多环芳烃(PAHs)污染土壤中接种平滑白蛋巢菌对蒿柳光合作用的影响

Effects of Crucibulum laeve inoculation on photosynthesis of Salix viminalis cultivated in PAHs-contaminated soil

【目的】虽然已有研究表明植物-白腐真菌联合修复是一种更高效的多环芳烃(PAHs)污染土壤修复策略,但由于该策略的作用机理尚不清楚,其在土壤修复实践中的应用前景仍存有疑问。光合作用不仅是植物生长发育的基础,也影响根系分泌物的释放水平,进而影响根际微生物的生长和土壤中PAHs的降解。基于此,我们研究了PAHs污染土壤中接种白腐真菌对植物光合作用的影响。【方法】在温室中设置了PAHs污染土壤的盆栽修复实验,以蒿柳做为植物修复材料,选取光合色素含量、气体交换参数的光响应曲线和叶绿素荧光参数做为蒿柳的光合生理指标,探究了PAHs污染土壤中接种白腐真菌对蒿柳光合作用的影响。【结果】PAHs污染土壤中接种白腐真菌对蒿柳光合色素含量、净光合速率(Pn)、蒸腾速率(Tr)、最大光化学效率(Fv/Fm)、光系统Ⅱ(PSⅡ)潜在活性(Fv/F0)等指标均有积极的促进作用,但降低了叶片的气孔导度(Gs)、胞间CO2浓度(Ci)、非光化学淬灭(NPQ)和光化学淬灭(qP)参数。不同的接种方法能改变Gs、Tr的光响应曲线的变化趋势。此外蒿柳-白腐真菌联合修复显著提高了土壤菲(PHE)、芘(PYR)的去除率。【结论】PAHs污染土壤中,白腐真菌能提高蒿柳的光合能力和蒸腾效率,促进土壤PHE和PYR的去除,这对揭示植物-白腐真菌联合修复的作用机理有重要意义。

[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 PAHscontaminated 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(Pn)and transpiration rate(Tr), maximum photochemical efficiency(Fv/Fm), potential activity of PSII(Fv/F0) of S. viminalis, but reduced their stomatal conductance(Gs) and intercellular CO2 concentrations(Ci), nonphotochemical quenching(NPQ) and photochemical quenching(qP). Different inoculation methods changed variation trend of light response curve of Gs and Tr. 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.