RESUMEN
Sedum plumbizincicola is a Cd and Zn hyperaccumulator, widely used for the phytoremediation of Cd-contaminated soil. Bacillus megaterium, a phosphate-solubilizing bacteria, can promote plant growth and improve the bioavailability of heavy metals in soil, and thus has a strengthening effect on the remediation of heavy metal-contaminated soil. Here, a pot experiment was carried out with S. plumbizincicola as a hyperaccumulator to investigate the effects of different inoculation amounts (10-60 mL) of B. megaterium on the phytoremediation efficiency of Cd-contaminated farmland soils. The results showed that inoculation of B. megaterium increased soil available Cd content by 15.0%-45.0% compared with the CK. Biomass of shoots and roots of S. plumbizincicola increased by 8.7%-66.7% and 13.6%-81.8%, respectively. Shoot Cd concentration was significantly increased by the application of B. megaterium by 29.2%-60.4%. Under the conditions of S. plumbizincicola inoculated with B. megaterium, Cd removal rate of soil reached 26.7%-42.9%. In conclusion, application of B. megaterium in phytoremediation significantly enhanced the Cd removal efficiency and increased plant biomass, which promoted Cd remediation efficiency.
Asunto(s)
Bacillus megaterium , Sedum , Contaminantes del Suelo , Biodegradación Ambiental , Cadmio , Granjas , Suelo , Contaminantes del Suelo/análisis , ZincRESUMEN
Root exudates are the most direct manifestation of the response of plants changes in the external environment. Therefore, based on non-targeted gas chromatography-time-of-flight mass spectrometry and metabolomics, the response of Sedum plumbizincicola root exudates to Cd stress was used to reveal the possible mechanism of resistance to or accumulation of Cd. The results showed that Cd significantly changed the composition and contents of S. plumbizincicola root exudates. A total of 155 metabolites were identified in S. plumbizincicola root exudates, among which 33 showed significant differences under Cd stress, including organic acids, amino acids, lipids, and polyols. Cd stress suppressed organic acid metabolism and lipid metabolism in S. plumbizincicola and significantly affected amino acid metabolism. There were 16 metabolic pathways related to Cd stress, among which arginine and proline metabolism, valine, leucine, and isoleucine biosynthesis, glycine, serine, and threonine metabolism, glutathione metabolism, and purine metabolism were the key pathways with the highest correlation, and were closely related to the stress resistance of S. plumbizincicola.