应用籽粒苋修复镉污染农田土壤的潜力

针对农田土壤镉污染问题，采用超富集植物籽粒苋并配施不同组合的外源活化剂进行盆栽实验和田间实验，并测定籽粒苋及根系土壤中镉含量并计算富集系数。结果表明，在盆栽实验的不同处理组中，施加磷酸二氢钾(0.74 mmol·kg^-1)、EDTA(2 mmol·kg^-1)和柠檬酸(4 mmol·kg^-1)最有助于提高籽粒苋对Cd的提取修复效率。田间实验中添加活化剂(EDTA和柠檬酸)后籽粒苋的根、茎和叶组织对Cd的富集能力分别是不添加活化剂处理组的2.10、1.84和2.76倍；与对照组相比，籽粒苋的根、茎和叶部分的Cd含量都显著提高(P < 0.05)，这说明外源活化剂促进了籽粒苋对土壤中Cd的吸收，提高了修复效率。每年种植两茬籽粒苋并添加活化剂，Cd的去除率可达4%~10%。种植超富集植物并配施活化剂既可以提高修复效率，又可以节约修复成本。

Potential for cadmium contaminated farmland remediation with Amaranthus hypochondriacus L.

In view of the problem of cadmium pollution in farmland soil, phytoremediation technology has become a research hotspot. Pot experiments and field trials were conducted using a kind of hyperaccumulator Amaranthus hypochondriacus L. and different combinations of exogenous activators. The cadmium contents in Amaranthus hypochondriacus L. and root soil were tested and the corresponding enrichment factors were determined. The results showed that in different treatment groups of the pot experiment, the most helpful effect for the improvement of Cd extraction and restoration efficiency occurred at potassium dihydrogen phosphate (0.1 g·kg-1), EDTA (ethylenediaminetetraacetic acid) (2 mmol·kg-1) and citric acid (4 mmol·kg-1). The addition of activators (EDTA and citric acid) in the field trials showed that Cd enrichment abilities of roots, stems and leaves of Amaranthus hypochondriacus L. were 2.10, 1.84 and 2.76 times as high as those without activator, respectively. In comparison with the control group, the contents of Cd in the roots, stems and leaves of the Amaranthus hypochondriacus L. increased significantly (P < 0.05), indicating that the exogenous activator promoted the absorption of Cd in the soil by the Amaranthus hypochondriacus L. and improved the repair efficiency. Amaranthus hypochondriacus L. is planted twice every year and activator is added. The Cd removal rate is 4%~10%. Planting Amaranthus hypochondriacus L. in combination with an activator can both improve the repair efficiency and save the repair cost.