氮素形态对薄壳山核桃生长生理特性的影响OA

[Objective]Ammonium nitrogen(NH4+-N)and nitrate nitrogen(NO3-N)are the two primary inorganic nitrogen forms absorbed by plants and play crucial roles in plant growth and development.Screening the optimal nitrogen form ratio for pecan(Carya illinoinensis)growth can provide a theoretical basis for improving its nitrogen use efficiency.[Method]The experiment used 14-year-old pecan trees of the C.illinoinensis'Pawnee'cultivar as plant materials.Six treatments were established with NO3--N to NH4+-N mass ratios of 100∶0(T1),72∶25(T2),50∶50(T3),25∶75(T4),0∶100(T5),and a no-nitrogen fertilizer control(CK).Variance analysis,correlation analysis,and principal component analysis were conducted on the growth and physiological characteristics of pecan under different nitrogen form treatments to preliminarily determine the optimal nitrogen form ratio.[Result]The results showed that the T2 treatment significantly increased the contents of chlorophyll a,chlorophyll b,and total chlorophyll in pecan leaves,as well as the free amino acid and crude fat contents in the kernels.Under T3 treatment,tree height and diameter at breast height growth were significantly enhanced,ammonium nitrogen content in roots and kernels was significantly reduced,while ammonium nitrogen content in leaves was significantly increased.T4 treatment significantly increased the soluble sugar content in roots and leaves,as well as the soluble protein and free amino acid contents in both roots and kernels.The T5 treatment significantly increased the soluble sugar content in the kernels.Correlation analysis indicated positive relationships between the majority of the measured parameters in pecan.Principal component analysis and comprehensive evaluation revealed that the T4 treatment was most conducive to promoting the growth and development of pecan.[Conclusion]Through the analysis of growth and physiological characteristics,correlation analysis,and principal component analysis of pecan under different nitrogen form ratio treatments,it was found that the T4 treatment had the best promoting effect on the growth and development of pecan.This provides a theoretical foundation for improving nitrogen use efficiency in pecan.