Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees
Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees
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DOI：
10.1073/pnas.1601006113
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发表时间：
2016-08-02
影响因子：
11.1
通讯作者：
Eissenstat, David M.
中科院分区：
文献类型：
--
作者：
Chen, Weile;Koide, Roger T.;Eissenstat, David M.
植物生长需要叶片的光合作用和根部对水和矿物质的获取，这是许多生态系统功能的关键组成部分。虽然叶片功能性状在光合作用中的作用已被广泛了解，但根系功能性状与养分吸收的关系还不清楚。特别是，从特定的根性状的营养获取策略的预测往往是模糊的。几乎所有植物的根都与菌根真菌合作获取养分。大多数树种与丛枝菌根（AM）或外生菌根（EM）真菌形成共生。养分在土壤中的分布是不均匀的，富含养分的“热点”可能是植物的关键来源。因此，预测觅食策略，使菌根根系利用这些热点可以是至关重要的植物营养和生态系统的碳和养分循环的理解。在这里，我们表明，在13个同域温带树种，当养分供应是不完整的，薄根物种改变他们的觅食，利用补丁，而厚根物种不。此外，似乎有两个不同的途径，薄根树种增强觅食营养丰富的补丁：AM树产生更多的根，而EM树产生更多的菌根真菌菌丝。我们的研究结果表明，营养觅食的策略是互补的树种之间的对比菌根类型和根形态，地下性状和养分获取之间的可预测的关系出现时，只有根和菌根真菌一起考虑。
Photosynthesis by leaves and acquisition of water and minerals by roots are required for plant growth, which is a key component of many ecosystem functions. Although the role of leaf functional traits in photosynthesis is generally well understood, the relationship of root functional traits to nutrient uptake is not. In particular, predictions of nutrient acquisition strategies from specific root traits are often vague. Roots of nearly all plants cooperate with mycorrhizal fungi in nutrient acquisition. Most tree species form symbioses with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. Nutrients are distributed heterogeneously in the soil, and nutrient-rich "hotspots" can be a key source for plants. Thus, predicting the foraging strategies that enable mycorrhizal root systems to exploit these hotspots can be critical to the understanding of plant nutrition and ecosystem carbon and nutrient cycling. Here, we show that in 13 sympatric temperate tree species, when nutrient availability is patchy, thinner root species alter their foraging to exploit patches, whereas thicker root species do not. Moreover, there appear to be two distinct pathways by which thinner root tree species enhance foraging in nutrient-rich patches: AM trees produce more roots, whereas EM trees produce more mycorrhizal fungal hyphae. Our results indicate that strategies of nutrient foraging are complementary among tree species with contrasting mycorrhiza types and root morphologies, and that predictable relationships between below-ground traits and nutrient acquisition emerge only when both roots and mycorrhizal fungi are considered together.