Cations make a difference: Soil nutrient patches and fine-scale root abundance of individual species in a mountain grassland

1. Root densities in the field vary at the centimetre scale, but we have no information on whether this variation is linked to variation in nutrient concentrations and availability. Roots of many species are able to proliferate in nutrient-rich patches in controlled conditions in culture, but because data on nutrient concentrations and, in particular, on their temporal stability in the field are scarce, we do not know to what extent root distribution in the soil bears traces of such a response.
2. Here, we linked centimetre-scale measurements of soil nutrient concentrations over a period of 6 weeks with estimation of root biomass and its species composition at the same points to determine whether there is any association between the two. In addition to phosphorus, nitrate and ammonium, we determined the concentrations of metal cations (magnesium, calcium and potassium). We used qPCR to determine the quantities of individual species in the root biomass samples.
3. We found that calcium a..., ,

1. 田间根系密度在厘米尺度上存在变异，但目前尚无证据表明该变异与土壤养分浓度及有效性的变异存在关联。诸多物种的根系在可控培养条件下，可在养分富集的斑块中发生增殖；但由于田间养分浓度（尤其是其时间稳定性）的相关数据十分匮乏，我们尚不清楚土壤中的根系分布在多大程度上留存了这类响应的痕迹。
2. 本研究将为期6周的厘米尺度土壤养分浓度测定数据，与同点位根系生物量及其物种组成的估算结果进行关联分析，以明确二者间是否存在关联。除磷、硝酸盐与铵盐外，我们还测定了金属阳离子（镁、钙、钾）的浓度；并采用实时定量聚合酶链式反应（quantitative PCR, qPCR）对根系生物量样本中的各物种种群数量进行了定量检测。
3. 本研究发现，钙……