Effects of Cadmium on the Growth of Tobacco and the Characteristics of Cadmium Accumulation by Tobacco

Tobacco is one of the most important crops in China. Pot experiments were carried out to study the effects of different concentrations of Cd (0, 1.2, 2.4 and 4.8 mg/kg) on the tobacco growth and the characteristics of Cd distribution and uptake by tobacco. The results show that, the dry matter weight of tobacco leaves significantly decreased with the increase of the Cd concentration at the same growth stages (p < 0.01). The dry matter weight of stem increased firstly and then sharply decreased. The dry matter weight of root gradually decreased at the early growth stage (30 d and 45 d), while it slightly increased at first and then decreased rapidly at the later growth stage (60 d and 75 d). The Cd content of leaves significantly higher than that of stems and roots except the control treatment. The Cd content of control performed as: root > stem > leaf. The content of Cd in tobacco leaves showed as: lower leaf >> middle leaf > upper leaf. The accumulation rate of Cd increased in different parts of tobacco with the increase of the Cd concentration. Cd accumulation rate of tobacco showed as: rapid accumulation- quick reduction -slow accumulation.