Department of Ecology and Evolutionary Biology, University of Tennessee Knoxville, Tennessee.
Ecol Evol. 2013 Jul;3(7):2322-33. doi: 10.1002/ece3.618. Epub 2013 Jun 12.
The role of plant intraspecific variation in plant-soil linkages is poorly understood, especially in the context of natural environmental variation, but has important implications in evolutionary ecology. We utilized three 18- to 21-year-old common gardens across an elevational gradient, planted with replicates of five Populus angustifolia genotypes each, to address the hypothesis that tree genotype (G), environment (E), and G × E interactions would affect soil carbon and nitrogen dynamics beneath individual trees. We found that soil nitrogen and carbon varied by over 50% and 62%, respectively, across all common garden environments. We found that plant leaf litter (but not root) traits vary by genotype and environment while soil nutrient pools demonstrated genotype, environment, and sometimes G × E interactions, while process rates (net N mineralization and net nitrification) demonstrated G × E interactions. Plasticity in tree growth and litter chemistry was significantly related to the variation in soil nutrient pools and processes across environments, reflecting tight plant-soil linkages. These data overall suggest that plant genetic variation can have differential affects on carbon storage and nitrogen cycling, with implications for understanding the role of genetic variation in plant-soil feedback as well as management plans for conservation and restoration of forest habitats with a changing climate.
植物种内变异在植物-土壤联系中的作用尚未得到充分理解，特别是在自然环境变化的背景下，但在进化生态学中具有重要意义。我们利用三个 18 至 21 年生的、沿着海拔梯度分布的普通园地，每个园地种植了 5 个不同的银白杨基因型的重复样本，以验证以下假设：树种基因型（G）、环境（E）和 G×E 相互作用会影响单个树下的土壤碳和氮动态。我们发现，所有普通园地的土壤氮和碳分别变化了 50%和 62%以上。我们发现，植物叶片凋落物（但不是根）特性随基因型和环境而变化，而土壤养分库则表现出基因型、环境，有时还有 G×E 相互作用，而过程速率（净氮矿化和净硝化）则表现出 G×E 相互作用。树木生长和凋落物化学的可塑性与土壤养分库和跨环境过程的变化密切相关，反映了紧密的植物-土壤联系。这些数据总体表明，植物遗传变异可以对碳储存和氮循环产生不同的影响，这对于理解遗传变异在植物-土壤反馈中的作用以及气候变化下森林栖息地的保护和恢复管理计划具有重要意义。
