土壤中水分和镉供应量对油菜器官中镉分布特征的影响

为探究油菜作为镉(Cd)污染农田修复植物的可行性,本研究以德油5号为试验材料,采用全生育期土培盆栽试验,设置高、中、低3个水平的土壤水分及4个水平的土壤镉含量,研究不同土壤水分条件下油菜对镉的吸收和富集规律。结果表明,土壤水分与镉浓度对油菜的吸镉能力影响显著,且其吸收量随着土壤水分与镉浓度的增加而增大;油菜不同器官的镉含量差异较大,其地上部分吸镉量为土壤总镉含量的0.41%～1.17%,叶片镉含量为总吸收量的46.4%～72.6%;不同水分条件下,油菜器官的镉富集量差异明显,高水、中水处理下油菜各器官的镉富集表现为叶>茎>根>角果壳>籽粒,低水处理下表现为叶>根>茎>角果壳>籽粒。综上,油菜整体具有较强的吸镉能力,但镉离子不溶于菜籽油,说明油菜可吸收土壤中的镉,又不影响菜籽油食用,是修复镉污染农田土壤的理想植物。本研究为利用油菜进行重金属土壤综合治理提供了理论依据。

Effect of Soil Water and Cadmium Content on Distribution Characteristics of Cadmium in Oilseed Rape

To explore the feasibility of oilseed rape as a repair plant of Cd polluted farmland, effects of Cd with different concentrations and water contents were studied through pot test. Three levels of soil moisture and four levels of soil cadmium content experiments were set to find out the law of absorption and accumulation ability of cadmium by oilseed rape. The absorbing capacity improved with the increasing water content and cadmium concentration; cadmium content varied a lot in different parts of the oilseed rape, with the above-ground parts absorbing 0.41%~1.17% of the total cadmium applied in the soil and leaves absorbing 46.4%~72.6% of the total volume. Under different water conditions, the increasing of Cd in different parts of the oilseed rape’s amount of enrichment varied a lot. When the soil moisture levels were high and medium, amount of cadmium in enrichment followed the order of leaf>stem>root> shell >seed, while under low soil moisture level, it ranked as leaf> root>stem>shell >seed. In conclusion, oilseed rape had a great ability of Cd absorption, but cadmium ion was insoluble in rapeseed oil, which showed that oilseed rape can not only take up cadmium from soil, but also had no effect on edible quality of the rapeseed oil. Thus, oilseed rape is an ideal plant for Cd-contaminated farmland remediation. This study provides a theoretical foundation for the soil contaminated by heavy metals with oilseed rape.