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Many methods have been devised to count pollen grains automatically; however, few combine speed, reliability, inexpensiveness and user friendliness. This study describes a combination of simple, glycerine-based extraction, digital imaging and free particle counting software configured to achieve semi-automated processing of a large volume of images. Pollen grains were extracted from anthers of 10 common perennial grass (Poaceae) species, all implicated in pollinosis in Europe, and samples, illuminated on slides and digitally imaged. ImageJ algorithms were designed to remove significant extraneous content and count just the pollen grains, then applied in batch mode on multiple images. Accuracy was assessed by comparing a sample of automated software counts to manual, visual counts of the same images and found to be high. Total pollen production per anther and per inflorescence was estimated by counting the number of pollen grains per anther and the number of florets per inflorescence. Methodological and natural variation in pollen counts is discussed. Results were compared to published pollen counts of the same species; new pollen production figures are published for Cynosurus cristatus. This method is portable to other plant species, and requires only readily available reagents, equipment and software, it is quick, reliable, inexpensive and user friendly. [ABSTRACT FROM AUTHOR]

This study is related to an overall analysis of the most relevant pollen season modifications as they emerge from the aerobiological monitoring activity in the network of stations in Emilia-Romagna, a region located in Northern Italy. The taxa selected for the study are among the most important from an allergenic point of view. The selected period goes from 1991 to 2017 in order to have a similar length for all the different taxa in all the stations, regardless of their date of activation. Statistical analysis of the time series of some pollen season indicators has been carried out in the period, with the aim of pointing out the most relevant changes in the ensemble of the monitoring stations. The available database lasting more than 25 years can be the basis for a robust statistical analysis of the long-term trends in the time series of pollen seasonal indicators. The stations are operating throughout the whole Emilia-Romagna territory, spanning a range of climatic conditions from the inner Po Valley to the coastal area. Results of the trend analysis indicate that the starting and the peak dates of the pollen season are in prevalent advance. This is true both for most herbaceous taxa, as well as for several arboreal ones. As for pollen production, a different behaviour characterizes herbaceous and arboreal taxa; in fact, a generally decreasing trend interests all herbaceous taxa, while a prevalent increasing trend is present in several of the latter. Pollen season indicators are certainly more directly affected by the changes associated with the meteo-climatic forcing and are possibly more influenced by climatic change. [ABSTRACT FROM AUTHOR]

Based on a five-year study of pollen production and release in two different natural populations of Mesua ferrea from Indo-Burma region of Northeast India, we determined that pollen output follows a spatio-temporal pattern. Pollen productivity determinations considered various sources of variability, including the number of flowers per branch, flowers per tree, anthers per tree and pollen grains per tree. Each of these parameters revealed significant year-to-year and population effects. Anthesis follows a forenoon pattern, whereas anther dehiscence pursues the diurnal pattern. The former was significantly correlated with the timing of floral visitation and pollen deposition on stigmas. The latter, however, had significant relationship with the deposition of pollen grains on microscopic slides. The Apis and Xylocopa bees are the efficient pollinators to achieve the reproductive success in M. ferrea. Annual production of pollen per tree varied from averages of 1.07 ± 0.10 × 10 and 3.24 ± 0.16 × 10 in years of low production, with alternate high years, producing 3.85 ± 0.34 × 10 and 8.22 ± 0.76 × 10 pollen grains per tree. [ABSTRACT FROM AUTHOR]

Artemisia pollen is an important allergen in Europe. In Poznań (Western Poland), three Artemisia species, A. vulgaris, A. campestris and A. absinthium, are widely distributed. However, the contributions of these species to the total airborne pollen are unknown. The aim of the study was to determine the flowering phenology and pollen production of the three abovementioned species and to construct a model of potential Artemisia pollen emission in the study area. Phenological observations were conducted in 2012 at six sites in Poznań using a BBCH phenological scale. Pollen production was estimated by counting the pollen grains per flower and recalculating the totals per inflorescence, plant and population in the study area. Airborne pollen concentrations were obtained using a Hirst-type volumetric trap located in the study area. Artemisia vulgaris began to flower the earliest, followed by A. absinthium and then A. campestris. The flowering of A. vulgaris corresponded to the first peak in the airborne pollen level, and the flowering of A. campestris coincided with the second pollen peak. The highest amounts of pollen per single plant were produced by A. vulgaris and A. absinthium. A. campestris produced considerably less pollen, however, due to its common occurrence, it contributed markedly (30 %) to the summation of total of recorded pollen. A. vulgaris is the most important pollen source in Poznań, but the roles of two other Artemisia species cannot be ignored. In particular, A. campestris should be considered as an important pollen contributor and likely might be one of the main causes of allergic reactions during late summer. [ABSTRACT FROM AUTHOR]

The present study sampled pollen grains in the atmosphere using a Burkard 7-day-recording trap and periodically checked the flowering phases of Plantago lanceolata L. in the locality of León (NW of Spain) from late March to early August during 2007 and 2008. The results showed that the phenological phases considered for P. lanceolata coincided in most sampling points. The differences between them depended mainly on the characteristics of the land on which the plants developed and water availability. In addition, the differences between the start and duration of the different phenological phases over the 2 years were mainly due to climatic variations each year. Plantago pollen concentration in the atmosphere and phenological data were related during these 2 years of study. The differences in Plantago pollen production per anther were determined by environmental conditions such as humidity. Another important factor was human action. [ABSTRACT FROM AUTHOR]

A comparison between the aerobiological and floristic data carried out for Platanus are reported. The source was constituted by 60 Platanus trees. When they were pollinating we calculated the total pollen prodution of the source, controlling the number of male inflorescences for each plant, the number of anthers for each inflorescence and the number of pollen for each anther. Aerobiological data were obtained with 16 Durham gravimetric samplers positioned over an area of approximately 25 km2 at variable distances and in different directions to capture pollen transported by winds coming from any direction. In the first year of analysis, we carried out two kind of aerobiological monitoring positioning a Hirst volumetric trap near the closest gravimetric sampler. The two methods showed a similar trend in Platanus pollen profiles. In the following years, only Durham gravimetric samplers were used to study pollen dispersion. The data showed that there were high concentrations of pollen on the soil near the source while at distances higher than 800 m pollen concentration decreased dramatically. About 1/4 of all the pollen produced fell in an area within 400 m from the source and at a distance of 2750 m only 9 pollen grains/cm2 fell throughout the entire season. [ABSTRACT FROM AUTHOR]

This paper deals with the production of pollen grains per anther per flower of 15 probably allergenic pollen producing angiospermic plant taxa growing in Eastern India. The selected plant taxa includes Ailanthus excelsa, Alstonia scholaris, Argemone mexicana, Azadirachta indica, Cassia alata, C. siamea, Dalbergia sissoo, Holarrhena pubescens, Lagerstroemia speciosa, Madhuca indica, Milletia pinnata, Mimusops elengi, Morus alba, M. indica and Murraya paniculata. Among the investigated taxa, A. excelsa produces the highest number of pollen grains (1635180) followed by C. siamea (1589245) and A. mexicana (463800). The production of pollen grains is lowest in H. pubescens (2500), followed by A. scholaris (5175), A. indica (6220) and M. paniculata (11200). [ABSTRACT FROM AUTHOR]