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Sorochkina K, Martens-Habbena W, Reardon CL, Inglett PW, Strauss SL. Nitrogen-fixing bacterial communities differ between perennial agroecosystem crops. FEMS Microbiol Ecol 2024; 100:fiae064. [PMID: 38637314 DOI: 10.1093/femsec/fiae064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 03/28/2024] [Accepted: 04/17/2024] [Indexed: 04/20/2024] Open
Abstract
Biocrusts, common in natural ecosystems, are specific assemblages of microorganisms at or on the soil surface with associated microorganisms extending into the top centimeter of soil. Agroecosystem biocrusts have similar rates of nitrogen (N) fixation as those in natural ecosystems, but it is unclear how agricultural management influences their composition and function. This study examined the total bacterial and diazotrophic communities of biocrusts in a citrus orchard and a vineyard that shared a similar climate and soil type but differed in management. To contrast climate and soil type, these biocrusts were also compared with those from an apple orchard. Unlike natural ecosystem biocrusts, these agroecosystem biocrusts were dominated by proteobacteria and had a lower abundance of cyanobacteria. All of the examined agroecosystem biocrust diazotroph communities were dominated by N-fixing cyanobacteria from the Nostocales order, similar to natural ecosystem cyanobacterial biocrusts. Lower irrigation and fertilizer in the vineyard compared with the citrus orchard could have contributed to biocrust microbial composition, whereas soil type and climate could have differentiated the apple orchard biocrust. Season did not influence the bacterial and diazotrophic community composition of any of these agroecosystem biocrusts. Overall, agricultural management and climatic and edaphic factors potentially influenced the community composition and function of these biocrusts.
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Affiliation(s)
- Kira Sorochkina
- Department of Soil, Water, and Ecosystem Sciences, University of Florida, Gainesville, FL, United States
- Southwest Research and Education Center, University of Florida, Immokalee, FL, United States
| | - Willm Martens-Habbena
- Fort Lauderdale Research and Education Center, University of Florida, Fort Lauderdale, FL, United States
| | - Catherine L Reardon
- Soil and Water Conservation Research Unit, U.S. Department of Agriculture, Agricultural Research Service (USDA-ARS), Pendleton, OR, United States
| | - Patrick W Inglett
- Department of Soil, Water, and Ecosystem Sciences, University of Florida, Gainesville, FL, United States
| | - Sarah L Strauss
- Department of Soil, Water, and Ecosystem Sciences, University of Florida, Gainesville, FL, United States
- Southwest Research and Education Center, University of Florida, Immokalee, FL, United States
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Zobel M, Koorem K, Moora M, Semchenko M, Davison J. Symbiont plasticity as a driver of plant success. THE NEW PHYTOLOGIST 2024; 241:2340-2352. [PMID: 38308116 DOI: 10.1111/nph.19566] [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: 08/04/2023] [Accepted: 01/12/2024] [Indexed: 02/04/2024]
Abstract
We discuss which plant species are likely to become winners, that is achieve the highest global abundance, in changing landscapes, and whether plant-associated microbes play a determining role. Reduction and fragmentation of natural habitats in historic landscapes have led to the emergence of patchy, hybrid landscapes, and novel landscapes where anthropogenic ecosystems prevail. In patchy landscapes, species with broad niches are favoured. Plasticity in the degree of association with symbiotic microbes may contribute to broader plant niches and optimization of symbiosis costs and benefits, by downregulating symbiosis when it is unnecessary and upregulating it when it is beneficial. Plasticity can also be expressed as the switch from one type of mutualism to another, for example from nutritive to defensive mutualism with increasing soil fertility and the associated increase in parasite load. Upon dispersal, wide mutualistic partner receptivity is another facet of symbiont plasticity that becomes beneficial, because plants are not limited by the availability of specialist partners when arriving at new locations. Thus, under conditions of global change, symbiont plasticity allows plants to optimize the activity of mutualistic relationships, potentially allowing them to become winners by maximizing geographic occupancy and local abundance.
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Affiliation(s)
- Martin Zobel
- Institute of Ecology and Earth Sciences, University of Tartu, J. Liivi 2, Tartu, 50409, Estonia
| | - Kadri Koorem
- Institute of Ecology and Earth Sciences, University of Tartu, J. Liivi 2, Tartu, 50409, Estonia
| | - Mari Moora
- Institute of Ecology and Earth Sciences, University of Tartu, J. Liivi 2, Tartu, 50409, Estonia
| | - Marina Semchenko
- Institute of Ecology and Earth Sciences, University of Tartu, J. Liivi 2, Tartu, 50409, Estonia
| | - John Davison
- Institute of Ecology and Earth Sciences, University of Tartu, J. Liivi 2, Tartu, 50409, Estonia
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Dagan R, Dovrat G, Masci T, Sheffer E. Competition-induced downregulation of symbiotic nitrogen fixation. THE NEW PHYTOLOGIST 2023; 240:2288-2297. [PMID: 37845824 DOI: 10.1111/nph.19322] [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: 05/10/2023] [Accepted: 09/12/2023] [Indexed: 10/18/2023]
Abstract
Controlled experiments at the level of individual plants show that legume species use different strategies for the regulation of symbiotic dinitrogen fixation in response to nitrogen availability. These strategies were suggested to improve legume fitness in the context of the plant community, although rarely studied at this level. We evaluated how nitrogen availability and conspecific vs heterospecific interactions influenced the strategy of regulation of nitrogen fixation. We grew two species of herbaceous legumes representing two different strategies of regulation without interaction, under treatments of deficient and sufficient nitrogen availability, with conspecific or heterospecific interaction. We found that Hymenocarpus circinnatus maintained a facultative strategy of downregulating nitrogen fixation when nitrogen was available under both con- and heterospecific interactions, as was also found for this species when grown alone. Vicia palaestina also downregulated nitrogen fixation under both con- and heterospecific interactions but did not regulate fixation when grown alone. Our results showed that under nitrogen limitation, interaction with a neighboring plant reduced fitness, reflecting a competitive effect. Our findings suggest that when interacting with other plants, downregulation of nitrogen fixation is more likely, therefore reducing the energetic cost of fixation, and improving plant performance in competitive ecological communities, especially when nitrogen is available.
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Affiliation(s)
- Rotem Dagan
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
| | - Guy Dovrat
- Department of Natural Resources, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, 30095, Israel
| | - Tania Masci
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
| | - Efrat Sheffer
- Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
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Van Cauwenberghe J, Simms EL. How might bacteriophages shape biological invasions? mBio 2023; 14:e0188623. [PMID: 37812005 PMCID: PMC10653932 DOI: 10.1128/mbio.01886-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2023] Open
Abstract
Invasions by eukaryotes dependent on environmentally acquired bacterial mutualists are often limited by the ability of bacterial partners to survive and establish free-living populations. Focusing on the model legume-rhizobium mutualism, we apply invasion biology hypotheses to explain how bacteriophages can impact the competitiveness of introduced bacterial mutualists. Predicting how phage-bacteria interactions affect invading eukaryotic hosts requires knowing the eco-evolutionary constraints of introduced and native microbial communities, as well as their differences in abundance and diversity. By synthesizing research from invasion biology, as well as bacterial, viral, and community ecology, we create a conceptual framework for understanding and predicting how phages can affect biological invasions through their effects on bacterial mutualists.
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Affiliation(s)
- Jannick Van Cauwenberghe
- Institute of Biodiversity, Faculty of Biological Sciences, Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Department of Integrative Biology, University of California, Berkeley, California, USA
| | - Ellen L. Simms
- Department of Integrative Biology, University of California, Berkeley, California, USA
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Zhang J, DeLuca TH, Chenpeng Z, Li A, Wang G, Sun S. Comparison of the seasonal and successional variation of asymbiotic and symbiotic nitrogen fixation along a glacial retreat chronosequence. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 896:165163. [PMID: 37391152 DOI: 10.1016/j.scitotenv.2023.165163] [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: 03/07/2023] [Revised: 06/01/2023] [Accepted: 06/25/2023] [Indexed: 07/02/2023]
Abstract
Climate change is resulting in accelerated retreat of glaciers worldwide and much nitrogen-poor debris is left after glacier retreats. Asymbiotic dinitrogen (N2) fixation (ANF) can be considered a 'hidden' source of nitrogen (N) for non-nodulating plants in N limited environments; however, seasonal variation and its relative importance in ecosystem N budgets, especially when compared with nodulating symbiotic N2-fixation (SNF), is not well-understood. In this study, seasonal and successional variations in nodulating SNF and non-nodulating ANF rates (nitrogenase activity) were compared along a glacial retreat chronosequence on the eastern edge of the Tibetan Plateau. Key factors regulating the N2-fixation rates as well as the contribution of ANF and SNF to ecosystem N budget were also examined. Significantly greater nitrogenase activity was observed in nodulating species (0.4-17,820.8 nmol C2H4 g-1 d-1) compared to non-nodulating species (0.0-9.9 nmol C2H4 g-1 d-1) and both peaked in June or July. Seasonal variation in acetylene reduction activity (ARA) rate in plant nodules (nodulating species) and roots (non-nodulating species) was correlated with soil temperature and moisture while ARA in non-nodulating leaves and twigs was correlated with air temperature and humidity. Stand age was not found to be a significant determinant of ARA rates in nodulating or non-nodulating plants. ANF and SNF contributed 0.3-51.5 % and 10.1-77.8 %, respectively, of total ecosystem N input in the successional chronosequence. In this instance, ANF exhibited an increasing trend with successional age while SNF increased only at stages younger than 29 yr and then decreased as succession proceeded. These findings help improve our understanding of ANF activity in non-nodulating plants and N budgets in post glacial primary succession.
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Affiliation(s)
- Jun Zhang
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, No.24 South Section 1, Yihuan Rd, Chengdu 610065, China; Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Thomas H DeLuca
- College of Forestry, Oregon State University, Corvallis, OR 97331-5704, USA
| | - Zhenni Chenpeng
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, No.24 South Section 1, Yihuan Rd, Chengdu 610065, China
| | - Andi Li
- South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Genxu Wang
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, No.24 South Section 1, Yihuan Rd, Chengdu 610065, China
| | - Shouqin Sun
- State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, No.24 South Section 1, Yihuan Rd, Chengdu 610065, China.
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Li C, Jia Z, Zhang S, Li T, Ma S, Cheng X, Chen M, Nie H, Zhai L, Zhang B, Liu X, Zhang J, Müller C. The positive effects of mineral-solubilizing microbial inoculants on asymbiotic nitrogen fixation of abandoned mine soils are driven by keystone phylotype. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 882:163663. [PMID: 37094687 DOI: 10.1016/j.scitotenv.2023.163663] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 04/03/2023] [Accepted: 04/18/2023] [Indexed: 05/03/2023]
Abstract
Toward the restoration of the increasing numbers of abandoned mines across China, external-soil spray seeding technologies have become more extensively utilized. However, considerable challenges remain that seriously hamper the effectiveness of these technologies, such as inadequate nutrient availability for plants. Previous studies have shown that mineral-solubilizing microbial inoculants can increase the nodules of legumes. However, their effects on symbiotic nitrogen fixation (SNF), asymbiotic nitrogen fixation (ANF), and diazotrophic communities remain unknown. Further, research into the application of functional microorganisms for the restoration of abandoned mines has been conducted either in greenhouses, or their application in the field has been too brief. Thus, we established a four-year field experiment in an abandoned mine and quantified the SNF, ANF, and diazotrophic communities. To the best of our knowledge, this study is the first to describe the long-term application of specific functional microorganisms for the remediation of abandoned mine sites in the field. We revealed that mineral-solubilizing microbial inoculants significantly increased the soil ANF rate and SNF content. There was no significant correlation between the diazotrophic alpha diversity and soil ANF rate; however, there were strong positive associations between the relative abundance and biodiversity of keystone phylotype (module #5) within ecological clusters and the ANF rate. Molecular ecological networks indicated that microbial inoculants increased network complexity and stability. Moreover, the inoculants significantly enhanced the deterministic ratio of diazotrophic communities. Furthermore, homogeneous selection predominantly mediated the assembly of soil diazotrophic communities. It was concluded that mineral-solubilizing microorganisms played a critical role in maintaining and enhancing nitrogen, which offers a new solution with great potential for the restoration of ecosystems at abandoned mine sites.
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Affiliation(s)
- Chong Li
- Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China; Institute of Plant Ecology, Justus-Liebig University Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany.
| | - Zhaohui Jia
- Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China.
| | - Shuifeng Zhang
- Faculty of Information Technology, Nanjing Forest Police College, Nanjing 210000, China.
| | - Tao Li
- Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China.
| | - Shilin Ma
- Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China.
| | - Xuefei Cheng
- Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China.
| | - Meiling Chen
- Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China.
| | - Hui Nie
- Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China.
| | - Lu Zhai
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK 74078, USA; Department of Integrative Biology, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Bo Zhang
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Xin Liu
- Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China.
| | - Jinchi Zhang
- Co-Innovation Center for Sustainable Forestry in Southern China, Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration, Nanjing Forestry University, 159 Longpan Road, Nanjing, Jiangsu 210037, China.
| | - Christoph Müller
- Institute of Plant Ecology, Justus-Liebig University Giessen, Heinrich-Buff-Ring 26, 35392 Giessen, Germany; School of Biology and Environmental Science and Earth Institute, University College Dublin, Belfield, Dublin, Ireland; Liebig Centre for Agroecology and Climate Impact Research, Justus Liebig University, Germany.
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Effects of Multiple Global Change Factors on Symbiotic and Asymbiotic N2 Fixation: Results Based on a Pot Experiment. NITROGEN 2023. [DOI: 10.3390/nitrogen4010011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023] Open
Abstract
Biological N2 fixation, a major pathway for new nitrogen (N) input to terrestrial ecosystems, largely determines the dynamics of ecosystem structure and functions under global change. Nevertheless, the responses of N2 fixation to multiple global change factors remain poorly understood. Here, saplings of two N2-fixing plant species, Alnus cremastogyne and Cajanus cajan, were grown at rural and urban sites, respectively, with the latter representing an environment with changes in multiple factors occurring simultaneously. Symbiotic N2 fixation per unit of nodule was significantly higher at the urban site than the rural site for A. cremastogyne, but the rates were comparable between the two sites for C. cajan. The nodule investments were significantly lower at the urban site relative to the rural site for both species. Symbiotic N2 fixation per plant increased by 31.2 times for A. cremastogyne, while that decreased by 88.2% for C. cajan at the urban site compared to the rural site. Asymbiotic N2 fixation rate in soil decreased by 46.2% at the urban site relative to the rural site. The decrease in symbiotic N2 fixation per plant for C. cajan and asymbiotic N2 fixation in soil was probably attributed to higher N deposition under the urban conditions, while the increase in symbiotic N2 fixation per plant for A. cremastogyne was probably related to the higher levels of temperature, atmospheric CO2, and phosphorus deposition at the urban site. The responses of N2 fixation to multiple global change factors and the underlying mechanisms may be divergent either between symbiotic and asymbiotic forms or among N2-fixing plant species. While causative evidence is urgently needed, we argue that these differences should be considered in Earth system models to improve the prediction of N2 fixation under global change.
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Ottinger SL, Miniat CF, Wurzburger N. Nitrogen and light regulate symbiotic nitrogen fixation by a temperate forest tree. Oecologia 2023; 201:565-574. [PMID: 36637524 DOI: 10.1007/s00442-023-05313-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 01/03/2023] [Indexed: 01/14/2023]
Abstract
Symbiotic nitrogen fixation (SNF) is a critical mechanism of ecosystem recovery, and in forests of the eastern United States, the most common tree species that supports SNF is black locust (Robinia pseudoacacia L.). Despite its prevalence, black locust's fixation strategy-whether it maintains fixation at a constant rate (obligate fixation) or reduces its fixation rate (facultative fixation)-is unknown. Here, we examined how nitrogen and light control SNF by black locust, by growing seedlings under two nitrogen levels and across four levels of light. Seedlings were harvested after 12 weeks to determine biomass changes, nodule activity, and photosynthetic rates. Black locust seedlings increased biomass growth with increasing light, but only in the absence of nitrogen addition, while seedling root:shoot (biomass) modestly declined with increasing light regardless of nitrogen level. We found that black locust behaved like a facultative fixer, and regulated fixation by excising or maintaining nodules, and by controlling nodule biomass and activity. Specifically, nitrogen addition reduced seedling investment in nodule biomass (g g-1) by 63%, and reduced seedling allocation to nitrogen fixation (µmol C2H4 g-1 h-1) by 66%. In contrast, light affected nitrogen fixation through two indirect pathways. First, light increased plant growth, and hence nitrogen demands, which caused an increase in nitrogen fixation proportional to biomass. Second, light increasd photosynthetic activity, which was positively associated with nodule activity, but only in the absence of nitrogen addition. Our findings for how black locust regulates SNF can improve predictions of ecosystem SNF under the changing environmental conditions.
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Affiliation(s)
| | - Chelcy Ford Miniat
- USDA Forest Service, Rocky Mountain Research Station, Albuquerque, NM, USA
| | - Nina Wurzburger
- Odum School of Ecology, University of Georgia, Athens, GA, USA.
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Lincoln N, Santiago RP, Tatum D, Del Valle-Echevarria AR. Evidence of Downregulation in Atmospheric Nitrogen-Fixation Associated with Native Hawaiian Sugarcane ( Saccharum officinarum L.) Cultivars. PLANTS (BASEL, SWITZERLAND) 2023; 12:605. [PMID: 36771690 PMCID: PMC9920620 DOI: 10.3390/plants12030605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/24/2023] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
The study of nitrogen fixation in sugarcane has a long history that has demonstrated high potential but with substantial variation in results. This 32-month study sought to assess the response of nitrogen fixation associated with sugarcane (Saccharum officinarum L. cvs. 'Akoki, Honua'ula, and 'Ula) to available soil nitrogen. Plants were grown in large pots of perlite along with a fixing and a non-fixing plant control and administered liquid fertigation with varying amounts of isotopically enriched nitrogen. Assessment of nitrogen fixation utilized nitrogen isotope tracing and acetylene reduction assay in the target and control plants. Isotope enrichment and acetylene reduction assay both indicated that nitrogen fixation peaked under low nitrogen application, and declined with higher application rates, with agreement between the two methods. These results suggest that sugarcane engages in a downregulation of nitrogen fixation under high nitrogen availability, potentially explaining the high variation in published experimental results. This suggests that nitrogen management and fertilization strategy can impact the atmospheric inputs of nitrogen in sugarcane cultivation, and the potential to improve nitrogen application efficiency in cropping systems utilizing sugarcane.
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Affiliation(s)
- Noa Lincoln
- Tropical Plant and Soil Sciences Department, University of Hawai‘i, Honolulu, HI 96822, USA
| | - Reinier Paul Santiago
- Department of Natural Resources and Environmental Management, University of Hawai‘i, Honolulu, HI 96822, USA
| | - Derek Tatum
- Tropical Plant and Soil Sciences Department, University of Hawai‘i, Honolulu, HI 96822, USA
| | - Angel R. Del Valle-Echevarria
- Hawai‘i Agriculture Research Center, Waipahu, HI 96797, USA
- Agricultural Sector Team, Deep Science Ventures, London EC3 1JP, UK
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Widespread herbivory cost in tropical nitrogen-fixing tree species. Nature 2022; 612:483-487. [PMID: 36477532 DOI: 10.1038/s41586-022-05502-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 10/31/2022] [Indexed: 12/12/2022]
Abstract
Recent observations suggest that the large carbon sink in mature and recovering forests may be strongly limited by nitrogen1-3. Nitrogen-fixing trees (fixers) in symbiosis with bacteria provide the main natural source of new nitrogen to tropical forests3,4. However, abundances of fixers are tightly constrained5-7, highlighting the fundamental unanswered question of what limits new nitrogen entering tropical ecosystems. Here we examine whether herbivory by animals is responsible for limiting symbiotic nitrogen fixation in tropical forests. We evaluate whether nitrogen-fixing trees experience more herbivory than other trees, whether herbivory carries a substantial carbon cost, and whether high herbivory is a result of herbivores targeting the nitrogen-rich leaves of fixers8,9. We analysed 1,626 leaves from 350 seedlings of 43 tropical tree species in Panama and found that: (1) although herbivory reduces the growth and survival of all seedlings, nitrogen-fixing trees undergo 26% more herbivory than non-fixers; (2) fixers have 34% higher carbon opportunity costs owing to herbivory than non-fixers, exceeding the metabolic cost of fixing nitrogen; and (3) the high herbivory of fixers is not driven by high leaf nitrogen. Our findings reveal that herbivory may be sufficient to limit tropical symbiotic nitrogen fixation and could constrain its role in alleviating nitrogen limitation on the tropical carbon sink.
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Hasan MM, Corpas FJ, Fang XW. Light: a crucial factor for rhizobium-induced root nodulation. TRENDS IN PLANT SCIENCE 2022; 27:955-957. [PMID: 35840482 DOI: 10.1016/j.tplants.2022.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 07/01/2022] [Accepted: 07/01/2022] [Indexed: 06/15/2023]
Abstract
Wang et al. recently showed that, in soybean (Glycine max), root nodule formation is induced by a light-triggered signal that moves from the upper part of the plant to the roots. This novel signaling process opens a new area of research aimed to optimize the carbon-nitrogen balance in plant-rhizobium symbiosis.
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Affiliation(s)
- Md Mahadi Hasan
- State Key Laboratory of Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, Gansu Province, China
| | - Francisco J Corpas
- Group of Antioxidants, Free Radicals and Nitric Oxide in Biotechnology, Food and Agriculture, Department of Biochemistry and Cell and Molecular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Profesor Albareda 1, 18008, Granada, Spain
| | - Xiang-Wen Fang
- State Key Laboratory of Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, Gansu Province, China.
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Host-Associated Rhizobial Fitness: Dependence on Nitrogen, Density, Community Complexity, and Legume Genotype. Appl Environ Microbiol 2022; 88:e0052622. [PMID: 35852362 PMCID: PMC9361818 DOI: 10.1128/aem.00526-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The environmental context of the nitrogen-fixing mutualism between leguminous plants and rhizobial bacteria varies over space and time. Variation in resource availability, population density, and composition likely affect the ecology and evolution of rhizobia and their symbiotic interactions with hosts. We examined how host genotype, nitrogen addition, rhizobial density, and community complexity affected selection on 68 rhizobial strains in the Sinorhizobium meliloti–Medicago truncatula mutualism. As expected, host genotype had a substantial effect on the size, number, and strain composition of root nodules (the symbiotic organ). The understudied environmental variable of rhizobial density had a stronger effect on nodule strain frequency than the addition of low nitrogen levels. Higher inoculum density resulted in a nodule community that was less diverse and more beneficial but only in the context of the more selective host genotype. Higher density resulted in more diverse and less beneficial nodule communities with the less selective host. Density effects on strain composition deserve additional scrutiny as they can create feedback between ecological and evolutionary processes. Finally, we found that relative strain rankings were stable across increasing community complexity (2, 3, 8, or 68 strains). This unexpected result suggests that higher-order interactions between strains are rare in the context of nodule formation and development. Our work highlights the importance of examining mechanisms of density-dependent strain fitness and developing theoretical predictions that incorporate density dependence. Furthermore, our results have translational relevance for overcoming establishment barriers in bioinoculants and motivating breeding programs that maintain beneficial plant-microbe interactions across diverse agroecological contexts. IMPORTANCE Legume crops establish beneficial associations with rhizobial bacteria that perform biological nitrogen fixation, providing nitrogen to plants without the economic and greenhouse gas emission costs of chemical nitrogen inputs. Here, we examine the influence of three environmental factors that vary in agricultural fields on strain relative fitness in nodules. In addition to manipulating nitrogen, we also use two biotic variables that have rarely been examined: the rhizobial community's density and complexity. Taken together, our results suggest that (i) breeding legume varieties that select beneficial strains despite environmental variation is possible, (ii) changes in rhizobial population densities that occur routinely in agricultural fields could drive evolutionary changes in rhizobial populations, and (iii) the lack of higher-order interactions between strains will allow the high-throughput assessments of rhizobia winners and losers during plant interactions.
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Casenave C, Bisson A, Boudsocq S, Daufresne T. Impact of biological nitrogen fixation and livestock management on the manure transfer from grazing land in mixed farming systems. J Theor Biol 2022; 545:111136. [DOI: 10.1016/j.jtbi.2022.111136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 04/14/2022] [Accepted: 04/17/2022] [Indexed: 10/18/2022]
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14
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Mao J, Mao Q, Gundersen P, Gurmesa GA, Zhang W, Huang J, Wang S, Li A, Wang Y, Guo Y, Liu R, Mo J, Zheng M. Unexpected high retention of 15 N-labeled nitrogen in a tropical legume forest under long-term nitrogen enrichment. GLOBAL CHANGE BIOLOGY 2022; 28:1529-1543. [PMID: 34800306 DOI: 10.1111/gcb.16005] [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: 08/10/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 06/13/2023]
Abstract
The responses of forests to nitrogen (N) deposition largely depend on the fates of deposited N within the ecosystem. Nitrogen-fixing legume trees widely occur in terrestrial forests, but the fates of deposited N in legume-dominated forests remain unclear, which limit a global evaluation of N deposition impacts and feedbacks on carbon sequestration. Here, we performed the first ecosystem-scale 15 N labeling experiment in a typical legume-dominated forest as well as in a nearby non-legume forest to determine the fates of N deposition between two different forest types and to explore their underlying mechanisms. The 15 N was sprayed bimonthly for 1 year to the forest floor in control and N addition (50 kg N ha-1 year-1 for 10 years) plots in both forests. We unexpectedly found a strong capacity of the legume forest to retain deposited N, with 75 ± 5% labeled N recovered in plants and soils, which was higher than that in the non-legume forest (56 ± 4%). The higher 15 N recovery in legume forest was mainly driven by uptake by the legume trees, in which 15 N recovery was approximately 15% more than that in the nearby non-legume trees. This indicates higher N-demand by the legume than non-legume trees. Mineral soil was the major sink for deposited N, with 39 ± 4% and 34 ± 3% labeled N retained in the legume and non-legume forests, respectively. Moreover, N addition did not significantly change the 15 N recovery patterns of both forests. Overall, these findings indicate that legume-dominated forests act as a strong sink for deposited N regardless of high soil N availability under long-term atmospheric N deposition, which suggest a necessity to incorporate legume-dominated forests into N-cycling models of Earth systems to improve the understanding and prediction of terrestrial N budgets and the global N deposition effects.
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Affiliation(s)
- Jinhua Mao
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg C, Denmark
| | - Qinggong Mao
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Per Gundersen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg C, Denmark
| | - Geshere A Gurmesa
- CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China
| | - Wei Zhang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Juan Huang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Senhao Wang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Andi Li
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Yufang Wang
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Yabing Guo
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Rongzhen Liu
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Jiangming Mo
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
| | - Mianhai Zheng
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
- Center for Plant Ecology, Core Botanical Gardens, Chinese Academy of Sciences, Guangzhou, China
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15
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Burnett MW, Bobbett AE, Brendel CE, Marshall K, von Sperber C, Paulus EL, Vitousek PM. Foliar ẟ 15N patterns in legumes and non-N fixers across a climate gradient, Hawai'i Island, USA. Oecologia 2022; 198:229-242. [PMID: 34984520 DOI: 10.1007/s00442-021-05089-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 11/24/2021] [Indexed: 11/26/2022]
Abstract
Recent studies from the Hawaiian Islands showed that pedogenic thresholds demarcate domains in which rock-derived nutrient dynamics remain similar across wide variations in rainfall. These thresholds appear related to certain aspects of N cycling, but the degree to which they correspond to patterns of biological N fixation (BNF)-the dominant input of N into less-managed ecosystems-remains unclear. We measured aboveground plant biomass, foliar nutrient concentrations, and foliar δ15N along a climate gradient on ~ 150,000-year-old basaltic substrate to characterize foliar N sources and spatially relate them to soil nutrients. Patterns in legume δ15N correspond to known pedogenic thresholds along the rainfall gradient, with low δ15N values (~ 0 to - 2‰) occurring in the dry, biologically inactive domain and the wet, highly weathered domain. Elevated δ15N in the middle, fertile domain suggests a greater reliance of legumes on soil N where it has accumulated over time. Non-legume face N deficiencies throughout most of the gradient while legumes maintain low C:N ratios via symbiotic BNF. However, legume abundance declines outside the fertile domain, limiting ecosystem N inputs. Breakpoints in legume δ15N data suggest that P (and potentially other nutrients) limits BNF and, by extension, legume abundance in wet region. Nutrients may also constrain legume abundance in the dry domain, but pedogenic effects could not be isolated from climatic constraints at the dry sites. We conclude that pedogenic thresholds defined by climate can be informative of foliar δ15N patterns in cases where legumes are not directly constrained by climate, land use, or other external factors.
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Affiliation(s)
- Michael W Burnett
- Earth Systems Program, Stanford University, Stanford, CA, USA.
- The Nature Conservancy, Kamuela, HI, USA.
| | - Ariel E Bobbett
- Earth Systems Program, Stanford University, Stanford, CA, USA
| | - Corinna E Brendel
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
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16
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Alon M, Dovrat G, Masci T, Sheffer E. Soil nitrogen regulates symbiotic nitrogen fixation in a legume shrub but does not accumulate under it. Ecosphere 2021. [DOI: 10.1002/ecs2.3843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Moshe Alon
- Institute of Plant Science and Genetics in Agriculture The Robert H. Smith Faculty of Agriculture, Food and Environment The Hebrew University of Jerusalem Rehovot Israel
| | - Guy Dovrat
- Department of Natural Resources Newe Ya’ar Research Center Agricultural Research Organization Ramat Yishay 30095 Israel
| | - Tania Masci
- Institute of Plant Science and Genetics in Agriculture The Robert H. Smith Faculty of Agriculture, Food and Environment The Hebrew University of Jerusalem Rehovot Israel
| | - Efrat Sheffer
- Institute of Plant Science and Genetics in Agriculture The Robert H. Smith Faculty of Agriculture, Food and Environment The Hebrew University of Jerusalem Rehovot Israel
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17
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Bytnerowicz TA, Menge DNL. Divergent Pathways of Nitrogen-Fixing Trees through Succession Depend on Starting Nitrogen Supply and Priority Effects. Am Nat 2021; 198:E198-E214. [PMID: 34762566 DOI: 10.1086/717017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractNitrogen-fixing trees are a major potential source of nitrogen in terrestrial ecosystems. The degree to which they persist in older forests has considerable implications for forest nitrogen budgets. We characterized nitrogen-fixing tree abundance across stand age in the contiguous United States and analyzed a theoretical model to help understand competitive outcomes and successional trajectories of nitrogen-fixing and nonfixing trees. Nitrogen-fixing tree abundance is bimodal in all regions except the northeastern United States, even in older forests, suggesting that competitive exclusion (including priority effects) is more common than coexistence at the spatial scale of our analysis. Our model analysis suggests conditions under which alternative competitive outcomes are possible and when they are transient (lasting decades or centuries) versus persistent (millennia). Critically, the timescale of the feedbacks between nitrogen fixation and soil nitrogen supply, which is thought to drive the exclusion of nitrogen-fixing trees through succession, can be long. Therefore, the long transient outcomes of competition are more relevant for real forests than the long-term equilibrium. Within these long-term transients, the background soil nitrogen supply is a major determinant of competitive outcomes. Consistent with the expectations of resource ratio theory, competitive exclusion is more likely at high and low nitrogen supply, while intermediate nitrogen supply makes coexistence or priority effects possible. However, these outcomes are modified by the nitrogen fixation strategy: obligate nitrogen fixation makes coexistence more likely than priority effects, compared with perfectly facultative fixation. These results advance our understanding of the successional trajectories of nitrogen-fixing trees and their effects on ecosystem development in secondary succession.
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18
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Freschet GT, Pagès L, Iversen CM, Comas LH, Rewald B, Roumet C, Klimešová J, Zadworny M, Poorter H, Postma JA, Adams TS, Bagniewska‐Zadworna A, Bengough AG, Blancaflor EB, Brunner I, Cornelissen JHC, Garnier E, Gessler A, Hobbie SE, Meier IC, Mommer L, Picon‐Cochard C, Rose L, Ryser P, Scherer‐Lorenzen M, Soudzilovskaia NA, Stokes A, Sun T, Valverde‐Barrantes OJ, Weemstra M, Weigelt A, Wurzburger N, York LM, Batterman SA, Gomes de Moraes M, Janeček Š, Lambers H, Salmon V, Tharayil N, McCormack ML. A starting guide to root ecology: strengthening ecological concepts and standardising root classification, sampling, processing and trait measurements. THE NEW PHYTOLOGIST 2021; 232:973-1122. [PMID: 34608637 PMCID: PMC8518129 DOI: 10.1111/nph.17572] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 03/22/2021] [Indexed: 05/17/2023]
Abstract
In the context of a recent massive increase in research on plant root functions and their impact on the environment, root ecologists currently face many important challenges to keep on generating cutting-edge, meaningful and integrated knowledge. Consideration of the below-ground components in plant and ecosystem studies has been consistently called for in recent decades, but methodology is disparate and sometimes inappropriate. This handbook, based on the collective effort of a large team of experts, will improve trait comparisons across studies and integration of information across databases by providing standardised methods and controlled vocabularies. It is meant to be used not only as starting point by students and scientists who desire working on below-ground ecosystems, but also by experts for consolidating and broadening their views on multiple aspects of root ecology. Beyond the classical compilation of measurement protocols, we have synthesised recommendations from the literature to provide key background knowledge useful for: (1) defining below-ground plant entities and giving keys for their meaningful dissection, classification and naming beyond the classical fine-root vs coarse-root approach; (2) considering the specificity of root research to produce sound laboratory and field data; (3) describing typical, but overlooked steps for studying roots (e.g. root handling, cleaning and storage); and (4) gathering metadata necessary for the interpretation of results and their reuse. Most importantly, all root traits have been introduced with some degree of ecological context that will be a foundation for understanding their ecological meaning, their typical use and uncertainties, and some methodological and conceptual perspectives for future research. Considering all of this, we urge readers not to solely extract protocol recommendations for trait measurements from this work, but to take a moment to read and reflect on the extensive information contained in this broader guide to root ecology, including sections I-VII and the many introductions to each section and root trait description. Finally, it is critical to understand that a major aim of this guide is to help break down barriers between the many subdisciplines of root ecology and ecophysiology, broaden researchers' views on the multiple aspects of root study and create favourable conditions for the inception of comprehensive experiments on the role of roots in plant and ecosystem functioning.
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Affiliation(s)
- Grégoire T. Freschet
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
- Station d’Ecologie Théorique et ExpérimentaleCNRS2 route du CNRS09200MoulisFrance
| | - Loïc Pagès
- UR 1115 PSHCentre PACA, site AgroparcINRAE84914Avignon cedex 9France
| | - Colleen M. Iversen
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Louise H. Comas
- USDA‐ARS Water Management Research Unit2150 Centre Avenue, Bldg D, Suite 320Fort CollinsCO80526USA
| | - Boris Rewald
- Department of Forest and Soil SciencesUniversity of Natural Resources and Life SciencesVienna1190Austria
| | - Catherine Roumet
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
| | - Jitka Klimešová
- Department of Functional EcologyInstitute of Botany CASDukelska 13537901TrebonCzech Republic
| | - Marcin Zadworny
- Institute of DendrologyPolish Academy of SciencesParkowa 562‐035KórnikPoland
| | - Hendrik Poorter
- Plant Sciences (IBG‐2)Forschungszentrum Jülich GmbHD‐52425JülichGermany
- Department of Biological SciencesMacquarie UniversityNorth RydeNSW2109Australia
| | | | - Thomas S. Adams
- Department of Plant SciencesThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Agnieszka Bagniewska‐Zadworna
- Department of General BotanyInstitute of Experimental BiologyFaculty of BiologyAdam Mickiewicz UniversityUniwersytetu Poznańskiego 661-614PoznańPoland
| | - A. Glyn Bengough
- The James Hutton InstituteInvergowrie, Dundee,DD2 5DAUK
- School of Science and EngineeringUniversity of DundeeDundee,DD1 4HNUK
| | | | - Ivano Brunner
- Forest Soils and BiogeochemistrySwiss Federal Research Institute WSLZürcherstr. 1118903BirmensdorfSwitzerland
| | - Johannes H. C. Cornelissen
- Department of Ecological ScienceFaculty of ScienceVrije Universiteit AmsterdamDe Boelelaan 1085Amsterdam1081 HVthe Netherlands
| | - Eric Garnier
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
| | - Arthur Gessler
- Forest DynamicsSwiss Federal Research Institute WSLZürcherstr. 1118903BirmensdorfSwitzerland
- Institute of Terrestrial EcosystemsETH Zurich8092ZurichSwitzerland
| | - Sarah E. Hobbie
- Department of Ecology, Evolution and BehaviorUniversity of MinnesotaSt PaulMN55108USA
| | - Ina C. Meier
- Functional Forest EcologyUniversity of HamburgHaidkrugsweg 122885BarsbütelGermany
| | - Liesje Mommer
- Plant Ecology and Nature Conservation GroupDepartment of Environmental SciencesWageningen University and ResearchPO Box 476700 AAWageningenthe Netherlands
| | | | - Laura Rose
- Station d’Ecologie Théorique et ExpérimentaleCNRS2 route du CNRS09200MoulisFrance
- Senckenberg Biodiversity and Climate Research Centre (BiK-F)Senckenberganlage 2560325Frankfurt am MainGermany
| | - Peter Ryser
- Laurentian University935 Ramsey Lake RoadSudburyONP3E 2C6Canada
| | | | - Nadejda A. Soudzilovskaia
- Environmental Biology DepartmentInstitute of Environmental SciencesCMLLeiden UniversityLeiden2300 RAthe Netherlands
| | - Alexia Stokes
- INRAEAMAPCIRAD, IRDCNRSUniversity of MontpellierMontpellier34000France
| | - Tao Sun
- Institute of Applied EcologyChinese Academy of SciencesShenyang110016China
| | - Oscar J. Valverde‐Barrantes
- International Center for Tropical BotanyDepartment of Biological SciencesFlorida International UniversityMiamiFL33199USA
| | - Monique Weemstra
- CEFEUniv Montpellier, CNRS, EPHE, IRD1919 route de MendeMontpellier34293France
| | - Alexandra Weigelt
- Systematic Botany and Functional BiodiversityInstitute of BiologyLeipzig UniversityJohannisallee 21-23Leipzig04103Germany
| | - Nina Wurzburger
- Odum School of EcologyUniversity of Georgia140 E. Green StreetAthensGA30602USA
| | - Larry M. York
- Biosciences Division and Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Sarah A. Batterman
- School of Geography and Priestley International Centre for ClimateUniversity of LeedsLeedsLS2 9JTUK
- Cary Institute of Ecosystem StudiesMillbrookNY12545USA
| | - Moemy Gomes de Moraes
- Department of BotanyInstitute of Biological SciencesFederal University of Goiás1974690-900Goiânia, GoiásBrazil
| | - Štěpán Janeček
- School of Biological SciencesThe University of Western Australia35 Stirling HighwayCrawley (Perth)WA 6009Australia
| | - Hans Lambers
- School of Biological SciencesThe University of Western AustraliaCrawley (Perth)WAAustralia
| | - Verity Salmon
- Environmental Sciences Division and Climate Change Science InstituteOak Ridge National LaboratoryOak RidgeTN37831USA
| | - Nishanth Tharayil
- Department of Plant and Environmental SciencesClemson UniversityClemsonSC29634USA
| | - M. Luke McCormack
- Center for Tree ScienceMorton Arboretum, 4100 Illinois Rt. 53LisleIL60532USA
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19
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Taylor BN, Menge DNL. Light, nitrogen supply, and neighboring plants dictate costs and benefits of nitrogen fixation for seedlings of a tropical nitrogen-fixing tree. THE NEW PHYTOLOGIST 2021; 231:1758-1769. [PMID: 34028829 DOI: 10.1111/nph.17508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 04/29/2021] [Indexed: 06/12/2023]
Abstract
The ability to fix nitrogen may confer a competitive advantage or disadvantage to symbiotic nitrogen-fixing plants depending on the availability of soil nitrogen and energy to fuel fixation. Understanding these costs and benefits of nitrogen fixation is critical to predicting ecosystem dynamics and nutrient cycling. We grew inoculated (with symbiotic bacteria) and uninoculated seedlings of Pentaclethra macroloba (a nitrogen-fixing tree species) both in isolation and with Virola koschnyi (a nonfixing species) under gradients of light and soil nitrogen to assess how the ability to fix nitrogen and fixation activity affect growth, biomass allocation, and responses to neighboring plants. Inoculation itself did not provide a growth advantage to nitrogen fixers, regardless of nitrogen limitation status. Higher nitrogen fixation rates increased biomass growth similarly for nitrogen-limited and nitrogen-saturated fixers. Nodule production was offset by reduced fine-root biomass for inoculated nitrogen fixers, resulting in no change in total belowground allocation associated with nitrogen fixation. Under nitrogen-limited conditions, inoculated nitrogen fixers partially downregulated fixation in the presence of a nonfixing neighbor. These results suggest that nitrogen fixation can provide a growth advantage, even under nitrogen-saturated conditions, and that nitrogen fixers may reduce fixation rates to minimize facilitation of neighbors.
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Affiliation(s)
- Benton N Taylor
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, USA
- The Arnold Arboretum, Harvard University, 1300 Centre Street, Boston, MA, 02131, USA
| | - Duncan N L Menge
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, 10th Floor Schermerhorn Extension, 1200 Amsterdam Avenue, New York, NY, 10027, USA
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20
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McCulloch LA, Porder S. Light fuels while nitrogen suppresses symbiotic nitrogen fixation hotspots in neotropical canopy gap seedlings. THE NEW PHYTOLOGIST 2021; 231:1734-1745. [PMID: 34058025 DOI: 10.1111/nph.17519] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 05/20/2021] [Indexed: 06/12/2023]
Abstract
Mature neotropical lowland forests have relatively lower symbiotic nitrogen fixation (SNF) rates compared with secondary forests. Canopy gap formation may create transient SNF hotspots in mature forests that increase overall SNF rates in these ecosystems, as canopy gaps are pervasive across the landscape and increasing in frequency. However, what environmental conditions are driving SNF upregulation in canopy gaps is unknown. In a field experiment to test these potential environmental controls on SNF, we grew 540 neotropical nitrogen-fixing legume seedlings (Pentaclethra macroloba, Zygia longifolia, and Stryphnodendron microstachyum) under manipulated light and soil nitrogen availability in canopy gaps and intact forests at La Selva Biological Station, Costa Rica. Seedling biomass, nodule biomass, and SNF (g N seedling-1 h-1 ) were 4-, 17- and 42-fold higher, respectively, in canopy gaps than in the intact forest. Nitrogen additions decreased SNF, but light had a stronger positive effect. Upregulation of SNF in canopy gaps was driven by increased plant growth and not a disproportionate increased SNF allocation. These data provide evidence that canopy gap SNF hotspots are driven, in part, by light availability, demonstrating a potential driver of SNF spatial heterogeneity. This further suggests that canopy gap dynamics are important for understanding the biogeochemistry of neotropical forests.
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Affiliation(s)
- Lindsay A McCulloch
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, 02912, USA
| | - Stephen Porder
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, 02912, USA
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21
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Bosse MA, Silva MBD, Oliveira NGRMD, Araujo MAD, Rodrigues C, Azevedo JPD, Reis ARD. Physiological impact of flavonoids on nodulation and ureide metabolism in legume plants. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 166:512-521. [PMID: 34171572 DOI: 10.1016/j.plaphy.2021.06.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/06/2021] [Indexed: 05/20/2023]
Abstract
Legume plants from Fabaceae family (phylogenetic group composed by three subfamilies: Caesalpinioideae, Mimosoideae, and Papilionoideae) can fix atmospheric nitrogen (N2) into ammonia (NH3) by the symbiotic relationship with rhizobia bacteria. These bacteria respond chemotactically to certain compounds released by plants such as sugars, amino acids and organic acids. Root secretion of isoflavonoids acts as inducers for nod genes in rhizobia and ABC transporters and ICHG (isoflavone conjugates hydrolyzing beta-glucosidase) at apoplast are related to the exudation of genistein and daidzein in soybean roots. Biological nitrogen fixation (BNF) occurs inside the nodule by the action of nitrogenase enzyme, which fixes N2 into NH3, which is converted into ureides (allantoin and allantoic acid). In this review, we bring together the latest findings on flavonoids biosynthesis and ureide metabolism in several legume plant species. We emphasize how flavonoids induce nod genes in rhizobia, affecting chemotaxis, nodulation, ureide production, growth and yield of legume plants. Mainly, isoflavonoids daidzein and genistein are responsible for nod genes activation in the rhizobia bacteria. Flavonoids also play an important role during nodule organogenesis by acting as auxin transporter inhibitors in root cells, especially in indeterminate nodules. The ureides are the main N transport form in tropical legumes and they are catabolized in leaves and other sink tissues to produce amino acids and proteins needed for plant growth and yield.
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Affiliation(s)
- Marco Antônio Bosse
- São Paulo State University (UNESP), Via de Acesso Prof. Paulo Donato Castellane s/n, Jaboticabal, SP, Postal Code 14884-900, Brazil
| | | | | | | | - Cleverson Rodrigues
- São Paulo State University (UNESP), Postal Code 15385-000, Ilha Solteira, SP, Brazil
| | | | - André Rodrigues Dos Reis
- São Paulo State University (UNESP), Rua Domingos da Costa Lopes 780, Postal Code 17602-496, Tupã, SP, Brazil.
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22
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Tognetti PM, Prober SM, Báez S, Chaneton EJ, Firn J, Risch AC, Schuetz M, Simonsen AK, Yahdjian L, Borer ET, Seabloom EW, Arnillas CA, Bakker JD, Brown CS, Cadotte MW, Caldeira MC, Daleo P, Dwyer JM, Fay PA, Gherardi LA, Hagenah N, Hautier Y, Komatsu KJ, McCulley RL, Price JN, Standish RJ, Stevens CJ, Wragg PD, Sankaran M. Negative effects of nitrogen override positive effects of phosphorus on grassland legumes worldwide. Proc Natl Acad Sci U S A 2021; 118:e2023718118. [PMID: 34260386 PMCID: PMC8285913 DOI: 10.1073/pnas.2023718118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Anthropogenic nutrient enrichment is driving global biodiversity decline and modifying ecosystem functions. Theory suggests that plant functional types that fix atmospheric nitrogen have a competitive advantage in nitrogen-poor soils, but lose this advantage with increasing nitrogen supply. By contrast, the addition of phosphorus, potassium, and other nutrients may benefit such species in low-nutrient environments by enhancing their nitrogen-fixing capacity. We present a global-scale experiment confirming these predictions for nitrogen-fixing legumes (Fabaceae) across 45 grasslands on six continents. Nitrogen addition reduced legume cover, richness, and biomass, particularly in nitrogen-poor soils, while cover of non-nitrogen-fixing plants increased. The addition of phosphorous, potassium, and other nutrients enhanced legume abundance, but did not mitigate the negative effects of nitrogen addition. Increasing nitrogen supply thus has the potential to decrease the diversity and abundance of grassland legumes worldwide regardless of the availability of other nutrients, with consequences for biodiversity, food webs, ecosystem resilience, and genetic improvement of protein-rich agricultural plant species.
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Affiliation(s)
- Pedro M Tognetti
- Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura-Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Agronomía, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires C1417DSE, Argentina;
| | - Suzanne M Prober
- Land and Water, Commonwealth Scientific and Industrial Research Organisation, Wembley, WA 6913, Australia;
| | - Selene Báez
- Department of Biology, Escuela Politécnica Nacional del Ecuador, 17-01-2759 Quito, Ecuador
| | - Enrique J Chaneton
- Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura-Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Agronomía, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires C1417DSE, Argentina
| | - Jennifer Firn
- Centre for the Environment, School of Biological and Environmental Sciences, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Anita C Risch
- Community Ecology, Swiss Federal Institute for Forest, Snow, and Landscape Research, 8903 Birmensdorf, Switzerland
| | - Martin Schuetz
- Community Ecology, Swiss Federal Institute for Forest, Snow, and Landscape Research, 8903 Birmensdorf, Switzerland
| | - Anna K Simonsen
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
- Department of Biological Sciences, Florida International University, Miami, FL 33199
| | - Laura Yahdjian
- Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura-Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Agronomía, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires C1417DSE, Argentina
| | - Elizabeth T Borer
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108
| | - Eric W Seabloom
- Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, MN 55108
| | - Carlos Alberto Arnillas
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada
| | - Jonathan D Bakker
- School of Environmental and Forest Sciences, University of Washington, Seattle, WA 98195
| | - Cynthia S Brown
- Graduate Degree Program in Ecology, Department of Agricultural Biology, Colorado State University, Fort Collins, CO 80523
| | - Marc W Cadotte
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada
| | - Maria C Caldeira
- Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, 1349-017 Lisbon, Portugal
| | - Pedro Daleo
- Instituto de Investigaciones Marinas y Costeras, Universidad Nacional de Mar del Plata-Consejo Nacional de Investigaciones Científicas y Técnicas, 7600 Mar del Plata, Argentina
| | - John M Dwyer
- School of Biological Sciences, The University of Queensland, St. Lucia, QLD 4072, Australia
- Ecosciences Precinct, Commonwealth Scientific and Industrial Research Organisation, Dutton Park, QLD 4102, Australia
| | - Philip A Fay
- Grassland, Soil, and Water Research Lab, US Department of Agriculture-Agricultural Research Service, Temple, TX 76502
| | | | - Nicole Hagenah
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, 0028 Pretoria, South Africa
| | - Yann Hautier
- Ecology and Biodiversity Group, Department of Biology, Utrecht University, 3584 CH Utrecht, The Netherlands
| | | | - Rebecca L McCulley
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546-0312
| | - Jodi N Price
- Institute of Land, Water and Society, Charles Sturt University, Albury, NSW 2640, Australia
| | - Rachel J Standish
- Environmental and Conservation Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - Carly J Stevens
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom
| | - Peter D Wragg
- Department of Forest Resources, University of Minnesota, St. Paul, MN 55108
| | - Mahesh Sankaran
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bengaluru 560065, Karnataka, India
- School of Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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23
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The direct and interactive effects of elevated CO2 and additional nitrate on relative costs and benefits of legume-rhizobia symbiosis. Symbiosis 2021. [DOI: 10.1007/s13199-021-00784-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
AbstractRising concentrations of carbon dioxide (CO2) is likely to have important effects on growth and development of plants and on their relationship with symbiotic microbes. A rise in CO2 could increase demand by plant hosts for nutrient resources, which may increase host investments in beneficial symbionts. In the legume-rhizobia mutualism, while elevated CO2 is often associated with increased nodule growth and investment in N2-fixing rhizobia, it is yet unclear if this response depends on the mutualistic quality of the rhizobia. To test if host carbon allocation towards more-beneficial nodules are similar to less-beneficial (but still effective) nodules when plant N demand changes, we manipulated plant C and N status with elevated CO2 and additional nitrate. We used two isogenic Rhizobium etli strains that differ in their ability to synthesize an energy reserve compound, poly-beta-hydroxybutyrate (PHB), as well as their efficiencies for nitrogen fixation and nodulation rates, resulting in two Phaseolus vulgaris host groups with either large number of small nodules or small number of large nodules. The addition of nitrate negatively affected carbon allocation towards nodules, and elevated CO2 reversed this effect, as expected. However, this alleviation of nodule inhibition was greater on plants that started with greater numbers of smaller nodules. If smaller nodules indicate less-efficient or low-fixing rhizobia, this study suggests that increased demand for nitrogen in the face of elevated CO2 has the potential to disproportionately favor less-beneficial strains and increase variation of nitrogen fixation quality among rhizobia.
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24
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Kou-Giesbrecht S, Funk JL, Perakis SS, Wolf AA, Menge DNL. N supply mediates the radiative balance of N 2 O emissions and CO 2 sequestration driven by N-fixing vs. non-fixing trees. Ecology 2021; 102:e03414. [PMID: 34041747 DOI: 10.1002/ecy.3414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 04/05/2021] [Accepted: 05/10/2021] [Indexed: 11/11/2022]
Abstract
Forests are a significant CO2 sink. However, CO2 sequestration in forests is radiatively offset by emissions of nitrous oxide (N2 O), a potent greenhouse gas, from forest soils. Reforestation, an important strategy for mitigating climate change, has focused on maximizing CO2 sequestration in plant biomass without integrating N2 O emissions from soils. Although nitrogen (N)-fixing trees are often recommended for reforestation because of their rapid growth on N-poor soil, they can stimulate significant N2 O emissions from soils. Here, we first used a field experiment to show that a N-fixing tree (Robinia pseudoacacia) initially mitigated climate change more than a non-fixing tree (Betula nigra). We then used our field data to parameterize a theoretical model to investigate these effects over time. Under lower N supply, N-fixers continued to mitigate climate change more than non-fixers by overcoming N limitation of plant growth. However, under higher N supply, N-fixers ultimately mitigated climate change less than non-fixers by enriching soil N and stimulating N2 O emissions from soils. These results have implications for reforestation, suggesting that N-fixing trees are more effective at mitigating climate change at lower N supply, whereas non-fixing trees are more effective at mitigating climate change at higher N supply.
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Affiliation(s)
- Sian Kou-Giesbrecht
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York, 10027, USA
| | - Jennifer L Funk
- Department of Plant Sciences, University of California, Davis, California, 95616, USA
| | - Steven S Perakis
- Forest and Rangeland Ecosystem Science Center, United States Geological Survey, Corvallis, Oregon, 97331, USA
| | - Amelia A Wolf
- Department of Integrative Biology, University of Texas, Austin, Texas, 78712, USA
| | - Duncan N L Menge
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York, 10027, USA
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25
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Soper FM, Taylor BN, Winbourne JB, Wong MY, Dynarski KA, Reis CRG, Peoples MB, Cleveland CC, Reed SC, Menge DNL, Perakis SS. A roadmap for sampling and scaling biological nitrogen fixation in terrestrial ecosystems. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13586] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Fiona M. Soper
- Department of Biology and Bieler School of Environment McGill University Montréal QC Canada
| | - Benton N. Taylor
- Department of Organismic and Evolutionary Biology Harvard University Cambridge MA USA
| | - Joy B. Winbourne
- Department of Earth and Environment Boston University Boston MA USA
| | | | - Katherine A. Dynarski
- Department of Ecosystem and Conservation Sciences University of Montana Missoula MT USA
| | - Carla R. G. Reis
- Department of Forest Ecosystem and Society Oregon State University Corvallis OR USA
| | - Mark B. Peoples
- Commonwealth Scientific and Industrial Research Organisation, Agriculture and Food Canberra ACT Australia
| | - Cory C. Cleveland
- Department of Ecosystem and Conservation Sciences University of Montana Missoula MT USA
| | - Sasha C. Reed
- U.S. Geological SurveySouthwest Biological Science Center Moab UT USA
| | - Duncan N. L. Menge
- Department of Ecology, Evolution and Environmental Biology Columbia University New York NY USA
| | - Steven S. Perakis
- Department of Forest Ecosystem and Society Oregon State University Corvallis OR USA
- U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center Corvallis OR USA
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26
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McCulloch LA, Piotto D, Porder S. Drought and soil nutrients effects on symbiotic nitrogen fixation in seedlings from eight Neotropical legume species. Biotropica 2021. [DOI: 10.1111/btp.12911] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Lindsay A. McCulloch
- Department of Ecology and Evolutionary Biology Brown University Providence Rhode Island USA
| | - Daniel Piotto
- Centro de Formação em Ciências Agroflorestais Universidade Federal do Sul da Bahia Ilhéus Bahia Brasil
| | - Stephen Porder
- Department of Ecology and Evolutionary Biology Brown University Providence Rhode Island USA
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27
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O'Brien AM, Jack CN, Friesen ML, Frederickson ME. Whose trait is it anyways? Coevolution of joint phenotypes and genetic architecture in mutualisms. Proc Biol Sci 2021; 288:20202483. [PMID: 33434463 DOI: 10.1098/rspb.2020.2483] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Evolutionary biologists typically envision a trait's genetic basis and fitness effects occurring within a single species. However, traits can be determined by and have fitness consequences for interacting species, thus evolving in multiple genomes. This is especially likely in mutualisms, where species exchange fitness benefits and can associate over long periods of time. Partners may experience evolutionary conflict over the value of a multi-genomic trait, but such conflicts may be ameliorated by mutualism's positive fitness feedbacks. Here, we develop a simulation model of a host-microbe mutualism to explore the evolution of a multi-genomic trait. Coevolutionary outcomes depend on whether hosts and microbes have similar or different optimal trait values, strengths of selection and fitness feedbacks. We show that genome-wide association studies can map joint traits to loci in multiple genomes and describe how fitness conflict and fitness feedback generate different multi-genomic architectures with distinct signals around segregating loci. Partner fitnesses can be positively correlated even when partners are in conflict over the value of a multi-genomic trait, and conflict can generate strong mutualistic dependency. While fitness alignment facilitates rapid adaptation to a new optimum, conflict maintains genetic variation and evolvability, with implications for applied microbiome science.
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Affiliation(s)
- Anna M O'Brien
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Chandra N Jack
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA
| | - Maren L Friesen
- Department of Plant Pathology, Washington State University, Pullman, Washington, USA.,Department of Crop and Soil Sciences, Washington State University, Pullman, Washington, USA
| | - Megan E Frederickson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
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28
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Dovrat G, Bakhshian H, Masci T, Sheffer E. The nitrogen economic spectrum of legume stoichiometry and fixation strategy. THE NEW PHYTOLOGIST 2020; 227:365-375. [PMID: 32175592 DOI: 10.1111/nph.16543] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 03/04/2020] [Indexed: 06/10/2023]
Abstract
Leaf nitrogen concentration often is higher in leguminous plants, which associate with dinitrogen-fixing bacteria, compared with nonlegume plants. However, the range of nitrogen concentrations in legumes is wide, likely related to the range of nitrogen fixation strategies. We evaluated how carbon and nitrogen allocation to roots, stems and leaves is influenced by the type of strategy of nitrogen fixation regulation. We grew herbaceous annual legumes (Medicago truncatula, Hymenocarpos circinnatus and Vicia palaestina) under two nitrogen availability treatments (none/sufficient), with and without bacterial inoculation. We found facultative downregulation of the rate of nitrogen fixation when nitrogen was available in H. circinnatus, and an obligate similar fixation rate in both nitrogen treatments in M. truncatula and V. palaestina. Uninoculated plants invested more biomass in roots and contained lower nitrogen concentrations. However, nitrogen concentration in the entire plant and in the leaves was lower and more plastic in the species with a facultative fixation strategy, whereas species with an obligate fixation strategy also maintained high nitrogen concentrations. Our results suggest a suite of functional traits associated with the strategies of allocation and symbiotic nitrogen fixation. This suite of traits probably shapes successional and functional niches of different leguminous species in specious plant communities.
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Affiliation(s)
- Guy Dovrat
- Department of Natural Resources, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, 30095, Israel
| | - Hila Bakhshian
- Institute of Plant Science and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
| | - Tania Masci
- Institute of Plant Science and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
| | - Efrat Sheffer
- Institute of Plant Science and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
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29
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Heath KD, Podowski JC, Heniff S, Klinger CR, Burke PV, Weese DJ, Yang WH, Lau JA. Light availability and rhizobium variation interactively mediate the outcomes of legume-rhizobium symbiosis. AMERICAN JOURNAL OF BOTANY 2020; 107:229-238. [PMID: 32072629 DOI: 10.1002/ajb2.1435] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 12/08/2019] [Indexed: 05/22/2023]
Abstract
PREMISE Nutrients, light, water, and temperature are key factors limiting the growth of individual plants in nature. Mutualistic interactions between plants and microbes often mediate resource limitation for both partners. In the mutualism between legumes and rhizobia, plants provide rhizobia with carbon in exchange for fixed nitrogen. Because partner quality in mutualisms is genotype-dependent, within-species genetic variation is expected to alter the responses of mutualists to changes in the resource environment. Here we ask whether partner quality variation in rhizobia mediates the response of host plants to changing light availability, and conversely, whether light alters the expression of partner quality variation. METHODS We inoculated clover hosts with 11 strains of Rhizobium leguminosarum that differed in partner quality, grew plants under either ambient or low light conditions in the greenhouse, and measured plant growth, nodule traits, and foliar nutrient composition. RESULTS Light availability and rhizobium inoculum interactively determined plant growth, and variation in rhizobium partner quality was more apparent in ambient light. CONCLUSIONS Our results suggest that variation in the costs and benefits of rhizobium symbionts mediate host responses to light availability and that rhizobium strain variation might more important in higher-light environments. Our work adds to a growing appreciation for the role of microbial intraspecific and interspecific diversity in mediating extended phenotypes in their hosts and suggests an important role for light availability in the ecology and evolution of legume-rhizobium symbiosis.
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Affiliation(s)
- Katy D Heath
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Justin C Podowski
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Stephanie Heniff
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Christie R Klinger
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Patricia V Burke
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Dylan J Weese
- Department of Biology, St. Ambrose University, Davenport, IA, 52803, USA
| | - Wendy H Yang
- Department of Plant Biology, University of Illinois at Urbana-Champaign, 505 S. Goodwin Ave., Urbana, IL, 61801, USA
| | - Jennifer A Lau
- W. K. Kellogg Biological Station and Department of Plant Biology, Michigan State University, East Lansing, MI, 48824, USA
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30
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More Than a Functional Group: Diversity within the Legume–Rhizobia Mutualism and Its Relationship with Ecosystem Function. DIVERSITY-BASEL 2020. [DOI: 10.3390/d12020050] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Studies of biodiversity and ecosystem function (BEF) have long focused on the role of nitrogen (N)-fixing legumes as a functional group that occupies a distinct and important niche relative to other plants. Because of their relationship with N-fixing rhizobial bacteria, these legumes access a different pool of N than other plants and therefore directly contribute to increases in productivity and N-cycling. Despite their recognized importance in the BEF literature, the field has not moved far beyond investigating the presence/absence of the legume functional group in species mixtures. Here, we synthesize existing information on how the diversity (species richness and functional diversity) of both legumes and the rhizobia that they host impact ecosystem functions, such as nitrogen fixation and primary productivity. We also discuss the often-overlooked reciprocal direction of the BEF relationship, whereby ecosystem function can influence legume and rhizobial diversity. We focus on BEF mechanisms of selection, complementarity, facilitation, competitive interference, and dilution effects to explain how diversity in the legume–rhizobia mutualism can have either positive or negative effects on ecosystem function—mechanisms that can operate at scales from rhizobial communities affecting individual legume functions to legume communities affecting landscape-scale ecosystem functions. To fully understand the relationship between biodiversity and ecosystem function, we must incorporate the full diversity of this mutualism and its reciprocal relationship with ecosystem function into our evolving BEF framework.
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31
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Minucci JM, Miniat CF, Wurzburger N. Drought sensitivity of an N 2 -fixing tree may slow temperate deciduous forest recovery from disturbance. Ecology 2019; 100:e02862. [PMID: 31386760 DOI: 10.1002/ecy.2862] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 06/14/2019] [Accepted: 07/11/2019] [Indexed: 11/05/2022]
Abstract
Increased drought intensity and frequency due to climate change may reduce the abundance and activity of nitrogen (N2 )-fixing plants, which supply new N to terrestrial ecosystems. As a result, drought may indirectly reduce ecosystem productivity through its effect on the N cycle. Here, we manipulated growing season net rainfall across a series of plots in an early successional mesic deciduous forest to understand how drought affects the aboveground productivity of the N2 -fixing tree Robinia pseudoacacia and three co-occurring nonfixing tree species. We found that lower soil moisture was associated with reduced productivity of R. pseudoacacia but not of nonfixing trees. As a result, the relative biomass and density of R. pseudoacacia declined in drier soils over time. Greater aboveground biomass of R. pseudoacacia was also associated with greater total soil N, extractable inorganic N, N mineralization rates, and productivity of nonfixing trees. These soil N effects may reflect current N2 fixation by R. pseudoacacia saplings, or the legacy effect of former trees in the same location. Our results suggest that R. pseudoacacia promotes the growth of nonfixing trees in early succession through its effect on the N cycle. However, the sensitivity of R. pseudoacacia to dry soils may reduce N2 fixation under scenarios of increasing drought intensity and frequency, demonstrating a mechanism by which drought may indirectly diminish potential forest productivity and recovery rate from disturbance.
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Affiliation(s)
- Jeffrey M Minucci
- Odum School of Ecology, University of Georgia, 140 East Green Street, Athens, Georgia, 30602, USA
| | - Chelcy F Miniat
- Coweeta Hydrologic Lab, U.S. Department of Agriculture Forest Service, Southern Research Station, 3160 Coweeta Lab Road, Otto, North Carolina, 28763, USA
| | - Nina Wurzburger
- Odum School of Ecology, University of Georgia, 140 East Green Street, Athens, Georgia, 30602, USA
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32
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Wei X, Reich PB, Hobbie SE. Legumes regulate grassland soil N cycling and its response to variation in species diversity and N supply but not CO 2. GLOBAL CHANGE BIOLOGY 2019; 25:2396-2409. [PMID: 30932274 DOI: 10.1111/gcb.14636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/07/2019] [Accepted: 03/25/2019] [Indexed: 06/09/2023]
Abstract
Legumes are an important component of plant diversity that modulate nitrogen (N) cycling in many terrestrial ecosystems. Limited knowledge of legume effects on soil N cycling and its response to global change factors and plant diversity hinders a general understanding of whether and how legumes broadly regulate the response of soil N availability to those factors. In a 17-year study of perennial grassland species grown under ambient and elevated (+180 ppm) CO2 and ambient and enriched (+4 g N m-2 year-1 ) N environments, we compared pure legume plots with plots dominated by or including other herbaceous functional groups (and containing one or four species) to assess the effect of legumes on N cycling (net N mineralization rate and inorganic N pools). We also examined the effects of numbers of legume species (from zero to four) in four-species mixed plots on soil N cycling. We hypothesized that legumes would increase N mineralization rates most in those treatments with the greatest diversity and the greatest relative limitation by and competition for N. Results partially supported these hypotheses. Plots with greater dominance by legumes had greater soil nitrate concentrations and mineralization rates. Higher species richness significantly increased the impact of legumes on soil N metrics, with 349% and 505% higher mineralization rates and nitrate concentrations in four-species plots containing legumes compared to legume-free four-species plots, in contrast to 185% and 129% greater values, respectively, in pure legume than nonlegume monoculture plots. N-fertilized plots had greater legume effects on soil nitrate, but lower legume effects on net N mineralization. In contrast, neither elevated CO2 nor its interaction with legumes affected net N mineralization. These results indicate that legumes markedly influence the response of soil N cycling to some, but not all, global change drivers.
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Affiliation(s)
- Xiaorong Wei
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, China
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota
- CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, China
| | - Peter B Reich
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith South DC, NSW, Australia
| | - Sarah E Hobbie
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, Minnesota
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33
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Bytnerowicz TA, Min E, Griffin KL, Menge DNL. Repeatable, continuous and real‐time estimates of coupled nitrogenase activity and carbon exchange at the whole‐plant scale. Methods Ecol Evol 2019. [DOI: 10.1111/2041-210x.13186] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thomas A. Bytnerowicz
- Department of Ecology, Evolution and Environmental Biology Columbia University New York NY
| | - Elizabeth Min
- Department of Earth and Environmental Sciences Columbia University Palisades NY
| | - Kevin L. Griffin
- Department of Ecology, Evolution and Environmental Biology Columbia University New York NY
- Department of Earth and Environmental Sciences Columbia University Palisades NY
| | - Duncan N. L. Menge
- Department of Ecology, Evolution and Environmental Biology Columbia University New York NY
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34
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Kou-Giesbrecht S, Menge D. Nitrogen-fixing trees could exacerbate climate change under elevated nitrogen deposition. Nat Commun 2019; 10:1493. [PMID: 30940812 PMCID: PMC6445091 DOI: 10.1038/s41467-019-09424-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 03/06/2019] [Indexed: 11/25/2022] Open
Abstract
Biological nitrogen fixation can fuel CO2 sequestration by forests but can also stimulate soil emissions of nitrous oxide (N2O), a potent greenhouse gas. Here we use a theoretical model to suggest that symbiotic nitrogen-fixing trees could either mitigate (CO2 sequestration outweighs soil N2O emissions) or exacerbate (vice versa) climate change relative to non-fixing trees, depending on their nitrogen fixation strategy (the degree to which they regulate nitrogen fixation to balance nitrogen supply and demand) and on nitrogen deposition. The model posits that nitrogen-fixing trees could exacerbate climate change globally relative to non-fixing trees by the radiative equivalent of 0.77 Pg C yr−1 under nitrogen deposition rates projected for 2030. This value is highly uncertain, but its magnitude suggests that this subject requires further study and that improving the representation of biological nitrogen fixation in climate models could substantially decrease estimates of the extent to which forests will mitigate climate change. The balance between CO2 sequestration by forests and soil N2O emissions is poorly constrained. Here, the authors use a theoretical model to demonstrate that symbiotic N2-fixing trees can either mitigate climate change or exacerbate it relative to non-fixing trees.
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Affiliation(s)
- Sian Kou-Giesbrecht
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, 10027, USA.
| | - Duncan Menge
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, 10027, USA
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35
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Taylor BN, Chazdon RL, Menge DNL. Successional dynamics of nitrogen fixation and forest growth in regenerating Costa Rican rainforests. Ecology 2019; 100:e02637. [PMID: 30698284 DOI: 10.1002/ecy.2637] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 11/14/2018] [Accepted: 01/03/2019] [Indexed: 11/08/2022]
Abstract
Regenerating tropical forests have an immense capacity to capture carbon and harbor biodiversity. The recuperation of the nitrogen cycle following disturbance can fuel biomass regeneration, but few studies have evaluated the successional dynamics of nitrogen and nitrogen inputs in tropical forests. We assessed symbiotic and asymbiotic nitrogen fixation, soil inorganic nitrogen concentrations, and tree growth in a well-studied series of five tropical forest plots ranging from 19 yr in age to old-growth forests. Wet-season soil inorganic nitrogen concentrations were high in all plots, peaking in the 29-yr-old plot. Inputs from symbiotic nitrogen fixation declined through succession, while asymbiotic nitrogen fixation peaked in the 37-yr-old plot. Consequently, the dominant nitrogen fixation input switched from symbiotic fixation in the younger plots to asymbiotic fixation in the older plots. Tree growth was highest in the youngest plots and declined through succession. Interestingly, symbiotic nitrogen fixation was negatively correlated with the basal area of nitrogen-fixing trees across our study plots, highlighting the danger in using nitrogen-fixing trees as a proxy for rates of symbiotic nitrogen fixation. Our results demonstrate that the nitrogen cycle has largely recuperated by 19 yr following disturbance, allowing for rapid biomass regeneration at our site. This work provides important insight into the sources and dynamics of nitrogen that support growth and carbon capture in regenerating Neotropical forests.
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Affiliation(s)
- Benton N Taylor
- Smithsonian Environmental Research Center, 647 Contees Wharf Road, Edgewater, Maryland, 21037, USA
| | - Robin L Chazdon
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, 06269, USA
| | - Duncan N L Menge
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, 10th Floor, Schermerhorn Extension, 1200 Amsterdam Avenue, New York, New York, 10027, USA
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36
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Dovrat G, Sheffer E. Symbiotic dinitrogen fixation is seasonal and strongly regulated in water-limited environments. THE NEW PHYTOLOGIST 2019; 221:1866-1877. [PMID: 30299536 DOI: 10.1111/nph.15526] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 09/25/2018] [Indexed: 05/26/2023]
Abstract
Plants, especially perennials, growing in drylands and seasonally dry ecosystems are uniquely adapted to dry conditions. Legume shrubs and trees, capable of symbiotic dinitrogen (N2 ) fixation, often dominate in drylands. However, the strategies that allow symbiotic fixation in these ecosystems, and their influence on the nitrogen cycle, are largely unresolved. We evaluated the climatic, biogeochemical and ontogenetic factors influencing nitrogen fixation in an abundant Mediterranean legume shrub, Calicotome villosa. We measured nodulation, fixation rate, nitrogen allocation and soil biogeochemistry in three field sites over a full year. A controlled experiment evaluated differences in plant regulation of fixation as a function of soil nutrient availability and seedling and adult developmental stages. We found a strong seasonal pattern, shifting between high fixation rates during the rainy season at flowering and seed-set times to almost none in the rainless season. Under controlled conditions, plants downregulated fixation in response to soil nitrogen availability, but this response was stronger in seedlings than in adult shrubs. Finally, we did not find elevated soil nitrogen under N2 -fixing shrubs. We conclude that seasonal nitrogen fixation, regulation of fixation, and nitrogen conservation are key adaptations influencing the dominance of dryland legumes in the community, with broader consequences on the ecosystem nitrogen cycle.
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Affiliation(s)
- Guy Dovrat
- Institute of Plant Science and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
- Department of Natural Resources, Beef Cattle Section, Newe Ya'ar Research Center, Agricultural Research Organization, Ramat Yishay, 30095, Israel
| | - Efrat Sheffer
- Institute of Plant Science and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 7610001, Israel
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Wilcots ME, Taylor BN, Kuprewicz EK, Menge DNL. Small traits with big consequences: how seed traits of nitrogen‐fixing plants might influence ecosystem nutrient cycling. OIKOS 2018. [DOI: 10.1111/oik.05798] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Megan E. Wilcots
- Ecology, Evolution and Environmental Biology, Columbia Univ., 1200 Amsterdam Ave New York NY 10027 USA
| | - Benton N. Taylor
- Ecology, Evolution and Environmental Biology, Columbia Univ., 1200 Amsterdam Ave New York NY 10027 USA
| | - Erin K. Kuprewicz
- Ecology and Evolutionary Biology, Univ. of Connecticut Storrs CT USA
| | - Duncan N. L. Menge
- Ecology, Evolution and Environmental Biology, Columbia Univ., 1200 Amsterdam Ave New York NY 10027 USA
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38
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Forrester NJ, Ashman TL. Nitrogen fertilization differentially enhances nodulation and host growth of two invasive legume species in an urban environment. JOURNAL OF URBAN ECOLOGY 2018. [DOI: 10.1093/jue/juy021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Nicole J Forrester
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Avenue, Pittsburgh, PA, USA
| | - Tia-Lynn Ashman
- Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Avenue, Pittsburgh, PA, USA
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39
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Taylor BN, Menge DNL. Light regulates tropical symbiotic nitrogen fixation more strongly than soil nitrogen. NATURE PLANTS 2018; 4:655-661. [PMID: 30127409 DOI: 10.1038/s41477-018-0231-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 07/23/2018] [Indexed: 05/13/2023]
Abstract
Nitrogen limits primary production in almost every biome on Earth1,2. Symbiotic nitrogen fixation, conducted by certain angiosperms and their endosymbiotic bacteria, is the largest potential natural source of new nitrogen into the biosphere3, influencing global primary production, carbon sequestration and element cycling. Because symbiotic nitrogen fixation represents an alternative to soil nitrogen uptake, much of the work on symbiotic nitrogen fixation regulation has focused on soil nitrogen availability4-8. However, because symbiotic nitrogen fixation is an energetically expensive process9, light availability to the plant may also regulate symbiotic nitrogen fixation rates10,11. Despite the importance of symbiotic nitrogen fixation to biosphere functioning, the environmental factors that most strongly regulate this process remain unresolved. Here we show that light regulates symbiotic nitrogen fixation more strongly than does soil nitrogen and that light mediates the response of symbiotic nitrogen fixation to soil nitrogen availability. In a shadehouse experiment, low light levels (comparable with forest understories) completely shut down symbiotic nitrogen fixation, whereas soil nitrogen levels that far exceeded plant demand did not fully downregulate symbiotic nitrogen fixation at high light. For in situ forest seedlings, light was a notable predictor of symbiotic nitrogen fixation activity, but soil-extractable nitrogen was not. Light as a primary regulator of symbiotic nitrogen fixation is a departure from decades of focus on soil nitrogen availability. This shift in our understanding of symbiotic nitrogen fixation regulation can resolve a long-standing biogeochemical paradox12, and it will improve our ability to predict how symbiotic nitrogen fixation will fuel the global forest carbon sink and respond to human alteration of the global nitrogen cycle.
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Affiliation(s)
- Benton N Taylor
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA.
| | - Duncan N L Menge
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA
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40
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Batterman SA, Hall JS, Turner BL, Hedin LO, LaHaela Walter JK, Sheldon P, van Breugel M. Phosphatase activity and nitrogen fixation reflect species differences, not nutrient trading or nutrient balance, across tropical rainforest trees. Ecol Lett 2018; 21:1486-1495. [PMID: 30073753 DOI: 10.1111/ele.13129] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 03/18/2018] [Accepted: 06/27/2018] [Indexed: 01/25/2023]
Abstract
A fundamental biogeochemical paradox is that nitrogen-rich tropical forests contain abundant nitrogen-fixing trees, which support a globally significant tropical carbon sink. One explanation for this pattern holds that nitrogen-fixing trees can overcome phosphorus limitation in tropical forests by synthesizing phosphatase enzymes to acquire soil organic phosphorus, but empirical evidence remains scarce. We evaluated whether nitrogen fixation and phosphatase activity are linked across 97 trees from seven species, and tested two hypotheses for explaining investment in nutrient strategies: trading nitrogen-for-phosphorus or balancing nutrient demand. Both strategies varied across species but were not explained by nitrogen-for-phosphorus trading or nutrient balance. This indicates that (1) studies of these nutrient strategies require broad sampling within and across species, (2) factors other than nutrient trading must be invoked to resolve the paradox of tropical nitrogen fixation, and (3) nitrogen-fixing trees cannot provide a positive nitrogen-phosphorus-carbon feedback to alleviate nutrient limitation of the tropical carbon sink.
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Affiliation(s)
- Sarah A Batterman
- School of Geography and Priestley International Centre for Climate, University of Leeds, Leeds, UK.,Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.,Smithsonian Tropical Research Institute, Ancon, Panama
| | - Jefferson S Hall
- Smithsonian Tropical Research Institute, Ancon, Panama.,ForestGEO, Smithsonian Tropical Research Institute, Ancon, Panama
| | | | - Lars O Hedin
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA
| | | | | | - Michiel van Breugel
- Smithsonian Tropical Research Institute, Ancon, Panama.,Yale-NUS College, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore
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41
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Adams MA, Buchmann N, Sprent J, Buckley TN, Turnbull TL. Crops, Nitrogen, Water: Are Legumes Friend, Foe, or Misunderstood Ally? TRENDS IN PLANT SCIENCE 2018; 23:539-550. [PMID: 29559299 DOI: 10.1016/j.tplants.2018.02.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 02/19/2018] [Accepted: 02/23/2018] [Indexed: 06/08/2023]
Abstract
Biological nitrogen fixation (BNF) by crop legumes reduces demand for industrial nitrogen fixation (INF). Nonetheless, rates of BNF in agriculture remain low, with strong negative feedback to BNF from reactive soil nitrogen (N) and drought. We show that breeding for yield has resulted in strong relationships between photosynthesis and leaf N in non-leguminous crops, whereas grain legumes show strong relations between leaf N and water use efficiency (WUE). We contrast these understandings with other studies that draw attention to the water costs of grain legume crops, and their potential for polluting the biosphere with N. We propose that breeding grain legumes for reduced stomatal conductance can increase WUE without compromising production or BNF. Legume crops remain a better bet than relying on INF.
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Affiliation(s)
- Mark A Adams
- Swinburne University, PO Box 218, Hawthorn, VIC 3122, Australia; Centre for Carbon Water and Food, The University of Sydney, 380 Werombi Road, Camden, NSW 2480, Australia.
| | - Nina Buchmann
- ETH Zurich, Universitätstrasse 2, 8092 Zürich, Switzerland
| | - Janet Sprent
- Division of Plant Sciences, University of Dundee at JHI, Invergowrie, Dundee, DD2 5DA, UK
| | - Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Tarryn L Turnbull
- Centre for Carbon Water and Food, The University of Sydney, 380 Werombi Road, Camden, NSW 2480, Australia
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42
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Ament MR, Tierney JA, Hedin LO, Hobbie EA, Wurzburger N. Phosphorus and species regulate N2 fixation by herbaceous legumes in longleaf pine savannas. Oecologia 2018; 187:281-290. [DOI: 10.1007/s00442-018-4129-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 03/25/2018] [Indexed: 10/17/2022]
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43
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Luo J, Balvert SF, Wise B, Welten B, Ledgard SF, de Klein CAM, Lindsey S, Judge A. Using alternative forage species to reduce emissions of the greenhouse gas nitrous oxide from cattle urine deposited onto soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 610-611:1271-1280. [PMID: 28851147 DOI: 10.1016/j.scitotenv.2017.08.186] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 08/17/2017] [Accepted: 08/17/2017] [Indexed: 06/07/2023]
Abstract
Grazed pastures are a major contributor to emissions of the greenhouse gas nitrous oxide (N2O), and urine deposition from grazing animals is the main source of the emissions. Incorporating alternative forages into grazing systems could be an approach for reducing N2O emissions through mechanisms such as release of biological nitrification inhibitors from roots and increased root depth. Field plot and lysimeter (intact soil column) trials were conducted in a free draining Horotiu silt loam soil to test whether two alternative forage species, plantain (Plantago lanceolate L.) and lucerne (Medicago sativa L.), could reduce N2O emissions relative to traditional pasture species, white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.). The amounts of N2O emitted from the soil below each forage species, which all received the same cow urine at the same rates, was measured using an established static chamber method. Total N2O emissions from the plantain, lucerne and perennial ryegrass controls (without urine application) were generally very low, but emissions from the white clover control were significantly higher. When urine was applied in autumn or winter N2O emissions from plantain were lower compared with those from perennial ryegrass or white clover, but this difference was not found when urine was applied in summer. Lucerne had lower emissions in winter but not in other seasons. Incorporation of plantain into grazed pasture could be an approach to reduce N2O emissions. However, further work is required to understand the mechanisms for the reduced emissions and the effects of environmental conditions in different seasons.
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Affiliation(s)
- J Luo
- AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand.
| | - S F Balvert
- AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand; University of Waikato, Faculty of Science and Engineering, Private Bag 3105, Hamilton 3240, New Zealand
| | - B Wise
- AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand
| | - B Welten
- AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand
| | - S F Ledgard
- AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand
| | - C A M de Klein
- AgResearch Limited, Invermay Research Centre, Private Bag 50034, Mosgiel 9053, New Zealand
| | - S Lindsey
- AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand
| | - A Judge
- AgResearch Limited, Ruakura Research Centre, Private Bag 3123, Hamilton 3240, New Zealand
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44
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Lu J, Yang F, Wang S, Ma H, Liang J, Chen Y. Co-existence of Rhizobia and Diverse Non-rhizobial Bacteria in the Rhizosphere and Nodules of Dalbergia odorifera Seedlings Inoculated with Bradyrhizobium elkanii, Rhizobium multihospitium-Like and Burkholderia pyrrocinia-Like Strains. Front Microbiol 2017; 8:2255. [PMID: 29209289 PMCID: PMC5702347 DOI: 10.3389/fmicb.2017.02255] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 10/31/2017] [Indexed: 01/01/2023] Open
Abstract
Rhizobia induce root nodules and fix atmospheric N2 for most legume species in exchange for carbon. However, the diverse endophytic non-rhizobial bacteria in legume nodules that co-exist with rhizobia are often ignored because they are difficult to cultivate using routine cultivation approaches. To enhance our understanding of the incidence and diversity of legume–bacteria associations, a high-throughput sequencing analysis of bacterial 16S rRNA genes was used to examine the bacterial community in the rhizospheres and root nodules of Dalbergia odorifera seedlings that were uninoculated or inoculated with Bradyrhizobium elkanii H255, Rhizobium multihospitium–like HT221, or Burkholderia pyrrocinia–like H022238, in two growth media (nitrogen [N]-supplied soil or N-omitted potting mix). Seedlings inoculated with Bradyrhizobium had significantly more nodules than seedlings in the other inoculation conditions, regardless of growth media. Using the 15N natural abundance method, it was shown that the inoculated plants had significantly higher N2 fixation efficiency (48–57%) and specific nodule activity [269–313 μg N mg−1 of dry weight (dwt) nodule] compared to the uninoculated plants (203 μg N mg−1 dwt nodule). The 16S rRNA gene analysis showed that there was generally a higher bacterial diversity in the rhizosphere than in the nodules in the corresponding condition. Both rhizobial inoculation and media status significantly altered the bacterial communities in the rhizospheres and nodules (P < 0.05), with the exception of the inoculated soil rhizospheres. Regarding non-rhizobial bacteria, three genera, i.e., Lactococcus, Bacillus, and Pseudomonas, were consistently enriched in the rhizosphere and Bradyrhizobium, Chloroplast norank (which belongs to Cyanobacteria), and Lactococcus were commonly found in the nodules. In contrast, common rhizobial genera (including Rhizobium, Mesorhizobium, and Burkholderia) were only present in the nodules at low relative abundances (0.01–3.41%). Regarding non-rhizobial bacteria, 32 genera were found in the nodules, with non-rhizobial bacteria being predominant in the N omitted potting mix (with a relative abundance of 56–87%). This study suggests that legume nodules are inhabited by a high diversity of non-rhizobial bacteria, which may play a vital role in nodulation and N2 fixation in the host plants.
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Affiliation(s)
- Junkun Lu
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
| | - Fucheng Yang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
| | - Shengkun Wang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
| | - Haibin Ma
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
| | - Junfeng Liang
- State Key Laboratory of Tree Genetics and Breeding, Research Institute of Tropical Forestry, Chinese Academy of Forestry, Guangzhou, China
| | - Yinglong Chen
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, China.,Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling, China.,Institute of Agriculture, and School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
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45
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Menge DNL, Batterman SA, Hedin LO, Liao W, Pacala SW, Taylor BN. Why are nitrogen‐fixing trees rare at higher compared to lower latitudes? Ecology 2017; 98:3127-3140. [DOI: 10.1002/ecy.2034] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/08/2017] [Accepted: 09/18/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Duncan N. L. Menge
- Department of Ecology, Evolution, and Environmental Biology Columbia University New York New York 10027 USA
| | - Sarah A. Batterman
- Department of Ecology and Evolutionary Biology Princeton University Princeton New Jersey 08544 USA
- School of Geography and Priestley International Centre for Climate University of Leeds Leeds LS2 9JT United Kingdom
- Smithsonian Tropical Research Institute Ancon Panama
| | - Lars O. Hedin
- Department of Ecology and Evolutionary Biology Princeton University Princeton New Jersey 08544 USA
| | - Wenying Liao
- Department of Ecology, Evolution, and Environmental Biology Columbia University New York New York 10027 USA
- Department of Ecology and Evolutionary Biology Princeton University Princeton New Jersey 08544 USA
| | - Stephen W. Pacala
- Department of Ecology and Evolutionary Biology Princeton University Princeton New Jersey 08544 USA
| | - Benton N. Taylor
- Department of Ecology, Evolution, and Environmental Biology Columbia University New York New York 10027 USA
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46
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Nitrogen-fixing trees inhibit growth of regenerating Costa Rican rainforests. Proc Natl Acad Sci U S A 2017; 114:8817-8822. [PMID: 28760948 DOI: 10.1073/pnas.1707094114] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
More than half of the world's tropical forests are currently recovering from human land use, and this regenerating biomass now represents the largest carbon (C)-capturing potential on Earth. How quickly these forests regenerate is now a central concern for both conservation and global climate-modeling efforts. Symbiotic nitrogen-fixing trees are thought to provide much of the nitrogen (N) required to fuel tropical secondary regrowth and therefore to drive the rate of forest regeneration, yet we have a poor understanding of how these N fixers influence the trees around them. Do they promote forest growth, as expected if the new N they fix facilitates neighboring trees? Or do they suppress growth, as expected if competitive inhibition of their neighbors is strong? Using 17 consecutive years of data from tropical rainforest plots in Costa Rica that range from 10 y since abandonment to old-growth forest, we assessed how N fixers influenced the growth of forest stands and the demographic rates of neighboring trees. Surprisingly, we found no evidence that N fixers facilitate biomass regeneration in these forests. At the hectare scale, plots with more N-fixing trees grew slower. At the individual scale, N fixers inhibited their neighbors even more strongly than did nonfixing trees. These results provide strong evidence that N-fixing trees do not always serve the facilitative role to neighboring trees during tropical forest regeneration that is expected given their N inputs into these systems.
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47
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Menge DNL, Batterman SA, Liao W, Taylor BN, Lichstein JW, Ángeles‐Pérez G. Nitrogen‐fixing tree abundance in higher‐latitude North America is not constrained by diversity. Ecol Lett 2017; 20:842-851. [DOI: 10.1111/ele.12778] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/20/2017] [Accepted: 04/07/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Duncan N. L. Menge
- Department of Ecology, Evolution, and Environmental Biology Columbia University New York NY 10027 USA
| | - Sarah A. Batterman
- Department of Ecology and Evolutionary Biology Princeton University Princeton NJ 08544 USA
- School of Geography and Priestley International Centre for Climate Leeds University Leeds LS2 9JT UK
| | - Wenying Liao
- Department of Ecology, Evolution, and Environmental Biology Columbia University New York NY 10027 USA
- Department of Ecology and Evolutionary Biology Princeton University Princeton NJ 08544 USA
| | - Benton N. Taylor
- Department of Ecology, Evolution, and Environmental Biology Columbia University New York NY 10027 USA
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48
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Menge DNL, Levin SA. Spatial heterogeneity can resolve the nitrogen paradox of tropical forests. Ecology 2017; 98:1049-1061. [DOI: 10.1002/ecy.1733] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 11/20/2016] [Accepted: 01/03/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Duncan N. L. Menge
- Department of Ecology, Evolution, and Environmental Biology Columbia University 1200 Amsterdam Avenue, Schermerhorn Ex 1014A New York New York 10027 USA
| | - Simon A. Levin
- Department of Ecology and Evolutionary Biology Princeton University 106A Guyot Hall Princeton New Jersey 08544 USA
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49
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Herben T, Mayerová H, Skálová H, Hadincová V, Pecháčková S, Krahulec F. Long‐term time series of legume cycles in a semi‐natural montane grassland: evidence for nitrogen‐driven grass dynamics? Funct Ecol 2017. [DOI: 10.1111/1365-2435.12844] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomáš Herben
- Institute of Botany Academy of Sciences of the Czech Republic CZ‐252 43 Průhonice Czech Republic
- Department of Botany Faculty of Science Charles University Benátská 2 CZ‐128 01 Praha 2 Czech Republic
| | - Hana Mayerová
- Institute of Botany Academy of Sciences of the Czech Republic CZ‐252 43 Průhonice Czech Republic
- Department of Botany Faculty of Science Charles University Benátská 2 CZ‐128 01 Praha 2 Czech Republic
| | - Hana Skálová
- Institute of Botany Academy of Sciences of the Czech Republic CZ‐252 43 Průhonice Czech Republic
| | - Věra Hadincová
- Institute of Botany Academy of Sciences of the Czech Republic CZ‐252 43 Průhonice Czech Republic
| | - Sylvie Pecháčková
- Institute of Botany Academy of Sciences of the Czech Republic CZ‐252 43 Průhonice Czech Republic
- The West Bohemian Museum in Pilsen Kopeckého sady 2 301 00 Plzeň Czech Republic
| | - František Krahulec
- Institute of Botany Academy of Sciences of the Czech Republic CZ‐252 43 Průhonice Czech Republic
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50
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Mao W, Felton AJ, Zhang T. Linking Changes to Intraspecific Trait Diversity to Community Functional Diversity and Biomass in Response to Snow and Nitrogen Addition Within an Inner Mongolian Grassland. FRONTIERS IN PLANT SCIENCE 2017; 8:339. [PMID: 28352278 PMCID: PMC5348515 DOI: 10.3389/fpls.2017.00339] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 02/27/2017] [Indexed: 05/28/2023]
Abstract
In recent years, both the intraspecific and interspecific functional diversity (FD) of plant communities have been studied with new approaches to improve an understanding about the mechanisms underlying plant species coexistence. Yet, little is known about how global change drivers will impact intraspecific FD and trait overlap among species, and in particular how this may scale to impacts on community level FD and ecosystem functioning. To address this uncertainty, we assessed the direct and indirect responses of specific leaf area (SLA) among both dominant annual and subordinate perennial species to the independent and interactive effects of nitrogen and snow addition within the Inner Mongnolian steppe. More specifically, we investigated the consequences for these responses on plant community FD, trait overlap and biomass. Nitrogen addition increased the biomass of the dominant annual species and as a result increased total community biomass. This occurred despite concurrent decreases in the biomass of subordinate perennial species. Nitrogen addition also increased intraspecific FD and trait overlap of both annual species and perennial species, and consequently increased the degree of trait overlap in SLA at the community level. However, snow addition did not significantly impact intraspecific FD and trait overlap of SLA for perennial species, but increased intraspecific FD and trait overlap of annual species, of which scaled to changes in community level FD. We found that the responses of the dominant annual species to nitrogen and snow additions were generally more sensitive than the subordinate perennial species within the inner Mongolian grassland communities of our study. As a consequence of this sensitivity, the responses of the dominant species largely drove impacts to community FD, trait overlap and community biomass. In total, our study demonstrates that the responses of dominant species in a community to environmental change may drive the initial trajectories of change to community FD and functioning.
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Affiliation(s)
- Wei Mao
- Northwest Institute of Eco-Environment and Resource, Chinese Academy of SciencesLanzhou, China
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort CollinsCO, USA
| | - Andrew J. Felton
- Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort CollinsCO, USA
| | - Tonghui Zhang
- Northwest Institute of Eco-Environment and Resource, Chinese Academy of SciencesLanzhou, China
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