玉竹对土壤Cd Pb的吸收和耐性研究

Absorption and Tolerance of Polygonatum Odoratum to Cd and Pb in Soil

以盆栽玉竹为试验材料,分别用不同浓度的Cd、Pb进行处理,研究玉竹的生物量、重金属积累和部分生理指标的变化。结果表明,当土壤Cd浓度≤1mg.kg-1或Pb浓度≤1000mg.kg-1时对玉竹的生长有促进作用,超过这个浓度范围就表现为抑制作用。玉竹叶、茎、根对两种重金属的吸收都呈极显著正相关,且根的吸收能力大于茎和叶,玉竹对Pb有较强的抗性。Cd、Pb处理后,玉竹叶片SOD酶和POD酶活性的增加能在一定程度上减轻重金属胁迫引起的膜脂过氧化伤害,但长时间的Cd胁迫会对植株产生明显的抑制作用。Cd、Pb处理会使玉竹叶片脯氨酸含量在短时间内上升,但是高浓度的重金属处理和长时间的胁迫环境则会导致脯氨酸含量下降。MDA含量均随着Cd、Pb处理浓度的升高而增加,并且时间越长,增加越多。

Cd and Pb are two important heavy metal pollutant elements in the urban soil.A pot experiment was conducted to investigate the biomass,physiological index of Polygonatum odoratum and its accumulation characteristics under Cd and Pb stress.The results showed that the growth of P.odoratum could be improved when the concentration of Cd was less than 1 mg.kg-1 or the concentration of Pb was less than 1 000 mg.kg-1,but when the concentrations of two elements went beyond these range,it would inhibit the growth of plant.The contents of Cd and Pb in leaves,stems and roots all increased with the increase of treatment concentrations.Besides,roots showed a higher capability to accumulate Cd and Pb.The activities of POD and SOD in leaves increased and relieved the injury of membrane lipid peroxidation,but with enduring Cd stress,the activities of POD and SOD turned to be inhibited.The content of proline in leaves increased in the short term but decreased with the long-time stress or high concentration of Cd,Pb.The content of MDA in leaves increased with the incresment of Cd,Pb concentrations and long-time stress.