根系分泌物及植物对土壤中Cu^(2+)、Cd^(2+)的活化与修复

Activation and Remediation of Cu^(2+)andCd^(2+) in Soil by Root Exudates and Plants

文章选取柠檬酸、甘氨酸、麦芽糖3种根系分泌物,采用活化试验,研究单一及复合重金属污染条件下根系分泌物对土壤中Cu^(2+)、Cd^(2+)的活化效果,通过盆栽试验,探究紫花苜蓿、白三叶草修复Cu污染土壤的潜力。结果表明:单一污染条件下,随着3种根系分泌物浓度的增加,Cu^(2+)、Cd^(2+)的活化率逐渐增加,但其增加的速率逐渐减小;3种根系分泌物对Cu^(2+)、Cd^(2+)活化效果的大小顺序为柠檬酸>甘氨酸>麦芽糖;复合污染条件下,Cu^(2+)、Cd^(2+)活化率均显著降低;柠檬酸对Cd的活化效果优于Cu。紫花苜蓿和白三叶草分别依靠茎部、茎-叶富集Cu,其生物量随土壤中Cu浓度的升高先增大后减小或整体下降;白三叶草对土壤中Cu的去除率高于紫花苜蓿,但其去除能力随Cu浓度的升高受到抑制。

Three kinds of plant root exudates,citric acid,glycine and maltose were selected to study the activation effect of different root exudates on Cu^(2+)and Cd^(2+)in soil under single and compound heavy metal pollution by activation test,and the potential of Medicago sativa and Trifolium repens on remediation of Cu^(2+)contaminated soil was explored through pot experiment.The results showed that the activation rate of Cu^(2+)and Cd^(2+)increased gradually as the concentration of three root exudates increased under the single heavy metal pollution condition,but the increasing rate decreased gradually.The order of activation effect of three root exudates on Cu^(2+)and Cd^(2+)was as citric acid>glycine>maltose.The activation rate of Cu^(2+)and Cd^(2+)decreased significantly under the combined pollution condition.The activation effect of citric acid on Cd^(2+)was better than that of Cu^(2+).Medicago sativa and Trifolium repens rely on the stem and stem-leaf to enrich Cu^(2+),respectively,and its biomass first increased and then decreased or decreased as a whole with the increase of Cu^(2+)concentration in soil.The Cu^(2+)removal rate of Trifolium repens was higher than that of Medicago sativa,but its removal ability was inhibited with the increase of Cu^(2+)concentration.