[Medicine-geography relationship of Gentiana rigescens based on habitat and quality suitability]

The spatial matching of habitat suitability and quality suitability of medicinal plants is a challenge in analyzing the medicine-geography relationship. Taking the traditional medicinal plant Gentiana rigescens as the object, and selecting Yunnan Province, the main producing area of the herb, as the research region, we integrated methods including species distribution models, machine learning, and geostatistical analysis to explore the medicine-geography relationship of G. rigescens and identify the key ecological driving forces behind the formation of high-quality medicinal material-producing areas by systematic resource surveys and sampling. The results showed that the suitable habitat area for G. rigescens in Yunnan Province was about 22.00×10⁴ km², accounting for 55.8% of the total land area. Highly suitable areas were mainly concentrated in central, eastern, and northwestern Yunnan. Quantitative analysis of bioactive compounds and medicinal quality zoning revealed that the total content of bioactive compounds in herbs from high-quality production areas (64.93±23.94 mg·g^-1) was significantly higher than that in herbs from other regions (41.34±11.71 mg·g^-1). The high-quality production areas were mainly located in western and northwestern Yunnan, within habitats classified as low to moderate suitability. Spatial autocorrelation analysis further confirmed a significant spatial mismatch between the "habitat suitability" and "medicinal quality" of G. rigescens. Eight environmental factors closely associated with the formation of high-quality medicinal material-producing areas were identified by screening key environmental variables combined with the GeoDetector model, including mean diurnal temperature range, isothermality, temperature seasonality, precipitation of the driest quarter, precipitation of the coldest quarter, and UV-B radiation in April, October and December. Factor detection and interaction analysis further showed that the combined effects of thermal, moisture, and UV-B radiation factors exhibited a significant non-linear enhancement effect. Our results indicated that the formation of high-quality G. rigescens production areas depends on a unique habitat driven by the synergistic effects of multiple environmental factors, rather than on ecologically optimal zones alone.