Effects Of Water And Salt Stress And Fertilization On The Quality Of Glycyrrhiza Uralensis Fisch. And G.macrophylla Pall.

Dao-di herbs refer to Chinese medicinal materials that grow in a specific area and are of better quality than the same medicinal materials grown in other areas.The formation of Dao-di herbs is inseparable from its origin.The main medicinal components of Dao-di herbs are secondary metabolites produced under specific environmental conditions.Special habitat conditions determine that the geographical location and ecological environment of authentic Chinese medicine production are mostly located in areas with fragile ecological environments such as mountains,hills,arid and semi-arid areas.The traditional view of plant nutrition believes that stress has an inhibitory effect on plant growth,and crop yield and quality can be improved by eliminating stress.However,Chinese herbal medicines are different from traditional crops.Artificial planting of Chinese herbal medicines blindly pursues yield and eliminates stress factors.Instead,the contents of medicinal components in Chinese herbal medicines is reduced and cannot be used medicinally,which seriously hinders the development of Chinese medicine industry in China.Therefore,it is particularly important to find out the stress factors that promote the accumulation of medicinal components of Chinese medicinal materials for the development of the Chinese medicine industry.This paper selects the research objects of Glycyrrhiza uralensis Fisch.and G.macrophylla Pall.,analyzes the changes in the yield and medicinal components of Glycyrrhiza uralensis Fisch.and G.macrophylla Pall.in different environments,and explores the external environment suitable for the growth of Glycyrrhiza uralensis Fisch.and G.macrophylla Pall.by setting different water stress,salt stress,and fertility stress gradients.It provides theoretical basis and technical support for the industrialized production and intensive cultivation of Glycyrrhiza uralensis Fisch.and G.macrophylla Pall.,and obtaining high-yield and high-quality Chinese medicinal materials.The result shows that:（1）Moderate water stress can promote the dry weight growth of Glycyrrhiza uralensis Fisch.root and the extremely significant accumulation of effective components.The dry weight,root length,glycyrrhizic acid and glycyrrhizin contents of Glycyrrhiza uralensis Fisch.root increased first and then decreased with the increase of water stress.The growth threshold of Glycyrrhiza uralensis Fisch.root dry weight,root length,and absolute contents of glycyrrhizin was 45%of field water capacity,and the relative contents of glycyrrhizic acid,the relative and absolute contents of liquiritin contents growth threshold is 60%of the field water capacity.Water stress inhibited the germination of Glycyrrhiza uralensis Fisch.seeds,and the degree of inhibition increased with the increase of stress;the water stress tolerance threshold of seeds was 15%PEG-6000.The dry weight,gentiopicroside and loganic acid contents of the roots of G.macrophylla Pall.under water stress treatment decreased with the increase of water stress.（2）Suitable species and degree of salinity stress can significantly increase the germination rate of Glycyrrhiza uralensis Fisch.seeds,dry weight of Glycyrrhiza uralensis Fisch.roots and the accumulation of effective components.The germination rate of Glycyrrhiza uralensis Fisch.seeds were the highest in Na Cl treatment（0.29%soil salinity）at50 mmol·L^-1 Na⁺concentration.The order of the inhibitory effect of five kinds of salts on Glycyrrhiza uralensis Fisch.seed germination under the same Na⁺concentration was:Na₂CO₃>Na HCO₃>mixed salt>Na₂SO₄>Na Cl.The dry weight of Glycyrrhiza uralensis Fisch.roots,the relative and absolute contents of glycyrrhizic acid and liquiritin contents increased first and then decreased according to the degree of salt stress,the growth thresholds were all treated with 0.4%salt contents.（3）The yield,liquiritin and glycyrrhizic acid contents of all fertilization treatments except K3 were higher than those of the control.The yield of Glycyrrhiza uralensis Fisch.was the highest under the K3 treatment,the contents of liquiritin was the highest under the N3P1K3treatment,and the contents of glycyrrhizic acid was the highest under the N2K2 treatment,compared with the control,significantly increased by 27.03%,34.02%and 28.67%respectively.Under N2P2 treatment,the yield of G.macrophylla Pall.was the highest,and the contents of gentiopicroside and loganic acid were the highest in N3P3K1 treatment,which were significantly increased by 24.24%,37.37%,and 27.61%,respectively,compared with the control.（4）In this experiment,the influences of nitrogen,phosphorus and potassium on the yield of Glycyrrhiza uralensis Fisch.were as follows:P>K>N;the influences on the contents of Glycyrrhiza uralensis Fisch.were as follows:N>P>K;the influences on the contents of glycyrrhizic acid were respectively The order is:P>N>K;the three elements of N,P and K have the following influences on the yield and the contents of gentiopicroside and loganic acid:P>N>K.（5）The frequency analysis method for optimizing each function indicated that the required fertilization pattern for a yield of Glycyrrhiza uralensis Fisch.>5300 kg·hm^-2,the contents of liquiritin of>1.25%and the contents of glycyrrhizic acid of>3.5%was112.36～148.91 kg·hm^-2of N,26.03～55.50 kg·hm^-2 of P（P₂O₅）and 126.64～160.24 kg·hm^-2 of K（K₂O）.To ensure the greatest yield and highest contents of liquiritin and glycyrrhizic acid,the optimal ratio of N,P₂O₅ and K₂O was 1:0.18～0.49:0.85～1.43;the required fertilization pattern for a yield of G.macrophylla Pall.>2100 kg·hm^-2,the contents of gentiopicroside of>7.5%and the contents of loganic acid of>2%was 147.2～185.1 kg·hm^-2of N,92.6～98.9kg·hm^-2 of P（P₂O₅）and 95.8～134.2 kg·hm^-2 of K（K₂O）.To ensure the greatest yield and highest contents of gentiopicroside and loganic acid,the optimal ratio of N,P₂O₅ and K₂O was1:1.49～2.00:1.10～1.93.In conclusion,the optimum environment for Glycyrrhiza uralensis Fisch.seeds germination was 0%PEG-6000,Na Cl treatment at 50 mmol·L^-1 Na⁺concentration（0.29%soil salinity）.Under water stress,the contents of liquiritin and glycyrrhizic acid were the highest under the treatment of 60%field water capacity,and the yield of Glycyrrhiza uralensis Fisch.was the highest under the treatment of 45%field water capacity.Under salt stress,the dry weight of Glycyrrhiza uralensis Fisch.root,liquiritin and glycyrrhizic acid were treated with 0.4%salt contents.Maximum.The optimal fertilization range of Glycyrrhiza uralensis Fisch.was 112.36～148.91 kg·hm^-2of N,26.03～55.50 kg·hm^-2 of P（P₂O₅）and 126.64～160.24kg·hm^-2 of K（K₂O）.The yield and the contents of gentiopicroside and loganic acid were the largest in Qinjie when they were not under water stress.The optimal fertilization range of G.macrophylla Pall.was 147.2～185.1 kg·hm^-2of N,92.6～98.9 kg·hm^-2 of P（P₂O₅）and95.8～134.2 kg·hm^-2 of K（K₂O）.To ensure the greatest yield and highest contents of gentiopicroside and loganic acid,the optimal ratio of N,P₂O₅ and K₂O was1:1.49～2.00:1.10～1.93.