无柄小叶榕对盐碱地Cd、Cu的吸收特性及修复潜力

采用盆栽试验,研究无柄小叶榕(Ficus concinna var.Subsessilis)对盐碱地土壤重金属Cd和Cu的富集和转运能力,并探讨投加生物表面活性剂鼠李糖脂(RL)对无柄小叶榕生长及其吸收Cd、Cu的影响.结果表明,人工模拟盐碱环境下无柄小叶榕能在不同浓度Cd、Cu单独或复合投加胁迫下正常生长,且体内重金属含量随投加浓度增大而升高,均表现为根地上部分;无柄小叶榕对Cd和Cu具有较强的富集能力,Cd的最大生物富集系数(BCF)为4.52±0.73,Cu为2.1±0.18,BCF值随着重金属投加浓度的增大逐渐减小,Cd、Cu转移系数(TF)均小于1;在Cd 50 mg·kg~(-1)、Cu 400 mg·kg~(-1)下的修复率最高分别为4.07%和2.66%;投加鼠李糖脂可以显著提高无柄小叶榕体内重金属的含量,土壤Cd 25 mg·kg~(-1)时,根部Cd含量最大提高了2.38倍,Cu 50 mg·kg~(-1)时根部Cu含量最大提高了1.91倍.综上,无柄小叶榕对温州重金属污染的盐碱地有很好的修复潜力,投加生物表面活性剂可有效提高无柄小叶榕对重金属Cd和Cu的吸收富集效率.

Cadmium, copper accumulation and remediation capability of Ficus concinna var. Subsessilis in saline-alkaline soil

Locally available Ficus microcarpa (Ficus concinna var.subsessilis) can be used as cost-effective, environment-friendly approach for treatment of heavy metal contaminated reclamation in Lingkun Island, Wenzhou, Zhejiang. In this study pot experiments were conducted to investigate the effect of species and concentrations of heavy metals and rhamnolipid biosurfactant on the growth, heavy metal content, uptake and their distribution in plants. Results showed that, comparing to the treatment CK (0 mg·kg^-1 Cd or Cu), Ficus concinna var.subsessilis in 5~50 mg·kg^-1 Cd or 50~400 mg·kg^-1 Cu or mixed Cd-Cu treatment appeared well growth during 90 days, not presenting a toxic condition, and heavy metal content was higher in root than that in above ground mass. However, Cd, Cu accumulation increases in plants with the increasing dose of heavy metals. Ficus concinna var.subsessilis had high tolerance capability on Cd, Cu, and the maximum biological concentration factor (BCF) of Cd and Cu was 4.52±0.73 and 2.1±0.18, respectively. The two heavy metals BCF decreased with the increasing concentration of heavy metals. The transfer coefficient (TF) of Cd and Cu was less than 1. And the maximum repair rates were respectively 4.07% and 2.66% with the addition of 50 mg·kg^-1 Cd and 400 mg·kg^-1 Cu. The addition of rhamnolipid biosurfactant can increase the heavy metal content in plants. The Cd content in root increased 2.38 times with the addition of 25 mg·kg^-1 Cd, and the Cu content in root increased 1.91 times with the addition of 50 mg·kg^-1 Cu. These results show that Ficus concinna var.subsessilis had hyperaccumulative characteristics of heavy metals and could be applied to bioremediation Cd-and Cu-contaminated soils. The addition of biosurfactant can increase the uptake of Cd and Cu by Ficus concinna var.subsessilis in reclamation district.