[Effects of DA-6 and EDDS on Growth and Cd Uptake by Solanum nigrum L. and on the Soil Bacterial Community Structure]

The effects of the plant growth regulator DA-6 and chelator EDDS on the growth, Cd absorption, and soil bacterial community structure of Solanum nigrum L. on Cd-polluted soil were examined through a pot experiment, so as to evaluate the practical application effects of different remediation treatments. The results showed that the addition of DA-6 alone and the combined application of DA-6 and EDDS could promote the growth of S. nigrum L., and the shoot fresh weight increased by 24.58% and 19.57%, respectively, compared with that in the control. At the same time, the chlorophyll content and antioxidant enzyme activity of S. nigrum L. leaves also increased, whereas the content of malondialdehyde decreased. The application of DA-6 and EDDS also significantly increased the content of soil available Cd and promoted the absorption of Cd by S. nigrum L. Compared with that in the control, the extraction amount of Cd from S. nigrum L. shoots was significantly increased by 39.42% (DA-6), 30.17% (EDDS), and 51.04% (DA-6+EDDS), respectively. It was also found that the application of EDDS alone significantly reduced the ACE index of the soil bacterial community and significantly increased the Simpson index, and the abundance of the Lysobacter genus in the soil was significantly reduced. After the combination of DA-6 and EDDS, the diversity and taxonomic composition of the soil bacterial community were improved.