Chemical Strategy of the Invasive Plant Alternanthera philoxeroides Leading Ecological Adaptation in Constructed Wetlands

Abstract

The plant diversity of Constructed Wetland (CW) is threatened by rapidly reproducing and highly adaptable invasive plant species. Plant ecological adaptation, a key driving force of ecosystem diversity, results from plant interactions with other organisms and the abiotic environment and is usually mediated by chemical metabolites. This study aimed to investigate ecological adaptation of the invasive species Alternanthera philoxeroides in CW in the perspective of metabolites. Several field surveys were conducted in a surface flow CW and seedlings and mature phase of A. philoxeroides were collected. The total secondary metabolites were extracted and MTT assay showed a significant cytotoxicity difference of two extracts which indicated the different chemical composition of total secondary metabolites. The extracts were further analyzed by High Performance Liquid Chromatography and Quadrupole Time-of- Flying Mass Spectrum. The results showed the high constituent diversity of the seedlings and highlight the seeding phase of A. philoxeroides with profuse metabolism which is critical for its adaptation and species competition. This study reveals the chemical metabolism traits of A. philoxeroides in different growth phases, provides theoretical basis for its adaptation in CW ecosystems from the chemical perspective, and suggests a potentially strategy for plant invasion control in CW by implementing the control measures during the seedling phase.