The Strategy Of Plant Leaf Explantation Based On Modular Theory And Functional Traits

Research on the interactions and effects between plants and the surrounding environment has always been an important issue in the study of ecology.The trade-off relationship between leaf size and number(ie,leaf size and leafing intensity)is closely linked to the plant's access to light,carbon absorption and other resources.Although many previous studies have reported,different results have been generated due to the different definitions of leaf size and leafing intensity,and these studies have been limited to the current year's shoots and leaves.This study intends to explore the factors of affecting the trade-off relationship between plant leaf size and number at the level of overall plant shoot structure,using the study of plant module theory and plant functional traits.Under a limited resource environment,the trade-off relationship between leaf size and number will have significant impact on plant life strategies.In this study,52 species of woody plants were selected from the south of Ziwuling in the Loess Plateau,the leaf size,leafing intensity,plant branching pattern,and plant functional traits were measured,and the effects of plant twig structure and plant traits on this trade-off relationship were also explored.The conclusions as follow:(1)The ways in which the leaf size and number are different defined have different effects on this trade-off relationship.When using calculation method of the volume-based leafing intensity,comparing the different definitions,the leafing intensity calculated from the diameter of the half shoot length and the average leaf fresh mass calculated from the leaf size are more representative of the plant actual state,and the allometric of them is more in line with the 3/4 model in metabolic theory.(2)There is indeed correlation between leafing intensity and plant branching pattern.There was a significant negative correlation(p<0.05)between the plant leafing intensity and based on volume of overall bifurcation ratio,stepwise bifurcation ratio,average length of 1st bifurcation,average diameter of 1st bifurcation,average volume of 1st bifurcation,average length of 2nd bifurcation,average diameter of 2nd bifurcation,average volume of 2nd bifurcation,average volume of 2nd bifurcation,average diameter of 3rd bifurcation,average volume of 3rd bifurcation.However,there was no significant correlation with aatio of branch diameter and number of shoots at all levels.This may be due to the fact that there is no direct relationship between the plant growth and based on the number of branches calculation method,but the correlation with the indicators such as plant branch length,base diameter,and volume can better reflect the actual state of plant growth.(3)There was a significant negative correlation between leafing intensity and plant stoichiometric traits of the leaf N,C,P contents,branch N,C,and P contents(p<0.001).As the plant invests more in the number of leaves,investment in the stoichiometric traits(leaf size and branch size)of the leaves and shoots will inevitably decrease accordingly.This indicates that there is a certain trade-off relationship between leafing intensity and the N,C,and P contents of the leaves and shoots.There was a significant positive correlation(p<0.05)between leafing intensity and leaf dry matter content,branch dry matter content,and wood density in plant structure traits,but it was significantly negatively correlated(p<0.05)with specific leaf area,branch cross-sectional area,branch length,and branch volume.The results indicate that the trade-off relationship between leaf size and number will be affected by plant branching patterns and plant functional traits.In the face of different habitat effects,different ecological strategies selected by plants will be reflected in the overall structure of the plant.Different plant branch structures will correspond to different trade-off strategies for leaf size and number,which is of crucial importance for studying the relationship between leaf size and number and even the different leafing strategies by plants chosen.