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土壤中酚酸类物质的积累是导致花生连作障碍的主要原因之一,真菌漆酶可以有效地转化酚酸类物质,但还没有报道将漆酶直接应用于连作土壤的修复。本研究使用盆钵试验研究了不同浓度的漆酶rLACB3对连作土壤修复的效果。处理30 d后,施加500 U·kg-1漆酶处理的修复效果优于20和100 U·kg-1。在花生根际土壤中,500 U·kg-1漆酶处理的可培养细菌、放线菌、固氮菌数量和对照相比分别提高33.0%、37.7%和30.2%。使用变性梯度凝胶电泳(DGGE)分析根际土壤微生物区系表明,500 U·kg-1漆酶处理的细菌、真菌和固氮菌的Shannon多样性指数比对照分别提高9.0%、17.3%和14.8%。根际土壤中3种酚酸物质香豆酸、4-羟基苯甲酸和香草酸,500 U·kg-1漆酶处理比对照分别减少41.2%、43.8%和35.9%。花生生物量和结瘤数量,500 U·kg-1漆酶处理比对照分别增加17.9%和17.4%。综上表明,内生真菌重组漆酶rLACB3在连作土壤修复中具有较好的应用潜力。
The accumulation of phenolic acids in soil is one of the major causes of the obstacle of continuous cropping of peanuts. Fungal laccase can effectively convert phenolic acids, but laccase has not been reported to be applied directly to the restoration of continuous cropping soil. In this study, pot experiments were conducted to study the effects of different concentrations of laccase rLACB3 on soil remediation. After 30 days of treatment, laccase treatment with 500 U kg -1 lasted more than 20 and 100 U kg -1. In peanut rhizosphere soil, the amount of laccase-culturable bacteria, actinomycetes and azotobacter in the soil increased by 33.0%, 37.7% and 30.2% respectively compared with the control. Analysis of rhizospheric microbial flora using denaturing gradient gel electrophoresis (DGGE) showed that the Shannon’s diversity index of bacteria, fungi and azotobacter treated with 500 U · kg-1 laccase increased by 9.0%, 17.3% and 14.8%, respectively %. Three kinds of phenolic acids coumarinic acid, 4-hydroxybenzoic acid and vanillic acid in the rhizosphere soil were reduced by 41.2%, 43.8% and 35.9% respectively compared with the control with 500 U · kg-1 laccase. The amount of peanut biomass and nodulation increased by 17.9% and 17.4% respectively compared with the control at the concentration of 500 U · kg-1 laccase. In conclusion, rLACB3, an endophytic fungal recombinant laccase, has good potential for application in soil remediation.