Biomass reallocation and increased plasticity might contribute to successful invasion of Chromolaena odorata

Abstract

Invasive plants are often genetically different from their native conspecifics. In the introduced range, the evolution of functional traits or plasticity might occur as an adaptive response to novel environmental pressures. Chromolaena odorata originates from the Americas, but now is a noxiously invasive species in some other tropical and subtropical areas. In this study, plant growth, morphology, photosynthesis and plasticity were compared between C. odorata plants from five introduced and five native populations under three light intensities (low, medium and full light). Compared to native C. odorata, introduced conspecifics had higher height under medium and full light, but lower root to shoot biomass ratio across all light conditions, and lower leaf N under medium light. This indicates genetic differences between native and introduced C. odorata. Furthermore, plasticity was higher for introduced C. odorata plants than for native conspecifics under various light environments. Our results indicate that biomass reallocation (from belowground into aboveground) and stronger plasticity could contribute to successful invasion of introduced C. odorata in frequently disturbed environments.