| Objective:Gentiana rigescens Franch.ex Hemsl.is a traditional Chinese medicine with functions such as protecting the liver,anti-inflammatory,analgesic,antibacterial,anti-tumor,promoting digestion,and preventing diabetes.It is widely used in the fields of traditional Chinese medicine,health care products,cosmetics,and animal medicine.G.rigescens is also a characteristic medicinal plant for rural revitalization of ethnic minority areas in Yunnan border region.Reasonable application of nitrogen,phosphorus,and potassium not only can improve the yield and quality of medicinal herbs but also can enhance the utilization efficiency of fertilizers.Research on the rational fertilization technology of medicinal herbs not only conforms to the new requirements of national resource and environmental protection and the strategic development of the traditional Chinese medicine industry but also provides strong support for realizing the national goal of green,low-carbon,and cyclic industry development driven by carbon peaking and carbon neutrality.However,at present,there is little research on fertilization of G.rigescens,irrational fertilization is widespread in production,which greatly restricts the development of G.rigescens industry.The purpose of this study is to explore the effect of different nitrogen,phosphorus,and potassium ratios on the growth,physiology,medicinal quality,and rhizosphere soil of G.rigescens so as to clarify its fertilization requirements,optimize fertilization formula,and provide data support for the rational fertilization of G.rigescens.Methods:（1）The study focuses on one-year-old G.rigescens seedlings,and utilizes the"3414"fertilization program with a combination of potted and field tests to investigate differences in growth characteristics,nutrient absorption and accumulation,photosynthetic properties,antioxidant properties,accumulation of effective components,and rhizosphere soil under different nitrogen,phosphorus,and potassium fertilizer combination ratios.（2）Using G.rigescens tissue-cultured seedlings as test materials,an L9（33）orthogonal design is employed to investigate the effects of different nitrogen,phosphorus,and potassium dosages and ratios in the culture medium on the growth indicators of G.rigescens,as well as the content of major effective components including gentiopicroside,swertiamarin,and sweroside.Results:（1）Nitrogen-phosphorus-potassium fertilization significantly affects the agronomic characteristics of G.rigescens.Appropriate nitrogen-phosphorus-potassium ratios promote plant growth and increase medicinal yield.In potted and field experiments,the N1P2K2 formula had the most significant increase in medicinal yield,with improvements of 3.09 fold and 3.49 fold respectively compared to the unfertilized control（CK）.In tissue culture experiments,the N1P2K3 formula produced the largest weight per plant,reaching 1.63 times that of the original formula（1/2 MS medium）.（2）Nitrogen-phosphorus-potassium fertilization can significantly affect the content of effective components in G.rigescens and improve medicinal quality.Under potted experimental conditions,the N2P2K1 treatment had the highest gentiopicroside content,which was 1.26times higher than the CK treatment,but the individual plant yield was lower.The N1P2K2treatment had the highest gentiopicroside yield per plant,reaching 3.69 times that of CK.Under field experimental conditions,the gentiopicroside content was highest in the unfertilized control（CK）,but the yield per unit area was lower.The highest gentiopicroside yield per unit area was observed in the N1P2K2 treatment,which was 3.37 times that of CK.The highest swertiamarin content and yield per unit area were observed in the N1P2K2treatment,which were 1.02 times and 3.37 times that of CK,respectively.The highest sweroside content and yield per unit area were observed in the N2P0K2 treatment,which were 1.09 times and 3.56 times that of CK,respectively.In tissue culture experiments,the N2P1K3 treatment had the highest gentiopicroside content,which was 2.4 times that of 1/2MS medium formula.The N1P2K3 treatment had the highest swertiamarin content,which was 1.57 times that of 1/2 MS medium formula.The highest sweroside content was observed in the N1P2K3 treatment,which was 2.86 times that of 1/2 MS medium formula.The yields of gentiopicroside,swertiamarin,and sweroside were highest in the N1P2K3treatment,reaching 2.57 times,2.5 times,and 4.5 times that of 1/2 MS medium formula,respectively.（3）Nitrogen-phosphorus-potassium fertilization can significantly affect the nutrient accumulation and utilization of G.rigescens plants.The nitrogen accumulation and nitrogen fertilizer utilization rate were highest in the N3P2K2 treatment and the N2P0K2treatment,respectively.The phosphorus accumulation and phosphorus fertilizer utilization rate were highest in the N2P2K2 treatment and the N2P1K2 treatment,respectively.The potassium accumulation and potassium fertilizer utilization rate were highest in the N2P2K2treatment.（4）Nitrogen-phosphorus-potassium fertilization can significantly affect the photosynthetic characteristics and antioxidant properties of G.rigescens plants.In the N1P2K2 treatment,the Pn value was highest,reaching 1.87 times that of CK.The Gs and Civalues were highest in the N2P2K1 treatment,reaching 3.27 times and 1.17 times that of CK,respectively.The Tr value was highest in the N3P2K2 treatment,reaching 1.81 times that of CK.The activities of SOD,POD,and CAT were highest in the N2P3K2,N2P2K1,and N2P2K2 treatments,respectively,reaching 1.78 times,3.06 times,and 2.01 times that of CK.The MDA content was higher in all fertilization treatments compared to CK.（5）Nitrogen-phosphorus-potassium fertilization can significantly affect the nutrient content of G.rigescens rhizosphere soil and decrease soil p H.The organic matter content in the soil was highest in the N2P3K2 treatment,reaching 1.19 times that of CK.The total nitrogen and available nitrogen contents were highest in the N2P1K2 treatment,reaching 1.15 times and1.16 times that of CK,respectively.The total phosphorus content was highest in the N1P2K2,N2P1K2,N2P3K2,and N2P2K0 treatments,reaching 1.30 times that of CK.The total potassium content was highest in the N1P2K1 treatment,reaching 1.01 times that of CK.The available phosphorus content was highest in the N1P2K2 treatment,reaching 2.41 times that of CK.The available potassium content was highest in the N0P2K2 treatment,reaching1.69 times that of CK.The soil p H was significantly lower in all fertilization treatments compared to CK,with the N2P1K2 treatment having the lowest p H of 4.88.Conclusion:Reasonable ratios of nitrogen,phosphorus,and potassium can enhance the photosynthetic capacity and antioxidant properties of G.rigescens,improve the absorption and utilization efficiency of nutrients,facilitate the growth and accumulation of effective components,and ameliorate the soil environment around its roots.This research provides some theoretical support for the scientific cultivation of G.rigescens. |
