• It is well-known that the mycorrhizal type of plants correlates with different modes of nutrient cycling and availability. However, the differences in drought tolerance between arbuscular mycorrhizal (AM) and ectomycorrhizal (EcM) plants remains poorly characterized.
• We synthesized a global dataset of four hydraulic traits associated with drought tolerance of 1457 woody species (1139 AM and 318 EcM species) at 308 field sites. We compared these traits between AM and EcM species, with evolutionary history (i.e. angiosperms vs gymnosperms), water availability (i.e. aridity index) and biomes considered as additional factors.
• Overall, we found that evolutionary history and biogeography influenced differences in hydraulic traits between mycorrhizal types. Specifically, we found that (1) AM angiosperms are less drought-tolerant than EcM angiosperms in wet regions or biomes, but AM gymnosperms are more drought-tolerant than EcM gymnosperms in dry regions or biomes, and (2) in both angiosperms and gymnosperms, variation in hydraulic traits as well as their sensitivity to water availability were higher in AM species than in EcM species.
• Our results suggest that global shifts in water availability (especially drought) may alter the biogeographic distribution and abundance of AM and EcM plants, with consequences for ecosystem element cycling and ultimately, the land carbon sink.

中文翻译：

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全球范围内木本植物的耐旱性状与菌根类型相关

• 
  众所周知，植物的菌根类型与不同的养分循环和利用率模式相关。然而，丛枝菌根（AM）和外生菌根（EcM）植物之间的耐旱性差异仍然知之甚少。
• 
  我们综合了 308 个田间地点的 1457 种木本物种（1139 AM 和 318 EcM 物种）与耐旱性相关的四种水力性状的全球数据集。我们比较了 AM 和 EcM 物种之间的这些特征，并将进化历史（即被子植物与裸子植物）、可用水量（即干旱指数）和生物群落视为附加因素。
• 
  总体而言，我们发现进化历史和生物地理学影响菌根类型之间水力特性的差异。具体来说，我们发现（1）在潮湿地区或生物群落中，AM 被子植物比 EcM 被子植物耐旱性较差，但在干旱地区或生物群落中，AM 裸子植物比 EcM 裸子植物更耐旱，（2）在被子植物和裸子植物中AM 物种的水力性状变异及其对水分可用性的敏感性高于 EcM 物种。
• 
  我们的研究结果表明，全球可用水量的变化（尤其是干旱）可能会改变 AM 和 EcM 植物的生物地理分布和丰度，从而对生态系统元素循环产生影响，并最终影响土地碳汇。