植物生态学报 ›› 2025, Vol. 49 ›› Issue (7): 1163-1176.DOI: 10.17521/cjpe.2024.0428  cstr: 32100.14.cjpe.2024.0428

• 研究论文 • 上一篇    

典型草原优势植物根际细菌群落多样性和功能群组成对长期放牧的响应机制

崔冬晴1,2, 田晨2, 宋慧敏2, 鲁小名2,3, 萨其日4, 徐国庆4, 杨培志1,*(), 白永飞2,3, 田建卿2,3,*()   

  1. 1西北农林科技大学草业与草原学院, 陕西杨凌 712100
    2中国科学院植物研究所植被与环境变化重点实验室, 北京 100093
    3国家植物园, 北京 100093
    4锡林浩特市草原工作站, 内蒙古锡林浩特 026099
  • 收稿日期:2024-12-02 接受日期:2025-01-20 出版日期:2025-07-20 发布日期:2025-01-20
  • 通讯作者: *杨培志, E-mail: yangpeizhi@126.com;
    田建卿, E-mail: tianjq@ibcas.ac.cn
  • 基金资助:
    国家重点研发计划(2023YFF1304101)

Response mechanisms of rhizosphere bacterial community diversity and functional group composition of dominant plants in typical grasslands to long-term grazing

CUI Dong-Qing1,2, TIAN Chen2, SONG Hui-Min2, LU Xiao-Ming2,3, SA Qi-Ri4, XU Guo-Qing4, YANG Pei-Zhi1,*(), BAI Yong-Fei2,3, TIAN Jian-Qing2,3,*()   

  1. 1College of Grassland Agriculture, Northwest A&F University, Yangling, Shaanxi 712100, China
    2Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    3China National Botanica Garden, Beijing 100093, China
    4Grassland Workstation of Xilinhot, Xilinhot, Nei Mongol 026099, China
  • Received:2024-12-02 Accepted:2025-01-20 Online:2025-07-20 Published:2025-01-20
  • Supported by:
    National Key R&D Program of China(2023YFF1304101)

摘要: 长期放牧深刻影响草地生态系统中植物生长发育的外部环境, 植物通过与根际微生物的相互作用来适应环境变化。然而, 目前关于放牧如何影响草地不同生存策略植物根际微生物多样性的研究十分有限。该研究依托内蒙古典型草原长期放牧实验平台, 选取优势植物大针茅(Stipa grandis)和糙隐子草(Cleistogenes squarrosa)作为研究对象, 利用高通量测序技术探讨不同放牧强度(对照, 轻度: 1.5 sheep·hm-2, 中度: 4.5 sheep·hm-2, 重度: 7.5 sheep·hm-2)下植物根际细菌多样性变化趋势, 解析两种优势植物根际细菌的响应差异, 及其与植物功能性状的内在联系。结果表明: (1)重度放牧显著降低大针茅根际细菌丰富度(8.97%)和Chao1指数(9.48%), 但对糙隐子草根际细菌α多样性无显著影响, 且大针茅根际细菌α多样性显著低于糙隐子草; 此外, 重度放牧显著改变了两种植物根际细菌的群落组成, 其中大针茅的变化幅度显著大于糙隐子草。(2)随着放牧强度增加, 大针茅富集了较多的根际促生菌和生物防治菌, 而糙隐子草则主要富集了根际促生菌。(3)大针茅根际细菌群落多样性和功能菌群相对丰度的变化与其较大的根系直径、较小的比叶面积和比根长等代表避牧和资源保守策略的功能性状显著相关; 而糙隐子草的根际细菌群落变化则与其较高的地上生物量碳氮比和较大的比叶面积等代表耐牧和资源消耗策略的功能性状显著相关。综上, 不同优势植物根际细菌群落对放牧压力的响应与其生存策略密切相关, 丰富了对长期放牧背景下植物与根际微生物群落协同适应机制的理解。

关键词: 放牧强度, 优势植物, 根际细菌, 植物功能性状, 微生物功能群

Abstract:

Aims Long-term grazing profoundly affects the external environment for plant growth and development in grassland ecosystems, and plants adapt to environmental changes through interactions with rhizosphere microbes. However, there is limited research on how grazing affects the rhizosphere microbial diversity of plants with different survival strategies in grasslands.
Methods In this study, based on a long-term grazing experiment on typical grasslands in Nei Mongol, we selected the dominant plant species Stipa grandis and Cleistogenes squarrosa as research subjects. Using high-throughput sequencing technology, we investigated the changes in rhizosphere bacterial diversity under different grazing intensities (control, light: 1.5 sheep·hm-2, moderate: 4.5 sheep·hm-2, and heavy: 7.5 sheep·hm-2), and analyzed the differences in the responses of two dominant plant rhizospheric bacteria and their intrinsic connection with plant functional traits.
Important findings The results showed that: (1) Heavy grazing significantly reduced the rhizosphere bacterial richness (8.97%) and Chao1 index (9.48%) for Stipa grandis, but had no significant effect on the rhizosphere bacterial α-diversity of Cleistogenes squarrosa. Additionally, the α-diversity of Stipa grandis was significantly lower than that of Cleistogenes squarrosa. Moreover, heavy grazing significantly altered the bacterial community composition of both plant species, with the change being more pronounced in Stipa grandis than in Cleistogenes squarrosa. (2) As grazing intensity increased, Stipa grandiswas enriched with both plant growth promoting rhizobacteria and biocontrol agents, whereas Cleistogenes squarrosa was primarily enriched with plant growth promoting rhizobacteria. (3) Changes in the diversity and relative abundance of rhizosphere bacterial communities in Stipa grandiswere significantly correlated with its larger root diameter, lower specific leaf area, and lower specific root length, which reflect grazing avoidance and resource-conserving strategies. In contrast, changes in the bacterial communities of Cleistogenes squarrosa were significantly correlated with its higher carbon to nitrogen ratio in aboveground biomass and larger specific leaf area, which reflect grazing tolerance and resource-consuming strategies. In conclusion, this study demonstrated that the responses of rhizosphere bacterial communities of different dominant plant species to grazing pressure are closely related to their survival strategies, enriching our understanding of the synergistic adaptations between plants and rhizosphere microbial communities in the context of long-term grazing.

Key words: grazing intensity, dominant plants, rhizosphere bacteria, plant functional traits, microbial functional groups