摘要:
为了探讨硝酸铊(Tl (I)-nitrate)对浮萍(Lemna gibba L.)的生长抑制作用及其可能的氧化损伤机制,设置了Tl (I)-nitrate的8个处理组(0.005、0.01、0.02、0.04、0.08、0.1、0.5和1.0 mg·L-1)和对照组(0.0 mg·L-1),进行96 h急性毒性实验,测定96 h内超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性及丙二醛含量。结果表明:96 h暴露时间下,浮萍生长受抑制程度与Tl (I)浓度之间呈正相关,Tl (I)-nitrate对浮萍的96 h EC50为0.076 mg·L-1,NOEC为0.01 mg·L-1。CAT活性随着Tl (I)-nitrate浓度升高逐渐降低,在0.5和1 mg·L-1时,有极显著差异(p < 0.01)产生,SOD活性在0.1 mg·L-1时显著升高(> 46%),POD活性和MDA含量在Tl (I)浓度0.5 mg·L-1时明显上升。当Tl (I)-nitrate胁迫超出浮萍抗氧化酶系统清除活性氧的能力时,活性氧积累导致浮萍受到不可逆转的氧化损伤。Tl (I)-nitrate对浮萍生长产生明显的抑制作用
关键词:
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Tl(I)
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浮萍
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抗氧化酶
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丙二醛
Abstract:
To evaluate the growth inhibition of thallium(I) -nitrate on duckweed (Lemna gibba L.) with relation to its possible oxidative damage mechanism, nine Tl(I) -nitrate concentration levels (0, 0.005, 0.01, 0.02, 0.04, 0.08, 0.1, 0.5, 1.0 mg·L-1) were set for 96 hours' acute toxicity test. The activities of SOD, POD, CAT and MDA were measured. Results showed that the growth inhibition of L. gibba was positively correlated with the concentrations of Tl(I) -nitrate, and the 96 h EC50 and NOEC of were 0.076 mg·L-1 and 0.01 mg·L-1, respectively. As Tl(I) -nitrate concentration increased, CAT activities in L. gibba gradually decreased, the statistically significant differences (p < 0.01) were observed at the concentrations of 0.5 and 1 mg·L-1, SOD activity increased significantly (the increasement ratio > 46%) at 0.1 mg·L-1. While the POD activities and the MDA contents significantly increased at 0.5 mg· L-1, compared with the control. With Tl(I) -nitrate concentration increasing, antioxidant enzymes were unable to eliminate the increased concentration of reactive oxygen species (ROS), which resulted in irreversible oxidative damage. Tl(I)-nitrate could obviously inhibit the growth of L. gibba.
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