镉、铅及其复合污染对油菜部分生理指标的影响

Effects of cadmium,lead,and their combined pollution on some physiological indices of Brassia campestris

采用盆栽试验的方法研究了土壤外源重金属Cd、Pb及其复合污染对油菜部分生理指标的影响。结果表明:Cd单一处理组中,油菜体内硝酸还原酶活性及根系活力均随Cd胁迫浓度的增加出现不同程度的先升后降的趋势,表明油菜对低浓度的Cd有一定的抵抗能力,但在高浓度的Cd胁迫下则受到伤害;Pb单一处理和Cd+Pb复合处理组中,硝酸还原酶活性及根系活力均随Cd、Pb浓度的增加而降低;Cd、Pb单一处理组中,随Cd、Pb浓度升高,油菜根内游离脯氨酸含量逐渐增加,Cd处理组的脯氨酸含量积累量显著大于Pb处理组,这进一步证实了Cd对植物毒害效应比Pb严重;Cd+Pb复合处理组中脯氨酸含量均高于所有单一处理,表明Cd、Pb复合污染对脯氨酸的积累有促进作用,Pb加强了Cd对植物的毒害,其交互作用机理值得进一步研究。

A pot experiment was conducted to study the physiological responses of Brassia carnpestris to cadmium （Cd）, lead （Pb）, and their combined pollution. When treated with Cd alone, the plant nitrate reductase activity and root vigor all increased at lower Cd but decreased at higher Cd, suggesting that B. campestris had definite Cd-tolerance capability at lower concentration Cd but was damaged by higher concentration Cd. In treatments Pb alone and Pb ＋ Cd, the nitrate reductase activity and root vigor all decreased with increasing concentrations of Pb and Cd. When treated with Cd or Pb alone, the free proline content in B. carnpestris roots increased with increasing concentrations of Cd and Pb, and was significantly higher when treated with Cd than with Pb, which further confirmed the higher toxicity of Cd. The root proline content was higher when treated with Pb ＋ Cd than with Pb or Cd alone, suggesting that the combined pollution of Cd and Pb promoted the accumulation of proline in roots, and Pb enhanced the Cd toxicity. The mechanisms of Cd-Pb interaction are deserved to be further studied.