亚热带常绿阔叶林丛枝菌根树种养分觅食策略及其与细根形态间的关系  

Nutrient foraging strategies of arbuscular mycorrhizal tree species in a subtropical evergreen broadleaf forest and their relationship with fine root morphology

作　　者：曲泽坤 朱丽琴 姜琦 王小红[1] 姚晓东 蔡世锋 罗素珍 陈光水[1] QU Ze-Kun;ZHU Li-Qin;JIANG Qi;WANG Xiao-Hong;YAO Xiao-Dong;CAI Shi-Feng;LUO Su-Zhen;CHEN Guang-Shui(School of Geosciences,Key Laboratory of Humid Subtropical Ecological and Geographic Processes,Ministry of Education,Fujian Normal University,Fuzhou 350007,China;Youxi State Owned Forest Farm,Fuzhou 365100,China)

机构地区：[1]福建师范大学地理科学学院,福建师范大学湿润亚热带生态地理过程教育部重点实验室,福州350007 [2]尤溪国有林场,福州365100

出　　处：《植物生态学报》2024年第4期416-427,共12页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(31830014)。

摘　　要：植物细根和丛枝菌根(AM)真菌的养分觅食策略直接影响植物的生产力与碳汇能力,是森林生态系统稳定性的关键影响因素。养分觅食精度是养分觅食策略的重要方面,指植物将其根系、菌丝精准地部署到养分相对丰富斑块中的能力。然而,目前对内生菌根树种细根和菌根菌丝觅食精度间的权衡关系,以及细根形态能否较好地预测觅食精度仍存在争议。该研究对中亚热带天然常绿阔叶林内17个AM树种进行野外原位根袋磷添加实验,以模拟土壤中磷养分斑块。施加磷肥4个月后,对对照组和磷添加组的细根进行形态扫描和分析,采用膜过滤法提取土壤中的菌丝并用电子显微镜观测,筛选中部无隔膜且易于染色的菌丝作为AM内生菌根菌丝,计算其长度。在此基础上,计算根长觅食精度和菌丝觅食精度,以研究亚热带AM树种的根长觅食精度与菌丝觅食精度间的权衡及其与细根形态间的相关关系。主要结果有:(1)AM树种根长觅食精度与菌丝觅食精度间相互独立;(2)细根组织密度与根长觅食精度呈显著正相关关系;(3)细根直径与菌丝觅食精度呈显著负相关关系,比根长与菌丝觅食精度呈显著正相关关系。该研究结果有助于理解亚热带常绿阔叶林AM树种根系养分觅食策略,表明细根形态等易观测指标可用于评估AM树种细根养分觅食精度。Aims The nutrient foraging strategies of fine roots and arbuscular mycorrhizal(AM)fungi directly affect plant productivity and carbon sequestration,which are a key factor influencing the stability of forest ecosystems.Nutrient foraging accuracy is an important aspect of the nutrient foraging strategy,which refers to the ability of plants to accurately deploy their roots and mycelia to relatively nutrient-rich patches.However,the tradeoff between foraging precision of root length and foraging precision of mycelia of arbuscular mycorrhizal tree species and whether fine root morphology can predict foraging accuracy are still controversial.Methods In this study,17 AM tree species in a natural broadleaf evergreen forest in the central subtropics were tested for responses to phosphorus addition to in situ root bags in the field to simulate phosphorus nutrient patches in the soil.After 4 months application of phosphorus fertilizer,morphological scanning and analysis were carried out on the fine roots of the control group and the phosphorus addition group.Mycelia in the soil were extracted by the membrane filtration method and observed by electron microscope.Mycelia with no septa in the middle and easy to stain were screened as AM mycelia,and their length was calculated.On this basis,root length foraging precision and mycelial foraging precision were calculated to investigate their trade-off and also their correlation with fine root morphology in subtropical AM tree species.Important findings Root length foraging precision and mycelial foraging precision of AM species were independent of each other.There was a significant positive correlation between fine root tissue density and root length foraging precision,a significant negative correlation between fine root diameter and mycelial foraging precision,and a significant positive correlation between specific root length and mycelial foraging precision.These results can help understand root nutrient foraging strategies of AM species in subtropical evergreen broadleaf forest

关 键 词：内生菌根 根长 菌丝 觅食精度 细根形态 植物地下生态 

分 类 号：S718.5[农业科学—林学]