Functional diversity of microbial decomposers facilitates plant coexistence in a plant-microbe-soil feedback model
Functional diversity of microbial decomposers facilitates plant coexistence in a plant-microbe-soil feedback model
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DOI：
10.1073/pnas.0914281107
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发表时间：
2010-08-10
影响因子：
11.1
通讯作者：
Kondoh, Michio
中科院分区：
文献类型：
--
作者：
Miki, Takeshi;Ushio, Masayuki;Kondoh, Michio
理论和经验证据表明，植物-土壤反馈（PSF）决定了陆地生态系统中植物群落的结构和养分循环。植物群落通过影响凋落物分解过程改变土壤中养分库的大小，进而塑造植物群落，形成PSF系统。然而，微生物分解者在PSF功能中的作用往往被忽视，目前仍不清楚分解者是否加强或削弱凋落物介导的植物对养分循环的控制。在这里，我们提出了一个理论模型，将植物和微生物分解的功能多样性。两个基本的微生物过程控制养分矿化从植物凋落物：（i）矿化的养分同化到微生物生物量（微生物固定化），和（ii）微生物养分释放到无机养分池（净矿化）。通过这个模型，我们表明，微生物多样性可以作为一种缓冲，削弱植物对土壤养分库的控制，扭转PSF的符号从积极到消极，促进植物共存。这是解释的脱钩凋落物分解和营养池的大小所产生的灵活的变化，在微生物群落组成和分解过程中，在植物凋落物分解的变化。我们的研究结果表明，微生物群落在PSF功能和植物群落结构中起着核心作用。此外，研究结果强烈暗示，以植物为中心的养分循环的观点应该改变为植物-微生物-土壤反馈系统，通过纳入微生物分解者的群落生态学及其功能多样性。
Theory and empirical evidence suggest that plant-soil feedback (PSF) determines the structure of a plant community and nutrient cycling in terrestrial ecosystems. The plant community alters the nutrient pool size in soil by affecting litter decomposition processes, which in turn shapes the plant community, forming a PSF system. However, the role of microbial decomposers in PSF function is often overlooked, and it remains unclear whether decomposers reinforce or weaken litter-mediated plant control over nutrient cycling. Here, we present a theoretical model incorporating the functional diversity of both plants and microbial decomposers. Two fundamental microbial processes are included that control nutrient mineralization from plant litter: (i) assimilation of mineralized nutrient into the microbial biomass (microbial immobilization), and (ii) release of the microbial nutrients into the inorganic nutrient pool (net mineralization). With this model, we show that microbial diversity may act as a buffer that weakens plant control over the soil nutrient pool, reversing the sign of PSF from positive to negative and facilitating plant coexistence. This is explained by the decoupling of litter decomposability and nutrient pool size arising from a flexible change in the microbial community composition and decomposition processes in response to variations in plant litter decomposability. Our results suggest that the microbial community plays a central role in PSF function and the plant community structure. Furthermore, the results strongly imply that the plant-centered view of nutrient cycling should be changed to a plant-microbe-soil feedback system, by incorporating the community ecology of microbial decomposers and their functional diversity.