Effects of Cadmium and Zinc on Growth and Cadmium Concentration of Flue-cured Tobacco

Compared to other crops, tobacco can accumulate relatively high levels of Cd. Cd accumulation in crop plants such as tobacco can lead to human exposure to this carcinogenic metal. Cd and Zn were added to the unpolluted soil with Cd concentration of 0、1、3、5、10 mg·kg-1 and Zn concentration with 0、100 mg·kg-1, respectively, and stabilized for 60 days in the pot experiment. One tobacco seedling was transplanted to each pot containing 5 kg soil. The results showed that the content of chlorophyll a、chlorophyll b in leaves of tobacco、dry weights decreased significantly with the increase of added Cd except for the treatment of 1 mg·kg-1 Cd. Zn enhanced the growth of tobacco plant and decreased Cd concentration. The concentrations of Cd in different parts of tobacco increased with the increase of Cd added in the soil. The concentration of Cd in different parts of tobacco followed the orders: leafrootstem; lower leaf middle leaf upper leaf. There was a competition system both for Zn and Cd uptake, which is useful to minimize the Cd uptake through Zn application in the field.