Effect of cadmium stress on growth and mineral composition of two tobacco cultivars

Cadmium (Cd) is a hazardous pollutant for humans, animals and plants when the certain threshold concentrations exceeded. Tobacco can accumulate higher concentrations of Cd, and the genotypic differences of tobacco in Cd uptake and the response to Cd have not been clearly determined. The aim of this work was to determine the effects of various cadmium levels (Cd 0, 0.25, 2.5 and 10 mg kg -1 ) on macro and micro nutrient concentrations and biomass production of two tobacco varieties. Tobacco plants were grown under controlled conditions, and required macro (N, P and K) and micro (Fe and Zn) nutrients were applied along with increased doses of Cd. The concentrations of N, P, K, Ca, Mg, S, Fe, Cu, Zn, Mn, B and Cd concentrations in leaves and dry matter yield of two tobacco varieties were determined. The increased doses of Cd significantly affected (P< 0.05) the dry matter yield and many nutrient concentrations evaluated. The changes in plant nutrient concentrations of tobacco leaves induced by Cd exposure were diverse. Concentrations of K, Ca, Mg, Zn, Fe, Mn and B decreased in the tobacco leaves in line with Cd exposure, concentrations of Cd and Cu increased, but N, P and S were not significantly changed. The results revealed that high Cd accumulation is possibly associated with a decline in dry matter weight induced by the disturbance of nutrient uptake. Precautions need to be taken for tobacco grown in Cd contaminated environments preventing Cd uptake of human through smoking cigarette.