黑麦草及其根际土壤酶对芘胁迫的响应与植物修复研究

Physiological Response of Ryegrass and Its Rhizospheric Soil Enzymes under Pyrene Stress and the Phytoremediation

采用盆栽试验研究土壤中添加不同含量的芘对黑麦草根和茎叶生长、根际土壤脱氢酶、过氧化氢酶和多酚氧化酶活性的影响,并研究黑麦草对芘胁迫土壤的修复作用。结果表明:黑麦草的根系鲜重在生长40和60d时均随着土壤施芘量的增加而增加。茎叶鲜重在生长60d时随土壤施芘量的增加而下降。根重比例随生长时间的延长而上升,40和60d时随土壤施芘量的增加而显著增加。黑麦草根际土壤脱氢酶活性在整个试验期间随生长时间的延长而上升,而随土壤施芘量的增加而下降,尤以20、40mg.kg-1施芘量下降显著。40d时100、200和400mg.kg-1施芘量下黑麦草根际过氧化氢酶活性与对照相比均呈显著增加。试验期间400mg.kg-1施芘量下黑麦草根际土壤多酚氧化酶活性均极显著高于对照和其他处理。种植黑麦草的根际土壤可提取态芘含量均低于无植物对照土壤和无植物无菌对照土壤。植物吸收造成的芘损失率极少,根际土壤芘损失率随施芘量增加而显著下降,芘含量越低,黑麦草对芘胁迫土壤的修复越完全。

A pot experiment was conducted to study the effects of different soil pyrene contents on the growth of ryegrass root and stem-leaf and the activities of dehydrogenase,hydrogen peroxidase and polyphenol oxidase in rhizospheric soil,and meanwhile the ryegrass phytoremediation for pyrene contaminated soil was investigated.The results showed that the fresh weight of ryegrass root increased at 40 d and 60 d as the pyrene content increasing.The stem-leaf fresh weight of ryegrass decreased at 60 d.The fresh weight ratio of root to the whole plant rose during growth and significantly increased at 40 d and 60 d.The dehydrogenase activities in rhizospheric soil of ryegrass increased as growing and declined as pyrene content increasing during experiment,especially treated by 20,40 mg·kg-1 pyrene.The hydrogen peroxidase activities were significantly higher than control under 100、200、400 mg·kg-1 pyrene stress at 40 d.When treated by 400 mg kg-1 pyrene in test,The polyphenol oxidase activities were higher than other treatments with very significant level.The content of extractable pyrene was lower in the ryegrass pots than in CK（pots without ryegrass and pots without both plant and bacteria）.Plant absorption made few loss of pyrene.The pyrene loss rate of rhizospheric soil decreased significantly as the pyrene content increasing.The phytoremediation of pyrene contaminated soil by ryegrass was more complete with less content of pyrene in soil.