Anatomia foliar e do lenho de árvores de Sebastiania commersoniana (Baillon) L.B.SM. & R.J. Downs (Euphorbiaceae) em solo contaminado pelo derramamento de petróleo

Abstract

Oil extraction has increased in recent years to meet the growing global energy demand, and this, has boosted the risk of oil being accidentally discharged into the environment. Thereby, the present study aims to determine the effect of the oil spill occurred in 2000, in Araucaria, Parana, in the tree species Sebastiania commersoniana, dominant in alluvial environments in southern Brazil. The study was conducted on remnants of the Joint Flood Rain Forest at two sites in south-central portion of the first plateau of Paraná, designated as contaminated area and control area. There were selected 17 trees of S. commersoniana from contaminated area and 12 trees from control area. The analysis performed were leaf anatomy, anatomical characterization of the growth rings, determination of bulk density of the growth rings, dendrochronological analysis and anatomical analysis of vessel elements. With the results obtained here, it concluded that the species is tolerant to contamination by oil. The differences observed in leaf anatomy may not be related to the effect of contamination by oil, since the soil composition may be playing a significant role on these differences. The X-ray densitometry allowed the identification and marking of the exact limits of the growth rings of the wood and the density growth of the intra and inter-rings and the radial direction. For dendrochronological studies, was observed a reduction in radial growth in the wood of trees in the years 2000 and 2001. The species show changes in the anatomy of the wood vessel elements, proving its great plasticity to occupy different environmental conditions. This kind of adaptability justifies its strong presence in disturbed habitats, as noted in the study area.