Abstract: This paper studied the acetylcholinesterase (AChE) activity in blood serum of tilapia exposed to 1.0, 2.0, 3.0, 5.0, and 10.0 μg·L^-1 of deltamethrin at water temperature 23 ℃-27 ℃. The results revealed that the AChE activity was （2.75±0.21） U·ml^-1 at 23 ℃ and （2.73±0.26） U·ml^-1 at 27 ℃, with the variation range of -12.0% to 13.1% and -11.0% to 14.2%, respectively. After ten days exposure to >2.0 μg·L^-1 of deltamethrin at 25 ℃±1 ℃, the AChE activity was inhibited, and the inhibition rate was surpassed 40% at the 20th day of exposure. The highest inhibition rate (62.3%) was observed on the 25th day of exposure to 5 μg·L^-1 of deltamethrin. The fluctuation of water temperature from 23 ℃ to 27 ℃ had no significant effects on the AChE activity, while high concentrations (≥2.0 μg·L^-1) of deltamethrin could inhibit the AChE activity, and the inhibition rate was increased with exposure time.

Key words: Subalpine coniferous forest, Ecological process, Artificial restoration, Natural succession, Forest litter, Picea asperata