Prediction of suitable distribution areas for Alismatis Rhizoma based on the MaxEnt model and study on...

Climate change profoundly impacts the suitable habitats of medicinal plants, and environmental factors in their production areas further determine their quality. Alismatis Rhizoma (AR) is a commonly used Chinese herbal medicine in clinical practice, derived from the dried rhizomes of Alisma plantago-aquatica Linn. and Alisma orientale (Sam.) Juzep., with an annual production exceeding 10,000 tons. However, the current uncontrolled expansion of cultivation has led to variations in the quality of medicinal herbs.

Clearly define the suitable distribution areas for the two source species of AR, reveal the relationship between the cultivation environment and the quality of the mainstream cultivar A. plantago-aquatica, and provide scientific support for optimizing planting layouts, improving medicinal quality, and responding to climate change.

We employed for the first time a MaxEnt model optimized using the Kuenm package to systematically predict the suitable habitat distribution and its shifts for the two source species of AR under current and future climate scenarios. utilizing high-performance liquid chromatography, we conducted correlation analyses between 43 environmental factors and 15 medicinal quality indicators for the primary cultivated variety (A. plantago-aquatica), establishing stepwise regression models.

Precipitation, altitude, and temperature are the key environmental factors influencing both the potential distribution and quality of AR. Currently, highly suitable habitats are mainly located in southern and eastern China (A. plantago-aquatica: Sichuan, Guangxi, and Guangdong provinces; A. orientale: Fujian, Jiangxi, Guangdong, and Hunan provinces). Under future climate scenarios, the range of suitable habitats will expand towards higher latitudes, with the migration range for A. plantago-aquatica being 26.12°N - 30.07°N and that for A. orientale being 29.95°N - 31.72°N. This study also newly identifies significant correlations between soil properties-total potassium, available phosphorus, available manganese, available molybdenum, and urease activity-and the color, size, and active constituents of AR.

The study has clarified the suitable habitats for the two source species of AR and the environment-quality coupling relationships of its mainstream cultivars. The integrated ecological-cultivation-quality control strategy developed provides critical guidance for advancing the ecological agriculture and enhancing the quality of AR.