Cultivation Base of State Key Laboratory for Humid Subtropical Mountain Ecology, Fujian Normal University/Institute of Geography, Fujian Normal University, Fuzhou 350007, China.
Ying Yong Sheng Tai Xue Bao. 2021 Feb;32(2):529-537. doi: 10.13287/j.1001-9332.202102.025.
We measured the morphology traits (specific root length, specific root surface area, root tissue density, average root diameter) and architecture traits (root fork, root fork ratio, increase rate of root length, root tip density, root fork density) of fine roots in two mycorrhiza tree species, (ectomycorrhizal) and (arbuscular mycorrhizal), in an evergreen broadleaved forest in the middle subtropical zone. Root bags method was used in an nitrogen deposition experiment. The aim of this study was to reveal the differences in the plastic responses of fine root morphology and architecture traits to nitrogen deposition between the different mycorrhizal trees. The plastic responses of specific root length, specific root surface area and root fork to nitrogen addition decreased from the first-order root to the fourth-order root, while root tissue density showed an opposite pattern. Such a result indicated a trade-off between nutrient acquisition and resource maintenance of different fine root orders. Different mycorrhizal tree species adopted diffe-rent adaptation strategies to the variations of soil nitrogen availability. adopted an opportuni-stic strategy, which relied on fine root to improve nutrient absorption efficiency, enhanced the capacity of space expansion and nutrient absorption to focus on rapid nutrient absorption strategy. did not change fine root morphological traits through the trade-off between nutrient absorption efficiency and root construction cost, but relied more on the complementarity between mycorrhizal fungi and fine root architecture traits for nutrient acquisition. The differences in the cost of maintaining and constructing fine root C between different mycorrhizal trees led to fine root adopting the most suitable nutrient capture strategy.
我们测量了两种菌根树种（外生菌根）和（丛枝菌根）细根的形态特征（比根长、比根表面积、根组织密度、平均根直径）和结构特征（根叉、根叉比、根长增长率、根尖密度、根叉密度）在中亚热带常绿阔叶林的氮沉降实验中。采用根袋法。本研究的目的是揭示不同菌根树种细根形态和结构特征对氮沉降的可塑性响应差异。比根长、比根表面积和根叉对氮添加的可塑性响应从一级根到四级根降低，而根组织密度则呈现相反的模式。这一结果表明不同细根级别的养分获取和资源维持之间存在权衡。不同的菌根树种对土壤氮有效性的变化采用了不同的适应策略。 采用了机会主义策略，依赖细根提高养分吸收效率，增强空间扩展能力和养分吸收能力，以关注快速养分吸收策略。并没有通过养分吸收效率和根建设成本之间的权衡来改变细根形态特征，而是更多地依赖菌根真菌和细根结构特征之间的互补性来获取养分。不同菌根树种之间细根碳维持和构建成本的差异导致细根采用最适合的养分捕获策略。
