Study On Leaf Function Characteristics Of Common Tree Species In Jiulian Mountain Evergreen Broad-leaved Forest

Plants are important among parts of the ecosystem,whose leaf functional traits can reflect that how plants adapt to the environment and how they take part in the circulation of materials and energy,with an important indicator significance for ecosystem stability and global climate change.Taking the subtropical evergreen broad-leaf forest in Jiulianshan Mountain,Jiangxi,as the research object,this paper studied the structure characteristics of the community and analyzed the correlation and differences of leaf functional traits of 81 common tree species.The main indicators of leaf functional traits involved are leaf area(LA),leaf thickness(LT),leaf tissue density(LTD),Leaf dry matter content(LDMC),leaf nitrogen content(LNC),leaf phosphorus content(LPC),leaf carbon content(LCC),chlorophyll(CC)and specific leaf area(SLA),nine in total.The conclusions obtained are as follows:(1)It is rich in species of the subtropical evergreen broad-leaf forest in Jiulianshan Mountain.The vertical structure distribution gradient is obvious,and the radial structure is overall stable in a spindletype structure.And the biodiversity of the shrub layer is higher than the tree layer.(2)Among the nine leaf functional traits from 81 species of evergreen broad-leaf forest in Jiulianshan Mountain,the magnitude of variation in single leaf area is the largest,followed by the magnitude of variation in LNC,LPC,LT and SLA.The magnitude of variation in chlorophyll content,leaf stem material content and leaf tissue density is smaller,and the magnitude of variation in leaf carbon content is the smallest.The five leaf functional characteristics,including single leaf area,LNC,LPC,LT and SLA,respond strongly to resource competition among evergreen broad-leaf forest plants in Jiulianshan Mountain.(3)There are two significant positive and significant negative correlations among the nine leaf functional traits from 81 species of evergreen broad-leaf forest in Jiulianshan Mountain.Among them,leaf functional traits with significant positive correlation are: single leaf area between LNC\LPC\LCC,LTD between LDMC\LCC,LT between chlorophyll;LDMC between LNC;LNC between LPC.Those with significant negative correlation are: LT between SLA\LTD,chlorophyll between LTD\LCC,SLA between LDMC\LCC.(4)Nine leaf functional traits show significant differences in single leaf area,SLA,LTD,LDMC,LCC,LNC and LPC in all three taxa(arbor,small arbor and shrub)of the evergreen broad-leaf forest in Jiulianshan Mountain.Three taxa of plants in Jiulianshan Mountain have the following characteristics:arbor plants have small SLA,LNC,LPC and chlorophyll;have high LTD,LT and LDMC.Shrub plants have small LTD,LT and LDMC;have high SLA,LNC,LPC and chlorophyll content.And small arbor plants are between the two species.According to the leaf economic spectrum theory,arbor plants adopts the "slow investment-return" strategy,shrub plants adopts the "fast investment-return" strategy,the strategy adopted by the small arbor type lies in between.