不同菌根类型植物细根形态性状的全球分异及其驱动机制OACHSSCD

Root functional traits are pivotal factors governing plant adaptation to environmental changes and driving belowground ecosystem functions,with their variation being significantly influenced by mycorrhizal type.A critical knowledge gap exists in our understanding of the global distribution patterns of fine root traits.However,the mechanisms underlying the global-scale divergence in fine root morphological traits between arbuscular mycorrhiza(AM)and ectomycorrhiza(ECM)plants,as well as the key environmental drivers involved,remain inadequately understood.This study aims to elucidate the differences in fine root morphological characteristics between AM and ECM plants and to uncover their response patterns to climatic factors-specifically mean annual temperature and mean annual precipitation-and root stoichiometric traits,including root nitrogen content,root carbon content,and root carbon to nitrogen ratio.Through this investigation,we seek to construct a more comprehensive theoretical framework for belowground ecology.To achieve this,we conducted a global-scale meta-analysis,employing a comprehensive analytical approach on a large-scale dataset from the FRED 2.0 database.We systematically compared key fine root morphological traits of AM and ECM plants and assessed their relationships with root stoichiometry and climate using a combination of analysis of variance(ANOVA)and path analysis,a powerful statistical technique for disentangling direct and indirect effects within a causal network.The results revealed that AM plants exhibited a significantly larger fine root diameter(0.44 mm)compared to ECM plants(0.41 mm),whereas root tissue density(0.23 g/cm3)and specific root length(27 m/g)were significantly lower in AM plants relative to ECM plants(0.42 g/cm3 and 29 m/g,respectively).These morphological differences suggest divergent resource acquisition strategies between the two mycorrhizal symbioses.Further variance analysis indicated distinct regulatory mechanisms between the two mycorrhizal types:trait variation in AM plants was mainly directly driven by root stoichiometry,with climate factors exerting a predominant indirect regulation mediated through stoichiometric changes.In contrast,ECM plant traits were directly influenced by both climate variables and root stoichiometry,indicating a more complex and immediate response to environmental gradients.Despite these differing dominant drivers,significant interactive effects between climate and root stoichiometry were identified,and their synergistic roles ultimately shaped the global distribution patterns of fine root morphological traits.Our path models quantitatively illustrated how these factors jointly create the observed biogeographical patterns.This study is the first to provide systematic evidence clarifying the synergistic roles of mycorrhizal type,root stoichiometry,and climate in co-driving the functional morphological differentiation of fine roots worldwide.The findings offer essential data support and mechanistic insights vital for understanding and predicting the impacts of global change on key belowground ecological processes.