Objective  Although the study has shown that plant-white rot fungi (WRF) combined remediation is a more efficient remediation strategy for PAHs-contaminated soil, the mechanism of this strategy is still unclear, and its application prospects remain questionable. Photosynthesis is the basis of plant growth and development, and it affects the release level of root exudates, which in turn alters the growth of rhizosphere microorganisms and the degradation of soil-borne PAHs. Based on this, for the first time, this study reported the effects of WRF inoculation on photosynthesis of Salix viminalis cultivated in PAHs-contaminated soil.

Method  In this study, a pot experiment was conducted in greenhouse for bioremediation of PAHs-contaminated soils and S. viminalis was used as phytoremediation materials. Photosynthetic pigment content, light response curve of gas exchange parameters and chlorophyll fluorescence parameters were selected as the photosynthetic physiological indexes of S. viminalis and the effects of WRF inoculation on the photosynthesis of S. viminalis were reported.

Result  Results showed that the inoculated WRF positively promoted photosynthetic pigment content, net photosynthetic rate (P_n) and transpiration rate (T_r), maximum photochemical efficiency (F_v/F_m), potential activity of PSII (F_v/F₀) of S. viminalis, but reduced their stomatal conductance (G_s) and intercellular CO₂ concentrations (C_i), non-photochemical quenching (NPQ) and photochemical quenching (qP). Different inoculation methods changed variation trend of light response curve of G_s and T_r. Besides, the combination of S. viminalis and WRF significantly increased the removal rate of soil-borne phenanthrene and pyrene.

Conclusion  In this study, WRF increases the photosynthetic rate and transpiration efficiency of S. viminalis, enhances the removal of soil-borne PHE and PYR. In general, our study is significant to reveal the mechanism of plant-WRF combined remediation.