Metaldehyde-Mediated Genotoxicity in Allium Cepa (L.) Root Meristem Cells

Abstract

The excessive use of metaldehyde (MA) in agriculture to combat molluscs endangers both the environment and non-target organisms. Allium cepa is a popular model organism for determining toxicity of commonly used chemicals such as pesticides. The aim of this study was to investigate the metaldehyde-mediated genotoxicity in A. cepa roots. To achieve this goal, five groups were formed and the first group considered as control was treated with tap water throughout the experiment. 20 ppm metaldehyde, 40 ppm metaldehyde, 100 ppm metaldehyde and 200 ppm metaldehyde solutions were applied to the other groups, respectively. Germination percentage, relative injury rate, root length and weight gain were analyzed to assess the effect of the pesticide on growth. Genotoxicity arisen from different doses of metaldehyde was investigated in terms of mitotic index (MI), micronucleus frequency (MN) and chromosomal aberrations (CAs). In addition, oxidative stress caused by metaldehyde was investigated by analyzing malondialdehyde (MDA) levels, as well as superoxide dismutase (SOD) and catalase (CAT) activities. The results of the growth parameters showed that metaldehyde had a growth-limiting effect in A. cepa, depending on the application dose. According to root elongation levels, EC50 (effective concentration) value for metaldehyde was 50 ppm in A.cepa. As the applied dose of metaldehyde increased, the incidence of MN and CAs gradually increased while MI decreased. Incrising doses of metaldehyde application also increased MDA levels, SOD and CAT activities. Data of the present study undoubtedly showed that metaldehyde had a suppressive effect in usual cell division, growth and chromosomal integrity while caused oxidative stress associated with genotoxicity.