污染条件下VAM玉米元素积累和分布与根际重金属形态变化的关系  

Uptake and distribution of Cu,Zn,Pb and Cd in maize related to metals speciation change in rhizosphere.

作　　者：黄艺[1] 陈有鑑[1] 陶澍[1] 

机构地区：[1]北京大学城市与环境学系,北京100871

出　　处：《应用生态学报》2002年第7期859-862,共4页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金资助项目 ( 40 0 31 0 1 0 ;40 0 2 41 0 1 )

摘　　要：为了了解重金属Cu、Zn、Pb、Cd在土壤 根际 植物系统中的行为 ,揭示VAM植物减弱土壤中过量重金属对植物生理毒害的抗性机理 ,采用原子吸收光谱测定了Cu、Zn、Pb、Cd在污灌土壤中生长的VA菌根玉米和无菌根玉米中的积累和分布 ,并用连续形态分析技术分析了菌根根际中Cu、Zn、Pb、Cd的形态分布和变化趋势 .结果表明 ,Cu、Zn、Pb在菌根玉米中的积累量比非菌根中积累量分别减少 1 0 %、1 8%和2 9% ,Cd积累量没有改变 .生长 7周后 ,菌根玉米是非菌根玉米生物量的 1 .5倍 .与对照土壤相比 ,根际中除Cu交换态显著增加外 ,Zn、Pb、Cd各形态相对改变量显著大于非菌根 ,且菌根根际土中Cu、Zn、Pb有机结合态增加量显著大于非根际土 ,说明菌根际金属向稳定状态转移的程度显著大于非菌根际 .同时 ,讨论了根际金属形态对金属有效性的影响 ,及其与菌根植物金属抗性机理的关系 .The behavior of heavy metals in terrestrial system and the mechanism of VAM plant in toleranting excessive heavy metals in soil were examined with VAM maize( Zea mays L.).After seven week cultivation in sewage sludging soil,the biomass of VAM ( Glomus mosseae) maize was found 1\^5 times higher than non mycorrhizal one.Compared with non mycorrhizal maize, the accumulation of Cu,Zn and Pb by mycorrhizal maize was reduced by 10%,18% and 29%, respectively,but the accumulation of Cd was the same.The distribution and speciation change of Cu,Zn,Pb and Cd in rhizosphere of VAM and non mycorrhizal maize were analyzed by using the technique of sequential extraction.Except a significant increase in exchangeable Cu in rhizosphere of VAM maize, the increased amount of test metals bound to organic matter, carbonates,iron and manganese oxides were significantly higher than those in rhizosphere of non mycorrhizal maize, indicating that the speciation of metals in rhizosphere of mycorrhizal maize growing in contaminated soil tended to be relatively stable. Meanwhile,the influence of metal speciation in rhizosphere on its bioavailability as well as the mechanism of mycorrhizal plant in toleranting excess metals were also discussed.

关 键 词：菌根 根际 重金属 形态 有效性 

分 类 号：X131.3[环境科学与工程—环境科学]