EFEITOS GENOTÓXICOS E CITOTÓXICOS DO ESTRESSE CAUSADO POR ARSÊNIO E CÁDMIO EM Allium cepa L.

Abstract

Environmental pollution caused by metals has become a serious problem for humanity, especially after the advent of the Industrial Revolution. Some elements occur naturally and are essential for plants. Others, however, are no essential and present toxic to living organisms, which can be cited arsenic (As) and cadmium (Cd). Compounds of these two elements are widely used in industry, and there are still pesticides based on arsenic. Thus, the objective of this study was to evaluate the genotoxicity and cytotoxicity of As and Cd elements, using Allium cepa L. as test organism. The roots were grown at different concentrations of sodium arsenate (5, 7.5, 10, 15 and 20 mgL?¹) and cadmium nitrate (4, 6, 8, 10 and 12 mgL?¹), and control for 48 hours. After this time, the roots were collected and carried out the procedures of fixation, hydrolysis, staining and mounting the slides for subsequent microscopic analysis. The main chromosomal aberrations observed were c-metaphase, stickiness, precocious chromosome migration at metaphase, chromosomal breakage at anaphase, and micronucleus, proving the genotoxicity of elements in A.cepa L. Also it was found that the mitotic index of root cells under both treatments altered compared to control, demonstrating that arsenic and cadmium were cytotoxic to A. cepa L., with statistically significant difference (p <0.05) in cadmium treatments compared to the control. PCA was carried out simultaneously with the data of mitotic phases and abnormalities of As and Cd treatments, which allowed the understanding of which components were most frequent in each element, allowing their division into two different groups. Although this study has provided important data will certainly contribute to the Ecotoxicology, future studies are required to investigate exactly which structures of the cell cycle are being harmed by these elements.