崇明岛滨岸滩地植物系统中重金属元素的分布累积与相互关系

以滩地几种常见大型植物为研究对象，系统地分析了Cd及Ni在芦苇、海三棱草和互花米草系统中的分布与累积，以及Cd，Ni，K及Ca 4种重金属元素在芦苇中的相互关系.结果表明:Cd及Ni在芦苇、海三棱草和互花米草根部的累积程度较高，约占总量的50%以上.w(Cd)在3种植物不同器官中均为根>茎>叶. 3种植物等量的地下部分中互花米草的阳离子交换量(CEC)可能最高; 互花米草各器官对Cd及Ni的累积能力均强于芦苇和海三棱草. 芦苇地下部分对K及Ca的吸收可以促进Ni的吸收与累积，但同时对Cd的吸收与累积却有一定的阻碍作用；茎中K及Ca与Ni及Cd均表现为一定的拮抗作用；在芦苇体中营养元素K及Ca呈一定的协同作用. 以w(Cd)及w(Ni)在上海市土壤分级标准中的相关背景值为参考，崇明岛滨岸滩地植物系统根际土壤中的w(Cd)及w(Ni)整体上处于清洁水平. 

Distribution, Accumulation and Correlation of Heavy Metal Elements in the Muddy Tidal Plant System around Chongming Island

Taking several common plants of muddy tidal flat as the research subject, a systematical analysis on the distributions and accumulations of Cd and Ni in Spartina alterniflora, Phragmites australis and Scirpus mariqueter systems and correlation of K, Ca, Cd and Ni in the roots, stems and leaves of Phragmitesaustralis was performed. It shows that the accumulation (over 50%) of Cd and Ni in the roots of the three plants is high. The concentration of Cd shows highest in roots then stems and the least in leaves of the three plants. Under the circumstance of equal weight for underground parts of the three plants, Spartinaalterniflora may own the highest cation exchange capacity (CEC). In different organs of Spartina alterniflora, Cd shows the highest accumulation whencompared with the counterparts of the other two plants. The absorbability of K and Ca can promote the accumulation of Ni and prevent the accumulation of Cd in Phragmites australis'' underground segment while K and Ca in its stem show the antagonism with Ni and Cd. The obvious synergism appears between K and Ca in Phragmites australis. Referring to the related background standards of Shanghai soil, the content of Cd and Ni in the rhizosphere soil of muddy tidal plant system around Chongming Island is still at the level of clearness.