Diversity of silicon release rates among tropical tree species during leaf-litter decomposition
Diversity of silicon release rates among tropical tree species during leaf-litter decomposition
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热带树种凋落物分解过程中硅释放速率的多样性
DOI：
10.1016/j.geoderma.2020.114288
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发表时间：
2020
期刊：
影响因子：
6.1
通讯作者：
Kaoru Kitajima
中科院分区：
文献类型：
--
作者：
Ryosuke Nakamura;Jean-Thomas Cornelis;Felix de Tombeur;Arata Yoshinaga;Michiko Nakagawa;Kaoru Kitajima
凋落物是生物硅的重要来源，凋落物分解过程中树种间硅释放速率的差异对森林生态系统硅循环的定量研究具有重要意义。我们利用婆罗洲沙捞越的低地热带树木进行了两个实验，以提高对枯叶中硅释放速率的机械理解。在第一个实验中，我们评估了叶凋落物在水中摇动四个小时时硅的浸出。在第二个实验中，凋落物样品在生长室内的网袋中分解两个月，以测定分解速率和硅的释放，并探索分解速率与初始凋落物化学之间的关系。在凋落物初始硅浓度差异较大的12个树种中(0.72~80.0mgSig−1)，硅淋溶到水中的差异很大(0.04~0.16mgSig−1)，且与初始硅浓度呈正相关(R2=0.87；P<；0.001)。分解实验中单位叶干重的硅释放量与凋落物初始硅浓度呈显著正相关(R2=0.998；P<；0.001)。而初始硅释放比例与其分解速率无显著关系，而分解速率与凋落物中活性碳含量(如半纤维素)呈正相关。我们的结果表明，分解叶凋落物的硅释放速率不能简单地由分解速率来预测。应考虑蛋白石植硅体在位置和稳定性上的物种差异及其对硅溶解速率的影响。
Leaf-litter is a significant source of biogenic Si, and differences among tree species in Si release rates during litter decomposition are important for quantifying Si cycles in forest ecosystems. We conducted two experiments to improve mechanistic understanding of Si release rates from dead leaves, using lowland tropical trees of Sarawak, Borneo. In the first experiment, we assessed Si leaching from leaf litter when they were shaken in water for four hours. In the second experiment, leaf litter samples were allowed to decompose in mesh bags in growth chambers for two months, in order to determine rates of decomposition and Si release, and to explore a relationship between decomposition rate and initial litter chemistry. Among the 12 species with large differences in initial leaf-litter Si concentration (0.72–80.0 mg Si g−1), Si leaching to water varied widely (0.04–0.16 mg Si g−1) and positively correlated with the initial Si concentration (R2= 0.87;P< 0.001). Si release per unit leaf dry weight in the decomposition experiment was also positively correlated with initial litter Si concentration among six species (R2= 0.998;P< 0.001). In contrast, proportion of initial Si content released did not exhibit a significant relationship with their decomposition rates, which were correlated with labile carbon content in leaf litter (e.g. hemicellulose). Our results suggest that Si release rates from decomposing leaf litter cannot be simply predicted from decomposition rates. The species differences in locations and stability of opal phytoliths and their resulting effects on Si dissolution rates should be considered.