Species divergence in seedling leaf traits and tree growth response to nitrogen and phosphorus additions in an evergreen broadleaved forest of subtropical China  

作　　者：Xuemin Ye Wensheng Bu Xiaofei Hu Bin Liu Kuan Liang Fusheng Chen 

机构地区：[1]Key Laboratory of National Forestry and Grassland Administration On Forest Ecosystem Protection and Restoration of Poyang Lake Watershed,Jiangxi Agricultural University,Nanchang 330045,People’s Republic of China [2]Jiangxi Provincial Key Laboratory of Silviculture,College of Forestry,Jiangxi Agricultural University,Nanchang 330045,People’s Republic of China [3]School of Management,Nanchang University,Nanchang 330045,People’s Republic of China

出　　处：《Journal of Forestry Research》2023年第1期137-150,共14页林业研究（英文版）

基　　金：National Natural Science Foundation of China(grant numbers 31870427&31730014);by Jiangxi Province 2019 Graduate Innovation Fund Project(grant number YC2019-b061)。

摘　　要：Tree competitiveness generally depends on trait plasticity in response to environmental change.The effects of nitrogen(N)and phosphorus(P)on leaf trait variability by species is poorly understood,especially in China’s subtropical forests.This study examined the seedling leaf traits and net primary productivity of all trees>5 cm DBH of two dominant species,Schima superba and Castanopsis carlesii,in an evergreen broadleaved forest fertilized with nitrogen(+N),phosphorus(+P),and nitrogen plus phosphorus(N+P).The effect of N on seedling leaf traits was stronger than P,while fertilization in general was species dependent.Leaf mass per unit area decreased with N for S.superba seedlings but not for C.carlesii.Leaf N,P,and N/P ratios changed with N addition for both species.All four N fractions of carboxylation,bioenergetics,cell wall,and other N metabolites in C.carlesii leaves responded significantly to fertilization,while only the cell wall in S.superb a leaves responded.Other leaf functional traits,including light-saturated photosynthetic rates,water,N,and P use efficiencies,chlorophyll and non structural carbohydrate contents increased with N addition in S.superb a and by P addition in C.carlesii.Canopy closure at the stand-level increased due to N.Litter biomass and relative growth rate of S.superb a was not affected by any treatments,while both for C.carlesii significantly decreased with N+P addition.Collectively,nutrient limitation may vary at a small scale among species in a subtropical forest based on their responses of seedling traits and net primary productivity to fertilization.Seedling traits are not correlated with the net primary productivity of larger trees except for N fractions,because low light conditions induced by fertilization reduces the proportion of N allocated to photosynthesis in seedlings.In addition,acclimation differences of tree species may increase the uncertainty of community succession.

关 键 词：ECOPHYSIOLOGY Fertilization acclimation N fractions Nutrient limitation Photosynthesis Relative growth rate 

分 类 号：S718.5[农业科学—林学]