Airborne phytoliths in a Pampean grassland relict: Parque Provincial Tornquinst (Buenos Aires, Argentina)

CALFUAN, M.; PÉREZ CUADRA, V.; RUEDA, M. A.

Ciudad Autónoma de Buenos Aires, Rep. Argentina

Congreso; 9th International Congress on Aerobiology; 2010

The ?Parque Provincial Ernesto Tornquist? located in central Ventania Mountains range, Buenos Aires, Argentina, is one of the few remaining protected areas of the Pampean Phytogeographic Province (Provincia Fitogeográfica Pampeana). The vegetation is the steppe dominated by Poaceae. The climate is temperate, with average annual precipitation values between 500 and 800 mm (spring and summer are the wetter times), the prevailing winds are from the northeast sector. The aim of this study is to describe the airborne phytoliths in this area and quantify their diversity. Samples were collected monthly using Tauber traps, and were processed using the standardized method. The total amount of phytoliths in the air was composed by unknown or unidentified phytoliths and different kinds of silica phytoliths of Monocotiledoneae and Dicotiledoneae as well as some calcium oxalate phytoliths of Dicotiledoneae. Among silica phytoliths of Monocotiledoneae have been identified typical and atypical bodies; in Poaceae were found elongated bodies, dumbbells and saddle between the typical ones and in Cyperaceae, cones. As atypical bodies were found many individual epidermal cells and groups of them (silica skeletons), prickles, trichomes and bulliform cells. The most part of Dicotiledoneae silica phytolihts are unicellular and multicellular trichomes and silica skeletons, the only type of calcium oxalate phytoliths are druses. There were also found vessel elements, parenchymatic cells and fibers, types of cells shared in both classes. There were found remains of not silicified epidermis of Cyperaceae. It should be noted that the processing of samples affect seriously the state of phytoliths, causing the fracture of many of them so therefore can not be identified. Although, the park is a natural refuge for grassland (typically Monocotiledoneae Poaceae), in the atmosphere there is a great amount of phytoliths belonging to other species (Dicotiledoneae) probably due to the influence of prevailing winds and plants cultivated in the region.