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Selenium alleviates phytotoxicity of phenanthrene and pyrene in Alternanthera Philoxeroides

Huang, Yingping, Song, Yizhi, Huang, Jueying, Xi, Ying, Johnson, David, Liu, Huigang
International journal of phytoremediation 2018 v.20 no.14 pp. 1438-1445
Alternanthera philoxeroides, chlorophyll, ecological restoration, fluorescence, gas exchange, hydrogen peroxide, molecular weight, oxidative stress, phenanthrenes, phytoremediation, phytotoxicity, plant stress, pollutants, pot culture, selenium, soil
To investigate if selenium can alleviate phytotoxicity of phenanthrene and pyrene, two high molecular weight (HMW) PAHs (polycyclic aromatic hydrocarbons) in Alternanthera philoxeroides are considered. A 60-day pot-culture experiment was carried out to assess the effects of selenium (0.5 mg Se·kg⁻¹ soil) on A. philoxeroides exposed to two PAH pollutants, pyrene (PYR) and phenanthrene (PHE), at levels of 10, 100, and 1000 mg·kg⁻¹. The test index included growth, chlorophyl, gas exchange and chlorophyl fluorescence parameters, and indicators of oxidative stress (H₂O₂ and malondialdehyde MDA). The response of plants to PAH exposure was concentration dependent; indicators of plant health declined, while indicators of plant stress rose. The maximum values of H₂O₂ and MDA were recorded at 1000 mg·kg⁻¹ PYR, followed by 1000 mg·kg⁻¹ PHE. However, application of Se (0.5 mg·kg⁻¹) to the soil significantly decreased the phytotoxic response to PAH exposure. This study demonstrated that Se increases the tolerance of A. philoxeroides to PYR and PHE, improving the feasibility of phytoremediating high level PAH contamination and expediting ecological restoration.