Effects Of Aldrin And Dieldrin On The Reproduction Of Freshwater Rotifer Brachionus Calyciflorus Pallas

The effects of aldrin and dieldrin on the reproduction of B. calyciflorus were studied using the life-table technique and population cumulative culture method, with 17β-estradiol (E2) as the positive control. The main contents and results were presented as the following:1. The effects of aldrin at 0.02, 0.04, 0.08, 0.16, 0.32, 0.64 and 1.28 mg/L on development, survival and reproduction of freshwater rotifer B. calyciflorus were studied by means of life-table technique. The results showed that compared to the control, aldrin at 0.04-1.28 mg/L, 1.28 mg/L, and 1.28 mg/L shortened significantly the durations of embryonic development and reproductive period, and the generation time of B. calyciflorus, respectively. However, aldrin at 0.16-1.28 mg/L, 0.04-0.16 mg/L, 0.02, 0.08 and 0.16 mg/L, and 0.08 and 0.16 mg/L markedly prolonged the durations of juvenile and reproductive periods, the mean lifespan and the generation time of rotifers, respectively. Aldrin at 0.02-0.64 mg/L, 0.02-0.32 mg/L, and 0.02, 0.08 and 0.16 mg/L increased significantly the intrinsic rate of population increase, the net reproduction rate and the life expectancy at hatching of rotifers, respectively.2. By means of life-table technique, the effects of dieldrin and E2 both at 0.001, 0.01, 0.1, 1, 10, 100 and 1000μg/L on development, survival and reproduction of freshwater rotifer B. calyciflorus were studied. Compared to the control, dieldrin and E2 influenced significantly the durations of embryonic development, juvenile period, reproductive and post-reproductive periods of the rotifers. 100μg/L diedrin decreased significantly the intrinsic rate of population increase of rotifers, but the reverse was true for 1μg/L E2. 0.001μg/L diedrin, and 100 and 1000μg/L E2 increased significantly the net reproduction rate. 0.001-1000μg/L diedrin, and 0.01, 100 and 1000μg/L E2 prolonged markedly the generation time. 0.001-1000μg/L diedrin, and 0.01, 1, 100 and 1000μg/L E2 increased significantly the life expectancy at hatching of the rotifers.3. The effects of aldrin, dieldrin and E2 all at 0.001, 0.01, 0.1, 1, 10, 100 and 1000μg/L on population growth and sexual reproduction of freshwater rotifer B. calyciflorus were studied by 72-h population growth and 96-h resting-egg-production test methods. The results showed that 1000μg/L aldrin made rotifer population disappear after 72-h exposure. Compared to the control, both 0.01μg/L E2 and 0.001, 0.1μg/L dieldrin significantly decreased the population growth rate of the rotifers, but 10μg/L aldrin increased it. 1000μg/L E2, 10 and 100μg/L aldrin, 0.001, 0.01, 100 and 1000μg/L dieldrin all significantly decreased the percentage of mictic females. 100μg/L E2 and 1000μg/L dieldrin both significantly decreased the fertilization rate of mictic females. 0.01, 1000μg/L E2, 0.1μg/L aldrin, 0.001, 0.01 and 1000μg/L dieldrin all markedly decreased the ratio of ovigerous mictic females/ ovigerous amictic females (MF/AF). 10, 100μg/L aldrin and 0.01, 1000μg/L dieldrin both significantly decreased the ratio of ovigerous females/non- ovigerous females (OF/NOF), but 0.1μg/L aldrin significantly increased it. 1000μg/L E2, 100μg/L aldrin, and 0.001, 0.01, 1000μg/L dieldrin all significantly decreased the resting egg production of the rotifers.4. The effects of aldrin at 0.0002, 0.002, 0.02, 0.2, 2, 20 and 200μg/L, and dieldrin and E2 both at 0.001, 0.01, 0.1, 1, 10, 100 and 1000μg/L on population growth of rotifer B. calyciflorus were studied using the population cumulative culture method. Compared to the control, all concentrations of E2, 0.0002, 0.02 and 0.2μg/L aldrin, and 0.01, 0.1, 100 and 1000μg/L dieldrin all significantly decreased the population growth rates of the rotifers. 0.001 and 1000μg/L E2, 2μg/L aldrin, 100 and 1000μg/L dieldrin all significantly decreased the maximum population density of the rotifers.