百草枯和草甘膦对多刺裸腹溞的毒性效应

采用急性毒性实验方法研究了两种常见除草剂百草枯和草甘膦对多刺裸腹溞(Moina macrocopa)的48hLC50值,应用生命表实验方法研究了亚致死浓度的百草枯(0、0.01和0.04mg·L-1)和草甘膦(0、0.4和1.6mg·L-1)对多刺裸腹溞生命表统计学参数的影响。结果表明:百草枯和草甘膦对多刺裸腹溞的48hLC50值分别为0.626和26.287mg·L-1;百草枯浓度对多刺裸腹溞的生命期望、世代时间、净生殖率和种群内禀增长率有显著影响(P<0.01),草甘膦浓度对多刺裸腹溞的生命期望、世代时间和种群内禀增长率有显著影响(P<0.01),百草枯和草甘膦的交互作用对多刺裸腹溞的世代时间和种群内禀增长率有显著影响(P<0.01)。多重比较显示:当忽略草甘膦的影响时,0.01mg·L-1的百草枯使多刺裸腹溞的生命期望显著延长,而0.04mg·L-1的百草枯则相反,0.04mg·L-1的百草枯使多刺裸腹溞的净生殖率显著降低;当忽略百草枯的影响时,0.4和1.6mg·L-1的草甘膦均使多刺裸腹溞的生命期望显著缩短;与空白对照组相比,0.01mg·L-1的百草枯和1.6mg·L-1的草甘膦混合液使多刺裸腹溞的世代时间显著延长;而0.04mg·L-1的百草枯和0、0.4、1.6mg·L-1的草甘膦混合液均使多刺裸腹溞的世代时间显著缩短,种群内禀增长率显著降低。随着草甘膦浓度的升高,0.04mg·L-1的百草枯对多刺裸腹溞的毒性显著降低,表现出明显的拮抗作用。

Toxicological effect of paraquat and glyphosate on cladoceran Moina macrocopa

This paper examined the acute toxicities of glyphosate and paraquat to Moina macrocopa, and studied the effects of the sub-lethal concentrations of paraquat (0, 0.01, and 0.04 mg·L-1) and glyphosate (0, 0.4, and 1.6 mg·L-1) on the life-table demography of this cladoceran. The 48 h LC50 values of glyphosate and paraquat to M. macrocopa were 0.626 mg·L-1 and 26.287 mg·L-1, respectively. Paraquat concentration had significant effects on the life expectancy at birth, generation time, net reproductive rate, and intrinsic rate of population increase (P<0.01), and glyphosate concentration affected the life expectancy at birth, generation time, and intrinsic rate of population increase significantly (P<0.01). The interaction between the two herbicides had significant effects on the generation time and intrinsic rate of population increase of M. macrocopa (P<0.01). Multiple comparisons indicated that regardless of the effect of glyphosate, the paraquat at 0.01 mg·L-1 had significant effect on the increase of the life expectancy at birth, but the reverse was also true for the paraquat at 0.04 mg·L-1. The paraquat at 0.04 mg·L-1 decreased the net reproductive rate of M. macrocopa significantly. Regardless of the effect of paraquat, the glyphosate at 0.4 and 1.6 mg·L-1 decreased the life expectancy at birth significantly. Compared with the blank control, the mixture of paraquat at 0.01 mg·L-1 and glyphosate at 1.6 mg·L-1 increased the generation time significantly, but the mixture of paraquat at 0.04 mg·L-1 and glyphosate at 0, 0.4, and 1.6 mg·L-1 decreased the generation time and the intrinsic rate of population increase. With the increase of glyphosate concentration, the toxicity of paraquat at 0.04 mg·L-1 to M. macrocopa decreased significantly, suggesting a significant antagonism existed between paraquat and glyphosate.