An Evaluation of the Effect of Treatment with Mixture of Cadmium and Lead on the Growth of Okra [Abelmoschus esculentus (L.) Moench]

Abstract

Abelmoschus esculentus (L.) Moench was grown from seeds in soil polluted with a mixture of cadmium and lead in the ratio 1:1. The experiment consisted of control and four treatments (25, 50, 75 and 100 mg/kg) in three replicates. Data for growth parameters (seedling emergence, plant height, number of leaves, leaf loss, leaf area, and stem girth) were collected weekly for 3 months and number of flowers and fruits later in the experiment. The research lasted for 5 months. Physico-chemical and heavy metal analysis were carried out on soil samples at the end of the experiment. The leaf, root and fruit of plant samples were also analyzed for heavy metal content at this time. There was significant difference between control and the 75mg/kg and 100mg/kg treatments at day 6 with percentage emergence values of 77.1, 82.9, 65.7, 60 and 57.1 percent for control, the 25mg/kg, 50mg/kg, 75mg/kg and 100mg/kg respectively. There was no significant difference between control and other treated plants for the other growth parameters investigated. There was a decrease in the nutrient composition of samples analyzed as concentration of treatment increased. The uptake of the metals was in the order Pb > Cd, with the highest accumulation recorded in the root; 1.58ppm Pb and 0.25ppm Cd, and the least accumulation recorded in the fruit; 0.26ppm Pb and 0.13ppm Cd.