Analysis of Physiological and Metabolite Response of Celosia argentea to Copper Stress

Copper-tolerant (Cu) plants with high ornamental value play an important role in the ecological landscape restoration of the copper tail mining area. We first discovered Celosia argentea adaptability in copper mine area in China. However, its copper resistance and mechanism are not clear. In this study, C. argentea was selected for pot culture experiments, and its heavy metal accumulation and translocation, physiological and metabolic products were analyzed under different concentrations of Cu (0-2400 mg • kg-1) stress. Our results indicated that the root with strong copper accumulation. The oxidative stress defense mechanisms were activated under Cu treatment of C. argentea leaves. Higher Cu concentration triggered higher electrolyte leakage (EL), Malondialdehyde (MDA), superoxide dismutase (SOD) and peroxidase (POD) activities, and consequently a higher capacity of scavenging oxygen radical and maintaining cellular membranes integrity. Results showed that the citrate cycle, some amino acids and sugars related biological pathways were alterted of C. argentea under Cu stress. Metabolomics data revealed that C. argentea elevated sugars content as an antioxidant to regulate ROS. Some organic acids and amino acids level were up-regulated compared with the control, indicating that they may act on chelating Cu in cells to detoxify excess Cu²⁺ . The up-regulation of polyamines (ethanolamine) and some organic acids may mitigate oxidative stress and enhance tolerance. These results indicate that C. argentea can be used as a copper-tolerant plant in copper mine restoration, and its copper tolerance mechanism also provides a basis for plant improvement or breeding in future mine restoration.

Keywords: Antioxidant defense; Copper Stress; Metabolic network; Secondary metabolites.