【摘要】 非结构性碳水化合物(non-structural carbohydrates, NSC)是植物碳收支平衡与响应外界环境变化的重要指标。为明确北热带喀斯特季节性雨林优势植物NSC的空间变异及其生态驱动因素,本研究以不同生境条件下共31个优势树种165株个体为研究对象,对其叶片NSC及组分(可溶性糖、淀粉)含量进行分析。运用贝叶斯系统发育混合效应模型将NSC变异划分为与物种系统发育相关的和无关的两部分,并探讨了这两部分变异与地形、土壤性质、生物群落特征及叶片功能性状之间的深层联系。结果表明:(1)优势树种叶片NSC及其组分含量在3个生境之间存在显著的空间差异性,总体表现为山顶>中坡>洼地。(2)物种系统发育背景对NSC、淀粉及可溶性糖总变异的解释率分别为53.97%、58.23%和57.88%。生态因子对这三者总变异的解释率分别为48.85%、32.54%和32.64%。值得注意的是,生态因子对可溶性糖变异的影响更多是通过系统发育相关途径(23.15%)实现,而对淀粉变异的影响则更依赖于非系统发育相关途径(26.89%)。(3)叶片厚度、枝条木质密度、南北坡向、比叶面积、群落平均胸径、平均海拔和叶绿素含量等对NSC的积累有显著正向效应,而群落胸高断面积之和与土壤总碳等有显著负向效应。综上所述,喀斯特季节性雨林中优势树种叶片NSC的空间变异既受到物种遗传差异与进化历史的深刻影响,也与一系列生态因子的综合作用密切相关。本研究结果体现了不同生境下植物在碳获取、储存及利用策略上的显著适应性分化,为深入理解喀斯特生态系统的碳循环机制及植物的适应策略提供了新视角。更多还原

【Abstract】 Aims: Non-structural carbohydrates(NSC) serve as a crucial indicator for plant carbon balance and their response to external environmental changes. This study aims to elucidate the spatial variability of NSC and its ecological drivers in dominant plant species within the northern tropical karst seasonal rainforest.Methods: This study analyzed the leaf NSC content and its components(soluble sugars and starch) in 165 individuals across 31 dominant tree species in various habitat conditions(depression, middle slope, and peak). A Bayesian phylogenetic mixed-effects model was applied to partition NSC variation into two components related to species phylogeny and unrelated factors. The relationships of these components with topography, soil properties, biotic community characteristics, as well as leaf functional traits were explored.Results:(1) Significant spatial differences in leaf NSC content and its components were observed, with the peak showing the highest NSC content, followed by the middle slope and the depression having the lowest values.(2) The phylogenetic background of species explained 53.97%, 58.23%, and 57.88% of the total variation in NSC, starch, and soluble sugars, respectively, while ecological factors explained 48.85%, 32.54%, and 32.64% of the total variation in these three components. Notably, ecological factors influenced soluble sugar variation more through phylogenetic pathways(23.15%) and starch variation more through non-phylogenetic pathways(26.89%).(3) Factors such as leaf thickness, wood density, slope aspect(north vs. south), specific leaf area, mean DBH of community, mean elevation,and chlorophyll content had significant positive effects on NSC accumulation. In contrast, the sum of community basal area and total soil carbon exhibited significant negative effects.Conclusions: The spatial variation in leaf NSC of dominant tree species in karst seasonal rainforests is profoundly influenced by both species’ genetic and evolutionary backgrounds and the integrated effects of ecological factors. This reflects significant adaptive differentiation in carbon acquisition, storage, and utilization strategies among plants in different habitats, providing new insights into carbon cycling mechanisms in karst ecosystems and the adaptation strategies of plants.更多还原