菲、芘污染土壤中丛枝菌根真菌对土壤酶活性的影响

Effects of arbuscular mycorrhizal fungi on enzymes activity in soils contaminated by phenanthrene and pyrene

采用温室盆栽试验方法,研究了丛枝菌根真菌(AMF)对菲、芘复合污染土壤中微生物数量和酶活性的影响.结果表明,接种AMF显著增加了三叶草根际和菌丝际土壤中细菌、真菌和放线菌的数量,并对微生物区系有选择性.在供试菲、芘污染浓度范围内,低浓度菲、芘对土壤多酚氧化酶、酸性磷酸酶和过氧化氢酶活性有激活作用;但当菲、芘浓度升高时,3种酶活性受到抑制.与无植物对照土壤相比,接种AMF后三叶草菌根际酸性磷酸酶活性降低了2.4%～23.1%,过氧化氢酶活性增加了12.6%～20.3%,除高浓度处理外多酚氧化酶活性均增加;菌丝际多酚氧化酶活性比菌根际低12.9%～62.9%,酸性磷酸酶活性比菌根际高3.3%～24.0%,过氧化氢酶活性则高于菌根际.

A greenhouse pot experiment was conducted to investigate the effects of arbuscular mycorrhiza （AM） on microbes and soil enzymes in rhizosphere and hyphosphere soil contaminated by phenanthrene and pyrene. The quantities of bacteria, fungi, and actinomyces in both rhizosphere and hyphosphere increased significantly, and the microflora changed with the inoculation of arbuscular mycorrhizal fungi （AMF）. The soil contamination of phenanthrene and pyrene with lower concentration clearly stimulated the activity of enzymes including acid pbosphatase, polyphenol oxidase and catalase. However, when the contamination dose was higher, their activities were inhibited. Compared with bulk soil, the activity of acid phosphatase in rhizosphere with AMF was decreased by 2.4%-23.1%, and catalase in rhizosphere was decreased by 12.6%-20.3%. By contrast, the activity of polyphenol oxidase in rhizosphere was stimulated except those treatments with high levels of PAH. Polyphenol oxidase activity in hypbosphere was 2.9%-62.9% lower, while acid phosphatase activity was 3.3%-24.0% higher than that in rhizosphere. In general, catalase activity in hypbosphere was higher than that in rhizosphere. In addition, both AM and hypha enhanced the activity of catalase in soils. The enhanced activity of polyphenol oxidase by AM in rhizosphere could be the results of improved plant growth and root activities with AMF inoculation .