Abstract: The soils under native plant community with and without Alternanthera philoxerodies invasion were taken as the growth medium to study whether plantsoil feedback contributes to the invasion success of A. philoxeroides. The soil under A. philoxeroidesinvaded community inhibited the growth of native A. sessilis significantly, which manifested in the decreases of root biomass, stem biomass, total biomass, relative growth rate, and net assimilation rate, and in the changes of morphological traits, e.g., the decreases of stem length, branch number, root length, and root volume. The biomass partitioning of native A. sessilis also changed, with a significantdecrease of leaf/mass ratio and increased root/mass ratio and root/shoot ratio. However, the soil under A. philoxeroidesinvaded community did not significantly affect the growth of invasive A. philoxeroides, according to the data of biomass and morphological traits. The soil under A. philoxeroidesinvaded community only significantly increased the leaf number and leaf/mass ratio of invasive A. philoxeroides. The significant negative and neutral effects of soil under A. philoxeroidesinvaded community on the native A. sessilis and invasive A. philoxeroides, respectively might contribute to a positive feedback loop, leading to the increased dominance of invasive A. philoxeroides in the invaded community. The results indicated that soil might play important role in the successful establishment and maintenance of A. philoxeroidespopulation in its invaded area.

Key words: economic development, environmental protection, adaptability, Tangshan.