The pooling of soil samples in plant-microbe interaction studies is commonly employed, but the impact of sample handling has rarely been explored experimentally. Concerns have been raised that sample pooling may reduce biological variation leading to inflated type I errors or may alter the magnitude of microbial effects observed, invalidating the results achieved. To assess the impact of inocula pooling on plant-microbe interactions, we examined the reciprocal influence of unpooled and pooled soil microbial inocula on growth of Solidago altissima and Schizachyrium scoparium, with and without inoculum sterilization. Soil pooling had no effect on the variance among replicates in either plant species. However, pooling dramatically altered the magnitude and direction of microbial impacts on plant performance. Pooling of S. altissima soil increased the antagonistic effects on growth of both target species. In contrast, pooling of S. scoparium soil shifted impacts on S. altissima from effectively neutral to slightly positive. Pooling in this system altered both the strength and direction of plant-microbe interactions relative to unpooled soils. Therefore soil mixing should be avoided when the research goal is to determine naturally occurring interaction strengths, even within a single habitat.

中文翻译：

---

接种处理改变植物-微生物相互作用的强度和方向

在植物-微生物相互作用研究中收集土壤样品是常用的方法，但很少通过实验探讨样品处理的影响。有人担心样本合并可能会减少导致 I 型错误膨胀的生物变异，或者可能会改变观察到的微生物效应的程度，从而使所取得的结果无效。为了评估接种物汇集对植物-微生物相互作用的影响，我们检查了未汇集和汇集的土壤微生物接种物对一枝黄花和 Schizachyrium scoparium 生长的相互影响，有和没有接种灭菌。土壤汇集对任一植物物种的重复之间的差异没有影响。然而，汇集显着改变了微生物对植物性能影响的幅度和方向。S 的池化。altissima 土壤增加了对两种目标物种生长的拮抗作用。相比之下，S. scoparium 土壤的汇集将对 S. altissima 的影响从有效中性转变为略微积极。相对于未汇集土壤，该系统中的汇集改变了植物-微生物相互作用的强度和方向。因此，当研究目标是确定自然发生的相互作用强度时，即使在单个栖息地内，也应避免土壤混合。