Polyphosphates (Poly-P) are known to fulfil several important physiological functions. Many microorganisms can accumulate large amounts of Poly-P in their biomass. Regardless of these facts, systematic research on Poly-P in soil is missing, probably due to the absence of any method of direct Poly-P quantification. In this study, we attempted to unequivocally prove the presence of Poly-P in the biomass of soil microorganisms and quantify their extractability and contribution to microbial biomass phosphorus. To do so, we combined several approaches that can indicate Poly-P presence in soil microbial biomass indirectly, i.e. growth of soil inoculum on media without phosphorus, associated with measurement of changes in the microbial biomass stoichiometry, and the colour of the microbial suspension stained by the Neisser method. All soil microbial communities exhibited growth on media without phosphorus. As the growth on this media depleted Poly-P content, the biomass carbon to phosphorus and nitrogen to phosphorus ratio increased and the colour of the microbial suspension stained by the Neisser method changed predictively. The associated Poly-P addition experiment indicated that the recovery of added Poly-P from soil in form of soluble reactive phosphorus in sodium bicarbonate extract may reach up to 93% mainly due to abiotic depolymerization. Using a simple stoichiometric model applied to measured data, we calculated that the Poly-P content of microbial biomass in our soils may be up to 45 or 70% of total microbial biomass phosphorus depending on the assumptions applied regarding parameter values. We discuss the magnitude of error associated with the measurement of soil microbial phosphorus due to the high extractability of Poly-P.

已知多磷酸盐 (Poly-P) 具有多种重要的生理功能。许多微生物可以在其生物量中积累大量聚磷。不管这些事实如何，对土壤中多聚磷的系统研究仍然缺失，这可能是由于缺乏任何直接定量多聚磷的方法。在这项研究中，我们试图明确证明土壤微生物生物量中存在聚磷，并量化其可提取性和对微生物生物量磷的贡献。为此，我们结合了几种可以间接表明土壤微生物生物量中多聚磷存在的方法，即土壤接种物在不含磷的培养基上的生长，与微生物生物量化学计量变化的测量以及微生物悬浮液染色的颜色相关通过奈瑟法。所有土壤微生物群落都在不含磷的培养基上表现出生长。随着该培养基上的生长耗尽了多聚磷含量，生物质碳磷比和氮磷比增加，并且通过奈瑟法染色的微生物悬浮液的颜色发生了预测性的变化。相关的聚磷添加实验表明，碳酸氢钠提取物中以可溶性活性磷形式从土壤中添加的聚磷的回收率可高达 93%，这主要是由于非生物解聚作用。使用应用于测量数据的简单化学计量模型，我们计算出土壤中微生物生物量的聚磷含量可能高达微生物生物量总磷的 45 或 70%，具体取决于参数值的假设。我们讨论了由于聚磷的高可提取性而与土壤微生物磷测量相关的误差大小。