Extraction of phytoliths from Arundo donax. Effect of temperature during the phytolith extraction process

S. FREZZIA; PATTERER N.I.; A. F. ZUCOL; E. PASSEGGI

Congreso; 4th Paleontological Virtual Congress; 2023

The present work reveals the response of bilobate phytoliths in leaves of Arundo donax L. treated by calcination in four thermal ranges: 500 ºC, 650 ºC, 800 ºC and 950 ºC. For this purpose, morphotype prospection was carried out by SEM and application of SEM-EDS analytical technique on the surface to characterize the elemental atomic components on the surface of the silicophytoliths and, in addition, analysis of morphometric variables of size and shape such as length, width, perimeter, area, convex perimeter, convex area, shape factor, roundness, convexity, solidity, and aspect ratio. The phytoliths association was characterized by elongate phytoliths, bulliform flabellate, bilobate, polylobate, cross, and stomata structures, both unicellular and multicellular. Bilobate morphotypes were selected for the above-mentioned analyses because of their high frequency of occurrence in the samples. Bilobate phytoliths processed at 950 ºC, showed changes in colouring and alterations in shape indicated by high values of convexity, solidity, shape factor, and roundness, and in size represented by a reduction in perimeter, which is indicative of a trend in size reduction and shape variation related to greater sphericity and convexity of the morphotypes. SEM observation and SEM-EDS analysis showed silica loss in phytoliths processed at 950 ºC. The present work contributes to the methodological knowledge of processing plant material for phytolith extraction.