Differentiation in growth and biomass allocation among three native Alternanthera philoxeroides varieties from Argentina

Knowledge about the life-history traits of native conspecifics of exotic invasive plants can be of fundamental importance in exploring their origin of invasiveness and disentangling distinct invasion mechanisms. We conducted a common garden experiment to examine genetically based differentiation in growth and biomass allocation among three native Alternanthera philoxeroides varieties (Alternanthera philoxeroides var. obtusifolia, Alternanthera philoxeroides var. acutifolia and Alternanthera philoxeroides var. lancifolia) from Argentina. Results showed that the high-latitude var. obtusifolia had lower values of relative growth rate and plant size. In contrast, the low-latitude var. acutifolia showed distinctly higher growth vigor. The mid-latitude var. lancifolia generally showed intermediate growth vigor. Regarding allocation, var. obtusifolia allocated a distinctly higher proportion of biomass to storage roots and leaves, whereas var. acutifolia and var. lancifolia allocated more biomass to stems. This pattern of variation might be the outcome of evolutionary differentiation in response to their geographic distributions and local habitats. The acutifolia and lancifolia varieties may have higher potential invasiveness than var. obtusifolia.