【摘要】 通过采集山药连作2年的植株根际土壤及根茎,采用高通量测序技术研究根际土壤细菌多样性,分析7个样本中菌群的组成、丰度、α多样性、β多样性、菌群差异性。采用典型相关分析(Canonical Correlation Analysis,CCA)分析优势菌群与土壤化学因子、根茎糖类物质的关系,探讨根际土壤中细菌群落与土壤化学指标、根茎糖类物质的相关性。结果表明:山药根际土壤细菌优势群落为变形菌、绿弯菌、酸杆菌、放线菌;土壤pH是影响细菌群落结构及分布的重要因子;酸杆菌和硝化螺旋菌与土壤中蔗糖酶、脲酶活性及总有机碳、碱解氮呈正相关,奇古菌和绿弯菌与土壤总有机碳、碱解氮呈正相关,土壤中碳、氮养分又与山药根茎中可溶性糖、粗多糖及淀粉呈正相关关系,说明这些微生态环境因子可能对山药根茎糖类物质积累有促进作用。更多还原

【Abstract】 【Objective】Chinese yam(Dioscorea opposita) is a parannial herbal liane popular as vegetable in this country. Its tuber is consumed as both food and medicinal herb for its functions of antioxidation, anti-aging, immunity regulation, blood sugar reduction, etc. Soil ecoenvironmental factors and soil nutrient status are major factors affecting growth and quality of the plant. Soil microbes, in particular, participate in recycling of carbon, nitrogen and some other nutrient elements in the soil, flowing of energy, formation of soil humus, shaping and amelioration of soil structure. This study aims to explore relationships of the soil bacterial community in the rhizosphere of yam with soil nutrients and contents of saccharides in the tuber, and to elucidate major soil ecological factors affecting nutrient accumulation in yam tuber, in an attempt to provide certain reference for development of yam-specfic bio-manure and assessment of soil environment for cultivation of the plant.【Method】Seven samples of rhizosphere soil and rhizomes of 2-year old Chinese yam plants were collected for analysis of composition, abundance, Alpha diversity, Beta diversity and bacteria diversity of soil microbes with the aid of the high-throughput sequencing technology, and for analysis of relationships dominant soil bacterial groups and soil microbial community in rhizosphere with soil chemical factors and saccharides in root with the canonical correlation analysis method.【Result】Results show that Shannon and Chaol indices were significantly and negatively related to soil phosphatese activity; proteobacteria, chloroflexi, acidobacteria and actinobacteria were the dominant bacterial groups in the rhizosphere of Chinese yam; soil pH was an important factor affecting structure and distribution of the soil bacterial community; acidobacteria and nitrifying spirulina was related to sucrase and urease activities in soil; archaea and chloroflexi was positively related to soil organic carbon and nitrogen; soil carbon, nitrogen nutrient was positively related to soluble sugar, crude polysaccharides and starch in the root of yam. Chloroflexi and Thaumarchaeota, dominant soil bacterial groups were positively related to total organic carbon, total nitrogen, AK, AP and phosphatase activity in rhizosphere soil, and to content of starch and crude polysaccharide(spearman correlation index is 0.54, P<0.01) in tuber, too, which indicate that the above-mentioned chemical properties plays important roles in growth of the plant; Acidobacteria was negatively related to soil pH, AP and catalase and positively to total organic carbon, AK and invertase activity in soil, and negatively related to crude polysaccharide in tuber, too; Nitrospirae and Actinobacteria was positively related to activity of urease and catalase, and negatively to phosphatase and sucrase; Proteobacteria and Nitrospirae was positively related to soluble sugar and negatively related to crude polysaccharide.【Conclusion】All the findings demonstrate that the dominant bacterial groups in the rhizosphere of Chinese yam are proteobacteria, chlorobacteria, acidobacteria and actinomycetes; Soil pH is an important factor affecting structure of the soil bacterial community.Acidobacteri and nitrospira may improve carbon and nitrogen levels in the soil through stimulating the activity of sucrase and urease in soil; archaea and chlorobacteria promotes TOC and AN recycling in rhizosphere soil and increase TOC and AN nutrient supply in the soil, which in turn promotes accumulation of soluble sugar, crude polysaccharides and starch in rhizome of yam.更多还原