METAL AND HERBICIDE TOXICITY EFFECT ON CROPS AND RHIZOSPHERE

This research has been designed to study the toxicity of heavy metal Cd with atrazine herbicide on Bean plant. Soil beneficial microorganisms are found to be very sensitive towards heavy metal toxicity specially the genus Rhizobium. Microbial life tested from roots, revealed that the low population structure of microorganism were isolated in which Rhizobium species were not observed which fixes nitrogen from the atmosphere into the roots of leguminous plants. Due to which nodulation failed to occur in the roots of bean plant which induced growth inhibitory effect on bean plant. Significant reduction in protein, amino acid, carbohydrate synthesis and mineral ion (Na, K, Ca, Po(IV), Mg and Mn) acquisition were associated with the increasing herbicide concentration with Cd metal at all experimental periods. Low population of microbiota due to the Cd toxicity inhibits the bioremedation of atrazine thus it could be persistent in the land and decreases the soil ability for crops cultivation. Cd causes the change in morphology of the plant where the leaves turns yellow to translucent and plant experienced more rapid death.