen stainability from 97.6% (‘Cipressino’) to 48.0% (‘Cellina di Nardò’). The number of stainable pollen grains per inflorescence averaged 2?559?512, ranging from a maximum of 3?913?678 (‘Nociara’) to a minimum of 940?143 (‘Sant'Agostino’). All parameters were positively correlated, whereas a linear negative correlation was found between stainability and total pollen grains both per anther and per inflorescence.     

北京主要气传致敏花粉年浓度峰值日期预测

花粉是我国北方引发过敏性鼻炎最主要过敏原,花粉症发病期与花粉浓度高峰期吻合。基于北京地区2012至2020年花粉季多站、逐日分类花粉浓度观测数据分析,得出北京地区花粉浓度在3月上旬至5月中旬(可进一步划分为3月中旬至4月上旬和4月下旬至5月上旬两个高峰期)和8月中旬至9月中旬分别存在两个高峰期,第一个高峰期内优势致敏花粉种类为柏科、杨柳科和松科,第二个高峰期内优势致敏花粉种类为桑科、菊科蒿属和藜科。根据优势致敏花粉年浓度峰值日期观测数据,使用与花粉采样站点位置相匹配的逐日气象观测数据累积值,基于作物模型概念和模糊逻辑原理建立了北京地区主要气传致敏花粉年浓度峰值日期预测模型。经检验,柏科、杨柳科、松科、桑科、菊科蒿属和藜科花粉模型预测准确率分别为87.8%、80.0%、64.4%、86.7%、78.8%和81.8%。基于北京地区主要气传致敏花粉年浓度峰值日期预测模型可为本地花粉症防治提供理论参考。     

The effect of meteorological parameters on diurnal patterns of airborne olive pollen concentration

Aerobiological studies carried out in the atmosphere of Granada using a Hirst-type volumetric spore trap during the period 1993-1996 show that there is not a single diurnal pattern for olive pollen (Olea europaea L.) over the course of the main pollen season. Examination of the behaviour of airborne olive pollen concentration allows the establishment of either regular (54.4% of the studied days) or irregular (45.6% of the time) patterns of diurnal variation. On a given day, the pattern found will depend on a combination of different factors: the origin of the captured pollen (either local or regional), source distribution in relation to the pollen sampler, topography, and different meteorological variables (mean air temperature, sunshine hours, total rainfall, relative humidity, wind speed and direction, and periods of calm). Regional sources were significant contributors to city centre pollen concentrations when moderate (< 10 km/h) winds from the 4th quadrant and warm temperatures (19-26 C) allow swift transport from the W-NW of the province.     

Vertical variation in urticaceae airborne pollen concentration

The pollen contents at different heights (1.5 and 15 m) of species of the Urticaceae family have been studied by sampling with Hirst type volumetric samplers. In order to achieve this, the two pollen types belonging to this family have been treated separately,Urtica urens-Parietaria sp. on the one hand andUrtica membranacea on the other, the latter having a smaller pollen grain. The results show that meteorological factors are bound to influence the behaviour of both these types of pollen in relation to height. With damp weather the pollen contents vary very slightly at different heights while when the weather is dry and calm, differences in pollen content at different heights become more significant. Nevertheless, when the atmosphere is stratified, the behaviour of each pollen type is different. The results show that, for most of the months considered, there is a higher pollen content ofU. membranacea at upper heights, whileU. urens-Parietaria sp. has higher levels of pollen content at a lower height. High temperatures, absence of rain and calm weather conditions favour the presence of convective phenomena which in turn create a favourable atmosphere for the vertical transportation of the small pollen grains ofU. membranacea, which are better represented in the samplers placed at 15 m.     

Fifteen years' record of airborne allergenic pollen and meteorological parameters in Thessaloniki,Greece

A pollen calendar has been constructed for the area of Thessaloniki and relationships between pollen transport and meteorological parameters have been assessed. Daily airborne pollen records were collected over a 15-year period (1987-2001), using a Burkard continuous volumetric pollen trap, located in the centre of the city. Sixteen allergenic pollen types were identified. Simultaneously, daily records of five main meteorological parameters (mean air temperature, relative humidity, rainfall, sunshine, wind speed) were made, and then correlated with fluctuations of the airborne pollen concentrations. For the first time in Greece, a pollen calendar has been constructed for 16 pollen types, from which it appears that 24.9% of the total pollen recorded belong to Cupressaceae, 20.8% to Quercus spp., 13.6% to Urticaceae, 9.1% to Oleaceae, 8.9% to Pinaceae, 6.3% to Poaceae, 5.4% to Platanaceae, 3.0% to Corylus spp., 2.5% to Chenopodiaceae and 1.4% to Populus spp. The percentages of Betula spp., Asteraceae (Artemisia spp. and Ambrosia spp.), Salix spp., Ulmaceae and Alnus spp. were each lower than 1%. A positive correlation between pollen transport and both mean temperature and sunshine was observed, whereas usually no correlation was found between pollen and relative humidity or rainfall. Finally, wind speed was generally found to have a significant positive correlation with the concentrations of 8 pollen types. For the first time in the area of Thessaloniki, and more generally in Greece, 15-year allergenic pollen records have been collected and meteorological parameters have been recorded. The airborne pollen concentration is strongly influenced by mean air temperature and sunshine duration. The highest concentrations of pollen grains are observed during spring (May).     

Comparison of Classical Models for Evaluating the Heat Requirements of Olive （Olea europeae L.） in Portugal

The aim of the present study was to compare the accuracy and reproducibility of six statistical models for the calculation of olive （Olea europeae L.） heat requirements to trigger the onset of flowering in three Portuguese regions： Reguengos de Monsaraz, Valenga do Douro, and Braga. Other alms were to ascertain the date on which the heat-accumulation period started and the threshold temperatures above which the development of reproductive structures starts in olives. The starting and peak dates for the regional O. europeae flowering season were estimated by monitoring airborne pollen from 1998 to 2004 using ＂Cour＂- type samplers. The threshold temperature values calculated for the three regions were very similar （9.0 ℃ for Valenca do Douro, 9.2 ℃ for Reguengos de Monsaraz, and 9.7 ℃ for Braga）. The accumulated daily mean temperature model had less interannual and inter-regional variation, showing best predictive results for 2004, with absolute differences between the observed and predicted dates of 4 d in Reguengos de Monsaraz and 2 d In Valenca do Douro and Braga for the onset of flowering date and of 2 d In Reguengos de Monsaraz, 7 d in Valenca do Douro, and 4 d in Braga for peak flowering dates. This model was the most accurate, reproducible, and operational to calculate heat requirements for olives to flower, with an average mean temperature accumulation of 1 446 ℃ In Reguengos, 1 642 ℃ in Valenga do Douro, and 1 703℃ In Braga to reach the onset of flowering. The best initial date for this accumulation was 1 January.     

The role of temperature in the onset of the Olea europaea L. pollen season in southwestern Spain

Temperature is one of the main factors affecting the flowering of Mediterranean trees. In the case of Olea europaea L., a low-temperature period prior to bud development is essential to interrupt dormancy. After that, and once a base temperature is reached, the plant accumulates heat until flowering starts. Different methods of obtaining the best-forecast model for the onset date of the O. europaea pollen season, using temperature as the predictive parameter, are proposed in this paper. An 18-year pollen and climatic data series (1982–1999) from Cordoba (Spain) was used to perform the study. First a multiple-regression analysis using 15-day average temperatures from the period prior to flowering time was tested. Second, three heat-summation methods were used, determining the the quantities heat units (HU): accumulated daily mean temperature after deducting a threshold, growing degree-days (GDD): proposed by Snyder [J Agric Meteorol 35:353–358 (1985)] as a measure of physiological time, and accumulated maximum temperature. In the first two, the optimum base temperature selected for heat accumulation was 12.5°C. The multiple-regression equation for 1999 gives a 7-day delay from the observed date. The most accurate results were obtained with the GDD method, with a difference of only 4.7 days between predicted and observed dates. The average heat accumulation expressed as GDD was 209.9°C days. The HU method also gives good results, with no significant statistical differences between predictions and observations. Received: 18 April 2000 / Revised: 14 September 2000 / Accepted: 19 September 2000     

Effects of meteorological parameters and plantdistribution on Chenopodiaceae-Amaranthaceae, Quercus and Olea airborne pollen concentrationsin the atmosphere of Cartagena (Spain)

We have studied the effects of various meteorologicalparameters and plant distribution on the airborneconcentrations of three different pollen types:Chenopodiaceae-Amaranthaceae, Quercus and Olea, in the city of Cartagena, situated in SouthwestEurope. The aerobiological study has been carried outfrom March 1993 to March 1997, using a Hirst-typeLanzoni 2000 trap, situated on the roof of the citytrain station. Meteorological data were supplied bythe Environmental Service of Cartagena's Town Hall.Daily pollen concentrations were standardised.Correlation analysis showed the importance ofmeteorological data on airborne pollen concentrations.On the other hand, ANOVA analyses depicted theinfluence of vegetation distribution in relation tosampler location and wind directions. Finally,multiple regression analyses allowed us to developcorrelation models for the three different pollentypes considered, accounting for 32%(Chenopodiaceae-Amaranthaceae), 19% (Quercus),and 26% (Olea) of the variation in the airbornepollen concentration.     

Improving early-season estimates of olive production using airborne pollen multi-sampling sites

The aim of this study was to improve the accuracy of aeropalynological models to forecast yields in areas with heterogeneous characteristics by applying principal component analysis to integrate the airborne pollen sampled from more than one trap. The sampling was performed during the past seven years (1998–2004) in the main northeast olive regions of Portugal. Annual crop production was forecasted on the basis of airborne pollen concentration measured at flowering, comparing the performance of three different independent variables: total airborne pollen concentration sampled in each trap and a derived variable that was determined by principal component analysis of the total airborne pollen concentration sampled. The best predictive results were obtained using a logarithmic relationship with airborne pollen concentration principal component scores describing about 97% of olive fruit production variability over the last seven years. The use of this technique improved the ability of pollen to explain the production interannual variations by about 13%. The comparison between actual reported and the adjusted production showed an average spread deviation of 5%.     

An automated system for surveying and forecasting Olea pollen dispersion

An automated system for Olea pollensurveying and forecasting is being developedfor the province of Cordoba, Spain, within theframework of the European ASTHMA project.Required input data have been split into threecategories: static data, calibration parametersand dynamic data. A 200 × 200 km potential pollenproduction map, centred on the city of Cordoba,was drawn up using digital high-resolutionsatellite data and reflecting average plantdensity, as derived from the observed spatialseparation of trees in 28 different locations.Based on archives of pollen data from 1982, thestart of the pollen season was determined byapplying both heat accumulation methods andneural network analysis including furthermeteorological parameters. The forecast andsurvey system is based on a set of twoelementary atmospheric physics modules andbiological models: emission and dispersionmodules. The system can run in different modes,allowing forecasting of the floweringstart-date and, from that date, charting theemission and dispersion of pollenconcentrations in the area. Also, wind andtemperature fields are regularly computed andupdated using deterministic numerical models tochart the spatial and temporal concentration ofOlea pollen.     

Variations in airborne pollen in central and south-western Spain in relation to the distribution of potential sources

The present study seeks to compare daily and hourly airborne pollen concentrations at eight different stations in Castilla-La Mancha (central Spain) and Extremadura (south-western Spain) and assess pollen distribution sources. Sampling stations were located 69–440 km apart in a straight line in Albacete, Toledo, Talavera de la Reina and Ciudad Real in Castilla-La Mancha, and in Badajoz, Plasencia, Santa Amalia and Zafra in Extremadura. Airborne pollen was collected using Hirst-type volumetric spore traps. Quercus was the most abundant pollen type at all stations except for Ciudad Real, where Olea pollen predominated. Comparisons of daily data between pairs of stations revealed statistically significant positive correlations in all cases for Poaceae and Olea. Comparisons of hourly data between stations indicated greater differences than daily data. Analysis of correlation coefficients and straight-line distances between stations revealed a strong negative correlation. Analysis of total airborne pollen data for the eight sampling stations suggests that airborne pollen concentrations decrease from west to east and from south to north, partly reflecting dominant wind patterns. A clear correlation was observed between airborne pollen concentrations and the surface area covered by olive crops in a 50 km radius around the sampling stations.     

The effects of meteorological factors on airborne fungal spore concentration in two areas differing in urbanisation level

Although fungal spores are an ever-present component of the atmosphere throughout the year, their concentration oscillates widely. This work aims to establish correlations between fungal spore concentrations in Porto and Amares and meteorological data. The seasonal distribution of fungal spores was studied continuously (2005–2007) using volumetric spore traps. To determine the effect of meteorological factors (temperature, relative humidity and rainfall) on spore concentration, the Spearman rank correlation test was used. In both locations, the most abundant fungal spores were Cladosporium, Agaricus, Agrocybe, Alternaria and Aspergillus/Penicillium, the highest concentrations being found during summer and autumn. In the present study, with the exception of Coprinus and Pleospora, spore concentrations were higher in the rural area than in the urban location. Among the selected spore types, spring-autumn spores (Coprinus, Didymella, Leptosphaeria and Pleospora) exhibited negative correlations with temperature and positive correlations both with relative humidity and rainfall level. On the contrary, late spring-early summer (Smuts) and summer spores (Alternaria, Cladosporium, Epicoccum, Ganoderma, Stemphylium and Ustilago) exhibited positive correlations with temperature and negative correlations both with relative humidity and rainfall level. Rust, a frequent spore type during summer, had a positive correlation with temperature. Aspergillus/Penicillium, showed no correlation with the meteorological factors analysed. This knowledge can be useful for agriculture, allowing more efficient and reliable application of pesticides, and for human health, by improving the diagnosis and treatment of respiratory allergic disease.     

Profiling and functional classification of esterases in olive (Olea europaea) pollen during germination

Background and Aims

A pollen grain contains a number of esterases, many of which are released upon contact with the stigma surface. However, the identity and function of most of these esterases remain unknown. In this work, esterases from olive pollen during its germination were identifided and functionally characterized.

Methods

The esterolytic capacity of olive (Olea europaea) pollen was examined using in vitro and in-gel enzymatic assays with different enzyme substrates. The functional analysis of pollen esterases was achieved by inhibition assays by using specific inhibitors. The cellular localization of esterase activities was performed using histochemical methods.

Key Results

Olive pollen showed high levels of non-specific esterase activity, which remained steady after hydration and germination. Up to 20 esterolytic bands were identified on polyacrylamide gels. All the inhibitors decreased pollen germinability, but only diisopropyl fluorophosphate (DIFP) hampered pollen tube growth. Non-specific esterase activity is localized on the surface of oil bodies (OBs) and small vesicles, in the pollen intine and in the callose layer of the pollen tube wall. Acetylcholinesterase (AChE) activity was mostly observed in the apertures, exine and pollen coat, and attached to the pollen tube wall surface and to small cytoplasmic vesicles.

Conclusions

In this work, for the first time a systematic functional characterization of esterase enzymes in pollen from a plant species with wet stigma has been carried out. Olive pollen esterases belong to four different functional groups: carboxylesterases, acetylesterases, AChEs and lipases. The cellular localization of esterase activity indicates that the intine is a putative storage site for esterolytic enzymes in olive pollen. Based on inhibition assays and cellular localization of enzymatic activities, it can be concluded that these enzymes are likely to be involved in pollen germination, and pollen tube growth and penetration of the stigma.     

Effect of agrometeorological parameters on the phenology of pollen emission and production of olive trees (Olea europea L.)

The pollination period and pollen concentrationof olive trees (Oleaeuropea L.) and olive production were analysedfor Prato and Florenceusing a data set of 8 years (1991–1998).Meteorological data have been usedto obtain information about weather conditionsduring vegetative seasonsand correlations were found both for thephenology and yield.The results showed that air temperatureprevious to the onset of floweringis of great importance in determining thereproductive cycle of olive treebut the chill period in January and Februaryshould also be considered.Olive pollen collected during thepollination period was positivelycorrelated with the production level for bothsites. Weather conditionfollowing pollination were also taken intoaccount for a better assessmentof the final yield.     

Monitoring pollinosis and airborne pollen in a Rome university

Pollen allergies and airborne pollen weremonitored at the University of Rome ``TorVergata' in 1999 in order to determine theconcentration and the quality of airbornepollen belonging to allergenic plants inrelationship to the prevalence of pollenallergies.Airborne pollen was monitored by volumetrictrap while data on allergies were collectedthrough a questionnaire distributed to theUniversity personnel belonging to variousworking categories. Meteorological data wereobtained through a daily monitoring carried outby a meteorological station while plantanthesis identification was done at theHerbarium of the University.Results indicated that prevalent allergies weredue to Gramineae, Urticaceae and Oleaceaepollen. Many subjects suffering from allergiesdid not know the responsible allergen(s) andmore than half of the allergic subjects statedto have allergic relatives.Data on pollen monitoring and prevalence ofallergies, collected in the same geographicalarea, were found to be in accordance with eachother, with the exception of the case ofCupressaceae/Taxaceae plants, whose pollen wasfound in high concentration although no case ofallergy due to this pollen was established.