Abstract: Many studies have focused on how clonal plants cope with stressful environments through clonal integration. We tested the hypothesis that clonal integration can help clonal plants resist parasitism by plants in an experiment in which stoloniferous alligator weed (Alternanthera philoxeroides) experienced partial infection by parasitic dodder (Cuscuta chinensis). Interconnecting ramets of alligator weed were assigned to the following treatments: M⁺-D^- (only mother ramets infected), M^--D⁺ (only daughter ramets infected), M⁺-D⁺ (both mother and daughter ramets infected), M^--D^- (no infection). Relative chlorophyll content, F_v/F_m, number of leaves, stolon length and number of ramets significantly responded to the infection while biomass did not. Our results did not support the hypothesis, which might be due to our relatively short experimental term, suggesting that adaptive expression of clonal integration is not unconditional. Further studies should be able to take both short and longterm effect into account.

Key words: analytic hierarchy process (AHP), comprehensive evaluation index, spatio-temporal characteristics, agricultural drought