Nitrogen (N) nutrients are crucial for poplar (Populus L.) survival and growth. However, whether N-fixing rhizosphere microorganisms (diazotrophs) regulate plant productivity and to what extent remain poorly understood. In this study, we analyzed differences in the morphological and chemical traits of poplar grown in the presence of different assemblies of rhizosphere microbiota. We found that the inoculation of diazotrophs into sterilized soils significantly promoted poplar growth with an average increase of 23.40 % for plant height and 51.16 % for root length as compared to the control (sterilization). More importantly, the inoculation of diazotrophs into soils with native microbiota aggravated the promotion of multiple poplars traits including plant height, stem weight, root volume, and root weight, particularly increasing root length by 114.27 %. This promotion of plant traits was facilitated by the greater diversity, niche breadth and ecological functions of the rhizosphere microbiota. Diazotroph inoculation enhanced the positive associations between plant traits and important microbial taxa while alleviating soil environmental stress. Our findings provide new insights into how inoculation with functional microorganisms contributes to poplar traits, with implications for plant cultivation and engineering programs.

中文翻译：

---

重氮营养生物与天然土壤微生物的协同作用改善了杨树的性状


氮 （N） 营养物质对杨树 （Populus L.） 的生存和生长至关重要。然而，固氮根际微生物 （重氮营养生物） 是否调节植物生产力以及调节到何种程度仍知之甚少。在这项研究中，我们分析了在不同根际微生物群存在下生长的杨树形态和化学特征的差异。我们发现，将重氮营养生物接种到无菌土壤中显着促进了杨树的生长，与对照（灭菌）相比，株高平均增加 23.40 %，根长平均增加 51.16 %。更重要的是，将重氮营养生物接种到具有天然微生物群的土壤中，加剧了杨树株高、茎重、根体积和根重等多种性状的促进，特别是根长增加了 114.27 %。根际微生物群的更大多样性、生态位广度和生态功能促进了植物性状的这种推广。重氮营养菌接种增强了植物性状与重要微生物类群之间的正关联，同时减轻了土壤环境压力。我们的研究结果为接种功能性微生物如何促进杨树性状提供了新的见解，对植物栽培和工程计划具有影响。