Centre for Research in Ecotoxicology and Environmental Remediation, Agro-Environmental Protection Institute, Ministry of Agriculture, Tianjin 300191, P. R. China.
Int J Phytoremediation. 2013;15(3):268-82. doi: 10.1080/15226514.2012.694500.
Fungal inoculation and elevated CO2 may mediate plant growth and uptake of heavy metals, but little evidence from Diffusive Gradients in Thin-films (DGT) measurement has been obtained to characterize the process. Lolium mutiforum and Phytolacca americana were grown at ambient and elevated CO2 on naturally Cd and Pb contaminated soils inoculated with and without Trichoderma asperellum strain C3 or Penicillium chrysogenum strain D4, to investigate plant growth, metal uptake, and metal bioavailability responses. Fungal inoculation increased plant biomass and shoot/root Cd and Pb concentrations. Elevated CO2 significantly increased plants biomass, but decreased Cd and Pb concentrations in shoot/root to various extents, leading to a metal dilution phenomenon. Total Cd and Pb uptake by plants, and DGT-measured Cd and Pb concentrations in rhizosphere soils, were higher in all fungal inoculation and elevated CO2 treatments than control treatments, with the combined treatments having more influence than either treatment alone. Metal dilution phenomenon occurred because the increase in DGT-measured bioavailable metal pools in plant rhizosphere due to elevated CO2 was unable to match the increase in requirement for plant uptake of metals due to plant biomass increase.
真菌接种和升高的 CO2 可能会影响植物生长和重金属的吸收，但从扩散梯度薄膜（DGT）测量中获得的证据很少，无法描述这一过程。在自然 Cd 和 Pb 污染的土壤上，将 Lolium mutiforum 和 Phytolacca americana 在大气和升高的 CO2 下种植，接种和不接种 Aspergillus asperellum 菌株 C3 或 Penicillium chrysogenum 菌株 D4，以研究植物生长、金属吸收和金属生物利用度的响应。真菌接种增加了植物生物量和地上/根 Cd 和 Pb 浓度。升高的 CO2 显著增加了植物生物量，但在不同程度上降低了地上/根 Cd 和 Pb 浓度，导致金属稀释现象。所有真菌接种和升高 CO2 处理的植物总 Cd 和 Pb 吸收量以及根际土壤中 DGT 测量的 Cd 和 Pb 浓度均高于对照处理，联合处理的影响大于单一处理。金属稀释现象发生是因为由于升高的 CO2，植物根际中 DGT 测量的生物有效金属池增加，但无法与由于植物生物量增加而对植物吸收金属的需求增加相匹配。
