Testing the mutualism disruption hypothesis: physiological mechanisms for invasion of intact perennial plant communities
Testing the mutualism disruption hypothesis: physiological mechanisms for invasion of intact perennial plant communities
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DOI：
10.1890/es11-00136.1
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发表时间：
2011-10-01
期刊：
影响因子：
2.7
通讯作者：
Kalisz, Susan
中科院分区：
文献类型：
--
作者：
Hale, Alison N.;Tonsor, Stephen J.;Kalisz, Susan
源自互惠丛枝菌根真菌（AMF）的土壤资源在许多本土植物物种的生理功能中发挥着至关重要的作用。化感植物入侵研究表明，被入侵土壤的 AMF 接种潜力下降，植物失去了形成新 AMF 组合的机会。然而，如果化感物质也会杀死已经与植物根相关的 AMF 外部菌丝，那么这种互利共生的破坏就会给本地植物带来生理应激。我们之前证明，被化感入侵者蒜芥（Alliaria petiolata）侵染的森林土壤表现出真菌菌丝丰度降低。在这里，我们首次证明用大蒜芥末组织处理会降低土壤呼吸速率，并削弱假所罗门海豹（Maianthemum racemosum）的生理功能，假所罗门海豹是一种依赖 AMF 的森林林下原生动物。与对照相比，经过处理的植物表现出气孔导度和光合作用降低，这与 AMF 功能丧失的建议一致。如果这种生理衰退持续几个生长季节，可能会降低本地林下多年生植物的生长速度并增加它们对环境压力的敏感性。这些数据提供了一个明确的机制，可以帮助解释被入侵的成熟森林中已建立的本地多年生植物的损失。我们认为，互利共生破坏的生理成本可能是一种广泛但以前未经测试的机制，可增强化感作用物种对未受干扰的生态系统的入侵。
Soil resources derived from mutualistic arbuscular mycorrhizal fungi (AMF) play a critical role in the physiological function of many native plant species. Allelopathic plant invasion studies have revealed declines in AMF inoculation potential of invaded soils, and lost opportunities for plants to form new AMF associations. Yet, if allelochemicals also kill AMF external hyphae already associated with plant roots, this mutualism disruption should result in physiological stress for native plants. We previously demonstrated that forest soils infested with garlic mustard (Alliaria petiolata), an allelopathic invader, exhibit reduced fungal hyphal abundance. Here, we demonstrate for the first time that treatment with garlic mustard tissue reduces soil respiration rates and diminishes physiological function of false Solomon's seal (Maianthemum racemosum), an AMF-dependant forest understory native. Treated plants exhibited reduced stomatal conductance and photosynthesis relative to controls, consistent with the proposed loss of AMF function. Such physiological declines, if sustained over several growing seasons, could decrease native understory perennials' growth rates and increase their susceptibility to environmental stresses. These data provide an explicit mechanism that can help explain the loss of established native perennials from invaded mature forests. We propose that the physiological costs of mutualism disruption may be a widespread but previously untested mechanism enhancing the invasion of undisturbed ecosystems by allelopathic species.