Abstract Intraspecific variations in leaf traits and tree growth along environmental gradients are crucial for survival and distribution of the tree species, but they are substantially less quantified than interspecific counterparts. Here, we examined the intraspecific variations in leaf hydraulics and economics traits and growth of Larix gmelinii Rupr. – the predominant tree species in the Eurasian boreal forests with a toposequence approach. The toposequence included three replicated 1000-m transects of the larch plantation (31-year-old), each of which consisted of three plots located at the toe-, mid-, and top-slope, respectively. We found that the leaf hydraulics traits showed a “high-low-high” pattern along the toposequence, while the leaf economics traits, total biomass (TB) and TB increment (TBI) displayed an opposite trend, largely consistent with changes in site conditions especially soil nitrogen concentration. This suggests that the intraspecific variation in tree growth is coupled with leaf traits and site conditions. Leaf mass per area explained 21.9% of the variability in TB, while and the ability of drought tolerance explained 22.5% of that in TBI; and the interactions of hydraulic and economic variables explained additional 23.1–26.2% of that in TB or TBI. This result indicates that leaf traits interactively affect TB and TBI, but the hydraulics and economics play major roles in the short-term growth rate and relatively long-term biomass stock, respectively. Together, our findings demonstrate that the larch trees acclimate the leaf traits and growth/biomass accumulation to site conditions, and provide insights into the mechanistic understanding of forest production.

中文翻译：

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与落叶松叶片性状相关的树木生长的拓扑序列变异性

摘要 叶性状和树木生长沿环境梯度的种内变异对于树种的生存和分布至关重要，但与种间对应物相比，它们的量化程度要低得多。在这里，我们研究了落叶松的叶片水力学和经济性状以及生长的种内变化。– 欧亚北方森林中的主要树种，采用拓扑序列方法。地形序列包括落叶松人工林（31 岁）的三个重复的 1000 米横断面，每个断面由分别位于坡脚、中坡和顶坡的三个地块组成。我们发现叶片水力性状沿拓扑序列呈现“高-低-高”模式，而叶片经济性状、总生物量（TB）和 TB 增量（TBI）显示出相反的趋势，与立地条件特别是土壤氮浓度的变化大体一致。这表明树木生长的种内变异与叶性状和立地条件有关。单位面积叶片质量解释了 TB 变异的 21.9%，而抗旱能力解释了 TBI 变异的 22.5%；水力和经济变量的相互作用解释了 TB 或 TBI 中额外的 23.1-26.2%。该结果表明，叶片性状交互影响 TB 和 TBI，但水力学和经济学分别在短期增长率和相对长期的生物量存量中起主要作用。总之，我们的研究结果表明落叶松树使叶子特征和生长/生物量积累适应现场条件，