The Characteristics of Cd Accumulation in Low-Cd Accumulating Tobacco Cultivars Exposed to Cd

In order to investigate the characteristics of Cd accumulation in different tissues of low-Cd accumulation tobacco cultivars at different growth stages, and to ensure the safe production of tobacco, a pot experiment was conducted to study plant growth, Cd accumulation and distribution in low-Cd accumulation tobacco cultivars at different growth stages. Two low-Cd accumulation tobacco cultivars (RG11andCF986) identified earlier were used with high-Cd accumulation tobacco cultivar Yuyan5 as control. The biomass of different tissues of RG11 and CF986 decreased with increasing Cd concentrations in soils at different growth stages. The leaf biomass of RG11 and CF986 showed the smallest decline of 22.64%-27.95%. The root and stem biomass of RG11 and CF986 were higher than those of Yuyan5. However, no significant difference was observed for leaf biomass among RG11, CF986 and Yuyan5. As Cd concentration in soil increased, so did the Cd concentration, Cd accumulation in tissues and leaf Cd accumulation rate of RG11 and CF986. The leaf Cd accumulation rate at the peak stage was the largest. The Cd concentrations and accumulation in root and stem of RG11 and CF986 were significantly higher than those of Yuyan5, while the Cd concentrations and accumulation in leaves were significantly lower than those of the Yuyan5. The Cd accumulation in different tissues of RG11 and CF986 showed the trend of leaf> stem > root. The proportions of Cd accumulation in leaves of RG11 and CF986 were lower than those of Yuyan5. However, the proportion of Cd accumulation in root and stem of RG11 and CF986 were higher than those of Yuyan5. These results indicated that the low-Cd accumulation tobacco cultivars possessed lower Cd accumulation at different growth stages, which will benefit the practical application of the low-Cd accumulation tobacco cultivars.