Fine root respiration is more strongly correlated with root traits than tree species identity
Fine root respiration is more strongly correlated with root traits than tree species identity
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DOI：
10.1002/ecs2.2944
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发表时间：
2019-11
期刊：
影响因子：
2.7
通讯作者：
Eva Paradiso;F. Jevon;J. Matthes
中科院分区：
文献类型：
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作者：
Eva Paradiso;F. Jevon;J. Matthes
分配给根系的碳占净初级生产力的很大一部分，但碳的命运知之甚少。吸收性细根是植物获取养分的主要途径。以前的研究已经评估了根形态性状之间的关系，包括比根长，根组织密度，和菌根定植，在广泛的功能和分类组，以测试存在的根经济谱（RES）。细根也通过呼吸释放二氧化碳，其他研究发现了单个树种的根形态特征和根呼吸之间的关系。本研究的目的是测量一套根性状在6个共同发生的温带树种，代表了一组不同的地上特征，以确定是否以及如何根特性影响根呼吸内和种间。在美国马萨诸塞州Petersham的哈佛森林，我们于2018年6月和7月测量了6个树种的292个根系的细根呼吸，根系形态，外生菌根物种的定殖率以及碳和氮浓度。我们发现，大多数细根形态特征的变化几乎尽可能多的每个树种之间的六个物种。在我们的研究的两个月期间，根性状随时间变化是动态的，在整个研究期间，每周平均性状值的幅度变化32-95%。性状之间的强相关性表明权衡频谱从资源获取（长，薄，高氮的根），以资源保护（厚，密，低氮的根），和性状不聚类树种在此范围内的频谱。沿着温度和周时变化，资源获取策略（高氮的细长根）与较高的根呼吸相关，且这种关系在6种植物中一致。这项研究支持RES和呼吸之间的强有力的联系，独立于物种的身份，这提供了深入了解功能轴缩放根呼吸从个别树木的林分，以更好地量化地下碳通量。
Carbon allocated to roots accounts for a large portion of net primary productivity, but the fate of that carbon is poorly understood. Absorptive fine roots are the primary way in which plants acquire nutrients. Previous studies have evaluated relationships among root morphological traits, including specific root length, root tissue density, and mycorrhizal colonization, across broad functional and taxonomic groups to test for the existence of a root economics spectrum (RES). Fine roots also release carbon dioxide through respiration, and other studies have found relationships between root morphological traits and root respiration within individual tree species. The objective of this study was to measure a suite of root traits in six co-occurring temperate tree species that represent a diverse set of aboveground traits to determine whether and how root characteristics influenced root respiration both within and among species. At the Harvard Forest in Petersham, Massachusetts, USA, we measured fine root respiration, root morphology, percent colonization for ectomycorrhizal species, and carbon and nitrogen concentrations on 292 roots from six tree species in June and July 2018. We found that most fine root morphological characteristics varied nearly as much within each tree species as they did among the six species. Root traits were dynamic over time during the two months of our study, where the magnitude of weekly mean trait values varied 32–95% across the study period. Strong correlations among traits suggested trade-offs on a spectrum from resource acquisition (long, thin, high-nitrogen roots) to resource conservation (thick, dense, low-nitrogen roots), and traits were not clustered by tree species within this spectrum. Along with temperature and weekly temporal variation, the resource acquisition strategy (long and thin roots that were high in nitrogen) was associated with higher root respiration, and this relationship was consistent among the six species. This study supported a strong link between the RES and respiration independent of species identity, which provides insight into functional axes for scaling root respiration from individual trees to the forest stand to better quantify belowground carbon flux.