Resources Of Wild Medicinal Plants In The Loess Hilly Region Of Northern Shaanxi

This study takes wild medicinal plants in the loess hilly area of northern Shaanxi as the research object.Based on the traditional investigation of medicinal plant resources,the survey of the wild medicinal plant resources in two representative districts and counties in the loess hilly area of northern Shaanxi is carried out.Combining relevant literature data,this paper studies the flora characteristics of local medicinal plants,the species diversity characteristics of medicinal plants,and the medicinal characteristics of medicinal plants,and combines Arc GIS to analyze the impact of environmental factors on the characteristics of wild medicinal plant resources.On this basis,this study provides basic theoretical basis for the sustainable utilization and protection of wild medicinal plant resources in the loess hilly area of northern Shaanxi.The main conclusions are as follows:There are 351 species of wild medicinal plants in 82 families and 242 genera in the study area,including 345 species of 236 genera and 78 families of angiosperms,50 species of 37 genera and 12 families of monocots,295 species of 199 genera and 66 families of dicots;2 families,4 genera and 4 species of gymnosperms;1 family,1 genus and 1 species of pteridophytes;1 family,1 genus and 1 species of fungi.Wild medicinal plants are rich in resources.Among them,there are a large number of wild medicinal plants in families containing 1 genus,families containing 2-9 genera,and genus containing 1 species,especially the high proportion and large number of oligo-species genera and single-species genera,which reflect the ancient origin of the flora.The species richness index,Simpson index and Shannon-Wiener index in the study area all showed the largest in the herbaceous layer.The Pielou evenness index is inconsistent with species richness index,Simpson index and Shannon-Wiener index,and the Pielou evenness index changes in the herb layer,shrub layer,and arbor layer for each vegetation type have no obvious laws.It shows that in each vegetation layer,the four vegetation types have high heterogeneity.The wild medicinal plants in the loess hilly area of northern Shaanxi are mostly used as medicine with whole plants,roots and rhizomes.The abundance of herbaceous wild medicinal plants in this area determines that its medicinal parts are more mainly whole plants,represented by Sonchus arvensis,Selaginella sinensis,and Viola philippica.Some wild medicinal plants are used as medicine with roots and rhizomes,represented by Saposhnikovia divaricata,Lotus corniculatus and Anemone vitifolia.The medicinal tastes of wild medicinal plants in the study area are most sweet and bitter,represented by Glycyrrhiza uralensis,Lilium pumilum,Sophora flavescens,Robinia pseudoacacia.The medicinal properties are mostly cold and warm,represented by Asparagus cochinchinensis,Plantago asiatica,Hippophae rhamnoides,and Artemisia argyi.The effect of medicinal plants is the most in heat-clearing category,represented by Setaria viridis,Forsythia suspensa,and Amorpha ornicula.There is an obvious parabolic model relationship between the species richness of wild medicinal plants in this area and the altitude gradient.The species richness of wild medicinal plants in the study area reaches the maximum between 900-1200m above sea level.The maximum values of the diversity index of wild medicinal plants all appear in the southwest.The dominant climatic factors affecting the distribution of thyme（Thymus mongolicus Ronn）include the highest temperature in September（Tmax₉）,the lowest temperature in September（Tmin₉）,annual average temperature（Bio₁）,seasonal temperature（Bio₄）and average temperature of September（Tavg₉）,etc.Based on this,we can further predict the suitable distribution area of thyme in the current and future periods,and establish thyme imitating wild cultivation areas.This will help increase the yield and quality of thyme,alleviate the contradiction between insufficient wild resources and large market demand,and boost the development of the medicinal plant industry in the Loess Plateau.In summary,the loess hilly region of northern Shaanxi is rich in wild medicinal plants resources.There are 351 species of wild medicinal plants in 82 families,242 genera,and 1genera in the study area.There are a large number of wild medicinal plants.The species richness index,Simpson index and Shannon-Wiener index all showed the largest in the herb layer.The Pielou evenness index and species richness index,Simpson index and Shannon-Wiener index are inconsistent,and the Pielou evenness index changes in the herb layer,shrub layer,and arbor layer for each vegetation type have no obvious laws.The wild medicinal plants in the study area are mostly used as medicine with whole plants,roots and rhizomes.The medicinal tastes of wild medicinal plants are mostly sweet and bitter.The medicinal properties of wild medicinal plants are mostly cold and warm.The medicinal effects of using plants are the most in the heat-clearing category.There is an obvious parabolic model relationship between the species richness of wild medicinal plants in the study area and the altitude gradient.The richness index of families,genus,and species reaches the maximum between 900-1200m above sea level,and the maximum diversity index appears in the southwest.The dominant climatic factors affecting the distribution of thyme include the highest temperature in September（Tmax₉）,the lowest temperature in September（Tmin₉）,the annual average temperature（Bio₁）,the seasonal temperature（Bio₄）and the average temperature of September（Tavg₉）.