Effect Of Nitrogen Addition On Growth And Physiology Of Phellodendri Chinense Schneid.seedings Under Three Soil Types

Understanding the effects of soil environment and nitrogen on the growth and physiology of Chinese medicinal materials is crucial to realize high quality and high yield.the The local characteristics of medicinal materials（such as climate,soil）play an important role in the effective components.At present,there are many studies on the effects of different producing areas and nitrogen addition on the effective components of Chinese medicinal materials,but the results are not the same.How does nitrogen addition affect the growth and physiological changes of P chinense Schneid.?Is there any difference in different soil types?There in still a lot of uncertainty about the current research.Therefore,in this study,through pot experiment,the effect of soil type and nitrogen addition on grown and physiological metabolism of P chinense Schneid.seedlings was investigated systematically through morphology,photosynthetic physiology,nutrient accumulation and nitrogen metabolism.It will provide valuable information on site selection and fertilizer application in the process of seedling cultivation of P chinense Schneid.The main results are as follows:（1）Nitrogen addition promoted growth of the P chinense Schneid.seedlings,increased the height and ground diameter,affected biomass accumulation and distribution,and increased the distrubution ratio of above ground parts of seedlings.The total biomass accumulation on the same nitrogen treatment:Alkaline purple soil>Red soil>Acid purple soil.T5 level was beneficial to seedling biomass accumulation on red soil,and T3 level was beneficial on Alkaline purple soil and Acid purple soil.（2）Nitrogen addition increased Pn,Gs,Ci,Tr of seedling leaves and decreased WUE..At the same nitrogen level,the net photosynthetic rate of seedling leaves was red soil>acid purple soil>alkaline purple soil.T2 level was beneficial to the synthesis of chlorophyll in alkaline purple soil and acid purple soil.Pn of seedling leaves on red soil reached the maximum at T2 level,and Acidic purple soil reached the maximum at T3 level.（3）Under red soil treatment,T1,T2,T3 levels of nitrogen promoted the accumulation of C,N and P contents in P chinense Schneid.seedlings,and N and P content was the highest in T3 lever under alkaline purple soil treatment.In Acid purple soil,the accumulation of N,P decreased with the increase of nitrogen while high nitrogen（>100mg/plant）level,indicating that the content of phosphorus in acid purple soil was saturated,and the addition of nitrogen inhibited the absorption of phosphorus by roots.In addition,the distribution ratio of N in seedling roots and P in seedling roots in Acid purple soil was increased by nitrogen addition in red soil and Alkaline purple soil.（4）Nitrogen addition increased the activities of nitrogen metabolism related enzymes in leaves of P chinense Schneid.on three soil types.Under Red soil treatment,the NR,Ni R,GS,GOGAT,Ala AT activity in leaves was significantly increased under T3,T4 nitrogen treatment.Under Alkaline purple soil treatment,NR activity increased significantly with the increase of nitrogen content,which indicated that the assimilation ability of NO₃^-was improved by adding nitrogen.The activities of GS,GOGAT,NAD-GDH and transaminase（Asp AT and Ala AT）were the highest at T2 level on alkaline purple soil and acid purple soil,which indicated that T2 nitrogen level was more beneficial to improve the nitrogen metabolism ability of leaves on Alkaline purple soil and Acid purple soil.In conclusion,the nitrogen treatment effectively affects the height,the biomass and the nutrient accumulation,the photosynthetic rate and the nitrogen metabolism-related enzyme activity of the P chinense Schneid.seedlings on the three soil types.T4,T5 nitrogen was beneficial to seedling height,basal stem growth and biomass accumulation in Red soil,while T2,T3 nitrogen was beneficial to photosynthetic capacity of seedling leaves、the improvement of nitrogen metabolism and the accumulation of nutrient elements.And on the Alkaline purple soil,T3 nitrogen was beneficial to photosynthetic capacity,nitrogen metabolism,the increase of seedling height basal stem,biomass and accumulation of C,N,P.And T2 nitrogen was beneficial to the increase of chlorophyll content,photosynthetic rate,the activity of enzymes related to nitrogen metabolism in the leaves of P chinense Schneid.seedlings in Acid purple soil.These results will provide a reference for understanding the site selection and cultivation and fertilizer application of P chinense Schneid.seedling orchard,and provide theoretical support for further study on the mechanism of alkaloid synthesis of P chinense Schneid.seedlings.