Growth Responses and Accumulation Characteristics of Three Ornamental Plants to Sn Contamination in Soil

Decorative ornamental plants have been applied as hyperaccumulators/phytoremediators to a wide spectrum of heavy metal contaminants. In this study, pot culture experiments were conducted to investigate the Sn tolerance and accumulation in Impatiens balsamina L., Mirabilis jalapa L. and Tagetes erecta L., in order to assess the possibility of these three ornamental plants to be used as phytoremediators of Sn-contaminated soil. Results show that all three plants exhibited strong tolerance to Sn contamination, and no significant visual toxicity was observed for all three plants grown under most of the Sn treatments. The amount of Sn accumulated in the three plants was positively correlated with the Sn concentration in the soil. The order of the Sn accumulative capacity was Impatiens balsamina > Mirabilis jalapa > Tagetes erecta. Impatiens balsamina and Tagetes erecta showed a low translocation ability (TF) (Impatiens balsamina showed a relatively high bioconcentration factor (BCF, Sn concentration in each part > 100 mg/kg after Sn treatment of 500 mg/kg). Meanwhile, the TF of Mirabilis jalapa was >1, and the fluorescence accumulated the most Sn. In combination with the adaptation to high concentrations of various heavy metals, these three ornamental plants are potential candidates for Sn mining tailings or contaminated soil.