降香黄檀不同混交林土壤细菌多样性差异分析

为探讨降香黄檀不同混交林土壤细菌的多样性及其与土壤性质的关系,应用高通量测序技术,比较降香黄檀(Dalbergia odorifera T.Chen)分别与奥氏黄檀(Dalbergia oliveri)、大果紫檀(Pterocarpus macarocarpus)、檀香(Santalum album L.)和母生(Homalium hainanense Gagnep.)混交的4种模式土壤细菌多样性,并结合土壤的理化、酶活进行了相关性分析。结果表明,14种混交林土壤的理化、酶活均存在差异。其中降香黄檀与檀香混交林土壤的含水量、有机质、全氮、有效钾和脲酶含量最高,分别为:5.24%、27.5 g/kg、0.85 mg/g、37.46 mg/kg和0.32 mg/kg,降香黄檀与大果紫檀混交林土壤的p H、有效磷和多酚氧化酶含量最高,分别为:4.48、6.04 mg/kg、4.19 mg/kg。2通过高通量测序表明四种混交模式土壤细菌的丰富度为:降香黄檀×檀香降香黄檀×大果紫檀降香黄檀×奥氏黄檀降香黄檀×母生,土壤细菌多样性为:降香黄檀×大果紫檀降香黄檀×奥氏黄檀降香黄檀×檀香降香黄檀×母生。其中,变形菌门、酸杆菌门、放线菌门、绿弯菌门和厚壁菌门为4种混交模式中的主要菌群。3经冗余分析和相关性分析表明,影响降香黄檀混交林土壤细菌群落结构和细菌多样性的主要土壤理化因子为:p H值、脲酶、多酚氧化酶和有机质。

Differential analysis of soil bacteria diversity in different mixed forests of Dalbergia odorifera

Dalbergia odorifera T. Chen is one of China''s endangered species. It is also an endemic species that mainly distributes in Hainan, Guangdong, Fujian, etc. Dalbergia odorifera has great values in medicine, economics and ecology, and its medicinal properties are specified in the Chinese Pharmacopoeia. But the resource was reduced and the productivity was declined due to years of deforestation. Developing mixed forests of Dalbergia odorifera has been becoming a major trend of Chengmai farm in Hainan Province, because mixed forests can not only adjust the temperature and relative humidity of woodland, but also improve soil fertility. Soil can provide nutrition for aboveground vegetations, as well as soil microorganisms. Soil bacteria, as one of the key members of soil microorganisms, plays an important role in promoting organic matter decomposition, accelerating mineral nutrition cycle, maintaining and improving soil fertility. People can understand the soil status better by analyzing the relationship between soil bacterial community and soil characteristics, and finally develop a method to improve the Dalbergia odorifera plantation. However, only about 1% bacteria could be assayed by traditional methods. High-throughput sequencing is a new method that can get the classification information of soil bacteria more conveniently and accurately, and avoid the limitations of traditional methods. This method has been widely used in studying soil microorganisms. We investigated soil bacteria diversity in four different mixed forests of Dalbergia odorifera plantation, i.e. Dalbergia odorifera mixed with Dalbergia oliveri, Pterocarpus macarocarpus, Santalum album L. and Homalium hainanense Gagnep., respectively, in Chengmai County, Hainan Province in China. A high-throughput sequencing technique was used to analyze the relationship and differences among these four plots to find a way that could improve soil fertility of Dalbergia odorifera plantation. After analyses, the results showed that soil physical-chemical characteristics and soil enzyme activities were different in the four mixed forest, i.e. the Dalbergia odorifera and Santalum album L. mixed forests with higher moisture content, organic matter, total N, available K and Ureas; Dalbergia odorifera and Pterocarpus macarocarpus mixed forests with higher pH, available P and polyphenol oxidase. The results of high-throughput sequencing showed that soil bacterial abundances of these four plantations were: Dalbergia odorifera × Santalum album L. > Dalbergia odorifera × Pterocarpus macarocarpus > Dalbergia odorifera × Dalbergia oliveri > Dalbergia odorifera × Homalium hainanense Gagnep., and the soil bacteria diversity of these four mixed models were: Dalbergia odorifera × Pterocarpus macarocarpus > Dalbergia odorifera × Dalbergia oliveri > Dalbergia odorifera × Santalum album L. > Dalbergia odorifera × Homalium hainanense Gagnep.. The dominant bacteria taxa in the four mixed forests were Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi and Firmicutes. The results of redundancy analysis and correlation analysis showed that pH, Ureas, polyphenol oxidase and organic matter were the main factors that had significant effect on the structure and diversity of soil bacterial community in this four mixed forests. Our analysis of bacteria 16S rRNA-based dataset showed differences in soil bacterial community structure among four mixed forests of Dalbergia odorifera. But further research is also needed to get more information in soil microorganisms.