蒌蒿(Artemisia selengensis)对土壤中镉的胁迫反应及修复潜力研究

以洞庭湖湿地新发现的Cd高富集植物——蒌蒿(Artemisia selengensis)为试验材料,采用盆栽方式,系统研究了蒌蒿在生长期内对Cd的性状反应及富集特征.结果表明,大于40mg.kg-1的Cd胁迫对蒌蒿叶片伤害明显,且导致生物量下降,但植株在100mg.kg-1胁迫下可完成生活史,对Cd有较强的耐受能力;土壤中有效态Cd的含量仅占土壤全Cd含量的15.3%～37.1%;相同胁迫浓度下,各生长阶段的植株体内Cd含量差别不大,但由于生物量的原因,幼苗期对Cd的提取量显著小于其他时期,其中40～60mg.kg-1的Cd处理可使蒌蒿地上部分Cd含量达492～588mg.kg-1(成株期),且植株对该浓度范围的Cd污染去除效果最好;蒌蒿可作为对湿地土壤Cd污染较理想的修复植物加以研究和利用.

Growth responses and phytoremediation potential of Artemisia selengensis to Cd stress

Artemisia selengensis grown in Dongting Lake wetland was recently found as a plant with good capacity in enriching Cd. A pot experiment was conducted to study the biological traits and the Cd accumulation characteristics of Artemisia selengensis to Cd stress during its growth period. The final results showed that the leaves were injured apparently in response to significant decrease of above-ground biomass when Cd concentrations in soil were higher than 40 mg·kg^-1. Artemisia selengensis could complete its life cycle at a high Cd concentration (100 mg·kg^-1) and showed strong resistence to soil Cd. The bioavailable Cd accounted for 15.3%~37.1% of total soil Cd. There were no significant differences of Cd concentrations in the plants during their different growth phases, but a lower Cd accumulation was observed in stems and leaves at the seedling stage than the other stages because of low biomass. During the adult stage of Artemisia selengensis, Cd accumulation was up to 492~588 mg·kg^-1 under the Cd treatment of 40~60 mg·kg^-1. These data suggested that Artemisia selengensis was an outstanding species that could be selected as a potential candidate to repair Cd pollution from lake soil.