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| 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 |
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王炳超1,许黎明2*,罗龙德1,李旗霞1,蒋国凤1*
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1. 广西大学 林学院,广西森林生态与保育重点实验室,广西高校亚热带人工林培育与利用重点实验室,南宁530004；2. 广西工业职业技术学院-医药康养学院,壮瑶医药药用生物产业技术工程研究中心,壮瑶医药药用植物园,大健康协同创新中心,南宁530001
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| 摘要: |
| 为解释喀斯特森林乔木根际土壤共生菌根真菌及其关联类群，探究不同菌根类型乔木根系抗旱性，该文主要通过PacBio三代测序和测定压力-容积曲线的方法，对广西河池市木论国家级自然保护区内17个树种的根系及根际土壤真菌进行了研究。结果表明：(1)从85个土壤样品中共检测并聚类得到8 028个真菌OTUs，真菌群落以子囊菌门(Ascomycota，相对丰度70.76%)、担子菌门(Basidiomycota，相对丰度13.17%)和未分类真菌为主(Unclassified fungi，相对丰度10.41%)。(2)喀斯特植物根际土壤真菌群落的多样性主要受到丛枝菌根真菌(arbuscular mycorrhizal fungi, AMF)、外生菌根真菌(ectomycorrhizal fungi, EMF)和病原菌(Pathogen)的相对丰度影响，其中AMF相对丰度显著高于EMF(1.691%>0.698%, P<0.01)，并且共生菌根真菌与其他真菌类群相对丰度均无显著相关性。(3)选取AMF、EMF占比较高的典型树种进行比较分析，发现AM植物类群根系的饱和渗透势Ψsft、膨压丧失点水势Ψtlp和膨压丧失点相对含水量RWCtlp均显著低于EM植物类群(P<0.05)。综上所述，喀斯特森林乔木根际土壤中的AMF优势程度高于EMF。根际土壤真菌群落中其他重要的组成菌群没有对共生菌根真菌造成直接的影响。喀斯特森林中AM植物根系的抗旱性比EM植物根系更强。该研究有助于后续菌根真菌的分离和鉴定，为石漠化治理中的树种选择和菌根生物技术应用提供科学依据。 |
| 关键词: 喀斯特，根际土壤真菌，多样性，共生菌根，PacBio三代测序，水力性状 |
| DOI：10.11931/guihaia.gxzw202410049 |
| 分类号:Q939 |
| Fund project:国家自然科学基金(32460373)；广西自然科学基金 (2022GXNSFDA035059)；广西巴马县科技人才计划项目(巴人科 20220011) |
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| Rhizosphere fungal community compostions and root hydraulic traits of different mycorrhizal trees in karst forests |
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WANG Bingchao1, XU Liming2*, LUO Longde1, LI Qixia1, JIANG Guofeng1*
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1.Guangxi Colleges and Universities Key Laboratory for Cultivation and Utilization of Subtropical Forest Plantation, Guangxi Key Laboratory of Forest Ecology and Conservation, College of Forestry, Guangxi University;2.Industrial Technology Engineering Center for Zhuang &3.Yao Medicinal Organisms, Botanical Garden of Zhuang &4.Yao Medicinal Plants, Collaborative Innovation Center of Great Health, College of Medicine and Health, Guangxi Vocational &5.Technical Institute of Industry
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| Abstract: |
| To elucidate the symbiotic mycorrhizal fungi and their associated groups in the rhizosphere soil of trees in karst forests, as well as to investigate the drought resistance of tree roots associated with different mycorrhizal types. Using PacBio third-generation sequencing and pressure volume curve analysis, we examined the root and rhizosphere soil fungi of 17 tree species in the Mulun National Nature Reserve, Hechi City, Guangxi.. The results are as follows: (1) A total of 8028 fungal operational taxonomic units (OTUs) were identified and clustered from 85 soil samples, predominantly comprising Ascomycota (relative abundance: 70.76%), Basidiomycota (relative abundance: 13.17%), 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), ectomycorrhizal fungi (EMF), and pathogenic fungi (Pathogen). AMF abundance significantly exceeded EMF (1.691%>0.698%, P<0.01), with no significant correlation between symbiotic mycorrhizal fungi and other fungal groups. (3) Comparative analysis of typical tree species revealed that AM plant roots exhibited significantly lower values for saturated osmotic potential (Ψsft), turgor loss point water potential (Ψtlp), and relative water content (RWCtlp) compared to EM plants (P<0.05). These findings demonstrate the clear dominance of AMF over EMF in the rhizosphere soils of karst forest trees, with AMF being more widely distributed. Notably, other fungal community components in the rhizosphere soil did not directly influence the symbiotic mycorrhizal fungi. Furthermore, comparative analysis showed significant differences in hydraulic traits between tree roots of different mycorrhizal types in karst forests. AM plants root exhibited higher drought tolerance, maintaining water absorption and physiological metabolism under drought stress, 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 fungi, providing scientific evidence for tree species selection and the application of mycorrhizal biotechnology in desertification control. |
| Key words: karst, rhizosphere soil fungi, diversity, mycorrhizal symbiosis, PacBio third-generation sequencing, hydraulic properties |
