紫云英根际微生物碳源利用多样性研究

Functional diversity of microbial community in bulk and rhizosphere soil of Astragalus sinicus

关键词:  重金属污染  土壤  BIOLOG  种群结构  多样性

Key words:  heavy metal pollution  soil  BIOLOG  population structure  diversity

摘要:

为探究绿肥根际调控效果的原因,采用碳素利用法-BIOLOG生态版,分析紫云英根际微生物种群结构和功能多样性。结果表明:紫云英根际土壤微生物总活性比非根际高,其主要贡献者是以氨基酸、糖类、酯类和醇类四大碳源为生的微生物,而与以磷酸盐、羧酸和胺类为碳源的微生物关系不大。进一步分析发现:紫云英根际产生了以α-酮丁酸、2-羟基安息香酸、4-羟基安息香酸、D-半乳糖醛酸、α-环式糊精、D-木糖、β-甲基-D-葡萄糖、D-甘露醇和L-精氨酸作为碳源的新微生物种群,完全抑制了以γ-羟基丁酸和苯乙基胺为碳源的微生物种群活性; 根泌物抑制了以D-苹果酸、衣康酸和肝糖为碳源的微生物活性,而对以D-化纤二糖、N-乙酰基-D-葡萄胺、丙酮酸甲酯、吐温40、吐温80、L-苯基丙氨酸、L-天门酰胺酸和腐胺为碳源的微生物有促进作用,但对以D-氨基葡糖酸、α-D-乳糖和Í-赤藻糖醇为碳源的微生物活性无显著影响; 另外,即使是以同一类物质为碳源的微生物种群,在紫云英根际的表现也不完全一样,如以D-乳酸γ-内酯和L-丝氨酸为碳源的可快速培养微生物受到抑制,可慢速培养的微生物活性则有提高,而以甘氨酰基-L-谷氨酸为碳源的微生物的表现正好与之相反。

Abstract:

This paper,by utilizing BIOLOG Eco-microplates,makes an analysis on the structural and functional diversity of microbial population in order to explore the rhizosphere effectiveness of green manure(A.sinicus )in enhancing phytoremediation. The finding is that the microbes of rhizosphere soil are generally more active than those of bulk soil. Such result has little to do with microbes whose carbon sources are phosphate,carboxylic and amines. Instead,the result attributes mainly to microbes whose carbon sources come from amino acids,glucide,FAT and alcohols. It's also found in the further research that,while the growth of microbes utilizing carbon sources(γ-Hydroxybutyric Acid and Phenylethyl-Amine included),is suppressed,new microbes emerge in rhizosphere soil,namely,ɑ-Ketobutyric Acid,2-Hydroxy Benzoic Acid,4-Hydroxy Benzoic Acid,D-Glucosaminic Acid,ɑ-Cyclodextrin,D-Xylose,β-Methyl-D-Glucoside,D-Mannitol and L-Arginine; that while Rhizosphere secretions of A.sinicus inhibit microbes utilizing D-Malic acid and Itaconic Acid and Glycogen as carbon sources,it promotes other microbes utilizing D-Cellobiose,N-Acetyl-D-Glucosamine,Pyruvic Acid Methyl ester,Tween 40,Tween 80,L-Phenylalanine,L-Asparagine and Putrescine as carbon sources,and has no effect on microbes utilizing D-Glucosaminic acid,α-D-Lactose,and Í-Erythritol as carbon sources. Another finding of the study is that even microbes derived from the same carbon source may perform differently at rhizosphere of A.sinicus. To illustrate,the growth of microbes feeding on D-Talactonic Acid,γ-Lactone and L-Serice is largely inhibited at first but be promoted in later; likewise,microbes that utilized Glycyl-L-Glutamic Acid as carbon sources perform just the opposite to general conception. A possible conclusion is that the population structure and liveness of microbes of the A.sinicus rhizosphere may contribute to the absorption of the heavy metals in the soil and the growth of accumulators.