U、Cd单一及复合污染对水芹生长和生理特性影响

通过土壤盆栽试验研究不同浓度的U、Cd单一及其复合污染对水芹的生长、叶绿素含量、根系活力、细胞膜透性和MDA含量的影响。结果表明:与对照相比,随U、Cd单一及其复合污染处理浓度的增加,水芹的生长受到显著抑制(P0.05);水芹叶绿素含量逐渐减少,其中以Cd元素对水芹叶绿素b胁迫作用最显著;水芹根系活力在低浓度(15 mg·kg~(-1))时受到促进,而在高浓度(150mg·kg~(-1))时受到抑制;叶片相对电导率处理组数据均显著高于对照组,U胁迫作用强于Cd;叶片丙二醛含量与对照相比随处理浓度的增加呈上升趋势。比较U、Cd单一及其复合处理对水芹的胁迫效应表明,高U高Cd(U150 mg·kg~(-1)+Cd150 mg·kg~(-1))对水芹生长和生理影响最显著,水芹在低浓度U、Cd胁迫下具有较好的抗逆性,因此,其在低浓度U、Cd单一及其复合污染的土壤修复方面具有潜在应用价值。

Effects of single and combined pollution of uranium and cadmium on growth and physiological characteristics of Oenanthe javanica

The growth, chlorophyll content, root activity, cell membrane permeability and MDA content of Oenanthe javanica(Blume)DC were studied under uranium(U)and cadmium(Cd)alone and in combination in pot experiment. Results showed that U and Cd stresses sig-nificantly inhibited the growth of O. javanica(P<0.05)when compared with the control. The inhibition increased with increasing concentra-tions of U and Cd. The chlorophyll content of O. javanica decreased remarkably under U and Cd stresses. Cadmium reduced the content of chlorophyll b of O. javanica more significantly than U did. The activity of O. javanica roots was enhanced by low concentrations(15 mg·kg-1) of U and Cd, but significantly inhibited at high concentrations(150 mg·kg-1). The relative electrical conductivities of leaves were higher under U and Cd stresses than under CK, with U showing greater effect than Cd. Leaf MDA content increased as U and Cd concentrations in-creased. Combined applications of U and Cd(U150 mg·kg-1+Cd 150 mg·kg-1)had greater influences on O. javanica’s growth and physio-logical characteristics than their single. The present findings showed that O javanica has high resistance to U and Cd, which has potential to remediate U and Cd single and combined pollution soils.