公路绿化植物油松(Pinus tabulaeformis)和小叶杨(Populus simonii)对重金属元素的吸收与积累

对内蒙古西部公路绿化植物油松（Pinus tabulaeformis）、小叶杨（Populus simonii）及其根际土壤中重金属元素（Cd、Hg、Pb、Cu、Zn、Ni、Cr）和类金属元素（As和Se）含量以及根际土壤重金属（Cu、Zn、Pb、Ni和Cr）形态、土壤pH值进行了测定。对比分析了公路沿线不同绿化植物及其不同器官对重金属元素的吸收与积累特征。结果表明：绿化植物根际土壤对重金属元素的吸附及污染程度以Cd为最高。随原子序数的递增,小叶杨和油松两种植物的根部和茎叶两种营养器官中重金属的含量均表现出“N”字形变动趋势。而且重金属元素在不同植物不同器官中的含量具有Zn〉Cu〉Ni,Cr,As,Pb〉Cd〉Hg的基本规律。小叶杨茎叶对重金属元素Cr、Ni和Pb的富集能力较根部为强,油松茎叶对重金属元素Cr、Ni、Cu和Pb的富集能力较根部为强。绿化植物根际土壤重金属元素有效态占总量百分比的大小序列为Zn〉Pb〉Ni、Cr〉Cu,与重金属元素在不同植物不同器官中的含量大小序列Zn〉Cu〉Ni、Cr、As、Pb〉Cd〉Hg并非趋于一致。公路绿化植物对根际土壤中重金属元素的吸收和积累与重金属元素有效态所占的比例有关。

The absorption and accumulation of heavy metals pollutants in plant along highway in western Inner Mongolia

The differences in absorption and accumulation of heavy metals were investigated in various plants and their organs, such as Pinus tabulaeformis and Populus simonii, along the highway in western Inner Mongolia. The result showed that the highest uptake to heavy metals and pollution degree in surface soils of plant is Cd. With the atomic number increased (Cr to Pb), the heavy metals concentration displayed "N" figure in the roots, stem-leaf of Pinus tabulaeformis and Populus simonii. Furthermore, the heavy metals concentration in different organs of different plants followed the order of Zn > Cu > Ni, Cr, As, Pb > Cd > Hg. A higher enrichment capacity was observed in stem-leaf of Populus simonii for Cr, Ni and Pb compared with its root whereas there was a reverse trend in stem-leaf of Pinus tabulaeformis. The levels of heavy metals in various plants were independent on total content of theirs with available phases, but dependent on their proportions. The comparison between the concentration of availability phases in the soils and the concentration of heavy metals in plants shows the same sequence. That is the sequence of percent of the availability phases concentration to the total concentration dissimilar the sequence of the concentrations of heavy metals in the different organs in the different plants.