Growth and Development of Vernonia amygdalina Del in Soils Treated with Lead

Abstract

The effect of lead on the growth and development of Vernonia amygdalina Del. was investigated. The plant as grown from uniform green cuttings in buckets (each with 5 kg dry soil) and allowed to stabilize for a month before
being treated with lead. The experiment was made up of control and four concentrations (25, 50, 75 and 100 mg/kg) in three replicates. Data were collected on a monthly basis for 12 months. The results for plant height, number of leaves, leaf area, number of branches and girth showed adverse effect of lead treatment on growth except for leaf area which apparently was enhanced. The soil treatment with lead, at 12 months after planting (MAT), had height values of 77.43±1.45, 72.47 ± 7.33, 57.27 ± 5.71, 68.67 ± 6.13 and 66.47 ± 5.60 cm and leaf area values of 17.45 ± 4.84, 21.47 ± 8.83, 14.55 ± 2.01, 32.12 ± 9.58 and 24.85 ± 7.07 cm 2 for control, the 25, 50, 75 and 100 mg/kg treatments respectively. Lead caused decrease in pH, nutrient element composition of soil and soil microbial population. It however caused increase in soil carbon. Lead taken up by plant was within tolerable limits. These effects were along the concentration gradient.