不同类型污染土壤中赤子爱胜蚓对伴矿景天重金属吸收的影响初报

Effect of Eisenia foetida on the metal uptake by Sedum plumbizincicola in different types of contaminated soils

摘要:

伴矿景天Sedum plumbizincicola是我国发现和报道的镉/锌 (Cd/Zn) 超积累植物，在土壤Cd污染修复方面已开展实际应用。由于超积累植物伴矿景天在不同类型土壤下的生长能力以及对镉锌的去除效果存在较大差异，因此需引入强化修复技术为植物修复提供辅助作用。作为大型土壤动物，蚯蚓对植物生长的促进作用已有较多研究，但其对伴矿景天生长和重金属吸取效率的影响则鲜有报道，为探究赤子爱胜蚓对不同类型土壤种植下的伴矿景天是否具有强化修复效应，以及不同类型土壤下的强化修复效应差异，设计以下盆栽试验。通过在常湿淋溶土 (Perudic Luvisols)、水耕人为土 (Stagnic Anthrosols)、湿润雏形土 (Udic Cambisols) 3种土壤上种植伴矿景天、引入赤子爱胜蚓Eisenia foetida，探究赤子爱胜蚓对伴矿景天生长及Cd/Zn吸收性的影响。选取Cd有效性较高、修复潜力较大的水耕人为土 (Stagnic Anthrosols) 进行第二季盆栽修复试验。第一季修复结果显示，在酸性的常湿淋溶土中，添加赤子爱胜蚓使伴矿景天地上部生物量较对照处理增加了106%，Cd和Zn吸收量分别提高了72.0%和36.0%，且蚯蚓结合伴矿景天的处理修复后土壤Cd有效性进一步降低，其余两种土壤仅添加蚯蚓无强化修复效应；第二季结果显示，同时添加秸秆和蚯蚓，可强化中性的水耕人为土上种植的伴矿景天生长，增大植物地上部生物量和Cd/Zn吸收量。结果表明，添加蚯蚓可增强伴矿景天在常湿淋溶土中的养分吸收，提高生物量，以此强化其修复效应。在水耕人为土中，外加秸秆可作为蚯蚓强化伴矿景天修复的配套技术。

Abstract:

Sedum plumbizincicola is a native cadmium/zinc (Cd/Zn) hyperaccumulator in China. At present, it has been applied to remediation of Cd contaminated soils. As the large differences in the removal efficiency of Cd and Zn for different soil conditions, the enhancement measure is important for the phytoremediation process. There have been many studies on the effects of earthworms on plant growth. But the effects on the growth of S. plumbizincicola and heavy metal removal efficiency have been rarely reported. There were 2 pot experiments: S. plumbizincicola was planted on 3 types of soils: Perudic Luvisols, Stagnic Anthrosols, and Udic Cambisols inoculated with Eisenia foetida to explore the effect of Eisenia foetida on the growth and Cd/Zn absorption of S. plumbizincicola. Stagnic Anthrosols with higher Cd effectiveness was selected in the second season pot experiment for further research the combined effect of earthworm and rich straw. The results of the first pot experiment showed that the addition of earthworms in acidic Perudic Luvisols increased the shoot biomass of S. plumbizincicola by 106% compared with the control treatment, and the Cd and Zn uptake increased by 72.0% and 36.0%, respectively. The soil available Cd was reduced by the addition of earthworms. The other two soils inoculated with earthworms had no enhancement on phytoremediation, addition of earthworms together with straw could improve the growth of S. plumbizincicola and the Cd/Zn uptake in Stagnic Anthrosols. The above results indicated that adding earthworm can enhance the phytoremediation of Cd/Zn hyperaccumulator, and the addition of straw is an important synergistic technique for earthworm-enhanced phytoremediation of S. plumbizincicola.