María del Mar Trigo

Modelling start of oak pollen season in different climatic zones in Spain

Quercus pollen and meteorological data for several years from eight sites in Spain have been statistically analysed to select the threshold temperature and calculate the mean heat accumulation for predicting the Quercus pollination start in different climatic areas. The growing degree days method, which assumes the daily temperature varies as a sine wave, was used for heat accumulation calculations. Threshold temperatures between 4 and 12 ◦ C were chosen using linear regression equations forced through the origin and their root mean square error (RMSE) of predicted against the observed dates for each observation site. Above the threshold, the average growing degree days (up to 1999) for the studied years was taken as the predictor value. Results showed a relationship between the selected threshold and elevation and a stronger and statistically significant correlation between threshold and yearly mean temperature, for each site. Regression analysis indicated that the selected threshold and the calculated heat accumulation were optimum for most of the localities. The validity of the results was tested using the meteorological data for the year 2000 as independent variable and this confirmed that there were only a few days difference between the predicted and observed day of the first pollen release for most of the studied localities.

ATMOSPHERIC TRANSPORTATION OF MARIHUANA POLLEN FROM NORTH AFRICA TO THE SOUTHWEST OF EUROPE

As a result of aerobiological samples taken on the Costa del Sol (S. Spain), Cannabis sativa L. (marihuana) pollen was detected from May to September 1991-1996, always sporadically and usually during the afternoons. Sampling was by two volumetric spore traps set up in Malaga and Estepona, two coastal towns approximately 90 km apart. A study of the days when this pollen was recorded points to the movement of air masses from North Africa to southern Spain. Furthermore, the isentropic air trajectories calculated for these days reinforce the possibility of the pollen originating in marihuana plantations in northern Morocco (Rif). This study demonstrates the application of aerobiology to the control of the source, quantity and phenology of the crop.

Fungal spore content of the atmosphere of the Cave of Nerja (southern Spain): diversity and origin.

Fungal spores are of great interest in aerobiology and allergy due to their high incidence in both outdoor and indoor environments and their widely recognized ability to cause respiratory diseases and other pathologies. In this work, we study the spore content of the atmosphere of the Cave of Nerja, a karstic cavity and an important tourist attraction situated on the eastern coast of Malaga (southern Spain), which receives more than half a million visitors every year. This study was carried out over an uninterrupted period of 4 years (2002-2005) with the aid of two Hirst-type volumetric pollen traps (Lanzoni VPPS 2000) situated in different halls of the cave. In the atmosphere of the Cave of Nerja, 72 different spore types were detected during the studied period and daily mean concentrations of up to 282,195 spores/m(3) were reached. Thirty-five of the spore types detected are included within Ascomycota and Basidiomycota (19 and 16 types, respectively). Of the remaining spore types, 32 were categorized within the group of so-called imperfect fungi, while Oomycota and Myxomycota were represented by 2 and 3 spore types, respectively. Aspergillus/Penicillium was the most abundant spore type with a yearly mean percentage that represented 50% of the total, followed by Cladosporium. Finally, the origin of the fungal spores found inside the cave is discussed on the basis of the indoor/outdoor concentrations and the seasonal behaviour observed.

Detection of airborne allergen (Ole e 1) in relation to Olea europaea pollen in S Spain

Background In recent years, it has been demonstrated that the air carries not only airborne pollen but also plant particles of smaller size that have allergenic activity, and, being within the respirable range, these particles can trigger rapid attacks in the lower respiratory tract. The study of particles according to size (0.7–40 μm) could provide valuable information on the real allergenic activity in the atmosphere.

Olea Europaea Pollen in the Atmosphere of Málaga (S. Spain) and its Relationship with Meteorological Parameters

Abstract The atmosphere of Malaga was sampled from 1992 to 1995 for the pollen of Olea europaea L., one of the most common airborne allergens in the Mediterranean area. A Burkard seven-day-recording trap showed that the pollen of this species is principally detected during spring with the highest concentrations occurring in May. During the main pollination period, the 24 hour intradiurnal variation pattern showed a high degree of homogeneity with no noteworthy peaks. The correlations between the pollen concentrations recorded and the different meteorological parameters show that temperature, sunshine hours and wind direction are those most closely correlated with variations in the daily pollen count.

Olive flowering trends in a large Mediterranean area (Italy and Spain).

The aim of this study was to investigate the main climatic and biological trends related to olive flowering in central-southern Italy compared to those in Andalusia, Spain. Results since 1982 were compared for the two long-series monitoring areas of Cordoba and Perugia, and since 1992–1999 for the short-series areas. The relationship between climatic trends and the biological response of the olive, a widespread culture in the Mediterranean basin, were investigated. An aerobiological method involving capturing pollen released into the atmosphere was utilised as a bioindicator of flowering phenology. The study results confirm the strong relationship between flowering periods and spring temperature trends for the olive. Temperature during March, April and May was the parameter most related to flowering date in the study areas, particularly in Italy. In some cases we found a significant correlation between flowering and past autumn temperatures, probably due to their effect on floral bud dormancy induction, but this phenomenon appeared to be of minor importance in the studied areas. The phenological trend results show the continuous advance of flowering dates to the late 1990s, followed by a relatively stationary time series related to a short-term temperature fluctuation in the Mediterranean area. This latter period probably represents a mesoscale event forced by a macroscale event—the North Atlantic Oscillation. The results reveal that the trend towards increased temperatures, and the consequent flowering advance of some species, indicated some years ago is nowadays not as clear as was expected and should be confirmed over the next few years in the Mediterranean areas under investigation.

Effects of low temperature on pepper pollen morphology and fertility: Evidence of cold induced exine alterations

SummaryThe effects of low night temperatures on pollen viability and pollen grain morphology were investigated in bell pepper (Capsicum annuum, L.) commercial hybrids ‘Latino’ and ‘Novi’. Night temperatures of 10 and 15°C decreased pollen viability, estimated by an in vitro assay and acetocarmine staining, and by decreased seed number per fruit. At anthesis, in a separate experiment, pollen grains that developed at low temperature (25/14°C, day/night) were smaller and appeared aggregated and shrunken with a differently sculptured exine which was thinner than the pollen exine developed at the 30/20°C temperature regime. The results obtained when a 10°C night-temperature treatment was applied to plants grown at 30/20°C with flower buds of different diameters, indicated that meiosis and the young microspore stage were affected. However, the later phases of microspore development and pollen maturation were not affected by the same temperature treatments.

Aerobiological analysis of Olea europaea L. pollen in different localities of southern Spain Forecasting models

Pollen from olive trees (Olea europaea L.) is one of the main airborne allergens of the Mediterranean region. We have performed a comparative analysis of the behaviour of Olea pollen in the atmosphere at different localities in southern Spain with different biogeographic and climatic characteristics. Sampling over several years with Burkard or Lanzoni volumetric collectors was performed in the four cities of Córdoba, Jaén, Málaga and Granada. The pollen season spans primarily April to June, with the heaviest concentrations in May and peak days registering: 3890 grains/m (Córdoba), 6730 grains/m (Jaén), 2819 grains/m (Málaga), and 1884 grains/m (Granada). These quantities make these cities prime centres of seasonal allergic rhinitis and bronchial asthma. The main pollen season was defined taking the days registering 95% of the total annual pollen, and by studying the fluctuations between years and seasons in terms of Olea pollen at the different sampling points. Correlation analysis showed that the pollen concentrations on the preceding days, as well as the average accumulated temperature, were the parameters that invariably had significant correlation indices at all sampling points. In addition, the forecast models indicated that these two variables, together with others, predicted a high percentage (up to 80% in Jaén) of the seasonality of this pollen observed in the atmosphere of the different localities studied.

Accumulative air temperature as a predicting parameter for daily airborne olive pollen (Olea europaea L.) during the pre‐peak period in Málaga (Western Mediterranean area)

Although olive pollen is one of the most widespread aeroallergens in the Mediterranean area, very few studies present predictive models. We have already seen that in Malaga (Southern Spain) the meteorological variables which have the greatest influence on airborne pollen concentrations during the pre‐peak period are accumulated rainfall and mean temperatures from the chilling requirement for flowers buds initiation. This work presents the simple and multiple linear regressions obtained by using daily pollen concentrations as a dependent variable and the daily values of the above mentioned meteorological parameters as independent variables. When establishing an overall predictive model, we chose the equation of the simple linear regression pollen‐accumulated temperatures obtained during 1992–94 (y = 0.003x‐3.863) since this provided the greatest lineal fitting.

Analysis of the predicting variables for daily and weekly fluctuations of two airborne fungal spores: Alternaria and Cladosporium.

Alternaria and Cladosporium are two fungal taxa whose spores (conidia) are included frequently in aerobiological studies of outdoor environments. Both spore types are present in the atmosphere of Malaga (Spain) throughout almost the entire year, although they reach their highest concentrations during spring and autumn. To establish predicting variables for daily and weekly fluctuations, Spearman’s correlations and stepwise multiple regressions between spore concentrations (measured using a volumetric 7-day recorder) and meteorological variables were made with results obtained for both spore types in 1996 and 1997. Correlations and regressions were also made between the different taxa and their concentrations in different years. Significant and positive correlation coefficients were always obtained between spore concentrations of both taxa, followed by temperature, their concentrations in different years, sunshine hours and relative humidity (this last in a negative sense). For the two spore types we obtained higher correlation and regression coefficients using weekly data. We showed different regression models using weekly values. From the results and a practical point of view, it was concluded that weekly values of the atmospheric concentration of Alternaria spores can be predicted from the maximum temperature expected and its concentrations in the years sampled. As regards the atmospheric concentration of Cladoposrium spores, the weekly values can be predicted based on the concentration of Alternaria spores, thus saving the time and effort that would otherwise be employed in counting them by optical microscopy.