Abstract

The purpose of this study was to explore dynamic accumulation and distribution of five heavy metal elements i. e. lead (Pb), cadmium (Cd), chromium (Cr), arsenic (As) and mercury (Hg) in different organs of tobacco plants. Field experiment was carried out in 2011. Leaf, stem and root samples of tobacco were prepared 30, 45, 60, 75, 90 and 110 days after transplanting (DAT), respectively, and the contents of these five elements were measured. The results showed that lead and chromium content in tobacco root was significantly higher than that in stem and leaf during tobacco whole growth period. Cadmium content in stem and root was significantly higher than that in leaf at early growth stage, except at 60 DAT, which was significantly lower. Arsenic content in root was significantly higher than that of stem and leaf, but at 45 and 75 DAT, the arsenic content of luggs was the highest among all tobacco organs. Tobacco leaf mercury content was significantly higher than that in root and stem. While at later growth stage, mercury content of middle leaf was obviously higher than the others. Our experimental data suggest that characteristics of tobacco heavy metal accumulation and distribution are quite different. Tobacco accumulates cadmium at its early growing stage, mercury at later stage, while lead, chromium and arsenic at middle stage. Tobacco has the special ability to accumulate cadmium and transport it from root to stem and leaf. Lead and chromium mainly store in tobacco root, cadmium mainly in leaf, while arsenic and mercury in root and leaf.