Ecological Farming Systems, Agroscope Reckenholz Tänikon Research Station ART, Reckenholzstrasse 191, CH-8046 Zürich, Switzerland.
Ecology. 2011 Jun;92(6):1303-13. doi: 10.1890/10-1915.1.
There is a great interest in ecology in understanding the role of soil microbial diversity for plant productivity and coexistence. Recent research has shown increases in species richness of mutualistic soil fungi, the arbuscular mycorrhizal fungi (AMF), to be related to increases in aboveground productivity of plant communities. However, the impact of AMF richness on plant-plant interactions has not been determined. Moreover, it is unknown whether species-rich AMF communities can act as insurance to maintain productivity in a fluctuating environment (e.g., upon changing soil conditions). We tested the impact of four different AMF taxa and of AMF diversity (no AMF, single AMF taxa, and all four together) on competitive interactions between the legume Trifolium pratense and the grass Lolium multiflorum grown under two different soil conditions of low and high sand content. We hypothesized that more diverse mutualistic interactions (e.g., when four AMF taxa are present) can ease competitive effects between plants, increase plant growth, and maintain plant productivity across different soil environments. We used quantitative PCR to verify that AMF taxa inoculated at the beginning of the experiment were still present at the end. The presence of AMF reduced the competitive inequality between the two plant species by reducing the growth suppression of the legume by the grass. High AMF richness enhanced the combined biomass production of the two plant species and the yield of the legume, particularly in the more productive soil with low sand content. In the less productive (high sand content) soil, the single most effective AMF had an equally beneficial effect on plant productivity as the mixture of four AMF. Since contributions of single AMF to plant productivity varied between both soils, higher AMF richness would be required to maintain plant productivity in heterogeneous environments. Overall this work shows that AMF diversity promotes plant productivity and that AMF diversity can act as insurance to sustain plant productivity under changing environmental conditions.
人们对生态学很感兴趣，希望了解土壤微生物多样性对植物生产力和共存的作用。最近的研究表明，共生土壤真菌（丛枝菌根真菌，AMF）的物种丰富度增加与植物群落地上生产力的增加有关。然而，AMF 丰富度对植物-植物相互作用的影响尚未确定。此外，尚不清楚物种丰富的 AMF 群落是否可以作为维持波动环境（例如土壤条件变化时）生产力的保险。我们测试了四种不同的 AMF 分类群以及 AMF 多样性（无 AMF、单一 AMF 分类群和全部四种）对在低砂含量和高砂含量两种不同土壤条件下生长的豆科三叶草和禾本科多花黑麦草之间竞争相互作用的影响。我们假设更多样化的共生相互作用（例如，当存在四种 AMF 分类群时）可以减轻植物之间的竞争效应，增加植物生长，并在不同的土壤环境中维持植物生产力。我们使用定量 PCR 来验证实验开始时接种的 AMF 分类群在实验结束时仍然存在。AMF 的存在通过减少禾本科对豆科的生长抑制，减少了两种植物之间的竞争不平等。高 AMF 丰富度增强了两种植物的组合生物量生产和豆科植物的产量，尤其是在低砂含量、生产力更高的土壤中。在生产力较低（砂含量较高）的土壤中，最有效的单一 AMF 对植物生产力的有益作用与四种 AMF 的混合物相当。由于单个 AMF 对植物生产力的贡献在两种土壤中均有所不同，因此需要更高的 AMF 丰富度来维持异质环境中的植物生产力。总的来说，这项工作表明 AMF 多样性促进了植物的生产力，并且 AMF 多样性可以作为在不断变化的环境条件下维持植物生产力的保险。
