Determination of resistance to cadmium toxicity in tobacco varieties (Nicotiana tabacum L.)

Cadmium (Cd), a heavy metal, is not needed for biological functions and has 2-20 times more toxic impacts for human, animal, and plants compared to the other heavy metals. Tobacco (Nicotiana tabacum L.) can accumulate higher concentrations of Cd. However, the genotypic differences of tobacco cultivars (Özbaş, Canik-190/5, Xanthi/81 and Birlik/124) in Cd uptake and the responses to Cd toxicity have not been clearly determined. This study was conducted to determine the resistance of different tobacco cultivars to Cd toxicity under greenhouse conditions. Four different doses of Cd (0, 5, 10 and 20 mg Cd kg-1 soil, (CdS04)3.8H20 form)) were used to test the resistance of four tobacco cultivars. Macro (N, P and K) and micro (Fe and Zn) nutrients required for tobacco plants were applied to soils. Increasing the Cd application doses significantly (P<0.01) decreased the shoot dry matter yields of 4 different tobacco plants, while shoot Cd concentration and contents significantly (P<0.01) increased. The highest decrease in dry matter yield under the highest Cd (Cd20) treatment was occurred in Özbaş (58.5% reduction), Birlik/124 (52.4% reduction) and Canik (51.1% reduction) cultivars, while the lowest decrease was in Xanthi/81 (44.6% reduction) cultivar. The amount of Cd removed from soil was significantly different among the tobacco cultivars. The highest Cd uptake was obtained in Cd20 treatment, while the lowest was in Xanthi/81 (395.2 g Cd plant-1) and Canik (232.6 g Cd plant-1) cultivars, respectively. Toxic Cd treatments resulted in a significant decrease in the shoot Zn concentrations, in contrast, to increase in Cu concentrations of the cultivars. However, the Fe and Mn concentrations have not significantly varied between cultivars. The results revealed that Canik cultivar removes lower Cd from soil compared to the other cultivars, whereas Cd uptake of Xanthi/81 cultivar is higher, thus is considered more resistant to Cd toxicity than other cultivars. 2019, 30 PAGES