有机污染胁迫对人工湿地中浮萍抗氧化系统的影响

湿地植物在处理高负荷有机废水时会受到不同程度的氧化胁迫。本研究基于对浮萍的有机污染胁迫模拟系统,通过对浮萍脂质过氧化和抗氧化防御系统的监测与分析,研究了浮萍对有机污染胁迫的耐受能力及胁迫去除后浮萍的恢复规律。结果表明,浮萍对有机污染胁迫具有较高的耐受性,在胁迫去除后,具有一定的恢复能力。在COD小于400mg/L时,浮萍并未受到氧化胁迫;当COD达到800 mg/L时,浮萍体内ROS含量上升,细胞膜脂过氧化加剧,但抗氧化酶活性升高,抗氧化物质含量增加,浮萍可保持生长,胁迫去除后,抗氧化防御系统可恢复到对照水平;当COD过高（≥1 000mg/L）,ROS急剧上升,抗氧化防御系统遭受破坏,造成不可逆伤害,胁迫去除后不能恢复正常生长。

Effect of organic pollutants stresses on antioxidant defense system of duckweed（Lemna minor）

Wetland plants maybe suffered from the stress of oxidation when treating with high organic load wastewater.In the present study,we investigated the tolerance ability of the duckweed（Lemna minor）to the organic pollutants stresses and the law of recovery after removing the stresses through analyzing the organic pollutants stresses.Results showed that the duckweed had high tolerance to organic pollutants stresses and had a certain ability to recover after the stresses.When COD was less than 400 mg / L,the duckweeds were not suffered from the oxidation stresses.When COD reached 800 mg / L,the content of ROS increased and the membrane lipid peroxidation aggravated.But the increasing of the antioxidant enzymes activity and the antioxidant content ensured the duckweeds grow well.And the antioxidant defense system could restore to the control level after removing the stresses.When COD was too high（≥1 000 mg / L）,the ROS content increased sharply and the antioxidant enzymes system was destroyed.The irreversible damage was caused and the duckweeds could not restore to normal even after removing the stresses.