An annual study of airborne pollen in northern Mexico City

An investigation of airborne pollen in northern Mexico City was carried out for one year. A total of 24 taxa were identified and classified according to the growing form in pollen of trees, weeds and grasses. Pollen grains were recorded all year round with a peak in December. The trees group showed the highest quantity of pollen as well as taxa diversity, although its peak period was in the dry season. The weeds and grasses emitted a larger quantity of pollen in the rainy season. The dominant taxa wereAlnus, Casuarina, Compositae and Gramineae. As for their relation with meteorological parameters, we found that the increase of pollen concentration was related to high temperatures, low relative humidity and high wind speed, the latter causing an increase of airborne pollen with no dilution at all. The hours with the highest pollen concentration where from 16:00 to 18:00.     

An annual study of airborne pollen in northern Mexico City

An investigation of airborne pollen in northern Mexico City was carried out for one year. A total of 24 taxa were identified and classified according to the growing form in pollen of trees, weeds and grasses. Pollen grains were recorded all year round with a peak in December. The trees group showed the highest quantity of pollen as well as taxa diversity, although its peak period was in the dry season. The weeds and grasses emitted a larger quantity of pollen in the rainy season. The dominant taxa wereAlnus, Casuarina, Compositae and Gramineae. As for their relation with meteorological parameters, we found that the increase of pollen concentration was related to high temperatures, low relative humidity and high wind speed, the latter causing an increase of airborne pollen with no dilution at all. The hours with the highest pollen concentration where from 16:00 to 18:00.     

Seasonal airborne pollen pattern in Mar del Plata City, Argentina

Continuous aerobiological survey of the atmosphere of Mar del Plata was carried out from December 1991 to November 1993 with a Burkard volumetric spore trap. Daily slides were prepared and studied every 2 h with standard techniques. Weekly records were kept for 27 relevant pollen types selected either by their prevalence or relative high atmospheric concentration. Quantitative multivariate analysis enabled to distinguish three major pollen seasons, related to atmospheric dominance either arboreal pollen (AP) or non-arboreal pollen (NAP). June to October is the richest period in number of pollen types, mainly dominated by AP; while from November to May, there is an overwhelming dominance of NAP types, represented by grass, herb and weed pollen. The study and prediction of this phenomenon is of great interest not only from the ecosystem point of view, but in relation to human disease as well.     

Status of airborne spores and pollen in a coir factory in Kerala,India

The prevalence of airborne fungal spores and pollen grains in the indoor and outdoor environments of a coir factory in Thiruvananthapuram district of Kerala state, India was studied using the Burkard Personal Sampler and the Andersen 2-stage Sampler for 2 years (September 1997 to August 1999). The concentration of pollen grains was remarkably lower than that of fungal spores (ratio of 1:28). There was no large difference in the concentrations and types of fungal spores between the indoor and outdoor environments, with 26 spore types found to be present indoors and 27 types outdoors; of these, 22 were common to both the environments. Aspergillus/Penicillium, Cladosporium, ‘other basidiospores’ and ascospores were the dominant spore types. The total spore concentration was highest in February and lowest in September, and it was significantly higher in 1998–1999 than in 1997–1998. Twenty viable colony-forming types were isolated from inside the coir factory. The most dominant viable fungi isolated were Penicillium citrinum, Aspergillus flavus and Aspergillus niger. The total pollen concentration was higher in the outdoor environment of the coir factory than indoors, with 15 and 17 pollen types, respectively. Grass and Cocos nucifera pollen types were dominant. The dominant spore and pollen types trapped in the two environments of the coir factory are reportedly allergenic and, consequently, workers are at risk of catching respiratory/allergic diseases.     

Pinus pollen in the atmosphere of Vigo and its relationship to meteorological factors

The Pinus genus has an elevated pollen production and an anemophilous nature. Although considered to be hypoallergenic, numerous cases of allergies caused by Pinus pollen have been cited and different authors believe that its allergenicity should be studied in more depth. In the city of Vigo several patients have tested positive for Pinus pollen extracts in skin tests, some of them being mono-sensitive to such pollens. In order to ascertain the behaviour of Pinus pollen and its correlation to the main meteorological factors, we carried out an aerobiological study in the city of Vigo from 1995 to 1998 by using a Hirst active-impact volumetric sporetrap, model Lanzoni VPPS 2000, placed on the left bank of the Vigo estuary (42°14’15’’N, 8°43’30’’W). Pinus has high quantitative importance in the airborne pollen spectrum of the city. It is one of the best represented taxa constituting 13%–20% of the total annual pollen levels. The quantity of Pinus pollen present in the atmosphere of the city of Vigo throughout a year is 5751 grains (as the average for the sampled years), with a very long pollination period, from the middle of January until May. The maximum concentration was recorded in 1998 with 1105 grains/m³ on 3 March, a much greater value than those for the previous years. At the end of its pollination period there is usually a final increase in Pinus pollen concentrations coinciding with the pollination of Pinus silvestris, which are more abundant in mountainous areas far from the city. Received: 17 March 1999 / Revised: 20 December 1999 / Accepted: 20 December 1999     

Feasibility study on automated recognition of allergenic pollen: grass, birch and mugwort

Quantification of airborne pollen is an important tool in scientific research and patient care in allergy. The currently available method relies on microscopic examination of pollen slides, performed by qualified researchers. Although highly reliable, the method is labor intensive and requires extensive training of the researchers involved. In an approach to develop alternative detection methods, we performed a feasibility study on the automated recognition of the allergenic relevant pollen, grass, birch, and mugwort, by utilizing digital image analysis and pattern recognition tools. Of a total of 254 pollen samples (including 79 of grass, 79 of birch and 96 of mugwort), 97.2% were recognized correctly. This encouraging result provides a promising prospect for future developments.     

Structural study of biologically significant ligands with major birch pollen allergen Betv1 by docking and molecular dynamics simulation

The major birch pollen allergen, Betv1 of Betula verrucosa is the main causative agent of birch pollen allergy in humans. Betv1 is capable of binding several physiological ligands including fatty acids, flavones, cytokinins and sterols. Until now, no structural information from crystallography or NMR is available regarding binding mode of any of these ligands into the binding pocket of Betv1. In the present study thirteen ligands have been successfully docked into the hydrophobic cavity of Betv1 and binding free energies of the complexes have been calculated using AutoDock 3.0.5. A linear relationship with correlation coefficient (R2) of 0.6 is obtained between ΔG(b)s values plotted against their corresponding IC50 values. The complex formed between Betv1 and the best docking pose for each ligand has been optimized by molecular dynamics simulation. Here, we describe the ligand binding of Betv1, which provides insight into the biological function of this protein. This knowledge is required for structural alteration or inhibition of some of these ligands in order to modify the allergenic properties of this protein.     

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 airborne pollen grains in Huddinge and Stockholm,Sweden

Summary Airborne pollen studies were carried out, by means of Burkard volumetric spore traps, at two different sites (the city of Stockholm and the suburb Huddinge) 15 km apart in the Stockholm region. Within the city of Stockholm the study was carried out in 1973–89 while in Huddinge the investigation period was 1977–82. In all the years under investigation the total pollen catch and the number of pollen types were higher in Stockholm than in Huddinge. The reason for this is not explained by the composition of the local vegetation surrounding the traps. It is concluded that parameters such as qualitative changes in the daily catches and occurrence during the main pollen season are more important than the absolute daily figures. The cyclic trends in the local annual sums over a long period of years do not show any periodicity that is altogether regular and reliable.     

Specific ornamentation of orbicular walls and pollen grains,as exemplified by Acanthaceae

For the first time in Acanthaceae a comparative study of orbicules forming stable, coherent orbicular walls and the respective pollen ornamentation was undertaken. A peculiar acetolysis resistant, often species specific orbicular wall is typical for many genera. In some cases the orbicular wall ornamentation resembles closely the pollen ornamentation, in others it differs to a variable degree. The presumed function of orbicular walls is discussed.     

Diagnostics in allergic diseases by correlating pollen/fungal spore counts with patient scores of symptoms

Pollen/fungal spore counts have been performed since 1977 in Copenhagen and since 1979 in Copenhagen, Viborg, Nykobing Falster and Nykobing Mors. Four Burkard Seven Day Recording Volumetric Spore Traps were used. Fungal spore counts were performed in the same period using a BIAP Slit Sampler (placed in the Copenhagen area). The study was carried out by the Danish Asthma-Allergy Association's interdisciplinary Aerobiology Group. In 1979 at the Allergy Clinic, Copenhagen County Hospital at Lyngby, data from the pollen/fungal spore counts were compared with daily scores of 95 patients' symptoms and medicine-index. Seventy-eight patients were scored in the entire period where symptoms occurred. For diagnostic purposes of allergy to pollen and fungal spores, previous patient history and symptom scores correlated to the pollen/fungal spore counts showed similarity and to some extent supplementary corrections to the diagnosis based on previous patient history, skin tests, laboratory tests, and provocation tests.     

Reconstruction of local vegetation in ad 915 at an oligotrophic mire in northern Japan from pollen, present-day vegetation and tephra data

The use of data for present-day vegetation, modern and pretephra pollen have, together, allowed reconstruction of the spatial pattern of the vegetation of an oligotrophic mire, Shimo-kenashi Mire, in ad 915. The modern pollen data were compared with the surrounding vegetation, showing that pollen of Ericaceae, Rosaceae (excluding Sanguisorba), Sphagnum and Liliaceae, together with trees and shrubs, which form scrub or thicket, indicate the limits of the mires. Shimo-kenashi Mire was narrower in ad 915 and had more islands and peninsulas of scrub. Subsequently, the mire margin has advanced and the scrub islands and peninsulas have disappeared at some sites. The fact that the mire is spreading implies that conditions are wetter since ad 915, caused by changes in local hydrology. This history of vegetation at the site will contribute to the conservation and management of the mire as trends in vegetational change provide the basic information for conservation strategy.     

Carbon cycling and budget in a forested basin of southwestern Hokkaido,northern Japan

Quantification of annual carbon sequestration is very important in order to assess the function of forest ecosystems in combatting global climate change and the ecosystem responses to those changes. Annual cycling and budget of carbon in a forested basin was investigated to quantify the carbon sequestration of a cool-temperate deciduous forest ecosystem in the Horonai stream basin, Tomakomai Experimental Forest, northern Japan. Net ecosystem exchange, soil respiration, biomass increment, litterfall, soil-solution chemistry, and stream export were observed in the basin from 1999–2001 as a part of IGBP-TEMA project. We found that 258 g C m^–2 year^–1 was sequestered annually as net ecosystem exchange (NEE) in the forested basin. Discharge of carbon to the stream was 4 g C m^–2 year^–1 (about 2% of NEE) and consisted mainly of dissolved inorganic carbon (DIC). About 43% of net ecosystem productivity (NEP) was retained in the vegetation, while about 57% of NEP was sequestered in soil, suggesting that the movement of sequestered carbon from aboveground to belowground vegetation was an important process for net carbon accumulation in soil. The derived organic carbon from aboveground vegetation that moved to the soil mainly accumulated in the solid phase of the soil, with the result that the export of dissolved organic carbon to the stream was smaller than that of dissolved inorganic carbon. Our results indicated that the aboveground and belowground interaction of carbon fluxes was an important process for determining the rate and retention time of the carbon sequestration in a cool-temperate deciduous forest ecosystem in the southwestern part of Hokkaido, northern Japan.     

Airborne pollen sampling in a wildlife reserve in the south of Buenos Aires province,Argentina

The objective of this project was to study the pollen spectrum of the Marahué Wildlife Reserve (Central Argentina), the quantity and quality of airborne pollen grains, and to evaluate the contribution of outside sources, to protect a natural habitat with xerophytic shrub vegetation (“monte”) (the term “monte” is used for the dominant xerophytic shrub vegetation in the “partido” of Villarino) approximately 90 km south of Bahía Blanca. Sampling was performed weekly throughout a whole calendar year (January–December, 2003) using a volumetric impact sampler. Observations of flowering in the field were performed at the same time as the aerial sampling. Herbarium specimens were collected to make pollen collections of the species found in the study area, for reference purposes. The most abundant pollen types were Poaceae (31.3% total annual pollen), Amaranthus/Chenopodiaceae (25.3%), Eucalyptus (5%), Brassicaceae (3.9%), and Plantago (3.9%). This study showed the dispersion dynamics of pollen grains from characteristic species of the “partido” (the province of Buenos Aires is divided into partidos which are roughly equivalent to counties) of Villarino, the exotic flora of the surrounding area, and the pollen types from outside the region.

Comparative pollination biology in two sympatric varieties of Cypripedium macranthos (Orchidaceae) on Rebun Island,Hokkaido, Japan

Cypripedium macranthos sensu lato typically has purple‐pink flowers with no nectar and harvestable pollen. On Rebun Island, Hokkaido, Japan, purple‐pink‐flowered C. macranthos var. macranthos individuals rarely grow among numerous pale‐cream‐flowered C. macranthos var. rebunense plants. In both varieties, flower size is similar, their flowering periods completely overlap, and they share the same pollinator (Bombus pseudobaicalensis). However, in only one of 12 years from 2001 to 2012 did var. macranthos attain an annual fruit‐set ratio (an estimate of pollination success) higher than that of sympatric var. rebunense plants. These findings strongly suggest that in C. macranthos on Rebun Island, flower color results in the differential pollination success, because the pollinator prefers pale‐cream Cypripedium flowers and/or avoids purple‐pink ones, thereby producing pollinator‐mediated selection favoring pale‐cream flowers.     

Variation of sterility and fertility in Utricularia australis f. australis in Hokkaido, northern Japan

Seed-production ability was studied in Utricularia australis R. Br. f. australis Komiya and Shibata through field observation, pollination experiment, pollen culture, and isozyme analysis for populations in various regions of Hokkaido, northern Japan. Utricularia australis f. australis has previously been postulated to be sterile in Japan, however, in the present study, fertile populations were found in eastern Hokkaido. Bisexual sterility and male sterility were suspected to be present in populations in the western part of Hokkaido. There was also a strain that seemed to produce no seed because of intra-clonal inbreeding depression or self-incompatibility. Isozyme analysis of three enzyme systems indicated a uniformity of multienzymatic phenotype (MEP) in each population or region. The MEP grouping of populations corresponded to the type of sterility and fertility revealed by pollination and pollen culture experiments. These experiments suggested that each regional strain had its own sterility or fertility type.     

The effect of missing rings on stand-age estimation of even-aged forests in northern Hokkaido,Japan

The effectiveness of estimating stand age from increment core samples taken at stump height (20 cm above ground) was tested in an even-aged stand ofBetula ermanii that had regenerated after a forest fire in 1945 in Hokkaido, Japan. Careful cross-dating revealed that annual rings were missing in 11 cores out of a total of 42 cores sampled, and that all these missing rings occurred in the outermost part of the core. These facts indicate that precaution has to be taken in selecting trees from which cores are to be sampled. The present work also revealed that those trees with missing rings have a characteristic appearance, with a thinner stem and less crown foliage than normal trees with complete rings. It was also found that even if this appearance test failed, the possibility of missing rings could be detected from a declining growth pattern, with extremely narrow rings on the increment core which normal trees did not show.     

Climatic preferences and frequent co-occurrence of boreal and temperate plants in Hokkaido Island,northern Japan

Effects of climatic factors on the forest plant distribution were examined in Hokkaido Island, northern Japan, where boreal and temperate plants frequently co-occur, and the relationship of floral make-up with phytogeography and life form was analysed. From the climatic preference of tree species consisting of mixed forest, the co-occurrence of boreal and temperate plants was found over a wider thermal range in regions of little rainfall. However, co-occurrence in a certain forest site was more notable in the understory than in the crown. A particular case of this involves southern evergreen shrubs and herbs in a boreal coniferous forest. Another is the presence of northern summergreen herbs in a temperate hardwood forest. It is speculated that the co-occurrence dates back at least to the late Quaternary, when a decrease in temperature associated with the glacial period forced understory plants to adapt their life form or leaf habit to snowcover and the light conditions of interior forests. Recent geographical evidence suggests that the island has been isolated from the southern island for at least 70000 years. Thus, the postglacial re-expansion of southern species does not appear to be due to immigration but rather due to their expansion from refuges on the island such as Oshima Peninsula for snow-tolerant species and Hidaka District for snow-intolerant species.