Root functional parameters along a land-use gradient: evidence of a community-level economics spectrum
Root functional parameters along a land-use gradient: evidence of a community-level economics spectrum
复制标题
DOI：
10.1111/1365-2745.12351
复制
发表时间：
2015-03-01
影响因子：
5.5
通讯作者：
Stokes, Alexia
中科院分区：
文献类型：
--
作者：
Prieto, Ivan;Roumet, Catherine;Stokes, Alexia
在与资源获取或资源保护相关的叶性状之间存在基本的权衡。这种性状变异的梯度，称为经济谱，也适用于细根，但它是否是一致的粗根或在植物群落水平仍然未经检验。我们测量了一组形态和化学根性状在社区水平（功能参数; FP）在20个植物群落位于沿着土地利用强度梯度和跨越三个气候带（热带，地中海和山地）。我们假设：（i）在植物群落中存在与根系类型一致的根系经济谱（细，<2 mm;粗，2- 5 mm），（ii）根系FP随土壤深度（土壤顶部20 cm和100- 150 cm深）发生变化，（iii）沿着土地利用梯度。根FP协变，符合资源获取-保护权衡，从与资源获取相关的根FP（如高比根长，SRL;细直径和低根干物质含量，RDMC）的社区到与资源保护相关的根FP（如低SRL，粗直径和高RDMC）。这种模式是一致的细根和粗根，表明植物根系的资源获取和保护之间的权衡强的一致性。根在不同深度具有不同的特征，表明根功能和利用能力的差异。浅，细根较薄，更丰富的氮和低木质素浓度与更大的开发能力相比，深，细根。浅，粗根更丰富的氮，碳和可溶性浓度比深，粗根。细根参数的高度干扰，草本占主导地位的植物群落在较贫困的土壤与觅食策略，即更大的SRL和较低的RDMC和木质素浓度比那些干扰较少的社区。粗根，然而，不太敏感的土地利用梯度。这项研究表明，存在一个一般的权衡在根结构在社会层面上，它在所有的根类型，这表明所有的植物组织控制的资源获取和保护之间的权衡。
There is a fundamental trade-off between leaf traits associated with either resource acquisition or resource conservation. This gradient of trait variation, called the economics spectrum, also applies to fine roots, but whether it is consistent for coarse roots or at the plant community level remains untested. We measured a set of morphological and chemical root traits at a community level (functional parameters; FP) in 20 plant communities located along land-use intensity gradients and across three climatic zones (tropical, mediterranean and montane). We hypothesized (i) the existence of a root economics spectrum in plant communities consistent within root types (fine, < 2mm; coarse, 2-5mm), (ii) that variations in root FP occur with soil depths (top 20cm of soil and 100-150cm deep) and (iii) along land-use gradients. Root FP covaried, in line with the resource acquisition-conservation trade-off, from communities with root FP associated with resource acquisition (e.g. high specific root length, SRL; thin diameters and low root dry matter contents, RDMC) to root FP associated with resource conservation (e.g. low SRL, thick diameters and high RDMC). This pattern was consistent for both fine and coarse roots indicating a strong consistency of a trade-off between resource acquisition and conservation for plant roots. Roots had different suites of traits at different depths, suggesting a disparity in root function and exploitation capacities. Shallow, fine roots were thinner, richer in nitrogen and with lower lignin concentrations associated with greater exploitation capacities compared to deep, fine roots. Shallow, coarse roots were richer in nitrogen, carbon and soluble concentrations than deep, coarse roots. Fine root parameters of highly disturbed, herbaceous-dominated plant communities in poorer soils were associated with foraging strategies, that is greater SRL and lower RDMC and lignin concentration than those from less disturbed communities. Coarse roots, however, were less sensitive to the land-use gradient.Synthesis. This study demonstrates the existence of a general trade-off in root construction at a community level, which operates within all root types, suggesting that all plant tissues are controlled by the trade-off between resource acquisition and conservation.