Experimentally reduced root-microbe interactions reveal limited plasticity in functional root traits in Acer and Quercus.
Experimentally reduced root-microbe interactions reveal limited plasticity in functional root traits in Acer and Quercus.
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DOI：
10.1093/aob/mct276
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发表时间：
2014-02
期刊：
影响因子：
4.2
通讯作者：
Mei-ho Lee;L. Comas;H. Callahan
中科院分区：
文献类型：
--
作者：
Mei-ho Lee;L. Comas;H. Callahan
背景和目的根系和土壤微生物之间的相互作用是地下生态的关键组成部分。量化物种间和物种内根部性状变异的程度至关重要，包括由于可塑性引起的变异。除了将可塑性的大小与物种之间的差异联系起来之外，可塑性的研究还可以确定可塑性是否可预测，以及环境因素是否会引起功能上有利的性状变化。方法为了比较细根组织的功能性状和性状可塑性与自然和降低的微生物共生体定植水平，对2年生红枫和红栎幼苗进行修剪和表面消毒的根段进行操作。然后将片段重新种植到装满对照土壤或热处理土壤的卫星盆中，这两种土壤最初都来自天然森林。在热处理土壤中生长的根中，菌根定殖几乎为零；在对照土壤中生长的根与从田间收集的未经处理的根样本中观察到的较高定植水平相匹配。主要结果 处理间比较显示，两个物种的根直径、分枝强度和氮浓度的可塑性可以忽略不计。经过处理的土壤的根部组织密度降低（约 10-20%），比根长度增加（约 10-30%）。相比之下，在组织密度以外的性状上，物种差异显着且大于治疗效果。田间样品中的种间性状差异也很显着，通常类似于温室样品。结论 与种间和种内性状变异相比，实验和现场方法的结合有助于将性状可塑性置于背景中。关于根性状在很大程度上取决于物种的发现（根组织密度除外），在当前关于根性状变异、与共生体的相互作用以及量化根性状方法标准化的最新进展的文献的背景下进行了讨论。
BACKGROUND AND AIMS Interactions between roots and soil microbes are critical components of below-ground ecology. It is essential to quantify the magnitude of root trait variation both among and within species, including variation due to plasticity. In addition to contextualizing the magnitude of plasticity relative to differences between species, studies of plasticity can ascertain if plasticity is predictable and whether an environmental factor elicits changes in traits that are functionally advantageous. METHODS To compare functional traits and trait plasticities in fine root tissues with natural and reduced levels of colonization by microbial symbionts, trimmed and surface-sterilized root segments of 2-year-old Acer rubrum and Quercus rubra seedlings were manipulated. Segments were then replanted into satellite pots filled with control or heat-treated soil, both originally derived from a natural forest. Mycorrhizal colonization was near zero in roots grown in heat-treated soil; roots grown in control soil matched the higher colonization levels observed in unmanipulated root samples collected from field locations. KEY RESULTS Between-treatment comparisons revealed negligible plasticity for root diameter, branching intensity and nitrogen concentration across both species. Roots from treated soils had decreased tissue density (approx. 10-20 %) and increased specific root length (approx. 10-30 %). In contrast, species differences were significant and greater than treatment effects in traits other than tissue density. Interspecific trait differences were also significant in field samples, which generally resembled greenhouse samples. CONCLUSIONS The combination of experimental and field approaches was useful for contextualizing trait plasticity in comparison with inter- and intra-specific trait variation. Findings that root traits are largely species dependent, with the exception of root tissue density, are discussed in the context of current literature on root trait variation, interactions with symbionts and recent progress in standardization of methods for quantifying root traits.