亚热带常绿阔叶林89种木本植物一级根碳氮浓度变异规律

Variation Patterns in C and N Concentrations in the First-order Roots of 89 Woody Species in Subtropical Evergreen Broad-leaved Forest

摘要:

为了解亚热带地区常绿阔叶林木本植物一级根养分元素变化规律，基于根序法对福建省建瓯市万木林自然保护区天然常绿阔叶林群落的89种树种一级根进行碳、氮浓度测定。结果表明，89种树种一级根的C、N质量浓度分别为433.9 和13.7 mg/g，C∶N为36.7，变异系数分别为6.4%、39.2%和39.9%；一级根C浓度在叶片习性和生长型间存在显著差异，而N浓度和C∶N在不同叶片习性和生长型间的差异不显著；6主要科[樟科（Lauraceae）、壳斗科（Fagaceae）、冬青科（Aquifoliaceae）、山矾科（Symplocaceae）、五列木科（Pentaphylacaceae）和杜英科（Elaeocarpaceae）]树种间一级根C、N浓度和C∶N均差异显著；一级根N浓度随物种系统发育由低级向高级呈现增加的趋势。因此，亚热带常绿阔叶林一级根C浓度种间变异低于N浓度；一级根N浓度受系统发育的影响，而C浓度则受叶片习性和生长型影响，表现出一定的趋同效应。

Abstract:

In order to understand the variation patterns of nutrient elements for the first-order roots of woody plants in subtropical evergreen broad-leaved forests, the carbon and nitrogen concentrations of the first-order roots of 89 tree species in Wanmu Forest Nature Reserve, Jian'ou, Fujian Province, were determined based on root order method. The results showed that the mean C, N concentrations in the first-order roots of 89 tree species were 433.9 and 13.7 mg/g, and C:N ratio was 36.7, which variation coefficients were 6.4%, 39.2% and 39.9%, respectively. There were significant differences in C concentration of the first-order roots among different leaf habits (such as evergreen and deciduous trees) and growth forms (including tree, semi-tree or shrub and shrub). However, there was no significant difference in N concentration and C:N ratio. The differences in C, N concentrations and C:N ratio of the first-order roots among six main families (Lauraceae, Fagaceae, Aquifoliaceae, Symplocaceae, Pentaphylacaceae and Elaeocarpaceae) were significant. The N concentration of first-order roots increased with the phylogeny level from low to high. Therefore, it was indicated that the interspecific variation of the first-order roots in C concentration was lower than N concentration in the subtropical evergreen broad-leaved forest, the N concentration of the first-order roots was influenced by phylogeny, however, the concentration of C was affected by leaf habits and growth forms, showing a certain convergence effect.