远志是《神农本草经》中位列上品的中药材。目前远志道地产区山西、陕西二省仍沿用较为传统和粗放的施肥模式，缺乏科学指导。微生物肥料在提升作物产量和品质、改善土壤质量等方面已有广泛应用，面对持续增长的市场需求，开发适用于远志的微生物肥料已成为推进远志规范化种植与产业升级的关键。然而，当前化肥、生长调节剂及微生物肥料的应用对远志品质和土壤的影响尚不明确，亟需建立科学合理的施肥方案。

本研究基于远志农艺性状、活性成分含量、土壤养分、根际微生物群落结构与组成等指标，探究了微藻肥料和芽孢杆菌微生物菌剂的化肥替代潜力，开发了卷枝毛霉（菌株zh、DF20）与微藻复配的新型微生物肥料，同时评估了生长调节剂24-表芸苔素内酯在远志栽培中应用的安全性及其与微生物肥料的协同效应。主要结果如下：

（1）化肥减量配施微生物肥料促进远志增产提质

微藻和芽孢杆菌微生物菌剂均可在减少20%和40%化肥施用的条件下，保证远志的品质和产量与100%化肥施用处理持平，其中微藻的促生提质效果最佳，替代40%化肥使远志地下部生物量增加了29.30%，活性成分3,6’-二芥子酰基蔗糖的含量显著增加了19.72%（P<0.05）。根际微生物群落的分析表明，微藻的添加显著影响了远志根际土壤细菌群落，使绿弯菌门Chloroflexi细菌的相对丰度增加，变形菌门Proteobacteria细菌相对丰度显著降低（P<0.05）。各微生物肥料处理均可富集具有促进植物生长、提高植物抗性和修复土壤功能的细菌和真菌，同时相对于100%化肥施用处理降低了土壤中有害菌属（如枝鼻菌属Cladorrhinum）的相对丰度，实现了根际微生物群落的优化。相关性分析表明，微藻部分替代化肥可能通过招募绿弯菌门Chloroflexi细菌提高土壤有机质含量，并促进远志地下部生长和3,6’-二芥子酰基蔗糖积累，而聚谷氨酸微生物菌剂部分替代化肥可能通过招募链霉菌属Streptomyces细菌显著提高土壤中的磷的有效性，从而促进远志生长和品质提升。

（2）卷枝毛霉和微藻联合应用促进远志生长

在远志种子萌发阶段，微藻浸种使种子活力指数提高53.62%（P<0.05），并对幼苗胚根和幼芽伸长及鲜重累积具有显著促进作用，分别显著提高了56.39%、90.51%和36.84%（P<0.05）。卷枝毛霉zh和DF20均可定殖于胚根表面，且与微藻复配后相较单菌能够促进远志胚根伸长和鲜重增加。在远志植株生长阶段，卷枝毛霉zh与微藻复配处理组的远志地下部鲜重显著增加（P<0.05），达到对照的2.09倍，较微藻单施和菌株zh单施分别显著增加了43.21%和103.86%（P<0.05）；该处理组还在维持土壤酶活性的同时特异性富集了金黄线菌属Chryseolinea促生细菌，并使致病菌枝孢菌属Cladosporium真菌相对丰度显著降低。

（3）微生物肥料可替代24-表芸苔素内酯并协同增效促进远志生长

微藻单施较24-表芸苔素内酯单用促生效果更佳，使远志根鲜重较24-表芸苔素内酯单用提高了21.57%，同时维持远志活性成分含量稳定并优化根际微生态，能够替代24-表芸苔素内酯用于远志栽培。残留检测证实，花期叶面喷施三次浓度为0.05 mg/L的24-表芸苔素内酯后，收获时远志根及土壤中均未检出24-表芸苔素内酯残留。进一步探究24-表芸苔素内酯与微生物肥料复配可行性的结果表明，24-表芸苔素内酯与微藻复配处理使根鲜重较对照显著提升109.89%（P<0.01），较24-表芸苔素内酯单用显著提升41.78%（P<0.05）；该处理还能够富集沙壤土杆菌属Ramlibacter、类芽孢杆菌属Paenibacillus、溶杆菌属Lysobacter、贪铜菌属Cupriavidus、假单胞菌属Pseudomonas、金孢属Chrysosporium和被孢霉属Mortierella等与促进植物生长密切相关的功能菌群。

综上所述，针对远志传统栽培中存在的问题，本研究证实了微生物肥料（尤其是微藻）能够部分替代化肥，通过改善根际微生态促进远志生长和品质提升；在此基础上，探索了卷枝毛霉与微藻联合应用于远志生产的可行性，建立了远志“育苗期微藻浸种-花期后菌藻联用”的阶段精准施肥方案；最后验证了远志花期喷施24-表芸苔素内酯的安全性，并证实其与微藻复配可发挥协同促生作用。本研究为远志高产优质栽培奠定了理论基础并提供了技术支撑。

As a top-grade medicinal herb recorded in Shennong Bencao Jing, Polygala tenuifolia (Yuanzhi) is renowned for its effects in treating insomnia, memory disorders, and neurosis. However, in its producing regions of Shanxi and Shaanxi provinces, traditional and extensive fertilization practices persist without scientific guidance. Microbial fertilizers, known for improving crop yield, quality, and soil fertility, have been widely applied in agricultural production. To address the continuously growing market demand, developing microbial fertilizers suitable for P. tenuifolia has become a critical breakthrough for advancing standardized cultivation and industrial upgrading. However, the effects of chemical fertilizers, plant growth regulators, and microbial fertilizers on soil properties and P. tenuifolia quality in current cultivation practices remain unclear, necessitating the establishment of scientifically sound fertilization protocols.

This study evaluated the chemical fertilizer substitution potential of microalgae fertilizer and Bacillus microbial inoculant by investigating multiple indicators including agronomic traits, active component content, soil fertility, and rhizosphere microbial community structure. Novel microbial fertilizers were developed using two growth-promoting Mucor circinelloides strains (zh and DF20) and their combinations with microalgae. Additionally, a safety assessment of the growth regulator 24-epibrassinolide application in P. tenuifolia cultivation and its synergistic effects with microbial fertilizers were assessed. The main results are as follows:

(1) Reduced chemical fertilizer combined with microbial fertilizers enhanced yield and quality of Polygala tenuifolia

Both microalgae fertilizer and Bacillus microbial inoculant ensured that the quality and yield of Polygala tenuifolia under 20% and 40% chemical fertilizer reduction remained comparable to those under 100% chemical fertilizer application. Among them, microalgae fertilizer demonstrated the optimal growth-promoting and quality-enhancing effects. Specifically, substituting 40% chemical fertilizer with microalgae fertilizer increased underground biomass by 29.30% and significantly elevated the content of the active component 3,6’-disinapoylsucrose by 19.72% (P<0.05). Analysis of the rhizosphere microbial community revealed that microalgae fertilizer addition significantly altered the bacterial community structure in P. tenuifolia rhizosphere soil, markedly reducing the relative abundance of Proteobacteria (P<0.05) while increasing that of Chloroflexi. Each microbial fertilizer treatment enriched bacterial and fungal taxa with plant growth-promoting, stress resistance-enhancing, and soil-remediating functions. Concurrently, these treatments reduced the relative abundance of harmful genera (e.g., Cladorrhinum) in soils under 100% chemical fertilizer application, thereby optimizing the rhizosphere microbial community. Correlation analysis indicated that partial substitution of chemical fertilizer with microalgae fertilizer may enhance soil organic matter content by recruiting specific Chloroflexi species, subsequently promoting underground biomass accumulation and 3,6’-disinapoylsucrose synthesis. Meanwhile, partial substitution with polyglutamic microbial inoculant likely improves soil phosphorus availability through enrichment of Streptomyces, ultimately driving P. tenuifolia growth and quality enhancement.

(2) Co-application of Mucor circinelloides and microalgae promoted Polygala tenuifolia growth

During the seed germination stage of Polygala tenuifolia, seed soaking with microalgae increased the seed vital index by 53.62% (P<0.05) and significantly enhanced radicle length, young shoot length, and fresh weight of seedlings by 56.39%, 90.51%, and 36.84%, respectively (P<0.05). Both Mucor circinelloides strains (zh and DF20) colonized the radicle surface, and their co-application with microalgae further promoted radicle elongation and fresh weight gain compared to single-strain treatments. At the plant growth stage, the co-application of M. circinelloides zh with microalgae significantly increased underground fresh weight (P<0.05), reaching 2.09 times that of the control. This represented a 43.21% and 103.86% increase compared to microalgae alone and M. circinelloides zh alone, respectively (P<0.05). This treatment also specifically enriched the plant-growth-promoting bacterium Chryseolinea while maintaining soil enzyme activity and markedly reduced the relative abundance of the pathogenic fungus Cladosporium.

(3) Microbial fertilizers can substitute 24-epibrassinolide while synergistically enhancing Polygala tenuifolia growth

Microalgae alone exhibited superior growth-promoting effects compared to 24-epibrassinolide alone, increasing Polygala tenuifolia root fresh weight by 21.57% relative to 24-epibrassinolide treatment while maintaining stable active component content and optimizing rhizosphere microecology, demonstrating its potential to replace 24-epibrassinolide in P. tenuifolia cultivation. Residue analysis confirmed that no 24-epibrassinolide residue were found in harvested P. tenuifolia roots or soil after three foliar sprays of 0.05 mg/L 24-epibrassinolide during the flowering stage, prompting further exploration of its co-application feasibility with microbial fertilizers. Results revealed that the co-application of 24-epibrassinolide with microalgae significantly enhanced root fresh weight by 109.89% compared to the control (P<0.01) and by 41.78% relative to 24-epibrassinolide alone (P<0.05). This combined treatment also enriched functional microbial taxa closely associated with plant growth promotion, including Ramlibacter, Paenibacillus, Lysobacter, Pseudomonas, Cupriavidus, Mortierella, and Chrysosporium.

In summary, addressing the challenges in traditional Polygala tenuifolia cultivation, this study first validated that microbial fertilizers (particularly microalgae fertilizer) can partially substitute chemical fertilizer by improving the rhizosphere microecology to enhance P. tenuifolia growth and quality. Subsequently, this research explored the feasibility of combined application of Mucor circinelloides and microalgae in P. tenuifolia production, establishing a stage-specific fertilization protocols: “microalgae seed soaking during seedling stage followed by combined microalgae-M. circinelloides zh application post-flowering”. Finally, this research confirmed the safety of foliar 24-epibrassinolide application during the flowering stage and demonstrated its synergistic growth-promoting effects when combined with microalgae. This research provides a theoretical foundation and technical framework for achieving high-yield, high-quality P. tenuifolia cultivation.