Condensed tannins increase nitrogen recovery by trees following insect defoliation
Condensed tannins increase nitrogen recovery by trees following insect defoliation
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DOI：
10.1111/nph.13444
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发表时间：
2015-10-01
期刊：
影响因子：
9.4
通讯作者：
Lindroth, Richard L.
中科院分区：
文献类型：
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作者：
Madritch, Michael D.;Lindroth, Richard L.
虽然植物次生代谢物对地下功能的重要性正在得到承认，但人们仍然认为次生代谢物是为食草动物防御而产生的，而它们对地下的影响是生态副产品或“来世”的影响。然而，植物投入大量的资源生产次生代谢产物，对草食动物抗性的影响很小（如。G.我们表明，在严重的落叶事件后，缩合单宁浓度的遗传介导的变化与植物氮恢复相关。我们利用N-15标记的单木围隔来追踪氮通过粪和枯落物循环途径的变化，在同一生长季和下一生长季中，高浓度的叶单宁与从粪中回收的N-15相关。同样，叶单宁浓度也与N-15恢复落叶树木在生长季节的落叶事件。相反，单宁没有很好的相关性与氮吸收的条件下名义herbivory.Our研究结果表明，单宁可能会通过保守的地下氮循环，而不是通过防御性能在响应草食动物的压力带来好处。因此，单宁可以被认为是耐受性的化学介质，而不是抗性。
While the importance of plant secondary metabolites to belowground functioning is gaining recognition, the perception remains that secondary metabolites are produced for herbivore defense, whereas their belowground impacts are ecological by-products, or 'afterlife' effects. However, plants invest a significant amount of resources into production of secondary metabolites that have minimal effects on herbivore resistance (e. g. condensed tannins and insect herbivores).We show that genetically mediated variation in condensed tannin concentration is correlated with plant nitrogen recovery following a severe defoliation event. We used single-tree mesocosms labeled with N-15 to track nitrogen through both the frass and litter cycling pathways.High concentrations of leaf tannins in Populus tremuloides were correlated with N-15 recovery from frass within the same growing season and in the following growing season. Likewise, leaf tannin concentrations were also correlated with N-15 recovery from the litter of defoliated trees in the growing season following the defoliation event. Conversely, tannins were not well correlated with nitrogen uptake under conditions of nominal herbivory.Our results suggest that tannins may confer benefits in response to herbivore pressure through conserved belowground nitrogen cycling, rather than via defensive properties. Consequently, tannins may be considered as chemical mediators of tolerance rather than resistance.