Assessment Of Suitable Production Areas For Panax Notoginseng In China Based On Saponin Content And MaxEnt Model

Panax notoginseng（Burkill）F.H.Chen is a perennial plant of the genus Panax,family Araliaceae.It is a valuable traditional Chinese herb with great medicinal value.Panax notoginseng is cultivated in Yunnan Province,China,where it has a long history of cultivation.In recent years,climate change,continuous cropping obstacles,and human activities have led to the relocation of the Panax notoginseng habitat and may result in changes in quality.With the current increasing demand for Panax notoginseng,a sustainable supply of Panax notoginseng has become particularly important.However,fewer studies have assessed how Panax notoginseng can respond to the challenges of climate change.This study assessed the suitable production areas for Panax notoginseng under climate change conditions regarding its habitat and saponin content.In this study,the habitat and quality of Panax notoginseng were combined to assess its suitable production areas under climate change conditions.To this end,occurrence records and samples of Panax notoginseng were collected through online and fieldwork,followed by the use of a Maximum Entropy（Max Ent）model optimized by the ENMeval data package.The past,present,and future distribution of suitable habitats for Panax notoginseng in China were analyzed by combining climatic,soil,and topographic data.In addition,High-Performance Liquid Chromatography（HPLC）was used to determine the content of Panax notoginseng saponin R₁and ginsenosides Rb₁,Rg₁,Re,and Rd in samples from different areas.Correlation and redundancy analyses were used to investigate the relationship between environmental factors and saponin content.Finally,this study explored production areas that also met habitat suitability and were conducive to saponin accumulation.The results of this study will provide a useful reference for the delineation of suitable production areas for Panax notoginseng.The main findings were as follows.1.The content of Panax notoginseng in different origins was determined according to HPLC method.Studies have shown that there are significant differences in the saponin content of Panax notoginseng from different producing areas.At present,the total saponin content of Panax notoginseng was currently higher in Datun Street,Zhelao City,Honghe Prefecture,Sanchuan Township,Yongsheng County,Lijiang City,Bushanuo Township,Shuangjiang County,Lincang City,Brown Mountain Brown Township,Menghai County,Xishuangbanna Prefecture,and Muyang Township,Funing County,Wenshan Prefecture.2.This study used the model after optimizing the parameters using the ENMeval data package.Its response curve was significantly smoother,closer to a normal distribution curve,and had lower values of Delta.AICc,AUC.DIFF and OR10.Higher values of AUC and TSS.Therefore the predictions made by this model were accurate.3.The Jackknife was applied to analyze the main environmental factors affecting the distribution of Panax notoginseng.The results showed that temperature and precipitation may have the most significant influence on Panax notoginseng distribution.The Bio4（temperature seasonality）,Bio6（min temperature of the coldest month）,Bio14（precipitation of driest month）,Bio5（max temperature of the warmest month）,and Bio12（annual precipitation）were the key variables affecting Panax notoginseng distribution.Among them,Bio4（temperature seasonality）and Bio6（min temperature of the coldest month）,with a cumulative percent contribution and permutation importance of 75.5%and 67%,were the most important environmental variables.4.Assessment of suitable habitats for Panax notoginseng across the country in the context of climate change using the Max Ent model.The results showed that during the Last Glacial Maximum（LGM）,suitable habitat for Panax notoginseng,centered in the central-eastern Yunnan Province,might have been formed.Under the current climate scenario,the most suitable habitat for Panax notoginseng（105277.78km²）was expected to be mainly in the central and eastern parts of Yunnan Province.Future climatic changes may lead to a reduction in the Panax notoginseng growing area and a gradual contraction towards the higher altitudes of central Yunnan Province.In particular,the most suitable habitat under the SSP585-2090s scenario nearly disappears,leaving only 5208.33 km².5.Analysis of the response of Panax notoginseng quality to environmental factors.Habitat suitability significantly influenced saponin content,with the most suitable habitats having significantly lower total saponin content of Panax notoginseng than other suitable habitats.The coldest monthly minimum temperature and annual precipitation were the most relevant environmental variables for total saponin content.6.The suitable producing areas of Panax notoginseng were determined by considering the habitat suitability and saponin content.Muyang Town,Funing County,Wenshan Prefecture,and Daping Town,Malipo County,Wenshan Prefecture,with their suitable habitats and high saponin content,may be ideal areas for Panax notoginseng production at present.