Soil microbial biomass C:N:P stoichiometry and microbial use of organic phosphorus
Soil microbial biomass C:N:P stoichiometry and microbial use of organic phosphorus
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DOI：
10.1016/j.soilbio.2015.02.029
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发表时间：
2015-06-01
影响因子：
9.7
通讯作者：
Spohn, Marie
中科院分区：
文献类型：
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作者：
Heuck, Christine;Weig, Alfons;Spohn, Marie
微生物矿化和养分固定对土壤肥力有很大影响。我们研究了微生物生物量的化学计量，微生物群落组成，和微生物利用的碳（C）和磷（P）来源于葡萄糖-6-磷酸在A和B层的两个温带形成土与对比P的可用性。在第一次培养实验中，在全因子设计中向土壤中添加C、氮（N）和P。微生物生物量C，N和P浓度进行了分析，通过熏蒸提取方法和微生物群落组成进行了分析，通过社区指纹法（自动核糖体基因间间隔区分析，ARISA）。在第二个实验中，我们通过向土壤中添加C-14或P-33标记的葡萄糖-6-磷酸盐来比较微生物对葡萄糖-6-磷酸盐中的C和P的利用。在第一次培养实验中，由于添加C，微生物生物量增加高达30倍，表明微生物生长主要是C限制的。微生物生物量C：N：P化学计量比的变化更强烈，由于元素添加在贫磷土壤，比在富磷土壤。微生物群落组成分析表明，元素的添加导致更强的变化，微生物群落中的贫磷土壤比富磷土壤。因此，改变微生物生物量的化学计量在磷贫土壤中可能是由微生物群落组成的转变。添加示踪剂后66 h，土壤微生物生物量和呼吸CO2中葡萄糖-6-磷酸衍生的C-14的总回收率在28.2 - 37.1%之间，而土壤微生物生物量中P-33的回收率为1.4- 6.1%。这表明，即使在贫磷土壤微生物矿化有机磷和采取更多的C比P从有机化合物。因此，有机磷的微生物矿化是由微生物对C的需求而不是对P的需求驱动的。总之，我们的实验表明：（i）在P-贫土壤中的微生物生物量化学计量比比在P-富土壤中更容易受到C，N和P的添加的影响;（ii）即使在P-贫土壤中，微生物是碳限制的，有机磷的矿化主要由微生物C（C）驱动2015 Elsevier Ltd.保留所有权利。
Microbial mineralization and immobilization of nutrients strongly influence soil fertility. We studied microbial biomass stoichiometry, microbial community composition, and microbial use of carbon (C) and phosphorus (P) derived from glucose-6-phosphate in the A and B horizons of two temperate Cambisols with contrasting P availability. In a first incubation experiment, C, nitrogen (N) and P were added to the soils in a full factorial design. Microbial biomass C, N and P concentrations were analyzed by the fumigation-extraction method and microbial community composition was analyzed by a community fingerprinting method (automated ribosomal intergenic spacer analysis, ARISA). In a second experiment, we compared microbial use of C and P from glucose-6-phosphate by adding C-14 or P-33 labeled glucose-6-phosphate to soil. In the first incubation experiment, the microbial biomass increased up to 30-fold due to addition of C, indicating that microbial growth was mainly C limited. Microbial biomass C:N:P stoichiometry changed more strongly due to element addition in the P-poor soils, than in the P-rich soils. The microbial community composition analysis showed that element additions led to stronger changes in the microbial community in the P-poor than in the P-rich soils. Therefore, the changed microbial biomass stoichiometry in the P-poor soils was- likely caused by a shift in the microbial community composition. The total recovery of C-14 derived from glucose-6-phosphate in the soil microbial biomass and in the respired CO2 ranged between 28.2 and 37.1% 66 h after addition of the tracer, while the recovery of P-33 in the soil microbial biomass was 1.4-6.1%. This indicates that even in the P-poor soils microorganisms mineralized organic P and took up more C than P from the organic compound. Thus, microbial mineralization of organic P was driven by microbial need for C rather than for P. In conclusion, our experiments showed that (i) the microbial biomass stoichiometry in the P-poor soils was more susceptible to additions of C, N and P than in the P-rich soils and that (ii) even in the P-poor soils, micro-organisms were C-limited and the mineralization of organic P was mainly driven by microbial C (C) 2015 Elsevier Ltd. All rights reserved.