为探究种植密度和施肥量对林下草珊瑚〔Sarcandra glabra (Thunb.) Nakai〕产量和品质的影响，采用裂区试验设计，设置高、中、低3个种植密度水平(分别为25.00、11.11、6.25 m^-2)，不施肥及低和高3个施肥量水平(分别为每株0、5和10 g)，通过测定草珊瑚的生长指标和主要药用成分含量及根际土壤养分含量，结合主成分分析和结构方程模型筛选最优种植密度和施肥量组合并明晰影响草珊瑚产量和品质的关键因子。结果表明：在不施肥和低施肥量下，单株干质量随种植密度降低而增加；在中种植密度-高施肥量下，单株干质量最高。低种植密度下的折合产量显著(P＜0.05)低于中和高种植密度；在高种植密度-高施肥量下，折合产量、根长、根表面积和根体积均最高；叶长、叶宽、叶周长和叶面积整体在中和低种植密度下较高。整体上看，总黄酮、迷迭香酸和异嗪皮啶单株产量在中种植密度-高施肥量下较高。土壤有机碳、全磷、全氮和速效磷含量均在低种植密度-高施肥量下最高，而土壤碱解氮含量在低种植密度-低施肥量下最高。主成分分析得出前2个主成分的累计贡献率达84.38%，综合评价得出高种植密度-高施肥量和高种植密度-低施肥量为较优组合。结构方程模型显示：种植密度是直接影响草珊瑚产量和品质的重要因子。从经济效益和生态效益考虑，生产上种植草珊瑚宜采用种植密度25.00 m-2配施每株5 g复合肥的方式。

To investigate the effects of planting density and fertilization amount on yield and quality of understory Sarcandra glabra (Thunb.) Nakai, a split-plot experimental design was employed, three planting density levels namely high, medium, and low (corresponding to 25.00, 11.11, and 6.25 m^-2, respectively) were set up, three fertilization amount levels namely non-fertilization, low, and high (corresponding to 0, 5, and 10 g per plant, respectively) were established, and the optimal combination of planting density and fertilization amount was screened out and the key factors affecting yield and quality of S. glabra were clarified by measuring the growth indexes, main medicinal component contents, and rhizosphere soil nutrient contents of S. glabra, combined with principal component analysis and structural equation model. The results show that under non-fertilization and low fertilization amount, the dry mass per plant increases with the decrease of planting density; the dry mass per plant is the highest under medium planting density-high fertilization amount. The converted yield under low planting density is significantly (P＜0.05) lower than that under medium and high planting densities; under high planting density-high fertilization amount, the converted yield, root length, root surface area, and root volume are all the highest; the leaf length, leaf width, leaf circumference, and leaf area are relatively high under medium and low planting densities in general. Overall, the yields of total flavonoids, rosmarinic acid, and isofraxidin per plant are relatively high under medium planting density-high fertilization amount. The contents of soil organic carbon, total phosphorus, total nitrogen, and available phosphorus are all the highest under low planting density-high fertilization amount, while the soil alkali-hydrolyzable nitrogen content is the highest under low planting density-low fertilization amount. The principal component analysis reveals that the cumulative contribution rate of the first two principal components reaches 84.38%, and the comprehensive evaluation indicates that high planting density-high fertilization amount and high planting density-low fertilization amount are the optimal combinations. The structural equation model shows that planting density is an important factor directly affecting the yield and quality of S. glabra. Considering both economic and ecological benefits, a planting density of 25.00 m^-2 with 5 g compound fertilizer per plant are recommended for the cultivation of S. glabra in production.