氧化沉降条件下草甘膦对福寿螺的急性毒性效应

    Acute toxic effect of glyphosate on Pomacea canaliculata under the condition of oxidative deposition

    • 摘要:
      目的  探究草甘膦与H2O2复合污染条件下草甘膦对福寿螺Pomacea canaliculata的急性毒性效应。
      方法  采用静水式生物测试法,采集田间生长均匀一致的成年福寿螺,使其暴露于不同浓度草甘膦和近似广州地区降水H2O2浓度(50 μmol·L−1)的水体中。研究氧化沉降条件下草甘膦对福寿螺生境的水质部分指标和急性毒性效应的影响。
      结果  水体水质指标中,氧化还原电位(Oxidation-reduction potential,ORP)随暴露时间增加而上升,由330 mV上升至540 mV左右;pH随暴露时间增加,不同处理有上升也有下降的趋势,最终都维持在7.0~8.5;溶解氧(Dissolved oxygen,DO)在8.5~16.0 mg·L−1之间,无固定变化规律;这3个指标都维持在福寿螺生长能适应的范围内。急性毒性试验表明,草甘膦对福寿螺为低毒,在有或无H2O2添加时其48 h的半致死浓度(LC50)均为133.479 mg·L−1。在高浓度草甘膦作用下,福寿螺抗氧化胁迫酶超氧化物歧化酶(SOD)和过氧化氢酶(CAT)以及能量代谢相关酶淀粉酶(AMS)和脂肪酶(LPS)活性呈先诱导上调、后被抑制、而后又适应上调的趋势,说明在染毒过程中福寿螺能慢慢适应所处胁迫环境并不断提高抗逆性,在逆境中正常生存。
      结论  氧化沉降条件下,草甘膦对福寿螺急性毒性效应为低毒,4种典型酶的酶活性总体呈上调升高的趋势,试图通过草甘膦除草的同时又抑制福寿螺是无效和不现实的。

       

      Abstract:
      Objective  To explore the acute toxic effect of glyphosate on Pomacea canaliculata under the combined pollution of glyphosate and H2O2.
      Method  Using the hydrostatic biological test method, adult Pomacea canaliculata with uniform growth in the field were collected, and exposed to water with different concentrations of glyphosate and similar to the average concentration of H2O2 (50 μmol·L−1) in precipitation of Guangzhou. The influences of glyphosate on some water quality indexes of P. canaliculata habitat and acute toxic effects of P. canaliculata under oxidative deposition conditions were studied.
      Result  For the water quality index, oxidation-reduction potential (ORP) increased with the increase of exposure time, from 330 mV to about 540 mV; The change of pH with the increase of exposure time increased or decreased under different treatments, and finally maintained between 7.0 and 8.5; The concentration of dissolved oxygen (DO) was between 8.5 and 16.0 mg·L−1, and there was no obvious variation trend. The three water quality indexes above were within the range that the growth of P. canaliculata could adapt to. Acute toxicity tests indicated that glyphosate had low toxicity to P. canaliculata, and the 50% lethal concentration (LC50) in 48 h was 133.479 mg·L−1 with or without H2O2 deposition. The anti-oxidative stress enzymes of superoxide dismutase (SOD) and catalase (CAT), as well as energy metabolism-related enzymes of amylase (AMS) and lipase (LPS) in P. canaliculata were firstly up-regulated, then suppressed, and finally adapted to up-regulation. It showed that in the process of poisoning, P. canaliculata could slowly adapt to the stress environment and continuously improve its stress resistance, so that it could survive normally in this stress.
      Conclusion  Under the condition of oxidative deposition, the acute toxic effect of glyphosate on P. canaliculata is low, and the activities of the four related typical enzymes are generally up-regulated. It is ineffective and unrealistic to try to inhibit P. canaliculata through herbicide weeding at the same time.

       

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