Effects of Fe3+ on Acute Toxicity and Regeneration of Planarian (Dugesia japonica) at Different Temperatures

Objective. To investigate the effects of different concentrations of Fe3+ on the acute toxicity and regeneration of planarian at different temperatures. Method. The planarians were treated with 40 mg/l, 50 mg/l, 60 mg/l, and 70 mg/l Fe3+ solution and placed in 15 degrees C, 20 degrees C, and 25 degrees C, respectively, to observe the mortality and the poisoning pattern of the planarian. In addition, the planarians were cut into three parts of head, trunk, and tail, then placed in Fe3+ solution at concentrations of 10 mg/l, 15 mg/l, 20 mg/l, and 30 mg/l, and placed in 15 degrees C, 20 degrees C, and 25 degrees C respectively, and the regeneration rate of the planarian was investigated. Results. At the same temperature, in the concentration of Fe3+ from 40 mg/l to 70 mg/l, the mortality of the planarian increased with the increasing of the concentration of Fe3+; at the same concentration and different temperatures, the death speed of the planarian is the fastest at 20 degrees C, the next at 25 degrees C, and the lowest at 15 degrees C, indicating that the toxic effect of Fe3+ can be accelerated at a suitable temperature of 20 degrees C. At the same temperature, in the low concentration of Fe3+ from 10 mg/l to 30 mg/l, the regeneration rate of the planarian gradually decreased with the increasing of the concentration of Fe3+; at the same concentration and different temperature, the regeneration rate of planarian was faster at 20 degrees C and 25 degrees C, but the difference between 20 degrees C and 25 degrees C was small, and the slowest at 15 degrees C, indicating that the low temperature significantly affects the planarian regeneration speed. The study also found the regeneration rates of the head, trunk, and tail of the planarian were different; the head regeneration was the fastest, the trunk was the second, and the tail was the slowest. Conclusion. Fe3+ had obvious toxic effects on the survival and regeneration of planarian; the planarian is sensitive to Fe3+ and may be used to detect Fe3+ water pollution; in addition, temperature can affect the toxic effects of Fe3+ and thus affect the survival and regeneration of the planarian. Therefore, the temperature should be taken into consideration when detecting water Fe3+ pollution.