Different benefit from clonal integration of stress signal between a stoloniferous alien invasive plantand its congeneric native one

Under heterogeneous resource supply, alien invasive plants with clonal growth can benefit more from clonal integration than their native ones. However, different benefit from clonal integration of non-resource substance (such as stress signal or hormone) between alien invasive plants with clonal growth and their congeneric native ones was poorly understood. A pot experiment was conducted to explore clonal integration of stress signal induced by local exogenous ABA application within clonal networks of alien invasive plant Wedelia trilobata and its congeneric native one W. chinensis subjected to drought stress (20% soil moisture). Chlorophyll fluorescence parameter (F_v/F_m, ΦPSII and qP) and photosynthetic parameter (P_n and G_s) of young ramets in W. trilobata significantly increased 2 or 3 days after exogenous ABA application to old ramets. F_v/F_m of young ramets in W. chinensis significantly increased 3 days after exogenous ABA application. Meanwhile, P_n and G_s significantly increased 17 days after exogenous ABA application. After exogenous ABA application to young ramets of W. trilobata 3 days, F_v/F_m and P_n of its old ramets significantly increased. In addition, significant increase of ΦPSII, P_n and G_s in old ramets of W. chinensis was delayed to 17 days after exogenous ABA application. At the end of experiment, exogenous ABA application significantly promoted biomass accumulation of clonal fragments in alien invasive plant W. trilobata. Similar pattern was not observed in its congeneric native one. It is suggested that clonal integration of stress signal may improve growth performance more in alien invasive plant with clonal growth than its congeneric native one, which further promoting its invasiveness.