Effects of chemical control on Solanum nigrum L. remediation to cadmium (Cd) from seriously-polluted soil.

Solanum nigrum L. is known to be one of the hyper-accumulators of cadmium ( Cd), a contaminant, from seriously-polluted soil. In order to enhance the plant's capacity of remediation to cadmium, the chemical control of diethyl aminoethyl hexanoate (DA-6) was tested for the accumulation effects of S. nigrum on Cd from soil. In this study, the soil with a rate of Cd, 100 mg/ kg, was prepared for the outdoor pot culture of S. nigrum, and four concentrations of DA-6 (5, 10, 20 and 40 mg/ L) were used as different treatments for both soaking of seed and foliage spray. The results showed that Cd absorption and accumulation from soil were increased with DA-6, especially in the 20 mg/ L treatment, at this level, not only the dry weights of root, stem, leaf and fruit were improved, but also the Cd concentrations were increased in various organs of seedling and matured plants. The increased extraction.rates of Cd were 46.33% in roots, 28.93% in stems, and 41.28% in leaves, respectively compared with the control without any DA-6. In 5 and 10 mg/ L treatments, the Cd extractions from different organs were also significantly higher, but only the dry weight of matured stem increased significantly. Finally, at 40 mg/ L, Cd extraction and dry weight were improved only in the leaves. Therefore, our data recommend DA-6 at 20 mg/ L to treat the seeds and leaves of S. nigrum for the remediation to Cd in its polluted soil.