4种草本植物对镉的富集特征

以4种草本入侵植物粗毛牛膝菊、洋野黍、莠狗尾草和欧黑麦草作为研究材料，利用盆栽实验研究了这4种植物在土壤镉（Cd）含量（mg·kg^-1）为0（T0）、5（T5）、25（T25）和50（T50）处理下的耐受和富集特征，以期筛选出对Cd污染土壤具有修复潜力的植物.结果表明，粗毛牛膝菊在T5~T50处理下，地上部分和根部生物量与对照（T0）相比均没有显著变化，而其他3种禾本科植物的地上部分和根部生物量在T25或T50处理下与对照相比显著降低，表明粗毛牛膝菊比其他3种植物具有更强的Cd耐受性.在不同土壤Cd含量处理下，4种植物地上部分和根中的Cd含量均随土壤Cd含量增加而显著升高，但4种植物地上部分富集系数随土壤Cd含量升高有显著降低的趋势.在不同土壤Cd含量处理下，粗毛牛膝菊和洋野黍的地上部分富集系数都大于1，莠狗尾草和欧黑麦草地上部分富集系数小于1.在T5、T25和T50处理下，粗毛牛膝菊的转移系数分别为0.93、0.73和1.04，分别显著高于同一Cd含量处理下的其他3种植物.此外，在相同的Cd处理下，粗毛牛膝菊积累的Cd总量和地上部分Cd含量均显著高于其它3种植物，并且粗毛牛膝菊能将90%以上的Cd转移到地上部分，显著高于其他3种植物.综合考虑对Cd的耐受和富集能力，本研究认为粗毛牛膝菊是一种潜在的Cd高富集植物，具有一定的植物修复潜力.

Cadmium Accumulation Characteristics of Four Herbs

A pot-based experiment was conducted to study the Cd tolerance and accumulation characteristics of four invasive herbs (Galinsoga quadriradiata, Panicum dichotomiflorum, Setaria geniculata, and Lolium persicum) under exposures of 0 (T0), 5 (T5), 25 (T25), and 50 mg·kg^-1 (T50) soil Cd concentrations to screen for potential Cd accumulators for phytoremediation. The results showed that the biomasses of both shoots and roots of G. quadriradiata had no significant changes compared to the control (T0) samples under all Cd treatments, whereas the biomass of the other three Poaceae species significantly decreased under the T25 or T50 treatment. The results indicate that G. quadriradiata had stronger Cd tolerance than the other three species. The Cd concentrations in the shoots and roots of the four herbs significantly increased with an increase in soil Cd concentrations, but the shoot bioconcentration factors (SBCF) of the four plant species significantly decreased under T5, T25, and T50 treatment. The SBCF of G. quadriradiata and P. dichotomiflorum were greater than 1 whereas those of S. geniculata and L. persicum were lower than 1. The translocation factors (TF) of G. quadriradiata were 0.93, 0.73, and 1.04 under T5, T25, and T50 treatment, respectively, which were significantly higher than those of the other three plants under the same soil Cd concentration. In addition, both the total Cd and shoot Cd contents of G. quadriradiata were notably higher than in the other three species under the same Cd treatment. Moreover, 90% of the Cd in G. quadriradiata could be transferred aboveground, which was significantly higher than for the other three plants. Based on our comprehensive comparison of Cd tolerance and accumulation capacity, we suggest that G. quadriradiata is a high-Cd accumulator with considerable phytoremediation potential.