Effect of lead accumulation on growth and mineral composition of eggplant seedlings (Solanum melongena)

To examine lead (Pb) accumulation and distribution, and its effects on growth and nutrient content, Solanum melongena seedlings were grown in pot culture conditions in a glasshouse. The experiment was arranged in a randomised block design with 75, 150, and 300 mg litre(-1) Pb applications, and replicated 3 times. The highest Pb applications represent severely contaminated land, the lowest representing above average pollution levels in industrial situations. Growth parameters such as root elongation and plant height; fresh and dry biomass of root, shoot, and leaf; leaf area; mineral elements (Ca, Mg, K, P, Fe, Zn, Cu, and Mn); chlorophyll content; and stomatal parameters were measured in roots, shoots, and leaves. The control treatment provided typical values for this plant as a reference, grown in alkaline soils. Growth parameters such as root elongation and plant height; fresh and dry biomass of root, shoot, and leaf; and leaf area were negatively affected by increasing Pb concentrations. Growth toxicity index increased as the concentration of Pb increased. Exposure to excess Pb caused accumulation of Pb in roots, shoots, and leaves of eggplant seedlings. At the higher Pb concentrations, roots accumulated 6-fold more Pb than shoots and 4-fold more than leaves. The highest level of Pb generally inhibited the uptake of all mineral elements compared with the low-level Pb treatment. The results of this experiment show the phytotoxicity of increasing Pb, which is apparent from the reduction of chlorophyll concentration in eggplant. In addition, a negative effect was determined by Ph concentration on stomatal parameters of stomata density, stomata length-width, and stomatal index in this study.