黑麦草对水体中镉-壬基酚复合污染的生理响应及修复

Physiological Responses of Ryegrass in Cadmium-Nonylphenol Co-contaminated Water and the Phytoremediation Effects

探讨了黑麦草对水体中镉-壬基酚(Cd-NP)复合污染的生理响应及修复作用.结果表明,单一Cd污染情况下,高浓度Cd^(2+)(10 mg·L^(-1))对黑麦草的生物量和叶绿素含量均有显著的抑制作用,植株过氧化物酶(POD)和多酚氧化酶(PPO)活性显著增大.单一NP污染情况下,黑麦草的生物量、叶绿素含量和MDA含量均无显著性变化;高浓度NP(5 mg·L^(-1))存在下,植株POD活性显著增大.当黑麦草受到复合污染胁迫时,高浓度NP的加入降低了Cd的抑制作用,使黑麦草的MDA含量有所回落,植株PPO活性有所下降.Cd^(2+)浓度为1 mg·L^(-1)时,黑麦草对Cd^(2+)有较好的去除效果,12 h的去除率达到了55.3%.吸收时间超过12 h,高浓度NP对黑麦草吸收Cd^(2+)有较显著的促进作用.NP浓度对植株地下部分Cd^(2+)吸收量有极显著影响,转移系数随着NP浓度增大而呈现上升趋势.NP浓度为5 mg·L^(-1)时,黑麦草对NP的吸收效果较好,24 h的吸收率为44.6%.低浓度Cd^(2+)的加入对黑麦草去除NP无显著性影响,而高浓度Cd^(2+)的加入对黑麦草吸收和降解NP均有极为显著的抑制作用.

Physiological responses of ryegrass in cadmium-nonylphenol（ Cd-NP） co-contaminated water, as well as the phytoremediation effect were studied under laboratory conditions. The experiment revealed that the biomass and chlorophyll content of ryegrass significantly declined at high concentrations of Cd^2＋（ 10 mg·L^-1）,while POD and PPO activities significantly increased. No significant changes to the biomass,chlorophyll content and MDA of ryegrass were observed in the presence of NP. POD activities significantly increased at high concentrations of NP（ 5 mg·L^-1）. The addition of high NP concentrate reduced the inhibition of Cd under co-contaminated stress,the MDA content and PPO activities both reduced. The experiment also revealed that the removal rate of Cd^2＋by ryegrass reached 55. 3% after 12 h. The absorption efficiency was improved by high NP concentration. Absorption efficiency of Cd^2＋by the subterranean part of the plant significantly increased in presence of NP,and the absorption efficiency increased with the increase of NP concentration. The absorption rate of NP was 44. 6% after 24 h at NP concentration of 5 mg·L^-1. The removal rate was slightly influenced at low concentrations of Cd^2＋,but significant inhibition of absorption and degradation was observed at high concentrations of Cd^2＋.