Grassland species root response to drought: consequences for soil carbon and nitrogen availability
Grassland species root response to drought: consequences for soil carbon and nitrogen availability
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DOI：
10.1007/s11104-016-2964-4
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发表时间：
2016-12-01
期刊：
影响因子：
4.9
通讯作者：
Stevens, Carly J.
中科院分区：
文献类型：
--
作者：
de Vries, Franciska T.;Brown, Caley;Stevens, Carly J.
根系性状越来越多地用于预测植物如何改变土壤过程。在这里，我们评估了干旱引起的四种常见的草地植物根系的变化如何影响土壤中的C和N的可用性。我们假设干旱会促进资源保守的根系性状，如高的根组织密度（RTD）和低的比根长（SRL），这些变化会通过减少根系N吸收而导致土壤N有效性的提高，但通过减少根系分泌而导致C有效性的降低。干旱通过降低根系生物量影响了大部分根系性状。只有SRL和RTD表现出可塑性，干旱降低SRL，并增加RTD在小的植物，但降低RTD在较大的植物。减少根生物量和转向更资源保守的根性状增加土壤无机氮的可用性，但没有直接影响土壤C availability.These研究结果确定机制，通过干旱引起的根系变化影响土壤C和N的可用性，并有助于我们了解根性状如何修改土壤过程中不断变化的世界。
Root traits are increasingly used to predict how plants modify soil processes. Here, we assessed how drought-induced changes in root systems of four common grassland species affected C and N availability in soil. We hypothesized that drought would promote resource-conservative root traits such as high root tissue density (RTD) and low specific root length (SRL), and that these changes would result in higher soil N availability through decreased root N uptake, but lower C availability through reduced root exudation.We subjected individual plants to drought under controlled conditions, and compared the response of their root biomass, root traits, and soil C and N availability, to control individuals.Drought affected most root traits through reducing root biomass. Only SRL and RTD displayed plasticity; drought reduced SRL, and increased RTD in small plants but decreased RTD in larger plants. Reduced root biomass and a shift towards more resource-conservative root traits increased soil inorganic N availability but did not directly affect soil C availability.These findings identify mechanisms through which drought-induced changes in root systems affect soil C and N availability, and contribute to our understanding of how root traits modify soil processes in a changing world.