Interspecific variation in leaf litter tannins drives decomposition in a tropical rain forest of French Guiana
Interspecific variation in leaf litter tannins drives decomposition in a tropical rain forest of French Guiana
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DOI：
10.1890/09-1076.1
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发表时间：
2010-07-01
期刊：
影响因子：
4.8
通讯作者：
Hattenschwiler, Stephan
中科院分区：
文献类型：
--
作者：
Coq, Sylvain;Souquet, Jean-Marc;Hattenschwiler, Stephan
单宁被认为在热带树叶中特别丰富，主要与植物食草动物防御有关。我们对热带凋落叶中单宁的数量、变化和潜在作用知之甚少。本文报道了法属圭亚那16种共生热带雨林树种凋落物缩合单宁（CT）浓度的种间变异，并探讨了CT浓度变化对凋落物分解的功能意义。我们将生态学文献中的一些经典方法与基于高效液相色谱（HPLC）的方法进行了比较，并结合了间苯三酚分解的CT降解方法。在有或没有土壤动物的情况下，允许相同的凋落物在野外分解。我们发现，通过HPLC测定的平均聚合度（2.7 ~ 21.3，不可提取的CT）和凋落物CT浓度（0 ~ 3.7%干质量，总CT）在种间存在很大差异，这与Folin总酚类物质无关，但与酸性丁醇CT相关性较好。hplc测定的CT浓度和聚合度是众多测定的初始凋落物质量参数中唯一能解释显著的变量。不考虑动物的存在，物种间凋落物质量损失的变化量。然而，动物的存在增加了平均凋落物质量损失的1.5倍，动物对分解的影响最好的解释是与总HPLC CT负相关，与半纤维素正相关。我们的结果表明，常用的酸性丁醇测定法可以可靠地估计CT浓度的种间变化。然而，ct的化学结构，如聚合度，为了解ct在凋落物分解中的功能作用提供了重要的信息。我们得出结论，热带树种凋落叶ct结构和浓度的广泛差异是这一营养贫乏的亚马逊雨林分解的重要驱动因素。
Tannins are believed to be particularly abundant in tropical tree foliage and are mainly associated with plant herbivore defense. Very little is known of the quantity, variation, and potential role of tannins in tropical leaf litter. Here we report on the interspecific variability of litter condensed tannin (CT) concentration among 16 co-occurring tropical rain forest tree species of French Guiana and explore the functional significance of variable litter CT concentration for litter decomposition. We compared some classical methods in the ecological literature to a method based on high-performance liquid chromatography (HPLC), coupled with CT degradation by phloroglucinolysis. The same litter was allowed to decompose in the field in the presence or absence of soil fauna. We found large interspecific differences in the average polymerization degree (2.7 to 21.3, for non-extractable CT) and concentration of litter CT (0-3.7% dry mass, for total CT) determined by HPLC, which did not correlate with Folin total phenolics but correlated reasonably well with acid butanol CT. The concentration and polymerization degree of HPLC-determined CT were the only variables of the multitude of measured initial litter quality parameters that explained a signi. cant amount of variation in litter mass loss among species, irrespective of animal presence. However, animal presence increased mean litter mass loss by a factor of 1.5, and the fauna effect on decomposition was best explained by a negative correlation with total HPLC CT and by a positive correlation with hemicellulose. Our results suggest that the commonly used acid butanol assay yields a reliable estimate of interspecific variation in CT concentration. However, the chemical structure of CTs, such as the polymerization degree, adds important information for the understanding of the functional role of CTs in litter decomposition. We conclude that the wide variation in structure and concentration of leaf litter CTs among tropical tree species is an important driver of decomposition in this nutrient-poor Amazonian rain forest.