Annual concentration, daily and intradiurnal variations of two native arboreal pollen types in the air of Atalaya, Buenos Aires, Argentina

GARDELLA SAMBETH, M.C; MORBELLI, M.A.; NITIU, D.S.

Buenos Aires

Congreso; 9Th. International Congress on Aerobiology; 2010

International Association Aerobiology

The analysis of the daily and intradiurnal dynamics of pollen grains of Celtis spp. and Salix spp. has been carried out in the coastal locality of Atalaya (NE of Buenos Aires province). In the area, these anemophyllous arboreal taxa are mainly represented by native species, like Celtis tala, C. iguanaea and Salix humboldtiana, and for a few specimens of exotic species like C. australis, S. babylonica and S. erythroflexuosa. Air sampling was conducted with a volumetric pollen trap (Lanzoni VPPS 2000) from mid-winter to early summer (August 19 - December 31, 2009) in order to include completely the pollen seasons of these taxa. The daily samples were observed by light microscopy with 200x magnification througout 3 transversal transects, corresponding to 10H, 14H and 18H respectively. Hourly and daily pollen concentration were calculated and expressed as number of pollen grains per cubic meter of air, and as percentage of the concentration. The total pollen concentration of Celtis  was 513 gr/m3, representing 13.6% of total annual pollen (TP) and 19.9% of annual arboreal pollen (AP). The main pollination period (MPP) was 25 days long, from the third week of October to mid-November, with a concentration peak on October 30. The hourly pollen concentration at 10H was of 25.7%, had its maximum value at 14H with 46.9% of its concentration, and 27.4% at 18H. Salix reached a total concentration of 96.8 gr/m3 (2.6% of TP, 3.8% of AP). Its MPP lasted 74 days, from late August to the second week of November, with a maximum on August 28. The hourly concentration at 10 was 35.4%, at 14H had its maximum value with 38%, and 26.6% at 18H. The pollen season of Celtis was short and late, with high concentrations and a single peak. Salix exhibited lower concentrations but its pollen season lasted longer, starting early and finishing a few days before the end of Celtis MPP. The intradiurnal variation of concentration of these taxa were similar. The pollen concentration of Celtis was low in the morning, it increased notoriously towards 14H, and decreased sharply through the afternoon, reaching at 18H values a little higher than those of the morning. In Salix, the concentration at 10H was high, slightly increased towards 14H, when it reached its maximun peak, and then decreased, with values at 18H much lower than those of the morning. Next steps in this study include the quantitative and qualitative analysis of the aerobiological content throughout complete annual periods andits correlation with meteorological variables