| 低浓度Cd暴露对金鱼藻营养元素吸收与植物络合素(PCs)合成的影响 |
| 摘要点击 2757 全文点击 1810 投稿时间：2008-04-16 修订日期：2008-06-12 |
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| 中文关键词 植物络合素(PCs) 镉(Cd) 生物标记物 金鱼藻 |
| 英文关键词 phytochelatins(PCs) cadmium biomarker Ceratophyllum demersum |
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| 中文摘要 |
| 采用溶液培养方式,研究了水环境低浓度Cd(0.01～0.64 μmol/L)不同暴露时间段下，金鱼藻(Ceratophyllum demersum)体内营养元素的吸收状况和植物络合素(PCs)的响应规律.结果表明,Cd促进了微量营养元素Cu、Zn的吸收,抑制了Mn的吸收,对Fe的吸收无明显影响.金鱼藻对Cd表现出明显的吸收和积累效应,0.08 μmol/L Cd胁迫对金鱼藻生长产生了抑制作用.Cd暴露期间各处理组PCs诱导量与Cd处理浓度存在显著的响应关系,处理前期(7 d)当Cd浓度≥0.02 μmol/L时,表现为显著的诱导效应(p<0.05).随着暴露时间的延长,PCs诱导量有下降趋势,但仍明显高于对照.各不同处理时间段下PCs诱导量与Cd处理浓度存在良好的剂量效应关系.胁迫7 d时呈线性关系,胁迫14 d和21 d均表现为抛物线型.回归分析显示金鱼藻体内PCs的合成水平与Cd的生物毒性存在极显著的正相关关系.表明PCs可作为Cd胁迫的一项敏感的生化指标(biochemical indicator)用来评价和预测实际水环境中Cd的污染. |
| 英文摘要 |
| A solution experiment with a range of lower cadmium concentrations (0.01-0.64 μmol/L) was conducted to study micronutrients uptake and production of phytochelatins (PCs) in a submerged aquatic plant Ceratophyllum demersum after exposure for 7 d, 14 d, 21 d. The results showed the uptake of Cu,Zn in Ceratophyllum demersum was promoted when exposed to lower concentrations of cadmium,whereas Mn uptake was inhibited. Unlike Cu,Zn and Mn, the content of Fe was unaffected by Cd uptake. Our data showed that Ceratophyllum demersum had stronger Cd tolerance and obvious absorption and cumulative effects to external lower concentrations of Cd exposure. The inhibition of growth was observed after 21 d in 0.08 μmol/L Cd. The production of PCs was significantly induced by 0.02-0.64 μmol/L Cd for 7 d (p<0.05), while declined after exposure for 14 d, 21 d. The good dose-related response of PCs was observed in manner of linear for 7 d and parabola for 14 d and 21 d. Regressive analysis showed that there was a significantly positive correlation between PC contents and Cd toxicity in Ceratophyllum demersum. The results suggested that PCs could be a sensitive biomarker for estimating Cd phytotoxicity and subsequently a qualitative tool for studies on Cd contamination. |
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