皂角苷强化黑麦草去除土壤PAHs效果及机制探究

Investigation on the Effects and Mechanism of Saponin - EnhancedRyegrass Removal of Soil PAHs

选取菲、芘两种典型多环芳烃(PAHs)模拟污染土壤,种植黑麦草,并施入植物源生物表面活性剂皂角苷,研究了皂角苷施入对黑麦草修复土壤PAHs的强化效果.结果表明:培养60 d后,皂角苷浓度达到在500 mg/kg时,强化效果最优:菲、芘的去除率分别达到74.9%、60.9%,而对修复植物黑麦草而言:首先,皂角苷的施入能够显著提高黑麦草体内CAT、SOD、POD三种抗氧化酶活性,减少黑麦草体内MDA的含量,显著提高了修复植物黑麦草的抗氧化能力;其次,皂角苷能够显著增强黑麦草对PAHs的吸收,当皂角苷施入浓度达到500 mg/kg时,菲、芘两种PAHs的富集系数是无皂角苷施入对照组的1.52及1.78倍,但对PAHs在黑麦草体内的转运系数影响不大.此外,皂角苷施入土壤后,能有效提升根系土壤中PAHs天然降解菌芽孢杆菌属(Bacillus)、鞘氨醇单胞菌属(Sphingomonas)、假单胞菌属(Pseudomonas)的相对丰度,进一步促进了PAHs土壤的修复.

Two typical polycyclic aromatic hydrocarbons(PAHs),phenanthrene and pyrene,were selected to simulate contaminated soil.By planting ryegrass and applying the plant-derived biosurfactant saponin,the enhancing efct of saponin on the remediation of PAHs in soil by ryegrass was studied.The results showed that after 60 days of cultivation,when the concentration of saponin reached 500 mgkg,the enhancing effect was optimal:the removal rates of phenanthrene and pyrene reached 74.9%and 60.9%.For ryegrass:frstly,the application of saponin significantly increased the activities of three antioxidant enzymes(CAT,SOD,and POD)in ryegrass and reduced the content of MDA,substantially improving the antioxidant capacity of ryegrass.Secondly,saponins significantly improved the absoption of PAHs by ryegrass.When the concentration of saponins reached 500 mg/kg,the enrichment coefficients of phenanthrene and pyrene were 1.52 and 1.78 times that of the control group without saponins,but it had lttle effect on the transport coefficient of PAHs in ryegrass.In addition,when saponin was applied to soil,it ffectively increased the relative abundance of natural PAH-degrading bacteria(Bacillus,Sphingomonas,and Pseudomonas)in the root soil,further promoting the remediation of PAHs in soil.