菌根组合类型对森林总初级生产力应对温度和降水变化的影响

摘要

Symbiotic associations between plant roots and mycorrhizal fungi are almost ubiquitous in forest ecosystems.Mycorrhizal fungi play a crucial role in the regulation of terrestrial gross primary production (GPP),coupled with climatic changes in temperature and precipitation altering the carbon cycle.This study aimed to explore how temperature and precipitation influence GPP in global forest ecosystems that are classified by the mycorrhizal association of the dominant plants.New databases were created to investigate GPP and mean annual temperature (MAT),mean annual precipitation (MAP) and leaf area index (LAI) of forests dominated by different mycorrhizal strategies based on an existing global forest database.The responses of forest GPP to changes of MAT,MAP,and LAI changed with the differences of mycorrhizal strategies.Of all forests dominated by five different mycorrhizal types including arbuscular mycorrhiza (AM),AM+ectomycorrhiza (ECM,ECM,ECM+ectendomycorrhiza (EEM) and ECM+EEM+ nonmycorrhiza (NM),GPP increased with the enhancement of MAT.The highest GPP was observed in AM dominated forest with the value of 1 994.05 g·m2·a-1.The GPP in AM dominated forest was most sensitive to temperature change with the explained rate of 88.27％.The responses of GPP were contrary to MAP change in different forests donated by five mycorrhizal strategies.The relationship between GPP and MAP in ECM+EEM dominated forest was contrary to others with negative relationship.As far as the effect of LAI was concerned,GPP enhanced with increase of LAI in all mycorrhizal dominated forest,though the pattern between them were varied in different mycorrhizal dominated forests.The relationship between LAI and GPP is bestly simulated in AM+EEM dominated forest with r2=0.423.This investigation highlights mycorrhizas important influence on GPP and responses of forest to global climatic changes.%菌根是自然界中普遍存在的一类互惠共生体,在植物生产力及其应对全球变化的过程中发挥着重要作用.文章基于全球森林数据库,建立了包括全球森林菌根类型、总初级生产力(Gross Primary Production,GPP)、年平均气温和年降水量以及叶面积指数等指标的新数据库.基于该数据库,分析了5种不同菌根组合类型[AM、AM+ECM(ectomycorrhiza)、ECM、ECM+EEM和ECM+EEM(ectendomycorrhiza)+NM(nonmycorrhiza)]森林GPP的状况;并在此基础上,研究了不同组合类型菌根对森林GPP应对温度、降水和叶面积指数变化的影响,旨在揭示菌根在全球变化过程中的重要角色,以丰富菌根生态功能的理论基础;并为更准确地估测生态系统对气候变化的响应及其规律提供菌根作用数据.结果表明,不同菌根组合类型森林GPP存在显著差异,森林GPP对温度、降水和叶面积变化的响应受到菌根组合类型的影响.在所研究的5种菌根组合类型中,森林GPP都随温度的升高而显著增加;其中,AM组合类型森林的GPP最高(1 994.05 g·m-2·a-1),受温度变化的影响也最大,温度变化对GPP的解释率达到88.27％.森林GPP对降水变化的反应则随菌根组合类型的变化而相差较大,在ECM+EEM组合类型森林中,GPP与降水呈现负相关关系;而在其他4种菌根组合类型的森林中,随降水的增大,GPP呈现出不同程度的增加.森林GPP虽然在所有菌根组合类型森林中,都随叶面积的增加而增大,却因菌根组合类型的不同,其变化过程有所差别;在AM+ECM中二者关系最密切(r2=0.423).因此,菌根组合类型在森林GPP及其对全球变化响应方面都发挥着重要作用.