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Ren H, Gao G, Ma Y, Li Z, Wang S, Gu J. Shift of root nitrogen-acquisition strategy with tree age is mediated by root functional traits along the collaboration gradient of the root economics space. TREE PHYSIOLOGY 2023; 43:1341-1353. [PMID: 37073458 DOI: 10.1093/treephys/tpad047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 03/22/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Root nitrogen (N)-uptake rate and uptake preference, and their association with root morphological and chemical traits are important to characterize root N-acquisition strategies of trees. However, how the root N-acquisition strategy varies with tree age, especially for those species that coexist at a common site, remains unknown. In this study, a field isotopic hydroponic method was used to determine the uptake rate and contribution of NH4+, NO3- and glycine, for three coexisting ectomycorrhizal coniferous species [Pinus koraiensis (Korean pine), Picea koraiensis (Korean spruce) and Abies nephrolepis (smelly fir)] at three age classes (young, middle-aged and mature) in a temperate forest. Concurrently, root morphological and chemical traits, as well as mycorrhizal colonization rate were determined. Our results show that the root uptake rate of total N and NH4+ gradually decreased across all three species with increasing tree age. The three species at all age classes preferred NH4+, except for middle-aged Korean spruce and mature smelly fir, which preferred glycine. In contrast, all three species showed the lowest acquisition of NO3-. According to the conceptual framework of 'root economics space', only a 'collaboration' gradient (i.e. dimension of root diameter vs specific root length or area) was identified for each species, in which root N-uptake rate loaded heavily on the side of 'do-it-yourself' (i.e. foraging N more by roots). Young trees of all species tended to exhibit the 'do-it-yourself' strategy for N uptake, and mature trees had an 'outsourcing' strategy (i.e. foraging N by a mycorrhizal partner), whereas middle-aged trees showed a balanced strategy. These findings suggest that shifts of root N-acquisition strategy with tree age in these species are mainly mediated by root traits along the 'collaboration' gradient, which advances our understanding of belowground competition, species coexistence and N cycling in temperate forests.
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Affiliation(s)
- Hao Ren
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Guoqiang Gao
- Sichuan Collegiate Engineering Research Center for Chuanxibei RHS Construction, Mianyang Normal University, Mianyang 621000, China
| | - Yaoyuan Ma
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Zuwang Li
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Siyuan Wang
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, China
| | - Jiacun Gu
- Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, China
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Khokon AM, Janz D, Polle A. Ectomycorrhizal diversity, taxon-specific traits and root N uptake in temperate beech forests. THE NEW PHYTOLOGIST 2023. [PMID: 37229659 DOI: 10.1111/nph.18978] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 04/19/2023] [Indexed: 05/27/2023]
Abstract
Roots of forest trees are colonized by a diverse spectrum of ectomycorrhizal (EM) fungal species differing in their nitrogen (N) acquisition abilities. Here, we hypothesized that root N gain is the result of EM fungal diversity or related to taxon-specific traits for N uptake. To test our hypotheses, we traced 15 N enrichment in fine roots, coarse roots and taxon-specific ectomycorrhizas in temperate beech forests in two regions and three seasons, feeding 1 mM NH4 NO3 labelled with either 15 NH4 + or 15 NO3 - . We morphotyped > 45 000 vital root tips and identified 51 of 53 detected EM species by sequencing. EM root tips exhibited strong, fungal taxon-specific variation in 15 N enrichment with higher NH4 + than NO3 - enrichment. The translocation of N into the upper parts of the root system increased with increasing EM fungal diversity. Across the growth season, influential EM species predicting root N gain were not identified, probably due to high temporal dynamics of the species composition of EM assemblages. Our results support that root N acquisition is related to EM fungal community-level traits and highlight the importance of EM diversity for tree N nutrition.
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Affiliation(s)
- Anis Mahmud Khokon
- Forest Botany and Tree Physiology, University of Göttingen, Göttingen, 37077, Germany
- Functional Forest Ecology, Universität Hamburg, Barsbüttel, 22885, Germany
| | - Dennis Janz
- Forest Botany and Tree Physiology, University of Göttingen, Göttingen, 37077, Germany
| | - Andrea Polle
- Forest Botany and Tree Physiology, University of Göttingen, Göttingen, 37077, Germany
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Dietrich P, Ferlian O, Huang Y, Luo S, Quosh J, Eisenhauer N. Tree diversity effects on productivity depend on mycorrhizae and life strategies in a temperate forest experiment. Ecology 2023; 104:e3896. [PMID: 36215064 DOI: 10.1002/ecy.3896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/26/2022] [Accepted: 08/03/2022] [Indexed: 02/03/2023]
Abstract
Tree species are known to predominantly interact either with arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. However, there is a knowledge gap regarding whether these mycorrhizae differently influence biodiversity-ecosystem functioning (BEF) relationships and whether a combination of both can increase community productivity. In 2015, we established a tree-diversity experiment by growing tree communities with varying species richness levels (one, two, or four species) and either with AM or EM tree species or a combination of both. We investigated basal area and annual basal area increment from 2015 to 2020 as proxies for community productivity. We found significant positive relationships between tree species richness and community productivity, which strengthened over time. Further, AM and EM tree species differently influenced productivity; however, there was no overyielding when AM and EM trees grew together. EM tree communities were characterized by low productivity in the beginning but an increase of increment over time and showed overall strong biodiversity effects. For AM tree communities the opposite was true. Although young trees did not benefit from the presence of the other mycorrhizal type, dissimilar mechanisms underlying BEF relationships in AM and EM trees indicate that maximizing tree and mycorrhizal diversity may increase ecosystem functioning in the long run.
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Affiliation(s)
- Peter Dietrich
- German Centre of Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.,Institute of Biology, Experimental Interaction Ecology, Leipzig University, Leipzig, Germany
| | - Olga Ferlian
- German Centre of Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.,Institute of Biology, Experimental Interaction Ecology, Leipzig University, Leipzig, Germany
| | - Yuanyuan Huang
- German Centre of Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.,Institute of Biology, Experimental Interaction Ecology, Leipzig University, Leipzig, Germany
| | - Shan Luo
- German Centre of Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.,Institute of Biology, Experimental Interaction Ecology, Leipzig University, Leipzig, Germany
| | - Julius Quosh
- German Centre of Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.,Institute of Biology, Experimental Interaction Ecology, Leipzig University, Leipzig, Germany
| | - Nico Eisenhauer
- German Centre of Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.,Institute of Biology, Experimental Interaction Ecology, Leipzig University, Leipzig, Germany
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Peng L, Zhang Y, Druzhinina IS, Kubicek CP, Wang Y, Zhu Z, Zhang Y, Wang K, Liu Z, Zhang X, Martin F, Yuan Z. A facultative ectomycorrhizal association is triggered by organic nitrogen. Curr Biol 2022; 32:5235-5249.e7. [PMID: 36402137 DOI: 10.1016/j.cub.2022.10.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 09/19/2022] [Accepted: 10/25/2022] [Indexed: 11/19/2022]
Abstract
Increasing nitrogen (N) deposition often tends to negatively impact the functions of belowground ectomycorrhizal networks, although the exact molecular mechanisms underlying this trait are still unclear. Here, we assess how the root-associated fungus Clitopilus hobsonii establishes an ectomycorrhiza-like association with its host tree Populus tomentosa and how this interaction is favored by organic N over mineral N. The establishment of a functional symbiosis in the presence of organic N promotes plant growth and the transfer of 15N from the fungus to above ground plant tissues. Genomic traits and in planta transcriptional signatures suggest that C. hobsonii may have a dual lifestyle with saprotrophic and mutualistic traits. For example, several genes involved in the digestion of cellulose and hemicellulose are highly expressed during the interaction, whereas the expression of multiple copies of pectin-digesting genes is tightly controlled. Conversely, the nutritional mutualism is dampened in the presence of ammonium (NH4+) or nitrate (NO3-). Increasing levels of NH4+ led to a higher expression of pectin-digesting genes and a continuous increase in hydrogen peroxide production in roots, whereas the presence of NO3- resulted in toxin production. In summary, our results suggest that C. hobsonii is a facultative ectomycorrhizal fungus. Access to various forms of N acts as an on/off switch for mutualism caused by large-scale fungal physiological remodeling. Furthermore, the abundance of pectin-degrading enzymes with distinct expression patterns during functional divergence after exposure to NH4+ or organic N is likely to be central to the transition from parasitism to mutualism.
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Affiliation(s)
- Long Peng
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Yan Zhang
- Liaoning Provincial Institute of Poplar, Gaizhou 115213, China
| | | | - Christian P Kubicek
- Institute of Chemical, Environmental & Bioscience Engineering (ICEBE), TU Wien, Vienna A1060, Austria
| | - Yuchen Wang
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Zhiyong Zhu
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Yuwei Zhang
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Kexuan Wang
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Zhuo Liu
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Xiaoguo Zhang
- Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China
| | - Francis Martin
- Université de Lorraine, INRAE, UMR 1136 "Interactions Arbres/Microorganismes," Centre INRAE Grand Est - Nancy, Champenoux 54280, France.
| | - Zhilin Yuan
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Dongxiaofu 1, Beijing 10091, China; Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Daqiao Road 73, Hangzhou 311400, China.
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