霍山石斛是兰科石斛属国家一级保护野生濒危植物，也是一种药食兼用的中药资源植物。目前，设施和林下栽培已经成为霍山石斛的主要培育模式，但两种栽培模式下霍山石斛地上部生物量、品质与基质/土壤中微生物群落间的关联特征尚不清楚，限制了关于霍山石斛地上-地下过程与机制的理解。鉴于此，本研究在安徽大别山霍山石斛种植基地开展了野外实验与采样，旨在探究霍山石斛设施和林下栽培模式中养分对植物-微生物之间的调控关系。结果发现：林下种植霍山石斛显著改变了土壤中的微生物群落，而设施栽培种植霍山石斛未改变基质的微生物群落。设施和林下栽培模式下，基质与土壤中微生物生物量、群落结构与多样性均存在显著的差异，表现在相较于林下土壤，基质中微生物生物量碳氮含量与被胞霉门真菌丰度更高，且细菌多样性更高。基质中霍山石斛鲜重显著高于林下霍山石斛，结构方程模型结果指示两种栽培模式中的基质/土壤中养分-微生物与霍山石斛鲜重之间的调控关系，具体地，设施富养条件塑造了更高的细菌多样性，促进了植株的地上部生物量；而在林下贫养条件下，病原菌丰度的升高降低了地上生物量，同时可能促使霍山石斛次生代谢产物升高，提高抗性。该研究理清了设施和林下栽培霍山石斛模式中植株生物量与微生物之间的关联性，为未来霍山石斛人工培育过程中促进植株生长和品质调控等功能菌剂的开发、珍稀濒危植物资源的保护提供了科学基础。

Aims Dendrobium huoshanense is a national category I Protected Endangered Wild Plant of the Orchidaceae family and the genus Dendrobium. It is also a traditional Chinese medicinal resource plant that can be used both as medicine and food. Currently, facility cultivation and underforest cultivation have become the primary methods for the cultivation of D. huoshanense. However, the correlation characteristics between the aboveground biomass, quality of D. huoshanense and the microbial community in the substrate/soil under these two cultivation modes remain unclear. This limitation hinders the understanding of the aboveground-belowground processes and mechanisms of D. huoshanense. Methods In light of this, a field experiment and sampling were conducted at the D. huoshanense cultivation base in the Dabie Mountains, Anhui, with the aim to investigate the regulatory relationship between nutrients and plant-microbe interactions in the facility and underforest cultivation modes of D. huoshanense. Important findings Underforest cultivation of D. huoshanense significantly altered the microbial community in the soil, whereas facility cultivation did not change the microbial community in the substrate. Significant differences in microbial biomass, community structure, and diversity were observed between the facility and underforest cultivation modes. Specifically, compared to the underforest soil, the substrate showed higher microbial biomass carbon (MBC) and nitrogen (MBN) contents, as well as a higher abundance of phylum Glomeromycota fungi and bacterial diversity. The fresh weight of D. huoshanense in the substrate was significantly higher than that in the underforest soil. Structural equation modeling (SEM) results indicated the regulatory relationships between nutrients-microbes in the substrate/soil and the fresh weight of D. huoshanense in the two cultivation modes. In detail, the eutrophic conditions in the facility cultivation shaped a higher bacterial diversity, which promoted the aboveground biomass of the plants. In contrast, under the oligotrophic conditions of the underforest, an increase in pathogen abundance reduced the aboveground biomass, while potentially prompting an increase in the resistance of secondary metabolites (such as flavonoids) in D. huoshanense. This study clarifies the associations between plant biomass and microbial communities in the facility and underforest cultivation modes of D. huoshanense, providing a scientific basis for the development of functional microbial inoculants to promote plant growth and quality regulation in the artificial cultivation process of D. huoshanense, as well as the conservation of rare and endangered plant resources.