萘、菲、芘在土壤中的降解及其对植物生长的影响

Degradation of naphthalene,phenanthrene,and pyrene in soil and their effects on plant growth

【目的】分析多环芳烃（PAHs）萘、菲、芘在土壤中随时间的降解情况及其对小麦、小白菜生长的影响。【方法】采用盆栽试验,以小麦和小白菜为供试植物,研究PAHs不同起始含量（0（空白对照）,50,100,200,500mg/kg）下土壤中萘、菲、芘残留量随时间的变化情况以及PAHs对植物发芽、生长的影响。设置小麦种植组、无植物对照组、无植物土壤灭菌对照组3个处理,研究种植小麦对土壤中PAHs萘、菲、芘含量的影响。【结果】小麦和小白菜种植90d时,土壤中萘、菲、芘的平均残留量分别为其起始含量的25.88%,29.84%和47.25%,萘、菲在土壤中的残留比率相差不大,而芘在土壤中的残留比率明显高于萘和菲。随着时间的推移,土壤中萘、菲、芘的残留量均逐渐降低,90d时残留量表现为芘〉菲〉萘。土壤中的萘、菲、芘对小白菜的发芽率和生长都有明显的抑制作用,并且土壤中PAHs起始含量越大,这种抑制作用越明显。PAHs对小麦发芽及生长情况的影响与小白菜有所差异,当土壤中PAHs的起始含量为0~100mg/kg时,PAHs对小麦的发芽具有一定的促进作用,而当PAHs起始含量超过100mg/kg时,其对小麦的发芽表现出抑制作用;与空白对照相比,不同含量PAHs对小麦生长的影响不明显。种植30d时,小麦种植组土壤中的萘、菲、芘残留量较起始含量（300mg/kg）分别减少了20.92%,21.75%和21.23%,较无植物对照组分别降低了9.75%,8.77%和9.96%,较无植物土壤灭菌对照组分别降低了8.88%,16.10%和16.14%。【结论】植物的存在能明显促进土壤中PAHs的降解,这是土壤微生物与植物共同作用的结果。

【Objective】This paper aimed to study the degradation of polycyclic aromatic hydrocarbons（PAHs）including naphthalene,phenanthrene and pyrene in soil along time and their effects on growth of wheat and pakchoi.【Method】Pot experiments were conducted with wheat and pakchoi.The changes of naphthalene,phenanthrene,and pyrene residual concentrations in soil over time under the different initial contents（0（blank control）,50,100,200,and 500mg/kg）and the influence on seed germination and plant growth were investigated.Effects of planting wheat on concentrations of PAHs were also investigated by comparing three groups of wheat group,no plant control group,as well as no plant and sterilized soil control group.【Result】When wheat and pakchoi were planted for 90 days,the average residual concentrations of naphthalene,phenanthrene and pyrene were 25.88%,29.84% and 47.25% of their initial concentra-tions,respectively.The difference between naphthalene and phenanthrene was small while the residue of pyrene was much higher.The residual concentrations of naphthalene,phenanthrene,and pyrene in soil reduced gradually and the concentrations had a decreasing order of pyrenephenanthrenenaphthalene after90 days.The germination and growth of pakchoi in contaminated soil were obviously inhibited,and greater PAHs concentrations caused more significant effect.PAHs had different effects on germination and growth of wheat from pakchois.When the initial concentrations of PAHs were 0-100mg/kg,PAHs had promoting effects on germination of wheat and the inhibitory effect showed up when the concentrations were higher than 100mg/kg.Compared with CK,the effects of different initial concentrations on wheat growth was not significant.After planting for 30 days,the residual concentrations of naphthalene,phenanthrene and pyrene in wheat field were reduced by 20.92%,21.75% and 21.23%from the initial concentration of300mg/kg.Compared to the no plant group,they decreased by 9.75%,8.77% and 9.96% while they decreased by 8.88%,16.10%,and 16.14% compared to no plant and sterilized soil control group.【Conclusion】The existence of plants improved the degradation of PAHs as the results of interactions of microbe and plants.