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Wang L, Zhang B, Fang Y, Yin H, Fu S, Chang SX, Cai Y. Distinct effects of canopy vs understory and organic vs inorganic N deposition on root resource acquisition strategies of subtropical Moso bamboo plants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172424. [PMID: 38614348 DOI: 10.1016/j.scitotenv.2024.172424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/07/2024] [Accepted: 04/10/2024] [Indexed: 04/15/2024]
Abstract
Atmospheric nitrogen (N) deposition inevitably alters soil nutrient status, subsequently prompting plants to modify their root morphology (i.e., adopting a do-it-yourself strategy), mycorrhizal symbioses (i.e., outsourcing strategy), and root exudation (i.e., nutrient-mining strategy) linking with resource acquisition. However, how N deposition influences the integrated pattern of these resource-acquisition strategies remains unclear. Furthermore, most studies in forest ecosystems have focused on understory N and inorganic N deposition, neglecting canopy-associated processes (e.g., N interception and assimilation) and the impacts of organic N on root functional traits. In this study, we compared the effects of canopy vs understory, organic vs inorganic N deposition on eight root functional traits of Moso bamboo plants. Our results showed that N deposition significantly decreased arbuscular mycorrhizal fungi (AMF) colonization, altered root exudation rate and root foraging traits (branching intensity, specific root area, and length), but did not influence root tissue density and N concentration. Moreover, the impacts of N deposition on root functional traits varied significantly with deposition approach (canopy vs. understory), form (organic vs. inorganic), and their interaction, showing variations in both intensity and direction (positive/negative). Furthermore, specific root area and length were positively correlated with AMF colonization under canopy N deposition and root exudation rate in understory N deposition. Root trait variation under understory N deposition, but not under canopy N deposition, was classified into the collaboration gradient and the conservation gradient. These findings imply that coordination of nutrient-acquisition strategies dependent on N deposition approach. Overall, this study provides a holistic understanding of the impacts of N deposition on root resource-acquisition strategies. Our results indicate that the evaluation of N deposition on fine roots in forest ecosystems might be biased if N is added understory.
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Affiliation(s)
- Lin Wang
- State Key Laboratory of Subtropical Silviculture, College of Environment and Resources, College of Carbon Neutrality, Zhejiang A&F University, Hangzhou 311300, China
| | - Baogang Zhang
- State Key Laboratory of Subtropical Silviculture, College of Environment and Resources, College of Carbon Neutrality, Zhejiang A&F University, Hangzhou 311300, China.
| | - Yunying Fang
- Australian Rivers Institute and School of Environment and Science, Griffith University, Nathan Campus, 4111, Queensland, Australia
| | - Huajun Yin
- CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province & China-Croatia "Belt and Road" Joint Laboratory on Biodiversity and Ecosystem Services, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Shenglei Fu
- College of Environment and Planning, Henan University, Kaifeng 475004, China
| | - Scott X Chang
- Department of Renewable Resources, University of Alberta, Edmonton T6G 2E3, Canada
| | - Yanjiang Cai
- State Key Laboratory of Subtropical Silviculture, College of Environment and Resources, College of Carbon Neutrality, Zhejiang A&F University, Hangzhou 311300, China
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Jia W, Huang P, Zhu K, Gao X, Chen Q, Chen J, Ran Y, Chen S, Ma M, Wu S. Zonation of bulk and rhizosphere soil bacterial communities and their covariation patterns along the elevation gradient in riparian zones of three Gorges reservoir, China. ENVIRONMENTAL RESEARCH 2024; 249:118383. [PMID: 38331152 DOI: 10.1016/j.envres.2024.118383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/26/2024] [Accepted: 01/30/2024] [Indexed: 02/10/2024]
Abstract
Zonation is a typical pattern of soil distribution and species assembly across riparian habitats. Microorganisms are essential members of riparian ecosystems and whether soil microbial communities demonstrate similar zonation patterns and how bulk and rhizosphere soil microorganisms interact along the elevation (submergence stress) gradient remain largely unknown. In this study, bulk and rhizosphere (dominant plant) soil samples were collected and investigated across riparian zones where the submergence stress intensity increased as the elevation decreased. Results showed that the richness of bacterial communities in bulk and rhizosphere soil samples was significantly different and presented a zonation pattern along with the submergence stress gradient. Bulk soil at medium elevation that underwent moderate submergence stress had the most abundant bacterial communities, while the species richness of rhizobacteria at low elevation that experienced serious submergence stress was the highest. Additionally, principal coordinate analysis (PCoA) and significance tests showed that bulk and rhizosphere soil samples were distinguished according to the structure of bacterial communities, and so were bulk or rhizosphere soil samples from different elevations. Redundancy analysis (RDA) and Mantel test suggested that bacterial communities of bulk soil mainly relied on the contents of soil organic matter, total carbon (TC), total nitrogen (TN), sodium (Na), calcium (Ca) and magnesium (Mg). Contrastingly, the contents of Na and Mg were the main factors explaining the variation in rhizobacterial community composition. Correlation and microbial source tracking analyses showed thatthe relationship of bulk and rhizosphere soil bacteria became much stronger, and the rhizosphere soil may get more bacterial communities from bulk soil with the increase in submergence severity. Our results suggest that the abiotic and biotic components of the riparian ecosystem are closely covariant along the submergence stress gradient and imply that the bacterial community may be a key node linking soil physiochemical properties and vegetation communities.
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Affiliation(s)
- Weitao Jia
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Ping Huang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Kai Zhu
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Xin Gao
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Qiao Chen
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Jilong Chen
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Yiguo Ran
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Shanshan Chen
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Maohua Ma
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Shengjun Wu
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China.
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Chen Q, Yuan Y, Hu Y, Wang J, Si G, Xu R, Zhou J, Xi C, Hu A, Zhang G. Excessive nitrogen addition accelerates N assimilation and P utilization by enhancing organic carbon decomposition in a Tibetan alpine steppe. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 764:142848. [PMID: 33268263 DOI: 10.1016/j.scitotenv.2020.142848] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 09/23/2020] [Accepted: 10/03/2020] [Indexed: 05/23/2023]
Abstract
High amounts of deposited nitrogen (N) dramatically influence the stability and functions of alpine ecosystems by changing soil microbial community functions, but the mechanism is still unclear. To investigate the impacts of increased N deposition on microbial community functions, a 2-year multilevel N addition (0, 10, 20, 40, 80 and 160 kg N ha-1 year-1) field experiment was set up in an alpine steppe on the Tibetan Plateau. Soil microbial functional genes (GeoChip 4.6), together with soil enzyme activity, soil organic compounds and environmental variables, were used to explore the response of microbial community functions to N additions. The results showed that the N addition rate of 40 kg N ha-1 year-1 was the critical value for soil microbial functional genes in this alpine steppe. A small amount of added N (≤40 kg N ha-1 year-1) had no significant effects on the abundance of microbial functional genes, while high amounts of added N (>40 kg N ha-1 year-1) significantly increased the abundance of soil organic carbon degradation genes. Additionally, the abundance of microbial functional genes associated with NH4+, including ammonification, N fixation and assimilatory nitrate reduction pathways, was significantly increased under high N additions. Further, high N additions also increased soil organic phosphorus utilization, which was indicated by the increase in the abundance of phytase genes and alkaline phosphatase activity. Plant richness, soil NO2-/NH4+ and WSOC/WSON were significantly correlated with the abundance of microbial functional genes, which drove the changes in microbial community functions under N additions. These findings help us to predict that increased N deposition in the future may alter soil microbial functional structure, which will lead to changes in microbially-mediated biogeochemical dynamics in alpine steppes on the Tibetan Plateau and will have extraordinary impacts on microbial C, N and P cycles.
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Affiliation(s)
- Qiuyu Chen
- CAS Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Yanli Yuan
- CAS Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Yilun Hu
- CAS Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Jian Wang
- Land and Resources College, China West Normal University, Nanchong 637009, Sichuan, China
| | - Guicai Si
- Lanzhou Center for Oil and Gas Resources, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Ri Xu
- CAS Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China
| | - Jizhong Zhou
- Institute for Environmental Genomics and Department of Microbiology and Plant Biology, University Oklahoma, Norman, OK 73019, USA; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Chuanwu Xi
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ang Hu
- College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China
| | - Gengxin Zhang
- CAS Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing 100101, China; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Beijing 100101, China.
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