Can Photoselective Nets' Influence Pollen Traits? A Case Study in 'Matua' and 'Tomuri' Kiwifruit Cultivars.

The increasing use of photoselective nets (PNs) raises the question of their influence on pollen traits. We aimed to evaluate the effect of PNs (yellow, pearl, and grey) on the pollen of 'Matua' and 'Tomuri' Actinidia deliciosa cultivars. The pollen size and the exine were studied with a light microscopy and a scanning electron microscopy, and the fertility was analysed by a viability assay and in vitro germination. The total soluble proteins (TSPs) and sugars (TSSs) were quantified by colorimetric assays. The molecular structure of the pollen grain's wall was analysed by a Raman spectroscopy. The pollen from the plants under the PNs had a larger width and area and a lower germination rate. No significant changes were observed in the exine's microperforations. The TSP and TSS contents were influenced by the cultivar and PNs (particularly the pearl PN). The Raman spectra of the pollen from the plants grown under the nets presented some bands that significantly shifted from their original position, indicating differences in the vibration modes of the molecules, but no overall changes at their structural or organisation level were found. Our study showed that the PNs could influence several pollen traits, with the pearl PN inducing greater modifications. Our results also support the idea that cultivars affect the outcome of some characteristics.

Differential Quercus spp. pollen-particulate matter interaction is dependent on geographical areas.

Particulate matter (PM) and pollen interaction, either airborne or at the respiratory mucosa needs further clarification, as allergic reaction intensification can be related to the PM physical characteristics and toxicity. This study aimed to investigate the physical-chemical properties of PM that can adhere to the pollen wall during its transport or inhalation, using Quercus spp. as a model, in three Portuguese cities with different geographical locations, meteorological influence and urbanization levels. Possible sources were evaluated through air masses trajectory analysis using the HYSPLIT model and correlation with meteorological factors. The sampling was performed using a 7-days Hirst-type volumetric sampler, and the pollen grains were observed using a Field Emission Electron Probe Microanalyser for PM analysis. A secondary electron image of each pollen grain was taken, to determine the adhered particles characteristics and energy dispersive x-ray spectroscopy (EDS) spectra were obtained for individual particles. A total of 484 pollen grains was observed, with 7683 particles counted and 1914 EDS spectra analyzed. The particle's equivalent diameter ranged from 0.3-16 µm, with most having a diameter < 3 µm. For the three cities, there were significant differences in the number of particles per pollen and the % area occupied by the particles. Particles adhered were mainly Si-rich, but variations in other dominant groups were observed. For Évora and Guarda, Ca-rich, SO-rich were second and third more representative, while Porto were Organic and Cl-rich. Metals&Oxides were found in all cities with the highest number in Porto. P-rich particles were only found in Évora. Sea salt particles were observed in Évora, coincide with air mass trajectories possible carrying them from the Mediterranean Sea. In conclusion, the PM physical characteristics are similar between the studied cities, however, the dominant chemical composition is different, certainly impacting the exposome influence and pollen-allergy intensification towards the same pollen type and concentration.

Short-Term Exposure of Dactylis glomerata Pollen to Atmospheric Gaseous Pollutants Is Related to an Increase in IgE Binding in Patients with Grass Pollen Allergies.

The concentrations of nitrogen dioxide (NO2) and tropospheric ozone (O3) in urban and industrial site atmospheres are considered key factors associated with pollen-related respiratory allergies. This work studies the effects of NO2 and O3 on the protein expression profile and IgE binding in patients with grass allergies to Dactylis glomerata pollen extracts. Pollens were collected during the flowering season and were exposed to NO2 and O3 in a controlled environmental chamber. The amount of soluble protein was examined using the Bradford method, and the protein expression profile and antigenic properties were analysed using the immunoblotting and enzyme-linked immunosorbent assay (ELISA), respectively. Our results showed apparent inter-sera differences concerning the number and intensity of IgE reactivity, with the most prominent at bands of 55 kDa, 35, 33, and 13 kDa. In the 13 kDa band, both gases tend to induce an increase in IgE binding, the band at 33 kDa showed a tendency towards a reduction, particularly pollen exposed to O3. Reactive bands at 55 and 35 kDa presented an increase in the IgE binding pattern for all the patient sera samples exposed to NO2, but the samples exposed to O3 showed an increase in some sera and in others a decrease. Regarding the ELISA results, out of the 21 tested samples, only 9 showed a statistically significant increase in total IgE reactivity after pollen exposure to the pollutants. Our study revealed that although airborne pollen allergens might be affected by air pollution, the possible impacts on allergy symptoms might vary depending on the type of pollutant and the patient's sensitisation profile.

Phenological Model to Predict Budbreak and Flowering Dates of Four Vitis vinifera L. Cultivars Cultivated in DO. Ribeiro (North-West Spain).

The aim of this study was to assess the thermal requirements of the most important grapevine varieties in northwestern Spain to better understand the impact of climate change on their phenology. Different phenological models (GDD, GDD Triangular and UniFORC) were tested and validated to predict budburst and flowering dates of grapevines at the variety level using phenological observations collected from Treixadura, Godello, Loureira and Albariño between 2008 and 2019. The same modeling framework was assessed to obtain the most suitable model for this region. The parametrization of the models was carried out with the Phenological Modeling Platform (PMP) platform by means of an iterative optimization process. Phenological data for all four varieties were used to determine the best-fitted parameters for each variety and model type that best predicted budburst and flowering dates. A model calibration phase was conducted using each variety dataset independently, where the intermediate-fitted parameters for each model formulation were freely-adjusted. Afterwards, the parameter set combination of the model providing the highest performance for each variety was externally validated with the dataset of the other three varieties, which allowed us to establish one overall unique model for budburst and flowering for all varieties. Finally, the performance of this model was compared with the attained one while considering all varieties in one dataset (12 years × 4 varieties giving a total number of observations of 48). For both phenological stages, the results showed no considerable differences between the GDD and Triangular GDD models. The best parameters selected were those provided by the Treixadura GDD model for budburst (day of the year (t0) = 49 and base temperature (Tb) = 5) and those corresponding to the Godello model (t0 = 52 and Tb = 6) for flowering. The modeling approach employed allowed obtaining a global prediction model that can adequately predict budburst and flowering dates for all varieties.

Effect of O3 and NO2 atmospheric pollutants on Platanus x acerifolia pollen: Immunochemical and spectroscopic analysis.

In the present study, the effects of two important oxidizing atmospheric pollutants (O3 and NO2) on the allergenic properties and chemical composition of Platanus x acerifolia pollen were studied. Pollen samples were subjected to O3 and/or NO2 under in vitro conditions for 6h at atmospheric concentration levels (O3: 0.061ppm; NO2: 0.025ppm and the mixture of O3 and NO2: 0.060 and 0.031ppm respectively). Immunoblotting (using Pla a 1 and Pla a 2 antibodies), infrared and X-ray photoelectron spectroscopy techniques were used. Immunochemical analysis showed that pollen allergenicity changes were different according to the pollutant tested (gas or mixture of gasses) and that the same pollutant gas may interact in a different manner with each specific allergen. The spectroscopy results showed modifications in the FTIR spectral features of bands assigned to proteins, lipids, and polysaccharides of the pollen exposed to the pollutants, as well as in the XPS spectra high-resolution components C 1s, N 1s, and O 1s. This indicates that while airborne, the pollen wall suffers further modifications of its components induced by air pollution, which can compromise the pollen function.

Characterisation of particulate matter on airborne pollen grains.

A characterization of the physical-chemical composition of the atmospheric PM adsorbed to airborne pollen was performed. Airborne pollen was sampled using a Hirst-type volumetric spore sampler and observed using a Field Emission Electron Probe Microanalyser for PM analysis. A secondary electron image was taken of each pollen grain and EDS spectra were obtained for individually adsorbed particles. All images were analysed and the size parameters of the particles adsorbed to pollen was determined. The measured particles' equivalent diameter varied between 0.1 and 25.8 µm, mostly in the fine fraction. The dominant particulates identified were Si-rich, Organic-rich, SO-rich, Metals & Oxides and Cl-rich. Significant daily differences were observed in the physical-chemical characteristics of particles adsorbed to the airborne pollen wall. These differences were correlated with weather parameters and atmospheric PM concentration. Airborne pollen has the ability to adsorb fine particles that may enhance its allergenicity.

Effects of atmospheric pollutants (CO, O3, SO2) on the allergenicity of Betula pendula, Ostrya carpinifolia, and Carpinus betulus pollen.

Pollen of Betula pendula, Ostrya carpinifolia, and Carpinus betulus was exposed in vitro to relatively low levels of the air pollutants, namely carbon monoxide, ozone, and sulfur dioxide. The allergenicity of the exposed pollen was compared with that of non-exposed pollen samples to assess if air pollution exposition affects the allergenicity potential of pollen. The immunodetection assays indicated higher IgE recognition by all sera of allergic patients to the pollen protein extracts in all exposed samples in comparison to the non-exposed samples. These results show that the pollen exposition to low pollutants' levels induces increased allergic reaction to sensitized individuals.

Changes in the IgE-reacting protein profiles of Acer negundo, Platanus x acerifolia and Quercus robur pollen in response to ozone treatment.

This study aims to investigate the effects of O3 in protein content and immunoglobulin E (IgE)-binding profiles of Acer negundo, Platanus x acerifolia and Quercus robur pollen. Pollen was exposed to O3 in an environmental chamber, at half, equal and four times the limit value for the human health protection in Europe. Pollen total soluble protein was determined with Coomassie Protein Assay Reagent, and the antigenic and allergenic properties were investigated by SDS-PAGE and immunological techniques using patients' sera. O3 exposure affected total soluble protein content and some protein species within the SDS-PAGE protein profiles. Most of the sera revealed increased IgE reactivity to proteins of A. negundo and Q. robur pollen exposed to the pollutant compared with the non-exposed one, while the opposite was observed in P. x acerifolia pollen. So, the modifications seem to be species dependent, but do not necessarily imply that increase allergenicity would occur in atopic individuals.

In vitro exposure of Ostrya carpinifolia and Carpinus betulus pollen to atmospheric levels of CO, O3 and SO 2.

Ostrya spp. and Carpinus spp. pollen was in vitro exposed to three atmospheric pollutants: CO, O3 and SO2. Two levels of each pollutant were used, and the first level corresponds to a concentration about the atmospheric hour-limit value acceptable for human health protection in Europe and the second level to about the triple of the first level. Experiments were done under artificial solar light with temperature and relative humidity controlled. The viability of the exposed pollen samples showed a significant decrease. Also, the germination percentage showed a significant decrease in both exposed pollens, and the effect was most pronounced for SO2, followed by O3 and CO. A general decreasing trend in the total soluble protein content of the exposed pollen samples when compared with the control was observed, but it was only statistically significant for the Ostrya spp pollen. The results showed marked effects were observed on the Ostrya spp. and Carpinus spp. pollen when exposed to air pollutant levels that can be considered safe for human health protection.

Effect of air pollutant NO2 on Betula pendula, Ostrya carpinifolia and Carpinus betulus pollen fertility and human allergenicity.

Pollen of Betula pendula, Ostrya carpinifolia and Carpinus betulus was exposed in vitro to two levels of NO2 (about 0.034 and 0.067 ppm) - both below current atmospheric hour-limit value acceptable for human health protection in Europe (0.11 ppm for NO2). Experiments were performed under artificial solar light with temperature and relative humidity continuously monitored. The viability, germination and total soluble proteins of all the pollen samples exposed to NO2 decreased significantly when compared with the non-exposed. The polypeptide profiles of all the pollen samples showed bands between 15 and 70 kDa and the exposure to NO2 did not produce any detectable changes in these profiles. However, the immunodetection assays indicated higher IgE recognition by patient sera sensitized to the pollen extracts from all exposed samples in comparison to the non-exposed samples. The common reactive bands to the three pollen samples correspond to 58 and 17 kDa proteins.

Organic matter characterization of sediments in two river beaches from northern Portugal for forensic application.

In a forensic investigation, the analysis of earth materials such as sediments and soils have been used as evidence at a court of law, relying on the study of properties such as color, particle size distribution and mineral identification, among others. In addition, the analysis of the organic composition of sediments and soils is of particular value, since these can be used as complementary independent evidence to the inorganic component. To investigate the usefulness of organic indicators in sediment characterization and discrimination, seventy-seven samples were collected during a period of one year in two river beaches located at the southern bank of the Douro River estuary in the North of Portugal. Isotopes of total carbon, pollen and plant wax-marker analyses were performed. In both beaches, an increase of the organic matter concentrations was noticeable, moving landward, related with the higher cover of associated plant material. The results obtained showed that the combination of all the techniques adopted showed a clear discrimination between samples from the two beaches, and also showed a differentiation of samples in relation to distance from the river in both beaches. The results also show that seasonality in these beaches was not a determining factor for discrimination, at the times considered. In addition, the effects of time was not marked.

Análise do efeito do pólen do milho transgênico resistente a insetos sobre o desenvolvimento de Galleria mellonella (Fabricius, 1754) (Lepidoptera, Pyralidae) e possíveis conseqüências ecológicas / The effect of the effect of the transgenic strings resistant a manufacturing on the development of Galleria mellonella (Fabrício, 1754) (Lepidoptera, Pyralidae) e espécies conseqüências ecológicas

O presente trabalho tem o objetivo de avaliar os efeitos do pólen do milho transgênico, que expressa a proteína entomopatogênica Cry1Ab, sobre aspectos biológicos da traça da cera (Galleria mellonella) e com isso propor uma discussão sobre as possibilidades de afecção desse piralídeo à campo, debatendo possíveis efeitos ecológicos. Um ensaio biológico foi realizado, onde se ofertou às larvas pólen do milho transgênico, pólen do milho convencional e pólen comercial. A duração da fase larval foi afetada pela composição da dieta, sendo que as constituídas de pólen de milho convencional e transgênico apresentaram os resultados mais expressivos. A mortalidade foi superior nos indivíduos alimentados com a mistura de cera virgem e pólen transgênico, no entanto não diferiu dos demais alimentos, quando junto ao pólen transgênico, foi associado favo de Apis mellifera. A largura e comprimento das pupas provindas de lagartas alimentadas com cera virgem adicionada com pólen transgênico ou convencional foram significativamente inferiores quando comparados aos valores das mensurações realizadas nas pupas provindas de outras dietas. O pólen do milho, convencional ou transgênico, por si só é um alimento menos adequado ao desenvolvimento de G. mellonella, em relação a uma dieta composta por pólen de várias plantas.

This study aims to evaluate the effects of transgenic corn pollen, which expresses the Cry1Ab protein entomopathogenic on biological aspects the wax moth (Galleria mellonella) and thus propose a discussion on the possibilities for this condition pyralid the field, discussing possible ecological effects. For this we performed a bioassay, where it was offered to the larvae conventional and commercial Bt pollen, The duration of the larval stage of G. mellonella was affected by the supply of Mays pollen, conventional or transgenic, provided the biggest records. Mortality was higher in individuals fed with transgenic pollen and bee wax, but did not differ from other foods, when they were fed with transgenic pollen and honeycomb of Apis mellifera. The width and the length of larvae originated from larvae fed with beeswax added to conventional or transgenic pollen were lower than other treatments. The Mays pollen, conventional or transgenic alone is a less suitable food for the development of G. mellonella, in relation to a diet consisting of pollen from various plants.

Spatial and temporal distribution of Alternaria spores in the Iberian Peninsula atmosphere, and meteorological relationships: 1993-2009.

This paper provides an updated of airborne Alternaria spore spatial and temporal distribution patterns in the Iberian Peninsula, using a common non-viable volumetric sampling method. The highest mean annual spore counts were recorded in Sevilla (39,418 spores), Mérida (33,744) and Málaga (12,947), while other sampling stations never exceeded 5,000. The same cities also recorded the highest mean daily spore counts (Sevilla 109 spores m(-3); Mérida 53 spores m(-3) and Málaga 35 spores m(-3)) and the highest number of days on which counts exceeded the threshold levels required to trigger allergy symptoms (Sevilla 38 % and Mérida 30 % of days). Analysis of annual spore distribution patterns revealed either one or two peaks, depending on the location and prevailing climate of sampling stations. For all stations, average temperature was the weather parameter displaying the strongest positive correlation with airborne spore counts, whilst negative correlations were found for rainfall and relative humidity.

In vitro exposure of Acer negundo pollen to atmospheric levels of SO2 and NO2: effects on allergenicity and germination.

In the last years, a rising trend of pollen allergies in urban areas has been attributed to atmospheric pollution. In this work, we investigated the effects of SO(2) and NO(2) on the protein content, allergenicity, and germination rate of Acer negundo pollen. A novel environmental chamber was assembled to exposure pollen samples with SO(2) or NO(2) at two different levels: just below and two times the atmospheric hour-limit value acceptable for human health protection in Europe. Results showed that protein content was lower in SO(2)-exposed pollen samples and slightly higher in NO(2)-exposed pollen compared to the control sample. No different polypeptide profiles were revealed by SDS-PAGE between exposed and nonexposed pollen, but the immunodetection assays indicated higher IgE recognition by all sera of sensitized patients to Acer negundo pollen extracts in all exposed samples in comparison to the nonexposed samples. A decrease in the germination rate of exposed in contrast to nonexposed pollen was verified, which was more pronounced for NO(2)-exposed samples. Our results indicated that in urban areas, concentrations of SO(2) and NO(2) below the limits established for human protection can indirectly aggravate pollen allergy on predisposed individuals and affect plant reproduction.

Characterization of soils from the Algarve region (Portugal): a multidisciplinary approach for forensic applications.

The Algarve is located at a very short distance from North Africa, in Southern Portugal, and as one of the most touristic regions of Portugal, it is accessible by air, land and sea. It is very susceptible to many illegal activities, such as illegal migration, drug trafficking, kidnapping, and murder, among others. Therefore, an Algarve soils database for forensic purposes is being conducted with the conjunction of geological and palynological methodologies on soils characterization, since this is of fundamental importance to assess reliable evidence on forensic investigations. In this study, the properties of soils from several proximate sites from the Algarve were investigated, namely: (i) colour determined by spectrophotometry; (ii) particle size distribution determined by laser granulometry; (iii) low-field magnetic susceptibility by a susceptibility meter; and (iv) pollen content using a light microscope. Finally, a hierarchical cluster analysis was applied to ascertain the capacity of the different soil properties for discrimination between samples. The study reveals the utility of geobotanical techniques for forensic discrimination of soils. Even though some similarities between some of the samples were found, each one presented a combination of colour, particle size distribution, magnetic susceptibility and pollen features that enable the determination of a fingerprint expected to reveal a specific site for future selection of coastal search areas in the Algarve region.

Main airborne Ascomycota spores: characterization by culture, spore morphology, ribosomal DNA sequences and enzymatic analysis.

The aim of this work was to identify the main allergy-related Ascomycetes fungal spores present in the atmosphere of Porto, using different and complementary techniques. The atmospheric sampling, performed in the atmosphere of Porto (Portugal) from August 2006 to July 2008, indicated Cladosporium, Penicillium, Aspergillus and Alternaria as the main fungal spore taxa. Alternaria and Cladosporium peaks were registered during summer. Aspergillus and Penicillium highest values were registered from late winter to early spring. Additionally, the Andersen sampler allowed the culture and isolation of the collected viable spores subsequently used for different identification approaches. The internal-transcribed spacer region of the nuclear ribosomal repeat unit sequences of airborne Ascomycetes fungi isolates revealed 11 taxonomically related fungal species. Among the identified taxa, Penicillum and Aspergillus presented the highest diversity, while only one species of Cladosporium and Alternaria, respectively, were identified. All selected fungal spore taxa possessed phosphatase, esterase, leucine arylamidase and beta-glucosidase enzymatic activity, while none had lipase, cystine arylamidase, trypsin or beta-glucuronidase activity. The association between the spore cell wall morphology, DNA-based techniques and enzymatic activity approaches allowed a more reliable identification procedure of the airborne Ascomycota fungal spores.

Fungal spores from Pleosporales in the atmosphere of urban and rural locations in Portugal.

Fungal spores are a significant fraction of the atmospheric bioparticles (bioaerosols) and many species are capable of inducing the production of specific immunoglobulin E (IgE), aggravating the clinical symptoms of allergic respiratory diseases in sensitized individuals. The aim of this work was to evaluate the distribution of potentially allergenic Pleosporales spores in two locations with different urbanization indexes, characterizing its seasonal pattern. The seasonal distribution of several spore types belonging to the Pleosporales (Alternaria, Drechslera, Epicoccum, Paraphaeosphaeria, Pithomyces, Pleospora and Stemphylium) in Amares (rural area) and Porto (urban area) was continually studied from January 2005 to December of 2007, using Hirst-type volumetric spore traps. Alternaria was the most abundant fungal spore type found in the atmosphere of Amares and Porto. This fungal type, together with Drechslera, Epicoccum, Pithomyces and Stemphylium, was mainly present during summer. Nevertheless, Leptosphaeria, Pleospora and Venturia spores were detected during winter and spring, while Paraphaeosphaeria spores were also observed during summer and autumn. These different seasonal patterns were responsible for the expansion of the exposure period for the Alt a 1 allergen. The concentration of the studied spore types was higher in the rural area than in the urban one, with exception for Pleospora and Drechslera. According to the correlations with meteorological factors, the selected fungal spores can be divided into two groups: (i) Alternaria, Drechslera, Epicoccum, Pithomyces and Stemphylium presented positive correlations with temperature and negative correlations with relative humidity and rainfall; (ii) Leptosphaeria, Paraphaeosphaeria, Pleospora and Venturia presented a contrary behavior. Usually, the occurrence of the Alt a 1 allergen has been associated with the presence of airborne Alternaria spores; the present work follows the seasonal distribution of other fungal spore species known to contain this molecule. The widespread occurrence of Alt a 1 plays an important role in the incidence and aggravation of allergic disorders.

Important phytopathogenic airborne fungal spores in a rural area: incidence of Botrytis cinerea and Oidium spp.

The effects of the climatic changes more and more frequently, favour the emergence and the development of plant diseases. Botrytis cinerea and Oidium spp. spores are often responsible for enormous productivity losses in cultures with high commercial interests such as the grapevine. This work aims to detect these airborne spores, before the emergence of lesions in Vitis vinifera. In the rural area of Amares, the seasonal distribution of the concentration of the 2 spore types, was continuously studied between 1 March-31 October (2005-2007), using a 7-day volumetric Hirst-type spore trap. These data was compared with phytopathological data. B. cinerea sporulation occurs in March-April while Oidium spp. occurs in April-May. Fluctuations were observed due to the influence of different meteorological factors. The emergence of the first signs of grey mould and powdery mildew were preceded by increments of B. cinerea and Oidium spp. spore concentration. The precocious detection of increasing trends in airborne spore concentration of B. cinerea and Oidium spp. can notify the probable onset of grey mould and powdery mildew leading to application of lower quantities of phytopharmaceutical products in the most favourable developmental stage.

Aeromycological profile of indoor and outdoor environments.

The aim of this work was to determine the differences between indoor and outdoor aeromicological composition. The aerobiological study was performed, from 15 January to 14 April 2008, using two volumetric spore traps, one placed indoors and another positioned outdoors on the roof of the Faculdade de Ciências building. A total of 23 000 spores were sampled outdoors and 15 500 spores were identified indoors. In both environments, the most abundant fungal spores were Cladosporium, Aspergillus/Penicillium, Agaricus, Rusts, Agrocybe and Lepthosphaeria. Moreover, Alternaria, Botrytis, Coprinus, Fusarium and Ganoderma spores were also detected in the outdoor air. The outdoor maximum (858 spores m(-3) day(-1)) was registered on the 9 February whereas the indoor peak (614 spores m(-3) day(-1)) was reached two days later. Qualitative similarities were found between the indoor and outdoor aeromicological content however quantitatively spore concentrations differed, suggesting the existence of airflows between the two environments due to ventilation, inefficient isolation or passive transport of spores. The majority of the selected fungal types were night sporulators, the exceptions were Aspergillus/Penicillium and Cladosporium, with daily maximum values during the morning and the afternoon, respectively. Several of the identified spores have been proved as causal agents of respiratory problems. Therefore, it is important to know the microbial composition of indoor air in order to take measures to improve air quality helping to reduce health problems related to respiratory allergic diseases in sensitized patients.

Definition of main pollen season using a logistic model.

This paper proposes a method to unify the definition of the main pollen season based on statistical analysis. For this, an aerobiological study was carried out in Porto region (Portugal), from 2003-2005 using a 7-day Hirst-type volumetric spore trap. To define the main pollen season, a non-linear logistic regression model was fitted to the values of the accumulated sum of the daily airborne pollen concentration from several allergological species. An important feature of this method is that the main pollen season will be characterized by the model parameters calculated. These parameters are identifiable aspects of the flowering phenology, and determine not only the beginning and end of the main pollen season, but are also influenced by the meteorological conditions. The results obtained with the proposed methodology were also compared with two of the most used percentage methods. The logistic model fitted well with the sum of accumulated pollen. The explained variance was always higher than 97%, and the exponential part of the predicted curve was well adjusted to the time when higher atmospheric pollen concentration was sampled. The comparison between the different methods tested showed large divergence in the duration and end dates of the main pollen season of the studied species.