农药胁迫对草履虫个体生长和种群动态的影响

Effects of pesticides on Paramecium caudatum individual’s growth and population dynamics

采用连续培养法探讨了草履虫(Paramecium caudatum)在甲胺磷、2,4-D丁酯和甲氰菊酯3种农药胁迫条件下的个体生长和种群动态,并利用Logistic种群增长模型对种群的增长曲线进行了分析。结果表明:甲胺磷和甲氰菊酯农药胁迫能改变草履虫细胞的大小和形态;不同农药不同浓度处理下,草履虫密度增长曲线均具有“S”型生长特点;农药胁迫下草履虫密度增长曲线符合Logistic模型(R2>0.8),3种农药胁迫下K值明显降低;甲胺磷和甲氰菊酯农药胁迫下种群最大增长率低于2,4-D丁酯胁迫和对照。

With continuous- culture in laboratory, this paper studied the individual＇ s growth and population dynamics of Paramecium caudatum under the stress of methamidophos, fen-propathrin and 2,4-D buiylate, with the population growth curves analyzed by using Logistic model. The results indicated that methamidophos and fen-propathrin could alter the cell size and form of P. caudatum. After treated with different concentrations of test pesticides, the population growth curves were all sigmoid, and accorded well with Logistic model （R^2 〉 0. 8 ）. The K value was decreased significantly under the stress of pesticides, and the maximal population growth rate was lower under methamidophos and fen-propathrin stress than under 2,4-D buiylate stress and the control.