采用水稻土盆栽试验,研究了黑麦草-蚯蚓-菌根对多氯联苯(PCB)污染土壤的联合修复效应.试验土壤中PCB含量为307.2ng·g^-1,并设添加蚯蚓(E)、种植黑麦草(R)、黑麦草-蚯蚓(RE)、黑麦草-接种菌根(RM)及黑麦草-菌根-蚯蚓三者联合修复(RME)5个处理,以不加黑麦草、蚯蚓、菌根的土壤为对照(CK),并置于人工培养箱中培养50d.结果表明,黑麦草具有较强的修复土壤PCB的能力,相对于CK和蚯蚓处理(E),黑麦草(R)和黑麦草-蚯蚓(RE)处理的土壤PCB去除率分别高出36.0%和38.3%,说明联合修复具有良好的应用潜力.菌根和蚯蚓均能够促进黑麦草降解土壤PCB,菌根对植物的强化作用大于蚯蚓的强化作用.同时接种蚯蚓和菌根,蚯蚓能使菌根的侵染率提高11.1%,菌根-蚯蚓相互作用可以显著提高黑麦草修复土壤PCB的能力,PCB去除率达到61.05%.土壤多酚氧化酶(PPO)和过氧化物酶(POD)与土壤PCB的降解有密切关系,其中,土壤PCB去除率与土壤PPO活性呈显著负相关关系(r=-0.869,p〈0.05),表明土壤PPO与PCB的降解或转化密切相关.
The combined remediation effects of ryegrass,Arbuscular mycorrhiza (AM) and earthworms on polychlorinated biphenyl (PCB) contaminated soil were investigated. The paddy soil was exposed to 307.2 ng PCB·g-1 soil. Six treatments were conducted in this contaminated soil for 50 days each. These treatments were inoculation with earthworms (E),cultivation with ryegrass (R),combination of ryegrass and earthworms (RE),combination of ryegrass and inoculation with AM(Glomus mosseae)(RM),combination of ryegrass,earthworms and AM (RM-E) and the control (CK). The results showed that:① Ryegrass was more significant and effective in the removal of PCBs as compared with the CK and E treatments. ②Both AM and earthworms could enhance the removal rate and degradation rate of PCB from soil planted with ryegrass. The enhancing effect of AM was higher than that of earthworms. ③In the RM-E treatment,earthworms were responsible for an 11.1% increase of the AM infection rate to ryegrass,and the earthworms-AM interaction significantly enhanced the removal rate of PCB from soil with ryegrass. The removal rate of PCB in the RM-E system reached 61.05% after 50 days. ④The activity of soil peroxidase (POD) and polyphenol oxidase (PPO) were closely related to the degradation of PCB. The removal rate of PCB from soil was significantly negatively correlated with the activity of PPO in the soil with a correlation coefficient-0.869 (p〈0.05),indicating the close relationship between soil PPO and the degradation or absorption of PCB in soil.