锰尾矿污染土壤上植物群落地上部分生物量及其细根的变化

Alteration of Biomass and Fine Roots of Several Plants in Soil Polluted by Manganese

通过野外采样调查,分析了湖南湘潭锰矿矿区内锰尾矿污染土壤以及其上生长的植物群落地上部分生物量、细根的变化。结果表明,锰尾矿污染土壤中的含水量、pH值和M n含量都有季节变化;在这种土壤上生长的植物群落地上部分生物量在夏季和秋季较高,春季和冬季较低,其年平均值为67.3g·m-2;该群落地下细根生物量的年平均值为50.1g·m-2,而活细根和死细根生物量年平均值分别为33.4和16.7g·m-2;活细根和死细根中M n含量年平均值分别为604.9和319.6m g·kg-1。

Remediation of sites contaminated by toxic metals is a particularlychallenge. As organic compounds, heavy metals are not degraded, and cleanup usually requires their removal therefore, removing process often employs stringent physicochemical agents which may dramatically inhibit soil fertility with subsequent negatively impacts on the ecosystem. Therefore, new technology with environmentally friendly and low-cost processes is urgently required. Phytoremediation has been proposed as a cost-effective, environmental-friendly alternatively technology. Phytoremediation is an emerging innovative technology that utilizes high plants to transport and concentrate pollutants (metals and organics) fromcontaminated soil into the harvestable parts of plants. The success applicationof a phytoremediation process depends on many factors including contaminated-site soil properties, the extent of soil contamination, metal availability for uptake into roots (bioavailability), plant root systems, adequate plant yield andhigh metal concentration in plant shoots.A survey of soils and above-ground biomass, fine roots of plant community on the soil polluted by manganese mine tailings in Xiangtan city was conducted by field experiment. Four10 m×10 m experimental plots were established in the manganese mine tailings zone. Soil and plant samples were collected from these plots every season in 2003. We measured soilwater contents, pH, Mn contents, fine root and above-ground biomass. We have found that the water contents, pH and Mn concentrations of the polluted soil changed with season by season. The mean annual biomasses of above-ground and fineroots of plant community were 67.3 and 50.1 g·m-2, respectively. The mean annual biomass of living fine roots and dead fine roots were 33.4 and 16.7 g·m-2, respectively. The mean annual Mn concentrations in living fine roots and dead fine roots were 604.9 and 319.6 mg·kg-1, respectively.