Karimi, M. (2014) LC50 24h determination of Deltamethrin and Imidacloprid insecticide and their effect on reproduction and population growth of freshwater rotifer (Brachionus calyciflorus). Masters thesis, University of Zabol.
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Abstract
Rotifers are important groups of zooplanktons in freshwater ecosystems and also they are presented as models in ecotoxicology studies. Pesticides are the most important factors that we can feel their hazards due to growing trend in technology which cause damage to aquatic communities. Therefore the lethal concentration (LC50 24h) of Deltamethrin and Imidaclopride -that are widely used in the Sistan region determined and their impact on reproduction and growth of the freshwater rotifer (Brachionus calyciflorus) were studied. Single cell algae Chlorella (Chlorella vulgaris) was used as food. Rotifers, in order to adapt to the environment and get the required amount of dormant eggs, were cultured for at least three months in the laboratory at 25 ° C and 3000 lux of light, under the darkness and light period of 16: 8 and then the lethal concentration (LC50) of Imidaclopride and Deltamethrin determined for freshwater rotifer (Brachionus calyciflorus) - based on OECD standards. Lethal concentration (LC50) of Deltamethrin and Imidaclopride for freshwater rotifer was 1.06 mgl-1 and 124.54 mg l-1 respectively. Based on these concentrations, the different treatments designated and the rotifer population responses to the four different concentrations of Deltamethrin (0.05, 0.10, 0.21 and 0.53 mgl-1) and Imidaclopride (6.22, 12.45, 24.91 and 62.27 mgl-1) plus a control treatment were studied. The results showed that the differences in density of rotifers in all treatments with the control group at tenth day of testing was significant (p<0.05). Deltamethrin at a concentration of 0.05 and imidaclopride at concentration of 6.22 had no significant differences with control group in specific growth rate (per day)(p<0.05). Ratio of vigorous females to nano-vigerous females and the ratio of meiotic females to amici females at all concentrations of both insecticides significantly affected compared with control group (p<0.05). Increase of mictic females to amictic females’ ratio in final days of test; indicate the dominance of sexual reproduction in rotifer life cycle. For Deltamethrin in 0.53 mgl-1 and Imidaclopride in 62.27 mgl-1 due to stop of growth and reproduction, the ratio of mictic females to amictic females was not defined.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Deltamethrin, Imidaclopride, Rotifer, Brachionus calyciflorus, LC50 |
| Subjects: | S Agriculture > SH Aquaculture. Fisheries. Angling |
| Depositing User: | admin admin1 admin2 |
| Date Deposited: | 25 Jun 2016 05:43 |
| Last Modified: | 25 Jun 2016 05:43 |
| URI: | http://eprints.uoz.ac.ir/id/eprint/846 |
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