Two color coreopsis,scientific name is Nutt.,alternate name is Kunlun chrysanthemum,Tianshan chrysanthemum,etc.It is an annual herb of the genus Coreopsis.Wild Coreopsis tinctoria in China mainly grow in the Kunlun Mountains,which is more than 3000 meters above sea level,for a long time,the Coreopsis tinctoria was used as a flower tea by local residents,and the Uygur medicine in Xinjiang also used it as a Uyghur medicinal material,which is a medicinal plant with broad prospects and research value.In recent years,the area of artificial introduction and cultivation of Coreopsis tinctoria has been continuously expanded,which solves the problem of low yield of wild Coreopsis tinctoria and meets the market demand.However,with the increase of consumption level,people pay more attention to the quality of Coreopsis tinctoria.As an important nutrient element of plants,nitrogen has a great impact on the quality of Coreopsis tinctoria.In this paper,six groups of nitrate nitrogen treatments with different concentrations were adopted to study the effects of nitrate nitrogen treatment on the growth,development and flavonoids metabolism of Coreopsis tinctoria in outdoor pots.By comparing the membership function values of Coreopsis tinctoria growth,yield and quality,the best fertilization scheme was determined to ensure the quality of Coreopsis tinctoria without affecting its yield.The results are as follows:(1)By measuring the growth and yield indicators of Coreopsis tinctoria at different growth stages,application of nitrate nitrogen is beneficial to increase the biomass accumulation of Coreopsis tinctoria,nitrate nitrogen can promote the plant height,fresh weight,and Stem sdiameter of Coreopsis tinctoria at different growth stages,and it has a certain inhibitory effect on the underground part of Coreopsis tinctoria.Among them,the effects on seedling stage and flower bud differentiation stage are more significant.The application of nitrate nitrogen was beneficial to increase the total flower number and average yield of single Coreopsis tinctoria,and the dry weight of hundred flowers decreased slightly,but there was no significant difference.(2)Through the determination of physiological indexes of leaves and roots of Coreopsis tinctoria in different growth stages,application of nitrate nitrogen can increase the protein content of the leaves in the Coreopsis finctoria seedlings and the flower bud differentiation stage,and reduce the protein content of the leaves at the full-bloom stage.The soluble sugar content was promoted at the seedling stage and inhibited at other stages.The application of nitrate nitrogen had a certain inhibitory effect on the total flavonoids,chlorogenic acid in leaves and flavonoids content in roots of the Coreopsis tinctoria in different periods.(3)Based on the determination of PAL activity in leaves of different growth stages of Coreopsis tinctoria and its correlation analysis with total flavonoids and chlorogenic acid,nitrate application had inhibitory effects on PAL activity in leaves of Coreopsis tinctoria at different growth stages,in which flower bud differentiation and flowering stages were more significant.Except that there was no significant correlation between total flavonoid content and PAL activity at seedling stage,there was a significant positive correlation between PAL activity and total flavonoids and chlorogenic acid content in leaves at other stages,and the correlations ranged from large to small to full-bloom stage>flower bud differentiation stage>Seedling stage.(4)Based on the quality determination of flavonoid metabolites in Coreopsis tinctoria,application of nitrate nitrogen can increase the protein content in Coreopsis tinctoria and inhibit the soluble sugar,total flavonoids and chlorogenic acid.Liquid chromatography was used to determine the flavonoid intermediates phenylalanine,cinnamic acid,and p-coumaric acid,and it was concluded that the application of nitrate nitrogen can increase the Coreopsis tinctoria content of phenylalanine and p-coumaric acid,and have little effect on cinnamic acid.(5)Based on the determination of flavonoid metabolism-related enzymes PAL,C4H,4CL in Coreopsis tinctoria,the application of nitrate nitrogen had a certain inhibitory effect on PAL,C4H,and 4CL,there was no significant difference in PAL and C4H.It is speculated that the difference in flavonoid metabolites in Coreopsis tinctoria may be caused to some extent by the transport of metabolites in the vegetative organs leaves to flowers of reproductive organs.(6)By comparing the membership functions of the growth and quality indicators of Coreopsis tinctoria at different growth stages,N4 treatment was the most suitable nitrogen application treatment for plants at seedling stage,which was nitrate nitrogen to nutrient soil of 0.25g/kg;N1 treatment was the most suitable for flower differentiation stage,which was nitrate nitrogen to nutrient soil of 0.05g/kg;comprehensive analysis on plants at blooming stage showed that N3 treatment had a small impact on yield with quality guaranteed.Comprehensive analysis of the results of this test,the N3 treatment was the most suitable nitrogen application,that is,supplemental application of 0.075g/kg of nitrate nitrogen respectively at the vegetative and flower bud differentiation periods,in the nitrate nitrogen based of 0.15g/kg of nutrient soil. |