不同类型菌根对土壤碳循环的影响差异研究进展

Research progress in the impact of different mycorrhizal types on soil carbon cycling

菌根是陆地生态系统植物与土壤间物质相互转移的桥梁,通过影响凋落物分解、土壤团聚作用、根系分泌物等作用于土壤碳循环过程。不同类型菌根存在生理功能差异,其中外生菌根(ectomycorrhiza,ECM)和丛枝菌根(arbuscular mycorrhiza,AM)是目前已知分布最广泛的菌根类型。已有研究表明:不同类型菌根通过宿主光合产物的分配影响土壤有机碳输入;通过代谢产物及缠绕作用的差异影响土壤有机碳稳定;通过调控凋落物分解特征及菌根真菌和微生物相互作用影响土壤有机碳矿化过程。为了深入了解ECM和AM影响土壤碳循环过程及其关键调控因素,本研究主要从4个方面综述了不同类型菌根对土壤碳循环的影响并深入探讨其中的影响机制:不同菌根宿主向菌根提供碳源和凋落物数量等光合产物分配过程差异;不同菌根的碳汇功能及对土壤团聚体形成的影响;不同优势菌根生态系统中凋落物分解、激发效应、土壤呼吸等土壤有机碳矿化过程差异;不同优势菌根生态系统中土壤有机碳积累能力及相应的微生物群落差异。最后展望了今后的研究方向,旨在为“碳中和”背景下如何依托菌根提升生态系统碳汇功能提供理论依据。

Mycorrhiza is a bridge between plants and soil in terrestrial ecosystems,and acts on soil carbon cycling by affecting litter decomposition,soil aggregation,and root exudates.Different types of mycorrhiza have different physiological functions,among which ectomycorrhiza(ECM)and arbuscular mycorrhiza(AM)are the most widely distributed mycorrhizal types.Previous studies showed that different mycorrhizal types affected soil organic carbon input through the distribution of host photosynthetic products.The stability of soil organic carbon was affected by the differences of metabolites and winding action,and the soil organic carbon mineralization was affected by regulating the litter decomposition characteristics and interrelationship between mycorrhizae and microbe.In order to understand how ECM and AM affect soil carbon cycling and its key regulatory factors,this study reviewed the effects of different types of mycorrhiza on soil carbon cycling from four aspects and discussed the influence mechanisms:differences in the distribution process of photosynthetic products such as providing carbon and litter quantity to mycorrhizae,carbon sink functions of different mycorrhizal types and the impacts on soil aggregation,differences in soil organic carbon mineralization such as litter decomposition,priming effect and soil respiration in different dominant mycorrhizal ecosystems,and different accumulation capacity for soil carbon and corresponding microbial communities in different dominant mycorrhizal ecosystems.Finally,the future research direction is proposed,aiming to provide theoretical basis for how to enhance the carbon sink functions of ecosystems by relying on mycorrhiza in the context of“carbon neutrality”.