野鸭湖湿地芦苇根际微生物多样性与磷素形态关系

以野鸭湖湿地芦苇(Phragmites communis)根际微生物为研究对象,采用化学连续提取法分析了芦苇根际/非根际土壤中各形态磷随植物生长(4、7、10月)的变化规律,同时基于细菌的16S rRNA高通量测序技术,分析了芦苇根际/非根际土壤微生物多样性,进一步采用CCA法分析了土壤样品中特定微生物与磷素形态转化关系.结果表明,无机磷含量的总体顺序大小为:钙磷(Ca-P)闭蓄态磷(Oc-P)铁磷(Fe-P)交换态磷(Ex-P)铝磷(Al-P),无机磷含量变化主要受芦苇生长状况影响,在芦苇旺盛期达到最低,且根际土壤中的总无机磷含量普遍低于非根际.有机磷含量分布为高稳定性有机磷(HR-OP)中稳定性有机磷(MR-OP)中活性有机磷(ML-OP)活性有机磷(L-OP),各组分含量均随芦苇生长先降低后升高.芦苇根际/非根际土壤微生物中的优势菌门均为变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)、绿弯菌门(Chloroflexi)、放线菌门(Actinobacteria),但在芦苇生长过程中,其根际和非根际微生物群落结构受季节影响变化显著,且根际和非根际的变化有所差异.同时发现了芽孢杆菌属(Bacillus)、肠杆菌属(Enterobacter)、假单胞菌属(Pseudomonas)、伯克霍尔德氏菌属(Burkholderia)、不动杆菌属(Acinetobacter)等可能是与磷形态转化有关的主要功能菌属,这些菌属能利用大部分的有机磷和无机磷,在湿地土壤磷素转化中起着关键作用.

Effects of Soil Microbial Diversity on the Phosphate Fraction in the Rhizosphere of Phragmites communis in the Yeyahu Wetland in Beijing, China

In this research, microorganisms in rhizosphere/non-rhizosphere soils of Phragmites communis in the Yeyahu Wetland were studied. A sequential extraction procedure was used to analyze the phosphorus (P) forms in the rhizosphere/non-rhizosphere soil with a variety of plant growth conditions (April, July, October). The soil bacteria community structure and the diversity was measured using the high-throughput of 16S rRNA amplicons. Furthermore, the complete crystallographic analysis (CCA) method was used to analyze the relationship between phosphate solubilizing microorganisms and P transformation in the soil samples. The results showed that the rank order of inorganic P (IP) fractions in the soil was generally as follows:Ca-bound P (Ca-P) > Occluded P (Oc-P) > Fe-bound P (Fe-P) > Exchangeable P (Ex-P) > Al-bound P (Al-P). The IP content was most affected by the growth of Phragmites communis. The minimum content of IP appeared in the vigorous growth period and the total IP content in the rhizosphere soil was generally lower than in the non-rhizosphere soil. The rank order of organic P (OP) fractions were highly resistant OP (HR-OP) > moderately resistant OP (MR-OP) > moderately labile OP (ML-OP) > labile OP (L-OP), and all the components of OP first decreased and then increased with the growth of plant. The major phylogenic groups in rhizosphere/non-rhizosphere soil of Phragmites communis, included Proteobacteria, Acidobacteria, Chloroflexi, and Actinobacteria among which, Proteobacteria was the majority group in the community composition. Furthermore, the rhizosphere/non-rhizosphere microbial community structure was significantly affected by seasonal changes and existing differences between the rhizosphere and non-rhizosphere soils. In addition, the main functional groups of the modal transformation of P bacteria genera were Bacillus, Enterobacter, Pseudomonas, Burkholderia, Acinetobacter, which can make use of most OP and IP, playing an important role in the transformation of P in wetland soils.