The differences in arsenic (As) tolerance, uptake and accumulation between Pteris vittata (an As hyperaccumulator) and P. semipinnata (nonaccumulator) were investigated under hydroponic conditions. The results showed that As uptake by P. vittata was significantly higher (p < 0.05) than that of R semipinnata. Significantly higher concentrations of As accumulated in the fronds of P. vittata, while in the roots of P. semipinnata. The short-term (<24h) uptake kinetics were fitted a hyperbolic equation which could be divided into linear and saturable components (described by Michaelis-Menten kinetics/model). The increase in hydrogen peroxide (H2O2) content in both plant species significantly correlated (p, < 0.05) with increasing As content in the plants and As exposure time, especially for midrib of P. semipinnata. P. semipinnata showed higher concentrations of H2O2 than those of P. vittata. The relative electrical conductivity (REC, %) values in the root and pinnae followed a similar trend as plant H2O2 contents, increasing with As exposure, especially for P. semipinnata. Significantly higher REC (%) values (p < 0.05) were observed in the root than that in pinnae of P. semipinnata. The results indicated that high doses of As produced oxidative damages in both plant species. (C) 2009 Published by Elsevier B.V.