Abstract: A laboratory experiment was carried out to study the variations of superoxide dismutase (SOD) and catalase (CAT) activities and malondialdehyde (MDA) content in the visceral mass and mantle of green mussel (Perna viridis) exposed to different concentrations (0, 0.38, 1.92, 9.60, and 48.00 mg·L^-1) of di-(2-ethylhexyl) phthalate (DEHP) for a long term, and the recovery of these indices after the stress released. During the exposure period, the SOD activity in the visceral mass had an initial significant increase (P<0.05) and followed by a gradual decrease, while the CAT activity was inhibited first but induced then, recovering to the level of the control after 15 days of exposure. The MDA content in the visceral mass increased significantly with increasing exposure time (P<0.05). In the early period of exposure, the SOD activity in the mantle of the P. viridis groups exposed to lower concentrations DEHP was inhibited but that of the groups exposed to higher concentrations DEHP was induced (P<0.05), while after 4 days of exposure, the SOD activity of all the groups recovered to the normal level. The MDA content in the mantle of all the groups increased significantly (P<0.05). During the releasing period, the SOD and CAT activities in the visceral mass of P. viridis exposed to 0.38 mg·L^-1 of DEHP recovered gradually to the normal level, but the MDA content increased. After 7 days of releasing, the SOD activity in the mantle of P. viridis exposed to all test concentrations (except 48.00 mg·L^-1) of DEHP recovered to the normal level, while the MDA content maintained at a stable level. The above results indicated that DEHP had no obvious effects on the enzymes of antioxidant defense systems in the visceral mass and mantle of P. viridis but could induce the lipid peroxidation damage in the 2 tissues, and this damage could not recover in a short term.

Key words: radial difference, thermal dissipation probe, atmospheric potential evapotranspiration, diurnal pattern.