Cadmium Toxicity and its Effects on Growth and Metal Nutrient Ion Accumulation in Solanaceae Plants
The effect of cadmium (Cd) toxicity was studied in four Solanaceae plants (tomato, Solanum lycopersicum L.; pepper, Capsicum annuum L.; eggplant, Solanum melongena L., and goldenberry, Physalis peruviana L.) grown in greenhouse under natural light conditions. The soil was treated with five levels of Cd (0, 2.5, 5, 10 and 20 mg kg-1). Except for the tomato, the shoot and root dry biomass decreased with increasing Cd. Plant growth, bioaccumulation and translocation of Cd and accumulation of metal nutrient ions [potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn)] were investigated. On the basis of the percent reductions in the shoot dry biomass, the tomato was determined to be Cd-tolerant, and the other plants Cd-sensitive. The shoot and root Cd contents, uptakes, and total accumulation rate (TAR) were increased with increasing rate of Cd applied, except for the shoot Cd content and root uptake of the goldenberry. The bioconcentration factor (BCF) and the translocation factor (TF) of Cd diminished at all plants, with the exception of the TF for tomato. With respect to Cd translocation, plant species showed a ranking as follows: goldenberry <pepper<eggplant<tomato. The accumulation of all metal nutrient ions increased with Cd applications in the goldenberry shoots. While the accumulation of divalent metal nutrient ions, except for Zn and Cu, increased for the pepper and eggplant, the accumulation of K as monovalent metal nutrient ion decreased for only the pepper.