While increasing numbers of studies report wide variations of leaf silicon (Si) accumulation among plant species, within-species variations of leaf Si accumulation have scarcely been examined for tree species. As in crop plants, environmental factors that affect transpiration rates may influence passive transpiration-dependent transport of Si uptake in trees. Here, we tested a hypothesis that leaf Si accumulation rate should be higher in shoots that receive more light and thus achieve faster growth, using Broussonetia papyrifera, a pioneer tree species with successive leaf production and Si accumulation with leaf age. We marked individual leaves weekly throughout the growing season (June–September), and measured Si concentration and light availability in relation to the chronosequence of leaf age in September. In shoots that continued growing and successively produced leaves throughout the growing season, leaf Si content increased linearly with leaf age. In support of our hypothesis, leaf Si accumulation rate varied widely among shoots with positive correlations with shoot growth and light availability. In conclusion, both leaf age and microenvironment affect within-species variations in leaf Si concentration of this species, a moderate Si accumulator.

虽然越来越多的研究报告了植物物种之间叶片硅 (Si) 积累的广泛差异，但几乎没有研究过树种的叶片硅积累的物种内变化。与作物植物一样，影响蒸腾速率的环境因素可能会影响树木中 Si 吸收的被动蒸腾依赖运输。在这里，我们测试了一个假设，即使用Broussonetia papyrifera，在接受更多光照从而实现更快生长的枝条中，叶片 Si 积累率应该更高，具有连续叶生产和随叶龄Si积累的先锋树种。我们在整个生长季节（6 月至 9 月）每周标记单个叶子，并测量与 9 月叶龄时间序列相关的 Si 浓度和光照可用性。在整个生长季节持续生长并连续产生叶子的枝条中，叶片Si含量随叶龄线性增加。为支持我们的假设，叶片 Si 积累率在各枝条之间变化很大，与枝条生长和光可用性呈正相关。总之，叶龄和微环境都会影响该物种叶片 Si 浓度的种内变化，该物种是一种中等的 Si 累积体。