三叶鬼针草幼苗对镉污染的耐性及其吸收积累特征研究

通过盆栽实验研究了镉(Cd)胁迫下三叶鬼针草(Bidens pilosaL.)幼苗的耐性能力(包括生长反应和生理生化特性)以及对Cd的吸收积累特征.结果表明,当土壤中投加的Cd浓度为≤32 mg/kg时,三叶鬼针草植物的生长和发育没有受到抑制,与对照相比,地上部和根部生物量分别增加了32.4%~44%和29.1%~57.6%,其中,当Cd处理浓度为8 mg/kg时,地上部干重达到最大值,为0.22 g/pot.在不同Cd处理下,叶绿素(Chl)和可溶性蛋白(SP)含量下降,分别比对照处理降低了23.3%和41.5%;超氧化物歧化酶(SOD)活性随着Cd浓度增加先有所抑制,后逐渐增大;过氧化物酶(POD)活性和丙二醛(MDA)含量随Cd处理浓度增加而增大,分别比对照增加了1.2~6.6和1.1~1.5倍.然而,当Cd浓度为50~100 mg/kg时,显示出对三叶鬼针草幼苗的生长发育和生理生化特征都产生了一定的负效应,说明三叶鬼针草对Cd污染的耐性能力具有一定的阈值.在梯度实验中,植物体内Cd的富集系数和转移系数都大于1.0.当土壤中Cd含量达到100 mg/kg时,地上部Cd含量达到119.1 mg/kg,具备...

Characteristics of Cadmium Tolerance and Bioaccumulation of Bidens pilosa L. Seedlings

Bidens pilosa L. has been identified as a newly found Cd-hyperaccumulator. In the present study, the characteristics of its Cd tolerance (growth response and physiological and biochemical characteristics) and accumulation were examined. The results showed that low Cd treatments(≤32 mg/kg) could enhance plant growth, the dry biomass of shoot and root increased by 32.4% -44.7% and 29.1%-57.6%,respectively,at Cd concentrations 8-32 mg/kg when compared with the control. The shoot dry biomass reached a maximum of 0.22 g/pot at a concentration 8 mg/kg of Cd. Meanwhile, under different Cd treatments, chlorophyll (Chl) and soluble protein contents in leaves slightly decreased, resulting in 23.3% and 41.5% reduction, respectively, compared with the control. The activities of superoxide dismutase (SOD) firstly decreased and then increased with increasing Cd concentration. Peroxidase (POD) activities and malondialdehyde (MDA) contents increased with increasing Cd concentration, with 1.2-6.6 and 1.1-1.5 times increase, respectively, relative to the control. However, the definite negative effects on the plant growth and characteristics of physiology and biochemistry were observed at higher Cd concentrations(50-100 mg/kg).In gradual experiments, the values of bioaccumulation and translocation were more than 1.0,furthermore,the concentration of Cd in shoots reached 119.1 mg/kg at the soil Cd level of 100 mg/kg. showing B.pilosa has the basic characteristics of a Cd-hyperaccumulator. The results above indicated that B.pilosa has strong capacity of Cd tolerance and accumulation, so it has potential and valuable application to phytoremediation of contaminated soils by Cd.