Cytogenetic Responses of Plant Root Meristematic Cells to the Arsenic (III) Contaminated Groundwater in Eastern Parts of Burdwan District, W.B., India

Abstract

Both geogenic and anthropogenic activities have resulted in arsenic pollution of groundwater especially in the Eastern region of Burdwan district in West Bengal. Response of Allium cepa L. genetic material to the presence of potential cytotoxic and genotoxic substances in aquatic environment was used to evaluate the arsenic contaminated groundwater-induced genotoxicity and hormesis. For in situ monitoring of the cytotoxicity level, the inhibition of mitosis in root meristematic cells was assayed. To study genotoxicity, micronucleus assay and DNA purity assay (by A260/280 ratio) were used. Treatment for 4 days of newly developed roots of Allium cepa L. with water samples with arsenic content 50 μg L-1 exhibited stimulation in mitotic activity whereas samples with arsenic 1000 μg L-1 showed inhibition of mitotic activity apparently indicating hormesis. Inhibition of mitosis was compared with the concentration dependent increase in generation of reactive oxygen species (ROS), cell death, decrease in activity of antioxidative enzymes (catalase, superoxide dismutase), the absorbance ratio (A260/280) of DNA, or micronuclei in root cells. These findings indicated that contaminated groundwater depending on the magnitude of the arsenic concentration, might either be mitogenic or mitostatic/toxic, which in turn has obvious implications in agriculture and human health.