The deteriorating effects of cadmium accumulation on the yield and quality of maize crops

Abstract

Food security is critical for survival but increasing heavy metal particularly cadmium concentration in the environment due to human activity poses a threat to both plants and animals. The experiment was designed to investigate the potential impact of varying concentrations of cadmium on the growth, metabolites, and accumulation of cadmium in the edible portion of maize. The objective was to gain scientific insights into the relationship between cadmium exposure and maize physiology, biochemistry, and accumulation of the heavy metal. Significant reduction was recorded in the agronomic attributes including root shoot length, fresh and dry weight and chlorophyll contents of the maize (p < 0.05). Higher level of cadmium imposes destruction of the antioxidant defense system of the host indicated by the lower catalases activity (92% reduction). Along with this, growth and stress related metabolites like IAA, salicylic acid, proteins, lipid and sugar contents decreased approximately by 50% at the lowest concentration while reaching 70 to 77% at the highest concentration of cadmium. Interestingly, plants exposed to cadmium for 60-days duration approximately 20 to 25 mg/kg of cadmium was accumulated in plants parts of which most of the cadmium (50% or higher) were translocated to the shoot of the host plants. This data also showed that the maximum concentration of cadmium is accumulated in the stem, followed by the leaf, and then the seed. The concentration of cadmium in seeds varies from 2 to 4 mg/kg, which is a highly prohibited amount of cadmium in food for human consumption.