Šmilauer Petr, Šmilauerová Marie, Kotilínek Milan, Košnar Jiří
Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic.
Mol Ecol. 2020 Apr;29(8):1574-1587. doi: 10.1111/mec.15425. Epub 2020 Apr 19.
To better understand the ecology of arbuscular mycorrhizal (AM) symbiosis, we need to measure functional traits of individual fungal virtual taxa under field conditions. The efficiency of AM fungi in locating nutrient-rich patches in soil space is one of their central traits in this symbiotic relationship. We used plots of a long-term field experiment in grassland with manipulated functional group composition of host plant community to establish ingrowth patches with substrate free of roots and fungi and with varying nutrient availability. Comparison of the original AM fungal community before patch creation with that present 9 weeks after patch establishment enabled us to estimate relative hyphal foraging speed for 41 fungal taxa, and a comparison of the fungal community in neighbouring patches differing in nutrient availability provided estimates of hyphal foraging precision for 22 taxa. Members of two dominant fungal families, Glomeraceae and Claroideoglomeraceae, differed in their foraging speed and precision. Glomeraceae taxa responded more slowly, but with a higher focus on enriched patches. We further demonstrated the usefulness of the obtained fungal functional traits by testing the differences between grass and dicotyledonous plant hosts using a data set obtained in another experiment at the same plots. Grass species hosted AM fungal communities with higher foraging speed, but lower foraging precision than the dicotyledonous species. Our study results support the use of field experiments for measuring comparative characteristics of AM fungi, which are highly elusive (or misrepresented) under controlled conditions.
为了更好地理解丛枝菌根（AM）共生的生态学，我们需要在田间条件下测量单个真菌虚拟类群的功能性状。AM真菌在土壤空间中定位营养丰富斑块的效率是它们在这种共生关系中的核心性状之一。我们利用一个长期草地田间试验的样地，通过操控宿主植物群落的功能组组成，建立了无根无真菌且养分有效性各异的内生长斑块。将斑块创建前的原始AM真菌群落与斑块建立9周后的群落进行比较，使我们能够估计41个真菌类群的相对菌丝觅食速度，而对养分有效性不同的相邻斑块中的真菌群落进行比较，则可以估计22个类群的菌丝觅食精度。两个优势真菌科，球囊霉科和类球囊霉科的成员在觅食速度和精度上存在差异。球囊霉科类群反应较慢，但对富集斑块的关注度更高。我们还利用在同一地块的另一个实验中获得的数据集，测试了禾本科植物宿主与双子叶植物宿主之间的差异，进一步证明了所获得的真菌功能性状的有用性。禾本科物种所承载的AM真菌群落觅食速度较高，但觅食精度低于双子叶物种。我们的研究结果支持利用田间试验来测量AM真菌的比较特征，这些特征在受控条件下极难捉摸（或被错误表述）。
