Investigating Phragmites Australis Response to Copper Exposure Using Physiologic，FTIR and Metabolomic Approaches

Abstract Background and aim Phragmites australis is a landscape plant with phytoremediation functions that is widely planted worldwide. However, little is known about the metabolomic background of the resistance mechanisms of Phragmites to heavy metals during its growth and development. Methods Here, we performed copper stress studies on Phragmites and monitored physiological indicators such as malondialdehyde (MDA) and electrolyte leakage (EL). In addition, FTIR was used to study chemical composition changes in the roots, stems and leaves of Phragmites seedlings under excessive copper stress. Furthermore, LC-MS technology combined with metabolomics data processing software was used to analyze the metabolic profile of samples.Result Copper contributed to the accumulation of MDA and EL. And the results of FTIR showed that the antioxidant effects of flavonoids and amino acids can be used by Phragmites leaf tissue to improve the tolerance of copper under 5 mg/L concentration. Further, the results of metabolomics reflected that Phragmites can improve its resistance to copper by increasing the accumulation of arginine and ayarin in the body. The former is accumulated through two pathways: the citrulline decomposition and conversion pathway and the circular pathway composed of ornithine, citrulline, L-Argininosuccinate and arginine. The latter is synthesized through the quercetin methylation pathway.Conclusion This study provides insights into the resistance mechanism and repair performance of Phragmites and other plant accumulators in response to copper stress.