Impacts of arbuscular mycorrhizae on plant uptake and phytoremediation of pyrene in soils

Uptake of pyrene from soils by clover (Trifolium subterraneum L.) and capsicum (Capsicum annuum L.) in the presence of arbuscular mycorrhizae (AM) fungi was investigated using a greenhouse study. The impacts of AM on phytoremediation of soil pyrene contaminant were also elucidated. Two arbuscular mycorrhizal fungi (AMF) including Glomus mosseae and Glomus etunicatum were experimented. The initial concentrations of pyrene in soils were 0–75.18 mg/kg. In 60 days, inoculation of AMF significantly enhanced the uptake of pyrene by clover from soils basing on the root concentrations, root concentration factors, and accumulated amounts of pyrene in root and shoot. However, no significant influence was observed for the inoculation of AMF on the uptake of pyrene by capsicum. This would be the results from the weaker mycorrhizal infection rate and Mycorrhizal Dependence (MD) for capsicum. Compared with phytoremediation, arbuscular mycorrhizal remediation (AMR) was more efficiency on soil pyrene contaminant reduction. In 60 days, 67.80%–92.40% of pyrene was degraded for AMR process. However, the accumulated amounts of pyrene by tested plants contributed less than 0.2% to the total degradation of pyrene in soils. In contrast, the enhanced microbial activities and consequently the increase of microbial degradation of pyrene in soils in the presence of AM should be the predominant mechanisms of AM bioremediation for soil pyrene contamination.