Deep roots of Carex aquatilis have greater ammonium uptake capacity than shallow roots in peatlands following permafrost thaw
Deep roots of Carex aquatilis have greater ammonium uptake capacity than shallow roots in peatlands following permafrost thaw
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DOI：
10.1007/s11104-021-04978-x
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发表时间：
2021-05
期刊：
影响因子：
4.9
通讯作者：
Lucas J. Albano;M. Turetsky;M. Mack;E. Kane
中科院分区：
文献类型：
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作者：
Lucas J. Albano;M. Turetsky;M. Mack;E. Kane
北部生态系统的气候变暖正在引发广泛的永久冻土融化，在此期间深层土壤养分（例如氮）可能可供生物吸收。永久冻土融化会使冷冻有机物转变为饱和状态，这可能会阻碍养分的吸收。我们评估了热岩溶沼泽中维管束植物的深根是否可以获取土壤氮，从而可能提高初级生产力。方法我们对苔草进行了铵吸收实验。从阿拉斯加内陆的热岩溶沼泽中挖掘出的树根。比较深根和浅根的铵吸收能力。我们还量化了主动解冻边缘和每个热喀斯特沼泽中心之间根部铵吸收能力和植物尺寸特征（植物地上和地下生物量、最大芽高和最大根长）的差异，作为解冻时间的代理。结果深根比浅根具有更大的铵吸收能力，而根部深度（而非地下生物量）与地上生物量呈正相关。尽管边缘和中心之间的地上生物量没有差异，但我们的研究结果表明，植物可以通过投资获取垂直解冻前沿附近的资源而受益。结论我们的结果表明，C. aquatiliscan 有助于植物吸收氮，因此能够耐受饱和热喀斯特沼泽的缺氧条件。这项工作进一步加深了我们对亚北极和湿地植物如何应对变暖的理解，以及增强植物生物量生产如何有助于抵消未来永久冻土融化带来的生态系统碳释放。
AimsClimate warming in northern ecosystems is triggering widespread permafrost thaw, during which deep soil nutrients, such as nitrogen, could become available for biological uptake. Permafrost thaw shift frozen organic matter to a saturated state, which could impede nutrient uptake. We assessed whether soil nitrogen can be accessed by the deep roots of vascular plants in thermokarst bogs, potentially allowing for increases in primary productivity.MethodsWe conducted an ammonium uptake experiment onCarex aquatilisWahlenb. roots excavated from thermokarst bogs in interior Alaska. Ammonium uptake capacity was compared between deep and shallow roots. We also quantified differences in root ammonium uptake capacity and plant size characteristics (plant aboveground and belowground biomass, maximum shoot height, and maximum root length) between the actively-thawing margin and the centre of each thermokarst bog as a proxy for time-following-thaw.ResultsDeep roots had greater ammonium uptake capacity than shallow roots, while rooting depth, but not belowground biomass, was positively correlated with aboveground biomass. Although there were no differences in aboveground biomass between the margin and centre, our findings suggest that plants can benefit from investing in the acquisition of resources near the vertical thaw front.ConclusionsOur results suggest that deep roots ofC. aquatiliscan contribute to plant nitrogen uptake and are therefore able to tolerate anoxic conditions in saturated thermokarst bogs. This work furthers our understanding of how subarctic and wetland plants respond to warming and how enhanced plant biomass production might help offset ecosystem carbon release with future permafrost thaw.