Analysis of the potential of 165 ramie germplasms to be used for cadmium-contamination remediation

Cadmium (Cd) pollution in both water bodies and farmlands seriously threatens human health, removing Cd from these environments is of great importance. Previous studies have proved ramie has great potential to remediate Cd pollution, however, its remediation efficiency depends greatly on the varieties of ramie. Therefore, in the present study, 165 ramie germplasms were selected to investigate their responses to Cd stress and the potential to remediate Cd pollution via a hydroponic trial. Results showed that Cd stress significantly inhibited the growth of ramie, the average ramie plant height, stem diameter, root length, and biomass under Cd stress were significantly decreased compared with that under control treatment; Cd stress can elevate the nutrient contents (B, Fe, K, Mg, P) in the aboveground part of ramie to some extent, but significantly reduce the accumulations of these elements. The Cd content in the aboveground part of ramie under Cd stress ranged from 61.7 mg kg(-1) to 643 mg kg(-1) with an average of 231 mg kg(-1), and the Cd uptake ranged from 0.001 mg plant(-1) to 0.71 mg plant(-1) with an average of 0.15 mg plant(-1). Correlation analysis indicated that the enrichment of K and Mg can significantly reduce the Cd absorption in ramie but the enrichment of P seemed to enhance the Cd accumulation in ramie. Hence, ramie has great potential to be used for phytoremediation of Cd and further studies are needed to explore the suitability of these ramie germplasms for remediation of Cd-contaminated soil as well as the interactions between nutrient elements and Cd, and the results of this study can provide valuable references for finding the genes related to Cd-resistance and Cd-accumulation in ramie and for further breeding transgenic varieties with higher Cd-remediation efficiency.