【作者】 孔凡美；

【导师】 史衍玺；

【作者基本信息】 山东农业大学 ， 土壤学， 2008， 博士

【摘要】 多环芳烃(Polycyclic Aromatic Hydrocarbons,PAHs)由于毒性强、降解周期长而成为环境中的一种重要的持久性有机污染物(Persistent Organic Pollutants,POPs)。土壤是环境中的多环芳烃库,土壤多环芳烃污染对土壤生态系统以及农产品的安全构成了极大的威胁。菌根真菌与植物联合修复是土壤多环芳烃污染生物修复的重要途径,也是目前土壤多环芳烃污染修复的热点研究领域。本研究以丛枝菌根菌(Abuscular Mcorrhizal Fnfus,AMF)与玉米联合修复土壤芘污染的效应为中心,采用外加芘的方法模拟芘污染条件,结合土培、砂培等生物培养试验和实验室分析研究了源于石油污染土壤中的AMF与玉米联合修复土壤芘污染的效应及其影响因素,分析了AMF与玉米联合效应中土壤微生物、玉米以及AMF的综合效应在土壤芘污染修复中的相对贡献率,并对AMF与玉米联合修复土壤芘污染的机理进行了探讨,论文取得的主要结果如下:1、从石油污染土壤中扩繁出的AMF与玉米联合对土壤芘污染的修复效果显著。5mg/kg、10mg/kg和50mg/kg土壤芘处理中AMF能够保持较高的侵染活性;各土壤芘浓度水平处理下,玉米接种AMF处理土壤的残留浓度比不灭菌的对照处理降低了23%~78%,土壤芘的去除率分别是不灭菌对照处理的1.4~2.3倍,表明AMF与玉米联合能够显著降低土壤中芘的残留浓度,促进土壤芘污染的修复;AMF与玉米联合在土壤芘污染的修复中的综合贡献率可达45%,其中玉米的综合贡献率34%,AMF的综合贡献率为11%。2、不同磷肥水平下AMF与玉米联合修复土壤芘污染均有显著效果,缺磷土壤中施磷对玉米与AMF联合修复土壤芘污染有一定的促进作用。50mg/kg芘处理低磷土壤中施用80mg/kg和20mg/kg磷对丛枝菌根的侵染率没有显著影响;培养60天后, 20mg/kg和80mg/kg施磷水平下芘处理土壤中玉米接种AMF处理土壤芘的残留浓度分别比无玉米的不灭菌对照处理(CK)降低了53%和58%,土壤芘去除率分别提高了30%和31%;玉米与AMF联合对土壤芘去除的贡献率为23%和23.8%;与20mg/kg磷处理相比,80mg/kg磷处理玉米接种AMF处理的土壤芘残留浓度降低了18.4%;施磷对AMF与玉米联合修复土壤芘污染的综合贡献率影响不大,但会降低AMF修复土壤芘污染的贡献率;土壤微生物碳量与土壤芘的去除率显著正相关,玉米接种AMF处理和80mg/kg磷处理均能够显著增加土壤微生物碳量,因此土壤微生物数量的增加可能是其促进土壤芘的去除的重要原因。3、表面活性剂TW80对AMF与玉米联合修复土壤芘污染有明显促进作用,但随着TW80处理浓度的增加,单位浓度的TW80引起的土壤芘残留浓度的降低幅度成幂函数下降。5000mg/kgTW80处理条件下每100mg/kgTW80引起的土壤芘残留浓度的下降幅度比相应的100mg/kgTW80处理降低了98%;500mg/kgTW80处理对玉米与AMF联合修复土壤芘污染效果最佳,其土壤芘残留浓度比相应的无TW80的对照处理降低了22.4%;TW80对AMF在土壤芘修复中的贡献有明显抑制作用,这可能是AMF与玉米联合修复土壤芘污染效率下降的重要原因。因此,在植物与AMF联合修复土壤芘污染中使用TW80应该注意控制TW80的浓度。4、从石油污染土壤中扩繁出的AMF混合菌群及其中的单一菌种与玉米联合均能促进土壤芘污染的修复,原始混合菌群具有明显的种群优势,其与玉米联合修复土壤芘污染的效果最佳。1mg/kg、10mg/kg和50mg/kg芘处理土壤中,玉米接种混合菌种M4(Glomus intraradices, Glomus mosseae, Glomus etunicatum和Arcaulospora tuberculata)处理土壤的芘残留浓度分别为0.12mg/kg,0.54mg/kg和3.92mg/kg,分别比接种单一菌种M1(G.mossea)处理降低了32.6%,58.6%和42.2%,比接种单一菌种M2(G.intradices)处理降低了28.1%,59.9%和36.6%,比接种复合菌种M3(G.intradices+G.mossea)处理降低了2.7%,55%和23.5%。5、从石油污染土壤中扩繁出的混合AMF菌群在无原始条件下的整体扩繁会改变菌群的组成及其结构,并会对菌群与玉米联合修复土壤芘污染的功能产生不利影响。供试混合AMF菌群含有4个菌种,经过三次无原始条件的扩繁以后,菌群中菌种的孢子数量、组成和比例均发生了显著变化;50mg/kg芘处理土壤中,玉米接种三次扩繁的AMF菌群土壤芘的去除率分别为86.24%、85.73%和82.76%,分别比相应的无玉米的不灭菌对照处理提高了110%、97%和85%,表明三次扩繁的混合AMF菌群与玉米联合修复土壤芘污染均有明显促进效果,但也可以看出,该效果有逐渐下降趋势,菌种可能出现了功能退化现象。因此利用AMF与玉米联合修复芘污染土壤应该考虑菌种的来源以及菌种功能的稳定性。6、玉米与AMF联合能够改变玉米根系吸收的芘在玉米体内的分配比例,但是对芘的总累积提取量影响不大。玉米通过根系吸收的芘主要累积在根系,芘10mg/kg、50mg/kg、100mg/kg处理条件下,各处理玉米根系中的芘含量是地上部的5~16倍;AMF与玉米联合能够进一步促进玉米根系吸收的芘在根系内累积,降低芘在玉米地上部的分配系数,各芘处理条件下接种AMF处理玉米地上部芘含量分别降低了30%~37%,而根系芘含量则提高了19%~35%;各接种AMF处理根外菌丝中的芘含量略低于根系内芘含量,但显著高于地上部芘含量,表明从枝菌根根外菌丝对芘也有较强的累积能力;玉米吸收累积芘的总量仅为加入量的0.02%~0.05%,因此玉米的吸收累积在玉米与AMF联合修复芘污染的效应中贡献不大。7、芘处理条件下,AMF与玉米联合对根系分泌物的组成及芘对玉米的氧化损伤有明显影响。芘处理条件下,接种AMF处理对玉米根际的pH值没有显著影响,但接种AMF处理能够促进玉米根系分泌琥珀酸和水杨酸,为芘的共代谢降解提供底物;芘处理条件下AMF与玉米联合能够提高玉米的根系活力,降低叶片MDA浓度和CAT活性,缓解芘对叶片的氧化损伤,从而提高玉米对芘污染的抗性。8、AMF与玉米联合能够显著提高芘处理土壤中的微生物数量或微生物碳总量,增强土壤中过氧化氢酶和多酚氧化酶的活性,为土壤芘污染的修复提供有利条件。更多还原

【Abstract】 Polycyclic Aromatic Hydrocarbons(PAHs) become an important Persistent Organic Pollutants(POPs) due to it’s strong toxicity, long cycle of degradation in the environment. Soil is the storeroom of PAHs in the environment , and Polycyclic aromatic hydrocarbons pollution in soil is a grave threat on the soil ecosystem and the safety of agricultural products.The remediation with Mycorrhizal fungus and plant integrated system is an important way and the current hot research field in the field of PAHs contaminated soil remediation. Simulating pyrene polluted conditions by adding pyrene, with the method of biological experiments (soil culture and sand culture) and room analysis, this study investigated the remediating effects and its impact factors of pyrene contaminated soil with AMF (Abuscular Mcorrhizal Fungus, AMF) coming from oil-contaminated soil and corn integrated system. Furthermore, the mechinesms and the relative contribution rate of soil microorganisms,corn and AMF in the remedition effects of pyrene contaminated soil by AMF and corn integrated system was also discussed. The main results were as follows: 1. AMF and corn integrated system had significant effect on remediation of pyrene contaminated soil . AMF maintained relatively high infection activity in the soils with 5mg/kg, 10mg/kg and 50 mg / kg soil pyrene treatment .Compared with the control which had no corn growth and no sterilization,the residual pyene concentration in the soils with different pyrene treatments decreased 23%~78% ,and that the removal rate of pyrene were 1.4 to 2.3 times of control.These results indicated that AMF and corn integrated system can significantly decreased the residual pyrene concentration in the soil,and accelerate the remediation of pyrene contamination in soil. The compositive contribution rates of AMF and corn integrated systerm reached 45% ,of which corn comprehensive contribution rate was 34%, and AMF comprehensive contribution rate was 11%.2.The AMF and corn integrated systerm had significant effects on pyrene contaminated soil remidation under different levels of phosphate fertilizer in soil, and the phosphorus input in the soil with phosphorus deficiency had positive effects on that. The application of 80 mg/kg and 20 mg/kg had no significant effects on AMF inoculation rate in the soil with 50mg/kg pyrene. Compared with the control which had no corn growth and no sterilization,the residual pyene concentration in the soils under 20mg/kg and 80mg/kg P treatments decreased 53% and 58% respectively,and that the removal rate of pyrene increased 30% and 31% respectively,and the compositive contribution rates of AMF and corn integrated systerm reached 23% and 23.8% respectively.Compared with 20mg/kg P treatments,the residual pyrene concentration of soil with 80mg/kg P treatments decreased 18.4%. P input had no significant effect on the compositive contribution rates of AMF and corn integrated systerm in soil pyrene removal,but could decrease the comprehensive contribution of AMF.The microbial biomass carbon of soil had significant positive correlation with the pyrene removal rate, AMF innoculation and P can significantly increase the microbial biomass carbon,therefore ,the increase of soil microbes may be the important reasons in the removal of pyrene in soil by AMF and corn integrated systerm.3.Surfactant TW80 had noteble positive effects on the remediation of pyrene contaminated soil by AMF and corn integrated systerm,but the decreaesing extent of the residual pyrene concentration which leaded by unit concentration of TW80 input in soil exponential dropped with the increase of TW80 concentration. The residual pyrene concentration of 500 mg/kg TW80 treatment decreased 22.4% than the control without TW80,representing the best effect.TW80 can inhibit the effects of AMF in soil pyrene removal.Therefore it’s necessary to contol the concentration of TW80 to use it in the remediation of pyrene contaminated soil by AMF and corn integrated systerm.4. The AMF community and the single species derived from rock oil-contaminated soil all can be combined with corn and promote the remidation of pyrene contaminated soil , the original AMF community has obvious advantages and behave best.The residual pyrene concentration of soil in the treatments with the mixed AMF community M4 (Glomus intraradices, Glomus mosseae, Glomus etunicatum and Acaulospora tuberculata) and corn integrated systerm got 0.12mg/kg,0.54mg/kg and 3.92mg/kg respectively in 1mg/kg, 10mg/kg and 50 mg/kg pyrene treatments,decreased 32.6%,58.6% and 42.2% respectively than that of the treatment of M1 (G.mossea),decreased 28.1%,59.9% and 36.6% than that of M2(G.intradices), decreased 2.7%,55% and 23.5% than that of M3 (G.intradices + G.mossea).5.Large scale reproduce overall of AMF community which coming from rud oil-contaminated soil in the absence of the original conditions will change the quantiy,composition and structure of the AMF population and may has negative impact on it’s function in the remedition of soil pyrene contamination. After three times of reproduce without original conditions ,the removal rate of pyrene in the treatments with corn and AMF got 86.24%、85.73% and 82.76% respectively after each time of reproduce, and that increased 110%,97% and 85% respectively than that of the control treatments without corn and sterilization.All the results above indicated that AMF community and corn integrated systerm can signifcantly promote the remedition of pyrene contaminated soil,but the effects decreased with the increase of reproduce times. So the function of AMF may be degradated in the process of reproduce.Therefore use of the AMF and corn in remediation of pyrene contaminated soil should consider the source of AMF and it’s functional stability.6.AMF inoculation can change the distribution of pyrene absorbed by root ,but had no significant effect on the total quantity of pyrene absorbed by corn. The pyrene concentrations of roots in corn were 5 to 16 times of that in shoots in the pyrene treatments of 10mg/kg,50mg/kg and 100mg/kg indicating that the pyrene absrobed by roots mainly cumulated in roots.AMF inoculation can promote the cumulation of pyrene in roots. The pyrene concentration of shoots in corn in the treatments with AMF inoculation decreased 30%~37% than that of the treatments without AMF inoculation, while that of the roots increased 19%~35% in the contrary. The pyrene concentration in the mycelium of AMF was little lower than that of roots in corn, but significantly higher than that of shoots indicating the stronger cumulative capacity of AMF mycelium. The total quantity of pyrene cumulated in corn was only 0.02% to 0.05% in the pyrene inputed in the soil,so the absorption and accumulated in corn contribute little in the remediation of pyrene polluted soil. 7.AMF inocilation had significant effects on the composition of corn’s root exudates and the oxidative damage to corn caused by pyrene in the pyrene treatments. The AMF inoculation of corn had no significant impact on pH value of rhizosphere ,but can promote the secretion of succinic acid and salicylic acid and which provied the substrate for the cometabolism of pyrene.AMF inoculation can improve the activity of corn’s roots ,decrease MDA concentration and CAT activity of corn’s leaves, alleviate the oxidative damage caused by pyrene ,thereby enhancing the resistant ability of corn to pyrene contamination.8. AMF and corn integrated systerm can significantly increase the number of microoganism or microbial biomass carbon,enhance soil catalase and polyphenol oxidase activity, and that provide favorable conditions for the remediation of pyrene contaminated soil.更多还原