BACKGROUND The coexistence of polycyclic aromatic hydrocarbons (PAHs) and heavy metals has deleterious effects on environmental quality. Few reports have studied the mechanisms of plant inoculation with Piriformospora indica to remediate PAH-metal co-contaminated soil by analyzing the chemical speciation of the contaminants. This study investigated the influence of the inoculation of Medicago sativa with P. indica to remediate soil co-contaminated with phenanthrene (a kind of PAH) and cadmium (a heavy metal) by analyzing plant growth, physiological parameters and chemical speciation in rhizosphere and nonrhizosphere soils. RESULTS The presence of P. indica significantly increased plant tolerance, chlorophyll a, chlorophyll b, maximum quantum efficiency of PSII photochemistry and electron transport rate values in phenanthrene- and/or cadmium-contaminated soil. P. indica inoculation in M. sativa roots increased fluorescein diacetate activities in soils contaminated with phenanthrene, cadmium or both, especially in the nonrhizosphere. The presence of phenanthrene prevented the inoculated plant from accumulating cadmium to some extent, whereas the presence of cadmium did not prevent the degradation of phenanthrene in either the rhizosphere or the nonrhizosphere after P. indica colonization. Although the low bioavailability of cadmium in the rhizosphere restricted its transportation into the stem, P. indica colonization in plants effectively increased cadmium accumulation in roots in soil co-contaminated with cadmium and phenanthrene. CONCLUSIONS In conclusion, this work provides a theoretical basis for the use of P. indica combined with M. sativa for the remediation of PAH-metal co-contaminated soil.

中文翻译：

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菲律宾P和镉共污染土壤中印度P梨定殖的紫花苜蓿的植物修复作用。

背景技术多环芳烃（PAH）和重金属的共存对环境质量具有有害影响。很少有报道通过分析污染物的化学形态来研究植物接种印度梨孢子虫以修复多环芳烃金属共污染土壤的机理。本研究通过分析根际和非根际植物的生长，生理参数和化学形态，研究了用紫花苜蓿接种紫花苜蓿来修复被菲（一种PAH）和镉（一种重金属）共同污染的土壤的影响。土壤。结果The稻的存在显着提高了植物的耐性，叶绿素a，叶绿素b，菲和/或镉污染的土壤中PSII光化学的最大量子效率和电子传输速率值。在被菲，镉或两者污染的土壤中，尤其是在非根际土壤中，在苜蓿根部接种印度。球会增加荧光素二乙酸酯的活性。菲的存在在某种程度上阻止了接种的植物积累镉，而镉的存在并不能阻止P稻定殖后根际或非根际中菲的降解。尽管根际中镉的低生物利用度限制了其向茎中的运输，但在植物中的in稻定居有效地增加了镉和菲共同污染的土壤根中的镉积累。结论总而言之，