Foliar And Soil Nutrients And Its Ecological Stoichiometry In Successional Stages Of Evergreen Broad-leaved Forest In Tiantong

Plant foliar and soil nutrients,i.e.C,N,P,K,Mg,S,and its ecological stoichiometry in four successional stages of subtropical evergreen broadleaved forest (EBLF) in Tiantong National Forest Park,Ningbo,Zhejiang Province,were studied.It aim to address(1)the temporal dynamics of leaf and soil nutrients;(2)whether are there nutrient limitations in plant and soil in successional stages of EBLF;(3)the relationship between various leaf traits,and(4)whether are there synergetic effect between leaf traits in small scale.The findings are as followed:(1)Leaf N,P,K and Mg contents,as well as photosynthetic rate,increased with successional progress in four successional satges of EBLF.Leaf N,P,K contents were positively correlated with plant photosynthesis.(2)The leaf C:N was rather stable,there were not significant differences in leaf C:N value between successional satges and between different seasons.(3)There were significant temporal variations in leaf C:P value between successional satges.The leaf C:P value decreased with the successional progress.The value of leaf C:P in spring was less than those in other seasons.(4) Plants' growth was suffered from co-limitation by soil nitrogen and phosphorus supply in the earlier successional stages,but tended to be only limited by soil phosphorus supply in later stages.In growing seasons,plant needed to be fueled sufficient N and P to maintain fast growth,so it was easily suffered from co-limotation of soil nitrogen and phosphorus supply,but in non-growing seasons,it was only limited by soil phosphorus supply.(5)In different seasons and successional satges of EBLF,the variations of foliar N,P,K and Mg contents were similar to those in soil.The leaf N,P contents were not significantly correlated with the soil total N and total P contents,but the leaf K,Mg contents were positively correlated with the soil total K and total Mg contents.(6)Leaf K contents and N:P ratio were only loosely ralated to the other leaf traits in leaf economic spectrum in EBLF at small scale such as Tiantong.(7)Leaf LMA was negatively correlated with leaf N,P contents and photosynthetivity,but positively correlated with leaf C content.(8)The mass-based photosynthetic rate(A_mass was stronger correlated with most of the other leaf parameters than the area-based photosynthetic rate(A_area) did,which indicated that Mass-based parameters may be more important in leaf economic characteristics.