Nitrogen-fixing and non-fixing trees differ in leaf chemistry and defence but not herbivory in a lowland Costa Rican rain forest
Nitrogen-fixing and non-fixing trees differ in leaf chemistry and defence but not herbivory in a lowland Costa Rican rain forest
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哥斯达黎加低地雨林中的固氮树和非固氮树在叶子化学和防御方面存在差异，但食草性则没有差异
DOI：
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发表时间：
2019
影响因子：
1.4
通讯作者：
Laura R. Ostrowsky
中科院分区：
文献类型：
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作者：
B. Taylor;Laura R. Ostrowsky
摘要固氮植物提供了支持热带森林高生产力的关键氮素输入，但我们对固氮植物的生态--特别是它们与食草动物的相互作用--的了解仍然不完整。由于叶片含氮量和食草动物防御策略的不同，食草动物与固氮剂和非固氮剂的相互作用可能不同。为了检验这些潜在的差异，我们的研究比较了低地热带雨林中4种固氮树种(Inga oerstediana、Inga Sapindodes、Inga thibaudiana和Pentaclethra macloba)和3种非固氮树种(Anaxagorea crassipetala、Casearia arborea和Dipteryx panamensis)的叶片碳、氮、韧性、化学防御和食草性。叶的化学防御，而不是营养成分，是我们物种中草食动物受到破坏的主要驱动力。尽管固氮剂表现出比不固氮剂高21.1%的叶片含氮量、20.1%的低C/N比和15.4%的叶片韧性，但我们发现这两个植物组在草食和化学防御方面没有差异。我们的结果不支持通常的假设，即固氮者优先食草，或者他们比非固氮者产生更多富含氮的防御性化合物。相反，这些发现表明，在固氮和不固氮的热带树木中，植物-草食关系存在强烈的物种特异性差异。
Abstract Nitrogen-fixing plants provide critical nitrogen inputs that support the high productivity of tropical forests, but our understanding of the ecology of nitrogen fixers – and especially their interactions with herbivores – remains incomplete. Herbivores may interact differently with nitrogen fixers vs. non-fixers due to differences in leaf nitrogen content and herbivore defence strategies. To examine these potential differences, our study compared leaf carbon, nitrogen, toughness, chemical defence and herbivory for four nitrogen-fixing tree species (Inga oerstediana, Inga sapindoides, Inga thibaudiana and Pentaclethra macroloba) and three non-fixing species (Anaxagorea crassipetala, Casearia arborea and Dipteryx panamensis) in a lowland tropical rain forest. Leaf chemical defence, not nutritional content, was the primary driver of herbivore damage among our species. Even though nitrogen fixers exhibited 21.1% higher leaf nitrogen content, 20.1% lower C:N ratios and 15.4% lower leaf toughness than non-fixers, we found no differences in herbivory or chemical defence between these two plant groups. Our results do not support the common hypotheses that nitrogen fixers experience preferential herbivory or that they produce more nitrogen-rich defensive compounds than non-fixers. Rather, these findings suggest strong species-specific differences in plant–herbivore relationships among both nitrogen-fixing and non-fixing tropical trees.