Cd^(++)对草履虫种群的毒性作用

Toxic effects of Cd^(++) on the population of Paramecium caudatum

通过研究20℃培养条件下Cd++对草履虫(Paramecium caudatum)种群毒性影响,结果表明:Cd++对草履虫的24hLC50为0.3294mg/L,Cd++浓度对草履虫的种群增长率有极显著影响,多重比较结果显示高浓度组(0.25和0.30mg/L)下草履虫的种群增长率显著小于低浓度下(0.05、0.15和0.20mg/L)的值。回归分析结果表明草履虫种群增长率(Y,/d)与Cd++浓度(X,mg/L)之间呈曲线相关。在一定浓度范围内,草履虫种群增长率随Cd++浓度的升高而呈增大,但高的Cd++浓度显著地降低了草履虫的种群增长率;当Cd++浓度为0.1179mg/L时,草履虫种群有最大增长率1.5442/d。各浓度组与对照组之间的t-检验结果表明在较低的Cd++浓度范围内(0.05、0.10和0.15mg/L)草履虫的种群增长率显著大于对照组的值,而Cd++浓度为0.30mg/L时的草履虫种群增长率显著小于对照组的值。

Toxic effects of cadmium on the population of Paramecium caudatum were studied at 20℃. The result showed that the concentration of 24 h LC50 of cadmium to P. caudatum was 0. 3294 mg/L. Cd^＋＋ concentration significantly affected the population growth rate of P. caudatum, The multiple comparison showed that the population growth rate of P. caudatum was larger at lower cadmium concentrations （0.05, 0.15 and 0.20 mg/L） than at higher concentrations （0.25 and 0.30 mg/L）. The relationship between cadmium concentration （X, mg/L） and population growth rate （Y, /d） of P. caudatum was curvilinear： y = -47. 2730X^2 ＋ 11.1504X ＋ 0. 8867. The population growth rate increased with the increasing cadmium concentration when the Cd^＋＋ concentration was low, but when the concentration got higher, the population decreased obviously. P. caudaturn got its maximum population growth rate （ 1. 5442/d） at the concentration 0.1179 mg/L. T - test found out that the population growth rate at lower cadmium （0.05, 0.10 and 0.15 mg/L） was significantly larger than that at the control, while the population growth rate at higher concentration was significantly smaller than that at the control.