CONTENIDO DE SÍLICE EN GRAMÍNEAS DEL PASTIZAL NATIVO DEL SUDESTE BONAERENSE,ARGENTINA

FERNÁNDEZ HONAINE, MARIANA; BERNAVA LABORDE, VERÓNICA; ZUCOL, ALEJANDRO

Matices interdisciplinarios en estudios fitolíticos y de otros microfósiles

British Archaeological Reports (BAR) International Series

Lugar: Oxford; Año: 2008; p. 57 - 63

The process of silica accumulation in plants is influenced by edaphic, climatic and biotic conditions. Silica concentration in plants varies between 0.1 and 10% of dry weight. A silica content analysis was carried out as a component of a larger phytolith study involving native species found in Paspalum quadrifarium grassland communities. Silica content of 18 species was analyzed using individual grass samples collected in different locations in Buenos Aires province. From these samples, subfamily, interspecies and intraspecific comparisons were made. Phytoliths were concentrated by a dry ashing technique and silica content was calculated as a percentage of dry plant weight. Statistical analyses were applied to these results (Kruskal-Wallis test for interspecies and subfamily data and a t-Student test for intraespecific data). Average silica content values for species ranged between 3.91 and 13.93 percent. Significant differences were found in only three species (Sorghastrum pellitum, Dactylis glomerata and  Festuca arundinacea) and two subfamilies (Pooideae and Panicoideae). The  results showed a tentative pattern of silica accumulation, where Pooideae – Stipoideae had lower values than Arundinoideae – Panicoideae. Intraspecific differences were notable in only one of the species studied (F = -2.52; df = 6; p = .04), which could be caused by variability in edaphic and/or climatic conditions in the different locations where the individual samples were collected. This study represents the first analysis of silica content of grass species from southeastern Buenos Aires province in Argentina.