Climate, soil and plant functional types as drivers of global fine-root trait variation
Climate, soil and plant functional types as drivers of global fine-root trait variation
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DOI：
10.1111/1365-2745.12769
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发表时间：
2017-09-01
影响因子：
5.5
通讯作者：
Roumet, Catherine
中科院分区：
文献类型：
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作者：
Freschet, Gregoire T.;Valverde-Barrantes, Oscar J.;Roumet, Catherine
1.生态系统的功能在很大程度上依赖于地下过程，而地下过程在很大程度上受植物细根及其功能特性的调节。然而，我们对细根性状分布的了解依赖于有限的物种、生长形式和环境变化的局部和区域尺度的研究。我们编制了一个世界范围内的细根性状数据集，具有1115种不同的气候地区，植物发生和生长形式，以测试一系列假设有关的影响植物功能类型，土壤和气候变量，以及植物生长条件的操作程度上物种细根性状变异。最特别的是，我们测试了竞争的假设，即细根性状的典型的更快的投资回报率将是最强烈的限制与有利的土壤资源可用性的条件。我们考虑了数据来源和物种系统发育相关性.我们证明：（一）促进土壤肥力的气候条件与有利于快速获得土壤资源的细根特性呈负相关，温度对细根直径有特别强的正效应，对比根长有特别强的负效应，降雨对根氮浓度有特别强的负效应;（3）草本植物细根比木本植物细根更细，具有更高的SRL，且固氮能力与根氮呈正相关;（4）盆栽植物的SRL高于大田植物.合成.这项研究揭示了在全球范围内遇到的细根性状的大的变化和几个关键的植物功能类型和土壤和气候变量的相关性，解释了这种变化的很大一部分。气候，特别是温度，和植物功能类型是两个最强的细根性状变异的预测因子。高性状变异发生在地方尺度上，这表明广泛的地下资源经济战略是可行的，在大多数气候地区和土壤条件。
1. Ecosystem functioning relies heavily on below-ground processes, which are largely regulated by plant fine-roots and their functional traits. However, our knowledge of fine-root trait distribution relies to date on local-and regional-scale studies with limited numbers of species, growth forms and environmental variation.2. We compiled a world-wide fine-root trait dataset, featuring 1115 species from contrasting climatic areas, phylogeny and growth forms to test a series of hypotheses pertaining to the influence of plant functional types, soil and climate variables, and the degree of manipulation of plant growing conditions on species fine-root trait variation. Most particularly, we tested the competing hypotheses that fine-root traits typical of faster return on investment would be most strongly associated with conditions of limiting versus favourable soil resource availability. We accounted for both data source and species phylogenetic relatedness.3. We demonstrate that: (i) Climate conditions promoting soil fertility relate negatively to fine-root traits favouring fast soil resource acquisition, with a particularly strong positive effect of temperature on fine-root diameter and negative effect on specific root length (SRL), and a negative effect of rainfall on root nitrogen concentration; (ii) Soil bulk density strongly influences species fine-root morphology, by favouring thicker, denser fine-roots; (iii) Fine-roots from herbaceous species are on average finer and have higher SRL than those of woody species, and N-2-fixing capacity positively relates to root nitrogen; and (iv) Plants growing in pots have higher SRL than those grown in the field.4. Synthesis. This study reveals both the large variation in fine-root traits encountered globally and the relevance of several key plant functional types and soil and climate variables for explaining a substantial part of this variation. Climate, particularly temperature, and plant functional types were the two strongest predictors of fine-root trait variation. High trait variation occurred at local scales, suggesting that wide-ranging below-ground resource economics strategies are viable within most climatic areas and soil conditions.