Abstract: A hydroponic experiment was conducted to study the growth and tolerance performance of Polygonum hydropiper exposed to different concentration mercury (0, 0.5, 1, 10, 20, and 50 μg·L^-1). In all treatments, the growth and physiological performances of P. hydropiper were not affected. The root tissue of P. hydropiper had the greatest accumulation of mercury, with the enrichment coefficient being 531.5%. The mercury accumulation in P. hydropiper stem, leaf, and root was significantly positively correlated with the mercury concentration in culture solution. Under a given mercury concentration, the mercury level in P. hydropiper plants increased with culture time. The subcellular mercury concentration in the stem, leaf, and root was in the order of cytoderm > cytoplasmic organelles > cytolymph. Due to the strong mercury-binding effect of cytoderm, the mercury translocation from cytoderm to cytoplasmic organelles and cytolymph was limited.  

Key words: Cuscuta australis, parasitism, defense, biological control, invasive plant.