Effects Of Different Fertilizer Types On Root Exudates Of Seedlings Phoebe Bournei Forest

Root exudates are exudates,exudates and excretions released by plant roots to rhizosphere soil through chelation,activation,degradation and other ways.By improving the physical and chemical properties of soil,they provide material and energy materials,and then affect the growth of soil microbial communities and plants nearby.They play an important role in maintaining the dynamic balance between plant and soil.The effects of fertilization methods on plant roots(including root nutrient elements,root exudates,biomass,etc.)are directly related to the growth and survival of plants.In this paper,five-year-old Phoebe bournei(Hemsl.)Yang seedlings forest in Jindong forest farm was selected as the research object.Three kinds of fertilizer treatments,including organic fertilizer,compound fertilizer and bacterial fertilizer,and control group were set up.The root exudates of different fertilizer treatments were identified by GC-MS,and the relative contents of root exudates were compared,The effects of different fertilizer types on root exudates and nutrient elements in seedlings Phoebe bournei forest were studied.Main conclusions as shown below:(1)By GC-MS,54 kinds of volatile chemical components were identified in the root exudates of Phoebe bournei seedlings forest treated with organic fertilizer,51 kinds of chemical components treated with compound fertilizer,51 kinds of chemical components treated with bacterial fertilizer and 48 kinds of chemical components treated with no fertilizer.The main compounds were calarene,α-santalene、3-carene and fenchene,etc.Most of the root exudates were terpenes and terpenoids,which were the main source of aromatic flavor in Phoebe bournei root exudates.Different fertilizer types did not significantly change the types of root exudates,but there were still differences.(2)The volatile root exudates of Phoebe bournei seedlings forest mainly included terpenes,esters and terpenoids.The overall trend of relative content of terpenoids was June<October,the overall trend of esters was June>October,and the overall trend of terpenoids was June>October.The results showed that the chemical composition of root exudates of Phoebe bournei seedlings forest under different fertilizer treatments changed with seasons.(3)Compared with the control group,organic fertilizer and compound fertilizer could significantly increase the content of root nutrient elements,and bacterial fertilizer could significantly increase the content of Phosphorus element;Application of organic fertilizer and compound fertilizer can promote the growth of Phoebe bournei seedlings forest.Different fertilization treatments will affect the accumulation of nutrient elements,and the accumulation of nutrient elements will affect the dynamics of root exudates.The accumulation of nutrient elements and the change of temperature under different fertilization treatments are the reasons for the change of root exudates.(4)According to the correlation analysis between Carbon,Nitrogen,Phosphorus,Kalium elements and the main root exudates of different fertilizer treatments,the fertilizer components,root nutrient elements and root exudates had significant correlation.The application of Nitrogen,Phosphorus,Kalium fertilizer and compound Bacillus could significantly affect the relative mass fraction ratio of terpenes;There was only significant correlation between root nutrient element and calarene in no fertilizer treatment.Different fertilization treatments had no significant effect on the species of root exudates,but could increase or decrease the relative mass fraction of some components in volatiles.Organic fertilizer and compound fertilizer can significantly increase the content of nutrient elements in the root system of Phoebe bournei seedlings forest,and bacterial fertilizer can reduce other nutrient elements except Phosphorus.in addition,fertilizer components and root nutrient elements have significant correlation with root exudates.Therefore,the application of organic fertilizer and compound fertilizer may mainly affect the relative content of a certain component of root exudates that is conducive to plant growth,And then promote the growth and development of Phoebe bournei seedlings forest.