Relationship Between Leaf Nutrient Characteristics Of Tree Layer And Soil Nutrient In Davidia Involucrata Community In Sichuan

Davidia involucrata belongs to China's rare and endangered plants and first-class protected plants.It has been widely concerned by the world since its discovery and has high theoretical and academic value.In this paper,the natural growth of Davidia involucrata community in Sichuan Province was studied.The dry matter content,specific leaf area,leaf carbon,nitrogen,phosphorus and potassium content of soil and tree nutrients in the tree layer of community were determined.The weighted average of the nutritional traits of the arbor layer of each community was calculated.The method of analysis of variance and Pearson correlation analysis were used to explore the relationship between the weighted values of nutrient traits and the soil nutrient of arbor layer in the community,which provided a reference for the in situ conservation of Davidia involucrata population.The research results are as follows:1.The soil nutrient factors among the communities in the study area showed extremely significant differences,and there were also different degrees of correlation between soil nutrient factors.The elevation is the main factor that shows the significant difference in soil nutrients between communities.2.The weighted average of leaf nutrient traits in the community of the study area showed different degrees of difference,and there were also different degrees of correlation between the traits.The leaf dry matter content of arbor layer in community was significantly positively correlated with leaf nitrogen content,leaf carbon content and leaf nitrogen-phosphorus ratio.The community could adapt to the unfavorable environment by increasing the content of nutrients in the leaves.There was a significant positive correlation between leaf phosphorus content and leaf potassium content.There was a significant positive correlation between leaf nitrogen content and leaf carbon content.Functionally similar nutrients in the leaves of the arbor layer in the community will cooperate with each other.3.The average nitrogen and phosphorus ratio of the leaves in the study area was less than 14,and the soil total nitrogen content was significantly negatively correlated with leaf dry matter content,leaf nitrogen content and leaf nitrogen-phosphorus ratio.The soil carbon-nitrogen ratio was significantly positively correlated with leaf dry matter content and leaf nitrogen content.Nitrogen is the main limiting element for the growth of arbor layer tree in community.There was a significant positive correlation between specific leaf area and soil total potassium content,and a significant positive correlation with leaf potassium content;soil total potassium content was significantly negatively correlated with leaf dry matter content.During the growth process,the arbor layer of the community uses potassium to enhance its ability to adapt to the environment.4.Through stepwise regression analysis and redundant analysis,the main soil nutrient factors affecting the leaf nutrient traits of the community were found to be soil carbon-nitrogen ratio,followed by soil total potassium content.However,the correlation between the leaf nutrient traits and soil nutrients and the stepwise regression relationship are not ideal,indicating that the leaf nutrient traits of the community level are not directly determined by soil nutrients,but also by the external environment and the species themselves.In summary,the leaf trophic traits and soil nutrient factors in the study area have different degrees of difference.The growth of arbor layer tree species is closely related to the nitrogen and potassium elements in the soil,and the soil carbon-nitrogen ratio under the forest is regulated.It is beneficial to improve the soil nutrient status of Davidia involucrata community,improve the productivity of Davidia involucrata community,and provide reference for the in situ conservation of Davidia involucrata community.