Effects Of Zinc And Ammonium Perchlorate On The Reproduction Of Freshwater Rotifer Brachionus Calyciflorus Pallas

The effects of zinc and ammonium perchlorate on the experimental population dynamics of Brachionus calyciflorus were studied using the life-table technique and population cumulative culture method. The main contents and results were presented as the following:1. By means of life-table technique, the effects of Zn2+ concentrations(0.1, 0.3, 0.5, 0.7 and 0.9 mg/L) on the population growth parameters of B. calyciflorus under different Scenedesmus obliquus densities(1.0×106, 2.0×106 and 4.0×106 cells/ml) were studied. The results showed that compared with the controls under the same food density, when food density was 1.0×106 cells/ml, all the concentrations of Zn2+ had no significant effects on all the population growth parameters of B. calyciflorus(P>0.05). When food density was 2.0×106 cells/ml, Zn2+ at all the test concentrations significantly prolonged the life expectancy at hatching, the generation time and the average lifespan, and increased the net reproductive rate, but Zn2+ at all the test concentrations except 0.3 mg/L decreased the intrinsic rate of population increase of B. calyciflorus. When food density was 4.0×106 cells/ml, Zn2+ at 0.1, 0.3 and 0.7 mg/L increased the intrinsic rate of population increase, Zn2+ at 0.7 and 0.9 mg/L increased the proportion of sexual offspring of B. calyciflorus. Food density had significant effects on the life table demographic parameters(P<0.01), Zn2+ concentration had significant effects on the life expectancy at hatching, the generation time, the net reproduction rate, the intrinsic rate of increase and the proportion of sexual offspring(P<0.01), and the interaction between food density and Zn2+ concentration had significant effects on the life expectancy at hatching, the intrinsic rate of population increase and the proportion of sexual offspring of B. calyciflorus(P<0.05). When food density was 2.0×106 cells/ml, there were significant dose-effect relationships between Zn2+ concentration and the life expectancy at hatching, the generation time, the net reproductive rate as well as the average lifespan. When food density was 4.0×106 cells/ml, there was a significant dose-effect relationship between Zn2+ concentration and the proportion of sexual offspring.2. The effects of Zn2+ concentrations(0.1, 0.3, 0.5, 0.7 and 0.9 mg/L) on the population growth parameters of B. calyciflorus under different S. obliquus densities(1.0×106, 2.0×106 and 4.0×106 cells/ml) were studied using the population cumulative culture method. The results showed that compared with the controls under the same food density, when food density was 1.0×106 cells/ml, Zn2+ at all the test concentrations significantly decreased population growth rate, Zn2+ at 0.9 mg/L decreased resting egg production of B. calyciflorus. when food density was 2.0×106 cells/ml, all the concentrations of Zn2+ had no significant effects on all the population growth parameters of B. calyciflorus(P>0.05). when food density was 4.0×106 cells/ml, Zn2+ at 0.5, 0.7 and 0.9 mg/L decreased the population growth rate, Zn2+ at 0.3 mg/L increased the resting egg production, but Zn2+ at 0.5, 0.7 and 0.9 mg/L decreased the resting egg production of B. calyciflorus. Food density had significant effects on the population growth rate, the average mixis and the resting egg production(P<0.05); Zn2+ concentration, the interaction between food density and Zn2+ concentration had significant effects on the population growth rate and the resting egg production(P<0.05). When food density was 1.0×106 cells/ml, there were significant dose-effect relationships between Zn2+ concentration and the population growth rate and the resting egg production. When food density was 2.0×106 cells/ml, there were significant dose-effect relationships between Zn2+ concentration and the resting egg production. When food density was 4.0×106 cells/ml, there were significant dose-effect relationships between Zn2+ concentration and the population growth rate.3. By means of life-table technique, the effects of NH4ClO4 concentrations(10, 20, 30, 40 and 50 mg/L) on the population growth parameters of B. calyciflorus under different S. obliquus densities(1.0×106, 2.0×106 and 4.0×106 cells/ml) were studied. The results showed that compared with the controls under the same food density, when food density was 1.0×106 cells/ml, all the concentrations of NH4ClO4 had no significant effects on all the population growth parameters of B. calyciflorus(P>0.05). When food density was 2.0×106 cells/ml, NH4ClO4 at 40 mg/L increased the proportion of sexual offspring of B. calyciflorus. When food density was 4.0×106 cells/ml, NH4ClO4 at 30, 40 and 50 mg/L decreased the life expectancy at hatching and the average lifespan, 40 and 50 mg/L shortened the generation time, NH4ClO4 at 30 mg/L decreased the intrinsic rate of population increase, NH4ClO4 at 30 and 40 mg/L increased the proportion of sexual offspring of B. calyciflorus. Food density and NH4ClO4 concentration had significant effects on all the life table demographic parameters(P<0.05), and the interaction between food density and NH4ClO4 concentration had a significant effect on the intrinsic rate of population increase(P<0.05). When food density was 2.0×106 cells/ml, there were significant dose-effect relationships between NH4ClO4 concentration and the life expectancy at hatching, the generation time, the average lifespan as well as the proportion of sexual offspring.4. The effects of NH4ClO4 concentrations(10, 20, 30, 40 and 50 mg/L) on the population growth parameters of B. calyciflorus under different S. obliquus densities(1.0×106, 2.0×106 and 4.0×106 cells/ml) were studied using the population cumulative culture method. The results showed that compared with the controls under the same food density, and at each food density, all the concentrations of NH4ClO4 had no significant effects on all the population growth parameters of B. calyciflorus(P>0.05). Food density had significant effects on the population growth rate, the average mixis and the resting egg production(P<0.05), and the interaction between food density and NH4ClO4 concentration had a significant effect on the resting egg production(P<0.05). When food density was 1.0×106 and 2.0×106 cells/ml, there were significant dose-effect relationships between NH4ClO4 concentration and the resting egg production.