丛枝菌根真菌菌丝对土壤微生物群落结构及 多氯联苯降解的影响

以摩西球囊霉(Glomus mosseae)为供试菌种,在光照培养箱内利用分室根箱研究丛枝菌根真菌菌丝对多氯联苯(polychlorinated biphenyls,PCBs)污染土壤的修复效应及其机理。试验设置接种丛枝菌根真菌的处理以及不接种的对照,选用美国南瓜(Cucurbita pepo L.)为供试植物,在南瓜生长40天后将接种菌根真菌处理的菌丝室土壤从尼龙网向外水平分为4层取样,测定PCBs及磷脂脂肪酸含量。结果表明:菌丝可以穿越尼龙网影响菌丝室土壤,且距离尼龙网越远菌丝量越低;菌丝显著促进了土壤微生物量(P0.05),并改变了不同土层土壤微生物群落结构;接种菌根真菌处理各土层PCBs降解率为35.67%~57.39%,均显著高于对照的17.31%,相关分析结果表明土壤三氯、四氯联苯以及PCBs总量与菌丝量呈极显著负相关(P0.01);菌丝际土壤微生物量,特别是细菌生物量与土壤三氯联苯含量呈显著负相关(P0.05)。可见,菌丝通过影响菌丝际土壤微生物群落结构及生物量,促进三氯及四氯联苯降解,从而提高土壤PCBs修复效率。

Effects of Arbuscular Mycorrhizal Fungal Hyphae on Soil Microbial Community Composition and Polychlorinated Biphenyls Degradation

To investigate the effect of arbuscular mycorrhizal fungal (AMF) hyphae on remediation of polychlorinated biphenyls (PCBs) contaminated soils and its related mechanisms, an illumination incubation experiment was conducted using rhizobox system to separate plant root and AMF hyphae. The experiment included a treatment inoculated with Glomus mosseae and a non-mycorrhizal control, using Cucurbita pepo L. as test plant. The soil in hyphal compartment was separated into 4 horizontal layers, which were used for PCBs and phospholipid fatty acid (PLFA) analysis. The results indicated that AMF hyphae can penetrate the nylon mesh and the hyphal length decreased with the increased distance from nylon mesh. PCBs dissipation rates in different soil layers of AMF inoculated treatment ranged from 35.67%-57.39%, and were significantly higher than that in the control (17.31%, P<0.05). Soil Tri-, Tetra-chlorinated biphenyls and total PCBs concentrations were found significantly and negatively correlated with soil hyphal length (P<0.01). Soil microbial PLFA biomass, especially bacterial biomass, negatively correlated with soil Tri-chlorinated biphenyls contents significantly (P<0.05). This study suggested that the AMF hyphae can promote the remediation of PCBs contaminated soil by increasing microbial biomass and altering microbial community composition in the hyphosphere soil.