Abstract: An indoor simulation method was conducted to study the effects of decabromodiphenyl ether (BDE-209) and Zn²⁺ (ZnSO₄·7H₂O) on the activity of soil enzymes (catalase and saccharase) and soil respiration during 93day incubation. The results indicated that catalase and saccharase showed high sensitivities to single and combined pollution of BDE-209 and Zn²⁺ in a short term (1-7 d). With the extension of exposure time, the activities of catalase and saccharase showed a trend of gradual recovery even up to control levels. But the activities of catalase and saccharase in the treatment with the highest concentration of 100 mg·kg^-1 BDE209 combined with the highest concentration of 1000 mg·kg^-1 Zn²⁺ were always in inhibited states. The effects of combined pollution of BDE209 and Zn²⁺ on soil catalase activities were characterized by antagonism in the early exposure and dominated by synergy in the later exposure, and the effects on soil saccharase showed additive, antagonistic and synergistic interactions at different times. The effects of combined pollution of BDE209 and Zn²⁺ on soil respiration presented a pattern of “promotionsuppressionpromotionsuppression”, and the intensity of promotion or suppression decreased as the exposure time increased.

Key words: middle growth stage, water consumption, irrigation regime, grain yield., wheat, photosynthesis