Page 61 - 《广西植物》2025年第6期
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6 期        王炳超等: 喀斯特森林不同菌根类型乔木根际真菌群落组成及根系水力性状差异                                           1 0 4 7

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                   WANG Bingchao ꎬ XU Liming ꎬ LUO Longde ꎬ LI Qixia ꎬ JIANG Guofeng
             ( 1. Guangxi Key Laboratory of Forest Ecology and Conservationꎬ Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization
             of Subtropical Forest Plantationꎬ College of Forestryꎬ Guangxi Universityꎬ Nanning 530004ꎬ Chinaꎻ 2. Industrial Technology Engineering Center
                for Zhuang & Yao Medicinal Organismsꎬ Botanical Garden of Zhuang & Yao Medicinal Plantsꎬ Collaborative Innovation Center of Great
                   Healthꎬ College of Medicine and Health Careꎬ Guangxi Vocational & Technical Institute of Industryꎬ Nanning 530001ꎬ China )

                 Abstract: To elucidate the symbiotic mycorrhizal fungi and their associated groups in the rhizosphere soil of trees in
                 karst forestsꎬ as well as to investigate the drought resistance of tree roots associated with different mycorrhizal
                 types. Mainly using PacBio third ̄generation sequencing and pressure volume curve analysisꎬ this paper examined the root
                 and rhizosphere soil fungi of 17 tree species in the Mulun National Nature Reserveꎬ Hechi Cityꎬ Guangxi. The results
                 were as follows: (1) A total of 8 028 fungal operational taxonomic units (OTUs) were identified and clustered from 85
                 soil samplesꎬ predominantly comprising Ascomycota (relative abundance 70.76%)ꎬ Basidiomycota (relative abundance
                 13.17%)ꎬ and unclassified fungi (relative abundance 10.41%). (2) Rhizosphere soil fungal community diversity in
                 karst plants was primarily influenced by the relative abundance of arbuscular mycorrhizal fungi (AMF)ꎬ ectomycorrhizal
                 fungi (EMF)ꎬ and pathogenic fungi (Pathogen). AMF abundance significantly exceeded EMF (1.691%>0.698%ꎬ P<
                 0.01)ꎬ with no significant correlation between symbiotic mycorrhizal fungi and other fungal groups. (3) Comparative
                 analysis of typical tree species with high AMF and EMF percentages revealed that AM plant roots exhibited significantly
                 lower values for saturated osmotic potential (Ψ )ꎬ turgor loss point water potential (Ψ )ꎬ and relative water content at
                                                   sft                          tlp
                 turgor loss point (RWC ) compared to EM plants (P<0.05). In conclusionꎬ the dominance of AMF over EMF in the
                                  tlp
                 rhizosphere soils of karst forest treesꎬ with AMF being more widely distributed. Notablyꎬ other fungal community
                 components in the rhizosphere soil did not directly influence the symbiotic mycorrhizal fungi. Furthermoreꎬ comparative
                 analysis showed significant differences in hydraulic traits between tree roots of different mycorrhizal types in karst
                 forests. AM plants root exhibited higher drought toleranceꎬ maintaining water absorption and physiological metabolism
                 under drought stressꎬ compared to EM plants root. This enhanced drought resistance in AM plants roots suggests greater
                 adaptability to the unique karst habitat conditions. Future research should focus on the application of advanced
                 sequencing technologies to further elucidate specific mycorrhizal fungi associations. This study contributes to the future
                 isolation and identification of mycorrhizal fungiꎬ providing scientific evidence for tree species selection and the
                 application of mycorrhizal biotechnology in desertification control.
                 Key words: karstꎬ rhizosphere soil fungiꎬ diversityꎬ mycorrhizal symbiosisꎬ PacBio third ̄generation sequencingꎬ
                 hydraulic traits



                喀斯特是一种高度特殊的地貌ꎬ主要由石灰                            生体( Brundrett & Tedersooꎬ 2018)ꎮ 丛枝菌根真
            岩和白云石组成(Ni et al.ꎬ 2015)ꎮ 中国南方亚热                   菌(arbuscular mycorrhizal fungiꎬ AMF) 与绝大部分
            带喀斯特地区面积超过 54 万 hm ꎬ近年来经历了                         的陆地植物形成共生关系ꎬ并被普遍认为能与植
                                           2
            快速 且 密 集 的 土 地 利 用 变 化 和 生 态 系 统 退 化               物互相传递养分 (Smith & Smithꎬ 2012)ꎮ 外生菌
            (Geekiyanage et al.ꎬ 2019ꎻ Green et al.ꎬ 2019)ꎮ    根真菌(ectomycorrhizal fungiꎬ EMF)会通过包裹式
            受到可溶性碳酸岩质地制约ꎬ典型喀斯特地区的                              对根供给养分并酸化土壤ꎬ保护根系不受土壤病
            表层裸岩土层浅薄ꎬ岩石孔隙密度大ꎬ导致其持水                             原体侵害(Tedersoo et al.ꎬ 2020)ꎮ 虽然 EMF、AMF
            能力非常低ꎬ降雨会迅速渗透到深层的喀斯特非                              和宿主的关系都是通过交换营养元素获取宿主植
            饱和或饱和潜水带( Ding et al.ꎬ 2020)ꎬ这将形成                  物光合作用的碳ꎬ但是它们的主要分布区域存在
            特殊的地质性干旱ꎬ给喀斯特地区森林植被的生                              明显 差 异 ( Tedersoo et al.ꎬ 2010 )ꎮ 丛 枝 菌 根

            存发展带来严峻考验ꎮ                                         (arbuscular mycorrhizalꎬ AM)植物往往在高降水和
                 菌根真菌共生是一种普遍且重要的植物功能                           高温的低纬度地区( 如热带雨林) 占主导地位ꎬ而
            特性ꎬ90%以上的植物会与菌根真菌结合形成共                             外生菌根( ectomycorrhizalꎬ EM) 植物主要生长在
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