Study On Fertilization Effect And Nutrition Diagnosis Of Fine Street Tree Species Of Cinnamomum Bodinieri In South China

Cinnamomum bodinieri（Cinnamomum bodinieri Levl.）is not only a gardening tree species with strong adaptability and high ornamental value,but also an excellent economic tree species,which is widely used in the fields of medicine,food and industry.At present,there are more and more research on the cultivation and breeding of Cinnamomum bodinieri,but people still have little understanding about its growth and development habits and characteristics of fertilizer requirements.Reasonable fertilization management measures can effectively improve the quality of Cinnamomum bodinieri tree seedlings,shorten its growth cycle,and promote the rapid growth of Cinnamomum bodinieri tree seedlings.In this study,the annual potted seedlings of Cinnamomum bodinieri was taken as the research object,and the experiment of N,P and K fertilization was carried out using the ternary quadratic regression design.The requirements of N,P and K nutrients of Cinnamomum bodinieri seedlings were explored from the aspects of growth and physiology.The DRIS graphic method and index method were used to diagnose the nutrition of Cinnamomum bodinieri seedlings,and the best formula suitable for the growth of Cinnamomum bodinieri seedlings was selected.At the same time,experiments with different magnesium supply levels(0 g·plant^-1、8.7 g·plant^-1、17.4 g·plant^-1、43.5 g·plant^-1)on perennial container large seedlings of Cinnamomum bodinieri were conducted in order to explore the amount of magnesium fertilizer that has the best effect on the growth and physiology of Cinnamomum bodinieri.The results of the study are as follows:（1）Different N,P and K fertilizer application had significant effects on the seedling height,ground diameter and biomass of annual Cinnamomum bodinieri seedlings,and the primary and secondary effects of N,P and K on each growth index are:N>P>K.Among different fertilizer application ratios,the increase in seedling height,ground diameter,and biomass of Cinnamomum bodinieri seedlings treated with 6(0.6 g·pot^-1 of N,2.4 g·pot^-1 of P,0.6 g·pot^-1 of K)all had the largest value-added,is the best formula to promote the growth of Cinnamomum bodinieri.（2）The differences in chlorophyll,soluble protein and soluble sugar contents of Cinnamomum bodinieri seedlings under different N,P and K fertilization treatments reached extremely significant levels.Chlorophyll content is most affected by N,and low levels(0.6g·pot^-1)of N is beneficial to the formation of chlorophyll.With the increase of N,the chlorophyll content decreases;Soluble protein contents is most affected by P.Insufficient or excessive P can inhibit the synthesis of soluble protein.The effect of N on soluble sugar content has reached a very significant level.With the increase of N,the soluble sugar content rises first and then decreases,medium levels(1.5 g·pot^-1)of N are most conducive to the formation of soluble sugars.（3）Under different N,P,and K fertilization treatments,treatment 6(0.6 g·pot^-1 of N,2.4 g·pot^-1 of P,0.6 g·pot^-1of K)kept the chlorophyll fluorescence parameters of the Cinnamomum bodinieri seedlings at a high level,maximizing fluorescence（Fm）,maximum light energy conversion efficiency（Fv/Fm）,and PSⅡpotential activity（Fv/Fo）increased significantly,which enhanced the photosynthetic capacity of Cinnamomum bodinieri leaves.（4）Applying DRIS graphic method and index method to carry out N,P and K nutritional diagnosis analysis of Cinnamomum bodinieri seedlings under various fertilization treatments,it was found that the most suitable ratios of N,P and K nutrient content in Cinnamomum bodinieri seedlings were:N/P:12.465～16.161,N/K:1.348～1.854,P/K:0.094～0.136.And overall,the Cinnamomum bodinieri seedlings had the largest demand for P,followed by N,and the demand for K is relatively small.（5）Under different magnesium supply levels,when the magnesium fertilizer was 8.7g·plant^-1,the ground diameter growth and height-diameter ratio of the giant Cinnamomum bodinieri container seedlings reached the maximum.The physiological indicators such as chlorophyll a,chlorophyll b,total chlorophyll,soluble protein,and soluble sugar all increased first and then decreased with the increase of magnesium dosage,and all reached the maximum value when the magnesium fertilizer was 8.7 g·plant^-1.（6）Different levels of magnesium supply had different effects on chlorophyll fluorescence parameters of the giant Cinnamomum bodinieri container seedlings.When the magnesium fertilizer was 8.7 g·plant^-1,the promotion effects on the chlorophyll fluorescence parameters Fo,Fm,Fv/Fm,and Fv/Fo of Cinnamomum bodinieri were the greatest,which significantly enhanced the photosynthetic conversion efficiency of Cinnamomum bodinieri,and promoted the accumulation of nutrients in Cinnamomum bodinieri,and contributed to its rapid growth.