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Hou J, McCormack ML, Reich PB, Sun T, Phillips RP, Lambers H, Chen HYH, Ding Y, Comas LH, Valverde-Barrantes OJ, Solly EF, Freschet GT. Linking fine root lifespan to root chemical and morphological traits-A global analysis. Proc Natl Acad Sci U S A 2024; 121:e2320623121. [PMID: 38607930 PMCID: PMC11032481 DOI: 10.1073/pnas.2320623121] [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: 12/22/2023] [Accepted: 03/12/2024] [Indexed: 04/14/2024] Open
Abstract
Fine root lifespan is a critical trait associated with contrasting root strategies of resource acquisition and protection. Yet, its position within the multidimensional "root economics space" synthesizing global root economics strategies is largely uncertain, and it is rarely represented in frameworks integrating plant trait variations. Here, we compiled the most comprehensive dataset of absorptive median root lifespan (MRL) data including 98 observations from 79 woody species using (mini-)rhizotrons across 40 sites and linked MRL to other plant traits to address questions of the regulators of MRL at large spatial scales. We demonstrate that MRL not only decreases with plant investment in root nitrogen (associated with more metabolically active tissues) but also increases with construction of larger diameter roots which is often associated with greater plant reliance on mycorrhizal symbionts. Although theories linking organ structure and function suggest that root traits should play a role in modulating MRL, we found no correlation between root traits associated with structural defense (root tissue density and specific root length) and MRL. Moreover, fine root and leaf lifespan were globally unrelated, except among evergreen species, suggesting contrasting evolutionary selection between leaves and roots facing contrasting environmental influences above vs. belowground. At large geographic scales, MRL was typically longer at sites with lower mean annual temperature and higher mean annual precipitation. Overall, this synthesis uncovered several key ecophysiological covariates and environmental drivers of MRL, highlighting broad avenues for accurate parametrization of global biogeochemical models and the understanding of ecosystem response to global climate change.
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Affiliation(s)
- Jiawen Hou
- Chinese Academy of Sciences Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang110016, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing100049, China
| | | | - Peter B. Reich
- Department of Forest Resources, University of Minnesota, St. Paul, MN55108
- Institute for Global Change Biology, University of Michigan, Ann Arbor, MI48109
- Hawkesbury Institute Environment, Western Sydney University, Penrith, NSW2753, Australia
| | - Tao Sun
- Chinese Academy of Sciences Key Laboratory of Forest Ecology and Silviculture, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang110016, China
| | | | - Hans Lambers
- School of Biological Sciences, University of Western Australia, Perth, WA6009, Australia
| | - Han Y. H. Chen
- Faculty of Natural Resources Management, Lakehead University, Thunder Bay, ONP7B 5E1, Canada
| | - Yiyang Ding
- Department of Forest Sciences/Institute for Atmospheric and Earth System Research, University of Helsinki, HelsinkiFI-00014, Finland
- Department of Physics, University of Helsinki, HelsinkiFI-00014, Finland
| | - Louise H. Comas
- Department of Soil & Crop Science, Colorado State University, Ft. Collins, CO80523
- United States Department of Agriculture, Agricultural Research Service, Water Management Research Unit, Ft. Collins, CO80526
| | | | - Emily F. Solly
- Helmholtz Centre for Environmental Research–Umwelt Forschungs Zentrum, Leipzig04318, Germany
| | - Gregoire T. Freschet
- Station d’écologie théorique et expérimentale, Centre National de la Recherche Scientifique, Moulis09200, France
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Gao Y, Zhang Z, Zeng F, Ma X. Root morphological and physiological traits are committed to the phosphorus acquisition of the desert plants in phosphorus-deficient soils. BMC PLANT BIOLOGY 2023; 23:188. [PMID: 37032339 PMCID: PMC10084647 DOI: 10.1186/s12870-023-04178-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 03/20/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND Phosphorus (P) deficiency in desert ecosystems is widespread. Generally, desert species may allocate an enormous proportion of photosynthetic carbon to their root systems to adjust their P-acquisition strategies. However, root P-acquisition strategies of deep-rooted desert species and the coordination response of root traits at different growth stages to differing soil P availability remains unclear. In this study, a two-year pot experiment was performed with four soil P-supply treatments (0, 0.9, 2.8, and 4.7 mg P kg-1 y-1 for the control, low-, intermediate-, and high-P supply, respectively). Root morphological and physiological traits of one- and two-year-old Alhagi sparsifolia seedlings were measured. RESULTS For two-year-old seedlings, control or low-P supply significantly increased their leaf Mn concentration, coarse and fine roots' specific root length (SRL), specific root surface area (SRSA), and acid phosphatase activity (APase), but SRL and SRSA of one-year-old seedlings were higher under intermediate-P supply treatment. Root morphological traits were closely correlated with root APase activity and leaf Mn concentration. One-year-old seedlings had higher root APase activity, leaf Mn concentration, and root tissue density (RTD), but lower SRL and SRSA. Two-year-old seedlings had higher root APase activity, leaf Mn concentration, SRL and SRSA, but a lower RTD. Root APase activity was significantly positively correlated with the leaf Mn concentration, regardless of coarse or fine roots. Furthermore, root P concentrations of coarse and fine roots were driven by different root traits, with root biomass and carboxylates secretion particularly crucial root traits for the root P-acquisition of one- and two-year-old seedlings. CONCLUSIONS Variation of root traits at different growth stages are coordinated with root P concentrations, indicating a trade-off between root traits and P-acquisition strategies. Alhagi sparsifolia developed two P-activation strategies, increasing P-mobilizing phosphatase activity and carboxylates secretion, to acclimate P-impoverished in soil. The adaptive variation of root traits at different growth stages and diversified P-activation strategies are conducive to maintaining the desert ecosystem productivity.
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Affiliation(s)
- Yanju Gao
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhihao Zhang
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China
| | - Fanjiang Zeng
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China.
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China.
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Xingyu Ma
- Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele, 848300, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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3
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Primka EJ, Adams TS, Buck A, Eissenstat DM. Topographical shifts in fine root lifespan in a mixed, mesic temperate forest. PLoS One 2021; 16:e0254672. [PMID: 34260660 PMCID: PMC8279377 DOI: 10.1371/journal.pone.0254672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 06/30/2021] [Indexed: 11/18/2022] Open
Abstract
Root lifespan, often is estimated in landscape- and ecosystem-level carbon models using linear approximations. In water manipulation experiments, fine root lifespan can vary with soil water content. Soil water content is generally structured by complex topography, which is largely unaccounted for in landscape- and ecosystem-scale carbon models. Topography governs the range of soil water content experienced by roots which may impact their lifespan. We hypothesized that root lifespan varied nonlinearly across a temperate, mesic, forested catchment due to differences in soil water content associated with topographic position. We expected regions of the landscape that were too wet or too dry would have soils that were not optimal for roots and thus result in shorter root lifespans. Specifically, we hypothesized that root lifespan would be longest in areas that consistently had soil water content in the middle of the soil water content spectrum, while in soils at either very low or very high soil water content, root lifespan would be relatively short. We tested this hypothesis by collecting and analyzing two years of minirhizotron and soil moisture data in plots widely distributed in the Shale Hills catchment of the Susquehanna-Shale Hills Critical Zone Observatory in Pennsylvania. We found that fine root lifespans were longer in traditionally wetter topographic regions, but detected no short term (biweekly) effect of soil moisture on root lifespan. Additionally, depth in soil, soil series, slope face orientation, and season of birth strongly affected root lifespans across the catchment. In contrast, lifespan was unaffected by root diameter or mycorrhizal association. Failure to account for these variables could result in erroneous estimates of fine root lifespan and, consequentially, carbon flux in temperate forested regions.
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Affiliation(s)
- Edward J. Primka
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Graduate Program in Ecology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Thomas S. Adams
- Department of Plant Science, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Alexandra Buck
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - David M. Eissenstat
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Graduate Program in Ecology, The Pennsylvania State University, University Park, Pennsylvania, United States of America
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Clark NM, Van den Broeck L, Guichard M, Stager A, Tanner HG, Blilou I, Grossmann G, Iyer-Pascuzzi AS, Maizel A, Sparks EE, Sozzani R. Novel Imaging Modalities Shedding Light on Plant Biology: Start Small and Grow Big. ANNUAL REVIEW OF PLANT BIOLOGY 2020; 71:789-816. [PMID: 32119794 DOI: 10.1146/annurev-arplant-050718-100038] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The acquisition of quantitative information on plant development across a range of temporal and spatial scales is essential to understand the mechanisms of plant growth. Recent years have shown the emergence of imaging methodologies that enable the capture and analysis of plant growth, from the dynamics of molecules within cells to the measurement of morphometricand physiological traits in field-grown plants. In some instances, these imaging methods can be parallelized across multiple samples to increase throughput. When high throughput is combined with high temporal and spatial resolution, the resulting image-derived data sets could be combined with molecular large-scale data sets to enable unprecedented systems-level computational modeling. Such image-driven functional genomics studies may be expected to appear at an accelerating rate in the near future given the early success of the foundational efforts reviewed here. We present new imaging modalities and review how they have enabled a better understanding of plant growth from the microscopic to the macroscopic scale.
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Affiliation(s)
- Natalie M Clark
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695, USA; ,
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa 50010, USA;
| | - Lisa Van den Broeck
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695, USA; ,
| | - Marjorie Guichard
- Center for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany; , ,
- CellNetworks Cluster of Excellence, Heidelberg University, 69120 Heidelberg, Germany
| | - Adam Stager
- Department of Mechanical Engineering, University of Delaware, Newark, Delaware 19711, USA; ,
| | - Herbert G Tanner
- Department of Mechanical Engineering, University of Delaware, Newark, Delaware 19711, USA; ,
| | - Ikram Blilou
- Department of Plant Cell and Developmental Biology, Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia;
| | - Guido Grossmann
- Center for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany; , ,
- CellNetworks Cluster of Excellence, Heidelberg University, 69120 Heidelberg, Germany
| | - Anjali S Iyer-Pascuzzi
- Department of Botany and Plant Pathology and Center for Plant Biology, Purdue University, West Lafayette, Indiana 47907, USA;
| | - Alexis Maizel
- Center for Organismal Studies (COS), University of Heidelberg, 69120 Heidelberg, Germany; , ,
| | - Erin E Sparks
- Department of Plant and Soil Sciences and the Delaware Biotechnology Institute, University of Delaware, Newark, Delaware 19711, USA;
| | - Rosangela Sozzani
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695, USA; ,
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5
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Kaushal R, Singh I, Thapliyal SD, Gupta AK, Mandal D, Tomar JMS, Kumar A, Alam NM, Kadam D, Singh DV, Mehta H, Dogra P, Ojasvi PR, Reza S, Durai J. Rooting behaviour and soil properties in different bamboo species of Western Himalayan Foothills, India. Sci Rep 2020; 10:4966. [PMID: 32188913 PMCID: PMC7080795 DOI: 10.1038/s41598-020-61418-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 02/18/2020] [Indexed: 12/04/2022] Open
Abstract
Due to extensive root system, connected rhizome bamboos are considered suitable for improving soil properties within a short period, though most of the claims are anecdotal and need to be supported with quantified data. The study evaluates seven bamboo species viz., Bambusa balcooa, Bambusa bambos, Bambusa vulgaris, Bambusa nutans, Dendrocalamus hamiltonii, Dendrocalamus stocksii and Dendrocalamus strictus for their rooting pattern and impact on soil health properties. Coarse and fine root intensity was maximum in B. vulgaris. Coarse root biomass ranged from 0.6 kg m−3 in B. nutans to 2.0 kg m−3 in B. vulgaris and B. bambos. Fine root biomass ranged from 1.1 kg m−3 in B. nutans to 4.5 kg m−3 in D. hamiltonii. Contribution of fine roots in terms of intensity and biomass was much higher than coarse roots. Fine root biomass showed declining trend with increase in soil depth in all the species. During sixth year, the litter fall ranged from 8.1 Mg ha−1 in D. stocksii to 12.4 Mg ha−1 in D. hamiltonii. Among soil physical properties significant improvement were recorded in hydraulic conductivity, water stable aggregates and mean weight diameter. Soil pH, organic carbon and available phosphorus under different species did not reveal any significant changes, while significant reduction was observed in total nitrogen and potassium. Significant positive correlation was observed between WSA and iron content. Soil microbial population and enzyme activities were higher in control plot. Considering root distribution, biomass, soil hydraulic conductivity and water stable aggregates, B. bambos, B. vulgaris and D. hamiltonii are recommended for rehabilitation of degraded lands prone to soil erosion.
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Affiliation(s)
- R Kaushal
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India.
| | - Indra Singh
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - S D Thapliyal
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - A K Gupta
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - D Mandal
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - J M S Tomar
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - Ambrish Kumar
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - N M Alam
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - D Kadam
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - D V Singh
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - H Mehta
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - Pradeep Dogra
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - P R Ojasvi
- ICAR-Indian Institute of Soil and Water Conservation, 218, Kaulagarh Road, Dehradun, 248 195, India
| | - S Reza
- International Bamboo and Rattan Organization, Addis Ababa, Ethiopia
| | - J Durai
- International Bamboo and Rattan Organization, Addis Ababa, Ethiopia
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6
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Zwetsloot MJ, Goebel M, Paya A, Grams TEE, Bauerle TL. Specific spatio-temporal dynamics of absorptive fine roots in response to neighbor species identity in a mixed beech-spruce forest. TREE PHYSIOLOGY 2019; 39:1867-1879. [PMID: 31504991 DOI: 10.1093/treephys/tpz086] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/07/2019] [Accepted: 07/18/2019] [Indexed: 06/10/2023]
Abstract
Absorptive fine roots are an important driver of soil biogeochemical cycles. Yet, the spatio-temporal dynamics of those roots in the presence of neighboring species remain poorly understood. The aim of this study was to analyze shifts in absorptive fine-root traits in monoculture or mixtures of Fagus sylvatica [L.] and Picea abies [L.] Karst. We hypothesized that root competition would be higher under single-species than mixed-species interactions, leading to changes in (i) root survivorship, diameter and respiration and (ii) spatio-temporal patterns of root growth and death. Using minirhizotron methods, we monitored the timing and location of absorptive fine-root growth and death at an experimental forest in southern Germany from 2011 to 2013. We also measured root respiration in the spring and fall seasons of 2012 and 2013. Our findings show that the absorptive fine roots of F. sylvatica had a 50% higher risk of root mortality and higher respiration rates in the single-species compared to mixed-species zones. These results support our hypothesis that root competition is less intense for F. sylvatica in mixture versus monoculture. We were unable to find confirmation for the same hypothesis for P. abies. To analyze spatio-temporal patterns of absorptive fine-root production and mortality, we used a mixed-effects model considering root depth (space) and seasons (time) simultaneously. This analysis showed that F. sylvatica shifts root production towards shallower soil layers in mixed-species stands, besides significant seasonal fluctuations in root production depths for both species. Ultimately, the impact of neighbor species identity on root traits observed in this study has important implications for where, when and how fast root-facilitated carbon cycling takes place in single-species versus mixed-species forests. In addition, our study highlights the need for inclusion of absorptive fine-root spatio-temporal dynamics when examining belowground plant interactions and biogeochemical cycles.
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Affiliation(s)
- Marie J Zwetsloot
- School of Integrative Plant Science, Cornell University, 236 Tower Road, Ithaca, NY 14853, USA
- Soil Biology Group, Wageningen University, Droevendaalsesteeg 3, 6708 PB Wageningen, the Netherlands
| | - Marc Goebel
- Department of Natural Resources, Cornell University, 111 Fernow Hall, Ithaca, NY 14853, USA
| | - Alex Paya
- School of Integrative Plant Science, Cornell University, 236 Tower Road, Ithaca, NY 14853, USA
| | - Thorsten E E Grams
- Ecophysiology of Plants, Technical University of Munich, Am Hochanger 13, 85354 Freising, Germany
| | - Taryn L Bauerle
- School of Integrative Plant Science, Cornell University, 236 Tower Road, Ithaca, NY 14853, USA
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7
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Huo C, Cheng W. Improved root turnover assessment using field scanning rhizotrons with branch order analysis. Ecosphere 2019. [DOI: 10.1002/ecs2.2793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Changfu Huo
- Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China
| | - Weixin Cheng
- Department of Environmental Studies University of California Santa Cruz California 95064 USA
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8
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Abstract
Stand density directly affects the distribution of ecological factors such as light, heat, and water in forest communities and changes the diversity and structure of undergrowth species, thereby affecting soil health. Fine roots can provide water and nutrients to plants rapidly in the fierce competition of soil resources, so as to get rid of environmental factors. This study examined the fine-root responses of the Populus tomentosa clone S86 to three stand densities (plant × row spacing: 2 × 2 m, 4 × 3 m, 4 × 5 m). We measured the biomass, morphology, and nitrogen content of lower- (1–3 order) and higher-order (>3 order) fine roots, and analyzed soil chemical properties in 10–30 cm. The soil from the density (2 × 2 m) stands showed lower soil organic matter content, available nitrogen, available phosphorous, and available potassium than others. Obviously, lower and higher-order fine roots were different: biomass of the >3 order accounted for 77–87% of the total biomass, 1–3-order fine-root diameter around 0.28–0.38 mm, while >3-order fine root were 1.28–1.69 mm; the length of 1–3-order fine root was longer than the >3 order, and root length density, specific root length, and nutrient content between the 1–3 and >3 orders were different. At 2 × 2 m, 1–3-order fine-root biomass was the highest, 132.5 g/m3, and the 1–3-order fine-root length, diameter, surface, root length density was also the highest; at the same time, the 1–3-order fine-root total nitrogen and organic matter content was also the highest, while the >3 order was highest under 4 × 3 m or 4 × 5 m. The findings of this study show that stand density affected the available nutrient content of the soil. When soil resources were poor, the biomass, morphology, and chemical content of fine roots were adjusted to increase the nutrient absorption rate, particularly in the lower-order roots.
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9
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Krasowski MJ, Lavigne MB, Szuter MA, Olesinski J, Kershaw JA, McGarrigle E. Age-related changes in survival and turnover rates of balsam fir (Abies balsamea (L.) Mill.) fine roots. TREE PHYSIOLOGY 2018; 38:865-876. [PMID: 29452424 DOI: 10.1093/treephys/tpy010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 02/01/2018] [Indexed: 06/08/2023]
Abstract
Fine-root (≤2 mm) demographics change as forests age, but the direction and extent of change are unknown. Knowledge of the change and understanding of causes will improve predictions of climate change impacts. We used minirhizotrons at three young and three mature balsam fir (Abies balsamea (L.) Mill.) sites to measure median lifespan (MLS) for each site and for annual cohorts. We computed turnover rate from the inverse of MLS (Tinv) and calculated a second turnover rate (T) from annual mortality, annual production and previous year-end standing crop. Median lifespan at mature sites (436 days) was half that at young sites (872 days). Median lifespan of annual cohorts varied widely at all sites. Age-class distributions of fine roots seen by minirhizotrons changed with increasing years of observation, with older age classes accumulating more slowly at mature sites. Our findings highlight the need to determine whether the proportional contributions of absorbing and transporting fine roots to annual production and their median lifespans change during stand development. Due to its variation among annual cohorts, we believe robust estimates of MLS at our sites require 5-7 years of observation, and reliable estimates of Tinv are reached earlier than T.
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Affiliation(s)
- Marek J Krasowski
- Faculty of Forestry and Environmental Management, University of New Brunswick, PO Box 4400, 28 Dineen Drive, Fredericton, NB E3B 5A6, Canada
| | - Michael B Lavigne
- Natural Resources Canada, Canadian Forest Service - Atlantic Forestry Centre, PO Box 4000, Fredericton, NB E3B 5P7, Canada
| | - Michael A Szuter
- Faculty of Forestry and Environmental Management, University of New Brunswick, PO Box 4400, 28 Dineen Drive, Fredericton, NB E3B 5A6, Canada
- Applied Ecological Services, Inc., 80 Franklin St., Dublin, OH 43017, USA
| | - Jakub Olesinski
- Faculty of Forestry and Environmental Management, University of New Brunswick, PO Box 4400, 28 Dineen Drive, Fredericton, NB E3B 5A6, Canada
- Environment and Natural Resources, PO Box 4354, 173 Hay River Dene Reserve, Hay River, NT X0E 0R7, Canada
| | - John A Kershaw
- Faculty of Forestry and Environmental Management, University of New Brunswick, PO Box 4400, 28 Dineen Drive, Fredericton, NB E3B 5A6, Canada
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10
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Ma Z, Guo D, Xu X, Lu M, Bardgett RD, Eissenstat DM, McCormack ML, Hedin LO. Evolutionary history resolves global organization of root functional traits. Nature 2018; 555:94-97. [PMID: 29466331 DOI: 10.1038/nature25783] [Citation(s) in RCA: 222] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 01/24/2018] [Indexed: 12/26/2022]
Abstract
Plant roots have greatly diversified in form and function since the emergence of the first land plants, but the global organization of functional traits in roots remains poorly understood. Here we analyse a global dataset of 10 functionally important root traits in metabolically active first-order roots, collected from 369 species distributed across the natural plant communities of 7 biomes. Our results identify a high degree of organization of root traits across species and biomes, and reveal a pattern that differs from expectations based on previous studies of leaf traits. Root diameter exerts the strongest influence on root trait variation across plant species, growth forms and biomes. Our analysis suggests that plants have evolved thinner roots since they first emerged in land ecosystems, which has enabled them to markedly improve their efficiency of soil exploration per unit of carbon invested and to reduce their dependence on symbiotic mycorrhizal fungi. We also found that diversity in root morphological traits is greatest in the tropics, where plant diversity is highest and many ancestral phylogenetic groups are preserved. Diversity in root morphology declines sharply across the sequence of tropical, temperate and desert biomes, presumably owing to changes in resource supply caused by seasonally inhospitable abiotic conditions. Our results suggest that root traits have evolved along a spectrum bounded by two contrasting strategies of root life: an ancestral 'conservative' strategy in which plants with thick roots depend on symbiosis with mycorrhizal fungi for soil resources and a more-derived 'opportunistic' strategy in which thin roots enable plants to more efficiently leverage photosynthetic carbon for soil exploration. These findings imply that innovations of belowground traits have had an important role in preparing plants to colonize new habitats, and in generating biodiversity within and across biomes.
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Affiliation(s)
- Zeqing Ma
- Center for Forest Ecosystem Studies and Qianyanzhou Ecological Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Dali Guo
- Center for Forest Ecosystem Studies and Qianyanzhou Ecological Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Xingliang Xu
- Center for Forest Ecosystem Studies and Qianyanzhou Ecological Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Mingzhen Lu
- Department of Ecology and Evolutionary Biology, Princeton University, New Jersey 08544, USA
| | - Richard D Bardgett
- School of Earth and Environmental Sciences, The University of Manchester, Manchester M13 9PT, UK
| | - David M Eissenstat
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - M Luke McCormack
- Center for Forest Ecosystem Studies and Qianyanzhou Ecological Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.,Department of Plant and Microbial Biology, University of Minnesota, St Paul, Minnesota 55108, USA
| | - Lars O Hedin
- Department of Ecology and Evolutionary Biology, Princeton University, New Jersey 08544, USA
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11
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Martínez-Vilalta J, Garcia-Forner N. Water potential regulation, stomatal behaviour and hydraulic transport under drought: deconstructing the iso/anisohydric concept. PLANT, CELL & ENVIRONMENT 2017; 40:962-976. [PMID: 27739594 DOI: 10.1111/pce.12846] [Citation(s) in RCA: 179] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 10/03/2016] [Accepted: 10/04/2016] [Indexed: 05/02/2023]
Abstract
In this review, we address the relationship between stomatal behaviour, water potential regulation and hydraulic transport in plants, focusing on the implications for the iso/anisohydric classification of plant drought responses at seasonal timescales. We first revise the history of the isohydric concept and its possible definitions. Then, we use published data to answer two main questions: (1) is greater stomatal control in response to decreasing water availability associated with a tighter regulation of leaf water potential (ΨL ) across species? and (2) is there an association between tighter ΨL regulation (~isohydric behaviour) and lower leaf conductance over time during a drought event? These two questions are addressed at two levels: across species growing in different sites and comparing only species coexisting at a given site. Our analyses show that, across species, a tight regulation of ΨL is not necessarily associated with greater stomatal control or with more constrained assimilation during drought. Therefore, iso/anisohydry defined in terms of ΨL regulation cannot be used as an indicator of a specific mechanism of drought-induced mortality or as a proxy for overall plant vulnerability to drought.
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Affiliation(s)
- Jordi Martínez-Vilalta
- CREAF, Cerdanyola del Vallès, Barcelona, E-08193, Spain
- Universitat Autònoma Barcelona, Cerdanyola del Vallès, Barcelona, E-08193, Spain
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12
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Liese R, Alings K, Meier IC. Root Branching Is a Leading Root Trait of the Plant Economics Spectrum in Temperate Trees. FRONTIERS IN PLANT SCIENCE 2017; 8:315. [PMID: 28337213 PMCID: PMC5340746 DOI: 10.3389/fpls.2017.00315] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/20/2017] [Indexed: 05/20/2023]
Abstract
Global vegetation models use conceived relationships between functional traits to simulate ecosystem responses to environmental change. In this context, the concept of the leaf economics spectrum (LES) suggests coordinated leaf trait variation, and separates species which invest resources into short-lived leaves with a high expected energy return rate from species with longer-lived leaves and slower energy return. While it has been assumed that being fast (acquisitive) or slow (conservative) is a general feature for all organ systems, the translation of the LES into a root economics spectrum (RES) for tree species has been hitherto inconclusive. This may be partly due to the assumption that the bulk of tree fine roots have similar uptake functions as leaves, despite the heterogeneity of their environments and resources. In this study we investigated well-established functional leaf and stature traits as well as a high number of fine root traits (14 traits split by different root orders) of 13 dominant or subdominant temperate tree species of Central Europe, representing two phylogenetic groups (gymnosperms and angiosperms) and two mycorrhizal associations (arbuscular and ectomycorrhizal). We found reflected variation in leaf and lower-order root traits in some (surface areas and C:N) but not all (N content and longevity) traits central to the LES. Accordingly, the LES was not mirrored belowground. We identified significant phylogenetic signal in morphological lower-order root traits, i.e., in root tissue density, root diameter, and specific root length. By contrast, root architecture (root branching) was influenced by the mycorrhizal association type which developed independent from phylogeny of the host tree. In structural equation models we show that root branching significantly influences both belowground (direct influence on root C:N) and aboveground (indirect influences on specific leaf area and leaf longevity) traits which relate to resource investment and lifespan. We conclude that branching of lower order roots can be considered a leading root trait of the plant economics spectrum of temperate trees, since it relates to the mycorrhizal association type and belowground resource exploitation; while the dominance of the phylogenetic signal over environmental filtering makes morphological root traits less central for tree economics spectra across different environments.
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Affiliation(s)
| | | | - Ina C. Meier
- Plant Ecology, Albrecht-von-Haller Institute for Plant Sciences, University of GöttingenGöttingen, Germany
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13
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Liu B, He J, Zeng F, Lei J, Arndt SK. Life span and structure of ephemeral root modules of different functional groups from a desert system. THE NEW PHYTOLOGIST 2016; 211:103-12. [PMID: 26856386 DOI: 10.1111/nph.13880] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/23/2015] [Indexed: 05/24/2023]
Abstract
The terminal branch orders of plant root systems have been proposed as short-lived 'ephemeral' modules specialized for resource absorption. The occurrence of ephemeral root modules has so far only been reported for a temperate tree species and it is unclear if the concept also applies to other woody (shrub, tree) and herb species. Fine roots of 12 perennial dicotyledonous herb, shrub and tree species were monitored for two growing seasons using a branch-order classification, sequential sampling and rhizotrons in the Taklamakan desert. Two root modules existed in all three plant functional groups. Among the first five branch orders, the first two (perennial herbs, shrubs) or three (trees) root orders were ephemeral and had a primary anatomical structure, high nitrogen (N) concentrations, high respiration rates and very short life spans of 1-4 months, whereas the last two branch orders in all functional groups were perennial, with thicker diameters, no or collapsed cortex, distinct secondary growth, low N concentrations, low respiration rates, but much longer life spans. Ephemeral, short-lived root modules and long-lived, persistent root modules seem to be a general feature across many plant functional groups and could represent a basic root system design.
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Affiliation(s)
- Bo Liu
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, Cele, 848300, Xinjiang, China
| | - Junxia He
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, Cele, 848300, Xinjiang, China
| | - Fanjiang Zeng
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, Cele, 848300, Xinjiang, China
- Key Laboratory of Biogeography and Bioresource in Arid Land, Chinese Academy of Sciences, Urumqi, 830011, China
| | - Jiaqiang Lei
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- Cele National Station of Observation and Research for Desert Grassland Ecosystem in Xinjiang, Cele, 848300, Xinjiang, China
| | - Stefan K Arndt
- School of Ecosystem and Forest Sciences, University of Melbourne, 500 Yarra Boulevard, 3121, Richmond, Vic, Australia
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14
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Larson JE, Funk JL. Seedling root responses to soil moisture and the identification of a belowground trait spectrum across three growth forms. THE NEW PHYTOLOGIST 2016; 210:827-38. [PMID: 26765506 DOI: 10.1111/nph.13829] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 11/25/2015] [Indexed: 05/03/2023]
Abstract
Root trait variation and plasticity could be key factors differentiating plant performance under drought. However, water manipulation and root measurements are rarely coupled empirically across growth forms to identify whether belowground strategies are generalizable across species. We measured seedling root traits across three moisture levels in 18 Mediterranean forbs, grasses, and woody species. Drought increased the root mass fraction (RMF) and decreased the relative proportion of thin roots (indicated by increased root diameters and decreased specific root length (SRL)), rates of root elongation and growth, plant nitrogen uptake, and plant growth. Although responses varied across species, plasticity was not associated with growth form. Woody species differed from forbs and grasses in many traits, but herbaceous groups were similar. Across water treatments, trait correlations suggested a single spectrum of belowground trade-offs related to resource acquisition and plant growth. While effects of SRL and RMF on plant growth shifted with drought, root elongation rate consistently represented this spectrum. We demonstrate that general patterns of root morphology and plasticity are identifiable across diverse species. Root trait measurements should enhance our understanding of belowground strategy and performance across growth forms, but it will be critical to incorporate plasticity and additional aspects of root function into these efforts.
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Affiliation(s)
- Julie E Larson
- Schmid College of Science and Technology, Chapman University, 1 University Dr., Orange, CA, 92866, USA
| | - Jennifer L Funk
- Schmid College of Science and Technology, Chapman University, 1 University Dr., Orange, CA, 92866, USA
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15
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Sun K, Luke McCormack M, Li L, Ma Z, Guo D. Fast-cycling unit of root turnover in perennial herbaceous plants in a cold temperate ecosystem. Sci Rep 2016; 6:19698. [PMID: 26791578 PMCID: PMC4726329 DOI: 10.1038/srep19698] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/30/2015] [Indexed: 11/10/2022] Open
Abstract
Roots of perennial plants have both persistent portion and fast-cycling units represented by different levels of branching. In woody species, the distal nonwoody branch orders as a unit are born and die together relatively rapidly (within 1-2 years). However, whether the fast-cycling units also exist in perennial herbs is unknown. We monitored root demography of seven perennial herbs over two years in a cold temperate ecosystem and we classified the largest roots on the root collar or rhizome as basal roots, and associated finer laterals as secondary, tertiary and quaternary roots. Parallel to woody plants in which distal root orders form a fast-cycling module, basal root and its finer laterals also represent a fast-cycling module in herbaceous plants. Within this module, basal roots had a lifespan of 0.5-2 years and represented 62-87% of total root biomass, thus dominating annual root turnover (60%-81% of the total). Moreover, root traits including root length, tissue density, and biomass were useful predictors of root lifespan. We conclude that both herbaceous and woody plants have fast-cycling modular units and future studies identifying the fast-cycling module across plant species should allow better understanding of how root construction and turnover are linked to whole-plant strategies.
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Affiliation(s)
- Kai Sun
- Department of Ecology, College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes of Ministry of Education, Peking University, Beijing 100871, China
| | - M. Luke McCormack
- Center for Forest Ecosystem Studies and Qianyanzhou Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Le Li
- Center for Forest Ecosystem Studies and Qianyanzhou Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zeqing Ma
- Center for Forest Ecosystem Studies and Qianyanzhou Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Dali Guo
- Center for Forest Ecosystem Studies and Qianyanzhou Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
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16
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Eissenstat DM, Kucharski JM, Zadworny M, Adams TS, Koide RT. Linking root traits to nutrient foraging in arbuscular mycorrhizal trees in a temperate forest. NEW PHYTOLOGIST 2015; 208:114-24. [PMID: 25970701 DOI: 10.1111/nph.13451] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 04/05/2015] [Indexed: 05/05/2023]
Affiliation(s)
- David M. Eissenstat
- Intercollege Graduate Degree Program in Plant Biology Penn State University University Park PA 16802 USA
- Department of Ecosystem Science and Management Penn State University University Park PA 16802 USA
| | - Joshua M. Kucharski
- Intercollege Graduate Degree Program in Plant Biology Penn State University University Park PA 16802 USA
| | - Marcin Zadworny
- Intercollege Graduate Degree Program in Plant Biology Penn State University University Park PA 16802 USA
- Institute of Dendrology Polish Academy of Sciences Parkowa 5 62‐035 Kórnik Poland
| | - Thomas S. Adams
- Department of Ecosystem Science and Management Penn State University University Park PA 16802 USA
| | - Roger T. Koide
- Intercollege Graduate Degree Program in Plant Biology Penn State University University Park PA 16802 USA
- Department of Biology Brigham Young University Provo UT 84602 USA
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17
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McCormack ML, Dickie IA, Eissenstat DM, Fahey TJ, Fernandez CW, Guo D, Helmisaari HS, Hobbie EA, Iversen CM, Jackson RB, Leppälammi-Kujansuu J, Norby RJ, Phillips RP, Pregitzer KS, Pritchard SG, Rewald B, Zadworny M. Redefining fine roots improves understanding of below-ground contributions to terrestrial biosphere processes. THE NEW PHYTOLOGIST 2015; 207:505-18. [PMID: 25756288 DOI: 10.1111/nph.13363] [Citation(s) in RCA: 399] [Impact Index Per Article: 44.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/07/2015] [Indexed: 05/17/2023]
Abstract
Fine roots acquire essential soil resources and mediate biogeochemical cycling in terrestrial ecosystems. Estimates of carbon and nutrient allocation to build and maintain these structures remain uncertain because of the challenges of consistently measuring and interpreting fine-root systems. Traditionally, fine roots have been defined as all roots ≤ 2 mm in diameter, yet it is now recognized that this approach fails to capture the diversity of form and function observed among fine-root orders. Here, we demonstrate how order-based and functional classification frameworks improve our understanding of dynamic root processes in ecosystems dominated by perennial plants. In these frameworks, fine roots are either separated into individual root orders or functionally defined into a shorter-lived absorptive pool and a longer-lived transport fine-root pool. Using these frameworks, we estimate that fine-root production and turnover represent 22% of terrestrial net primary production globally - a c. 30% reduction from previous estimates assuming a single fine-root pool. Future work developing tools to rapidly differentiate functional fine-root classes, explicit incorporation of mycorrhizal fungi into fine-root studies, and wider adoption of a two-pool approach to model fine roots provide opportunities to better understand below-ground processes in the terrestrial biosphere.
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Affiliation(s)
- M Luke McCormack
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ian A Dickie
- Bio-Protection Research Centre, Lincoln University, Canterbury, New Zealand
| | - David M Eissenstat
- Department of Ecosystem Science and Management, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Timothy J Fahey
- Department of Natural Resources, Cornell University, Ithaca, NY, 14853, USA
| | | | - Dali Guo
- Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | | | - Erik A Hobbie
- Earth Systems Research Center, University of New Hampshire, Durham, NH, 03824, USA
| | - Colleen M Iversen
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Robert B Jackson
- Department of Earth System Science, Stanford University, Stanford, CA, 94305, USA
| | | | - Richard J Norby
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | | | - Kurt S Pregitzer
- Department of Forest, Rangeland, and Fire Sciences, University of Idaho, Moscow, ID, 83844, USA
| | - Seth G Pritchard
- Department of Biology, College of Charleston, Charleston, SC, 29401, USA
| | - Boris Rewald
- Institute of Forest Ecology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Marcin Zadworny
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, 62-035, Poland
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18
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Valverde‐Barrantes OJ, Smemo KA, Blackwood CB. Fine root morphology is phylogenetically structured, but nitrogen is related to the plant economics spectrum in temperate trees. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12384] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Kurt A. Smemo
- Department of Biological Sciences Kent State University Kent OH 44242 USA
- The Holden Arboretum 9500 Sperry Rd Kirtland OH 44094 USA
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19
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Acquisition of ephemeral module in roots: a new view and test. Sci Rep 2014; 4:5078. [PMID: 24865985 PMCID: PMC4035572 DOI: 10.1038/srep05078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 05/06/2014] [Indexed: 11/22/2022] Open
Abstract
The terminal root branch orders composed mainly of primarily-developed tissues are increasingly recognized as an ephemeral module specialized for resource absorption. This root module is crucial in driving a range of ecosystem processes such as belowground productivity, carbon and nutrient cycling. Traditionally, acquisition of the ephemeral root module is achieved by separating these primarily-developed branch orders with forceps. However, obtaining this root segment with forceps approach is labor-intensive which may not be applicable for studies with an appreciable amount of root samples. To address this challenge, we developed a new idea to obtain the ephemeral root module. In this new view, root samples were tenderly kneaded by hand and the detached roots are considered as the ephemeral root module. To test this idea, four species with contrasting growing environment were selected and a range of chemicals were determined including C, N, P, Ca, S, Mg, Ba, Zn, Mn, Pb, Cu, V and Li. We found no or little difference of these chemicals in roots by hand-kneading approach from roots by forceps approach. These results suggested that hand-kneading method could be a convenient way to acquire ephemeral root module.
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20
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McCormack ML, Guo D. Impacts of environmental factors on fine root lifespan. FRONTIERS IN PLANT SCIENCE 2014; 5:205. [PMID: 24904605 PMCID: PMC4032987 DOI: 10.3389/fpls.2014.00205] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 04/28/2014] [Indexed: 05/17/2023]
Abstract
The lifespan of fast-cycling roots is a critical parameter determining a large flux of plant carbon into soil through root turnover and is a biological feature regulating the capacity of a plant to capture soil water and nutrients via root-age-related physiological processes. While the importance of root lifespan to whole-plant and ecosystem processes is increasingly recognized, robust descriptions of this dynamic process and its response to changes in climatic and edaphic factors are lacking. Here we synthesize available information and propose testable hypotheses using conceptual models to describe how changes in temperature, water, nitrogen (N), and phosphorus (P) availability impact fine root lifespan within a species. Each model is based on intrinsic responses including root physiological activity and alteration of carbohydrate allocation at the whole-plant level as well as extrinsic factors including mycorrhizal fungi and pressure from pathogens, herbivores, and other microbes. Simplifying interactions among these factors, we propose three general principles describing fine root responses to complex environmental gradients. First, increases in a factor that strongly constrains plant growth (temperature, water, N, or P) should result in increased fine root lifespan. Second, increases in a factor that exceeds plant demand or tolerance should result in decreased lifespan. Third, as multiple factors interact fine root responses should be determined by the most dominant factor controlling plant growth. Moving forward, field experiments should determine which types of species (e.g., coarse vs. fine rooted, obligate vs. facultative mycotrophs) will express greater plasticity in response to environmental gradients while ecosystem models may begin to incorporate more detailed descriptions of root lifespan and turnover. Together these efforts will improve quantitative understanding of root dynamics and help to identify areas where future research should be focused.
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Affiliation(s)
- M. Luke McCormack
- Key Laboratory of Ecosystem Network Observation and Modeling, Synthesis Research Center of Chinese Ecosystem Research Network, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of SciencesBeijing, China
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21
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Lee MH, Comas LH, Callahan HS. Experimentally reduced root-microbe interactions reveal limited plasticity in functional root traits in Acer and Quercus. ANNALS OF BOTANY 2014; 113:513-21. [PMID: 24363335 PMCID: PMC3906969 DOI: 10.1093/aob/mct276] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 10/14/2013] [Indexed: 05/22/2023]
Abstract
BACKGROUND AND AIMS Interactions between roots and soil microbes are critical components of below-ground ecology. It is essential to quantify the magnitude of root trait variation both among and within species, including variation due to plasticity. In addition to contextualizing the magnitude of plasticity relative to differences between species, studies of plasticity can ascertain if plasticity is predictable and whether an environmental factor elicits changes in traits that are functionally advantageous. METHODS To compare functional traits and trait plasticities in fine root tissues with natural and reduced levels of colonization by microbial symbionts, trimmed and surface-sterilized root segments of 2-year-old Acer rubrum and Quercus rubra seedlings were manipulated. Segments were then replanted into satellite pots filled with control or heat-treated soil, both originally derived from a natural forest. Mycorrhizal colonization was near zero in roots grown in heat-treated soil; roots grown in control soil matched the higher colonization levels observed in unmanipulated root samples collected from field locations. KEY RESULTS Between-treatment comparisons revealed negligible plasticity for root diameter, branching intensity and nitrogen concentration across both species. Roots from treated soils had decreased tissue density (approx. 10-20 %) and increased specific root length (approx. 10-30 %). In contrast, species differences were significant and greater than treatment effects in traits other than tissue density. Interspecific trait differences were also significant in field samples, which generally resembled greenhouse samples. CONCLUSIONS The combination of experimental and field approaches was useful for contextualizing trait plasticity in comparison with inter- and intra-specific trait variation. Findings that root traits are largely species dependent, with the exception of root tissue density, are discussed in the context of current literature on root trait variation, interactions with symbionts and recent progress in standardization of methods for quantifying root traits.
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Affiliation(s)
- Mei-Ho Lee
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY 10027, USA
| | - Louise H. Comas
- Department of Horticulture and Intercollege Program in Ecology, Penn State University, University Park, PA 16802, USA
| | - Hilary S. Callahan
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY 10027, USA
- Department of Biology, Barnard College, Columbia University, New York, NY 10027, USA
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22
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Rytter RM. The effect of limited availability of N or water on C allocation to fine roots and annual fine root turnover in Alnus incana and Salix viminalis. TREE PHYSIOLOGY 2013; 33:924-39. [PMID: 23963409 DOI: 10.1093/treephys/tpt060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effect of limited nitrogen (N) or water availability on fine root growth and turnover was examined in two deciduous species, Alnus incana L. and Salix viminalis L., grown under three different regimes: (i) supply of N and water in amounts which would not hamper growth, (ii) limited N supply and (iii) limited water supply. Plants were grown outdoors during three seasons in covered and buried lysimeters placed in a stand structure and filled with quartz sand. Computer-controlled irrigation and fertilization were supplied through drip tubes. Production and turnover of fine roots were estimated by combining minirhizotron observations and core sampling, or by sequential core sampling. Annual turnover rates of fine roots <1 mm (5-6 year(-1)) and 1-2 mm (0.9-2.8 year(-1)) were not affected by changes in N or water availability. Fine root production (<1 mm) differed between Alnus and Salix, and between treatments in Salix; i.e., absolute length and biomass production increased in the order: water limited < unlimited < N limited. Few treatment effects were detected for fine roots 1-2 mm. Proportionally more C was allocated to fine roots (≤2 mm) in N or water-limited Salix; 2.7 and 2.3 times the allocation to fine roots in the unlimited regime, respectively. Estimated input to soil organic carbon increased by ca. 20% at N limitation in Salix. However, future studies on fine root decomposition under various environmental conditions are required. Fine root growth responses to N or water limitation were less pronounced in Alnus, thus indicating species differences caused by N-fixing capacity and slower initial growth in Alnus, or higher fine root plasticity in Salix. A similar seasonal growth pattern across species and treatments suggested the influence of outer stimuli, such as temperature and light.
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Affiliation(s)
- Rose-Marie Rytter
- Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden; Present address: Rytter Science, Backavägen 16, S-268 68 Röstånga, Sweden
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23
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Luke McCormack M, Eissenstat DM, Prasad AM, Smithwick EAH. Regional scale patterns of fine root lifespan and turnover under current and future climate. GLOBAL CHANGE BIOLOGY 2013; 19:1697-708. [PMID: 0 DOI: 10.1111/gcb.12163] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 01/08/2013] [Indexed: 05/24/2023]
Affiliation(s)
| | | | - Anantha M. Prasad
- Northeastern Research Station; USDA Forest Service; 359 Main Road; Delaware; OH; 43015; USA
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24
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Long Y, Kong D, Chen Z, Zeng H. Variation of the linkage of root function with root branch order. PLoS One 2013; 8:e57153. [PMID: 23451168 PMCID: PMC3581569 DOI: 10.1371/journal.pone.0057153] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Accepted: 01/17/2013] [Indexed: 11/18/2022] Open
Abstract
Mounting evidence has shown strong linkage of root function with root branch order. However, it is not known whether this linkage is consistent in different species. Here, root anatomic traits of the first five branch order were examined in five species differing in plant phylogeny and growth form in tropical and subtropical forests of south China. In Paramichelia baillonii, one tree species in Magnoliaceae, the intact cortex as well as mycorrhizal colonization existed even in the fifth-order root suggesting the preservation of absorption function in the higher-order roots. In contrast, dramatic decreases of cortex thickness and mycorrhizal colonization were observed from lower- to higher-order roots in three other tree species, Cunninghamia lanceolata, Acacia auriculiformis and Gordonia axillaries, which indicate the loss of absorption function. In a fern, Dicranopteris dichotoma, there were several cortex layers with prominently thickened cell wall and no mycorrhizal colonization in the third- and fourth-order roots, also demonstrating the loss of absorptive function in higher-order roots. Cluster analysis using these anatomic traits showed a different classification of root branch order in P. baillonii from other four species. As for the conduit diameter-density relationship in higher-order roots, the mechanism underpinning this relationship in P. baillonii was different from that in other species. In lower-order roots, different patterns of coefficient of variance for conduit diameter and density provided further evidence for the two types of linkage of root function with root branch order. These linkages corresponding to two types of ephemeral root modules have important implication in the prediction of terrestrial carbon cycling, although we caution that this study was pseudo-replicated. Future studies by sampling more species can test the generality of these two types of linkage.
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Affiliation(s)
- Yingqian Long
- The Key Laboratory of Science and Technology of Urban Environment, Peking University Shenzhen Graduate School, Shenzhen, People’s Republic of China
| | - Deliang Kong
- The Key Laboratory of Science and Technology of Urban Environment, Peking University Shenzhen Graduate School, Shenzhen, People’s Republic of China
- School of Life Sciences, Henan University, Kaifeng, People’s Republic of China
| | - Zhengxia Chen
- The Key Laboratory of Science and Technology of Urban Environment, Peking University Shenzhen Graduate School, Shenzhen, People’s Republic of China
| | - Hui Zeng
- The Key Laboratory of Science and Technology of Urban Environment, Peking University Shenzhen Graduate School, Shenzhen, People’s Republic of China
- Department of Ecology, College of Urban and Environmental Sciences and the Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing, People’s Republic of China
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Luke McCormack M, Adams TS, Smithwick EAH, Eissenstat DM. Predicting fine root lifespan from plant functional traits in temperate trees. THE NEW PHYTOLOGIST 2012; 195:823-831. [PMID: 22686426 DOI: 10.1111/j.1469-8137.2012.04198.x] [Citation(s) in RCA: 175] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Although linkages of leaf and whole-plant traits to leaf lifespan have been rigorously investigated, there is a limited understanding of similar linkages of whole-plant and fine root traits to root lifespan. In comparisons across species, do suites of traits found in leaves also exist for roots, and can these traits be used to predict root lifespan? We observed the fine root lifespan of 12 temperate tree species using minirhizotrons in a common garden and compared their median lifespans with fine-root and whole-plant traits. We then determined which set of combined traits would be most useful in predicting patterns of root lifespan. Median root lifespan ranged widely among species (95-336 d). Root diameter, calcium content, and tree wood density were positively related to root lifespan, whereas specific root length, nitrogen (N) : carbon (C) ratio, and plant growth rate were negatively related to root lifespan. Root diameter and plant growth rate, together (R² = 0.62) or in combination with root N : C ratio (R² = 0.76), were useful predictors of root lifespan across the 12 species. Our results highlight linkages between fine root lifespan in temperate trees and plant functional traits that may reduce uncertainty in predictions of root lifespan or turnover across species at broader spatial scales.
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Affiliation(s)
- M Luke McCormack
- Department of Horticulture, The Pennsylvania State University, 103 Tyson Bldg, University Park, PA 16802, USA
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park PA, USA
| | - Thomas S Adams
- Department of Horticulture, The Pennsylvania State University, 103 Tyson Bldg, University Park, PA 16802, USA
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park PA, USA
| | - Erica A H Smithwick
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park PA, USA
- Department of Geography, The Pennsylvania State University, University Park, PA, USA
| | - David M Eissenstat
- Department of Horticulture, The Pennsylvania State University, 103 Tyson Bldg, University Park, PA 16802, USA
- Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, University Park PA, USA
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Lojewski NR, Fischer DG, Bailey JK, Schweitzer JA, Whitham TG, Hart SC. Genetic components to belowground carbon fluxes in a riparian forest ecosystem: a common garden approach. THE NEW PHYTOLOGIST 2012; 195:631-639. [PMID: 22642377 DOI: 10.1111/j.1469-8137.2012.04185.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Soil carbon dioxide (CO(2)) efflux is a major component of terrestrial carbon (C) cycles; yet, the demonstration of covariation between overstory tree genetic-based traits and soil C flux remains a major frontier in understanding biological controls over soil C. Here, we used a common garden with two native tree species, Populus fremontii and P. angustifolia, and their naturally occurring hybrids to test the predictability of belowground C fluxes on the basis of taxonomic identity and genetic marker composition of replicated clones of individual genotypes. Three patterns emerged: soil CO(2) efflux and ratios of belowground flux to aboveground productivity differ by as much as 50-150% as a result of differences in clone identity and cross type; on the basis of Mantel tests of molecular marker matrices, we found that c. 30% of this variation was genetically based, in which genetically similar trees support more similar soil CO(2) efflux under their canopies than do genetically dissimilar trees; and the patterns detected in an experimental garden match observations in the wild, and seem to be unrelated to measured abiotic factors. Our findings suggest that the genetic makeup of the plants growing on soil has a significant influence on the release of C from soils to the atmosphere.
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Affiliation(s)
- Nathan R Lojewski
- School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA
| | | | - Joseph K Bailey
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37919, USA
| | - Jennifer A Schweitzer
- Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37919, USA
| | - Thomas G Whitham
- Merriam Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ 86011, USA
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Stephen C Hart
- School of Natural Sciences and Sierra Nevada Research Institute, University of California Merced, Merced, CA 95343, USA
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Chang R, Fu B, Liu G, Yao X, Wang S. Effects of soil physicochemical properties and stand age on fine root biomass and vertical distribution of plantation forests in the Loess Plateau of China. Ecol Res 2012. [DOI: 10.1007/s11284-012-0958-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Neumann RB, Cardon ZG. The magnitude of hydraulic redistribution by plant roots: a review and synthesis of empirical and modeling studies. THE NEW PHYTOLOGIST 2012; 194:337-352. [PMID: 22417121 DOI: 10.1111/j.1469-8137.2012.04088.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Hydraulic redistribution (HR) - the movement of water from moist to dry soil through plant roots - occurs worldwide within a range of different ecosystems and plant species. The proposed ecological and hydrologic impacts of HR include increasing dry-season transpiration and photosynthetic rates, prolonging the life span of fine roots and maintaining root-soil contact in dry soils, and moving rainwater down into deeper soil layers where it does not evaporate. In this review, we compile estimates of the magnitude of HR from ecosystems around the world, using representative empirical and modeling studies from which we could extract amounts of water redistributed by plant root systems. The reported average magnitude of HR varies by nearly two orders of magnitude across ecosystems, from 0.04 to 1.3 mm H(2)O d(-1) in the empirical literature, and from 0.1 to 3.23 mm H(2)O d(-1) in the modeling literature. Using these synthesized data, along with other published studies, we examine this variation in the magnitude of upward and downward HR, considering effects of plant, soil and ecosystem characteristics, as well as effects of methodological details (in both empirical and modeling studies) on estimates of HR. We take both ecological and hydrologic perspectives.
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Affiliation(s)
- Rebecca B Neumann
- Department of Civil and Environmental Engineering, 201 More Hall, University of Washington, Seattle, WA 98195, USA
| | - Zoe G Cardon
- The Ecosystems Center, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543, USA
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Gu J, Yu S, Sun Y, Wang Z, Guo D. Influence of root structure on root survivorship: an analysis of 18 tree species using a minirhizotron method. Ecol Res 2011. [DOI: 10.1007/s11284-011-0833-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Abstract
Historically, ephemeral roots have been equated with 'fine roots' (i.e. all roots of less than an arbitrary diameter, such as 2 mm), but evidence shows that 'fine roots' in woody species are complex branching systems with both rapid-cycling and slow-cycling components. A precise definition of ephemeral roots is therefore needed. Using a branch-order classification, a rhizotron method and sequential sampling of a root cohort, we tested the hypothesis that ephemeral root modules exist within the branching Fraxinus mandshurica (Manchurian ash) root system as distal nonwoody lateral branches, which show anatomical, nutritional and physiological patterns distinct from their woody mother roots. Our results showed that in F. mandshurica, distal nonwoody root branch orders die rapidly as intact lateral branches (or modules). These nonwoody branch orders exhibited highly synchronous changes in tissue nitrogen concentrations and respiration, dominated root turnover, nutrient flux and root respiration, and never underwent secondary development. The ephemeral root modules proposed here may provide a functional basis for differentiating and sampling short-lived absorptive roots in woody plants, and represent a conceptual leap over the traditional coarse-fine root dichotomies based on arbitrary size classes.
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Affiliation(s)
- Mengxue Xia
- Department of Ecology, College of Urban and Environmental Sciences and Key Laboratory for Earth Surface Processes of Ministry of Education, Peking University, Beijing 100871, China
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Baltzer JL, Thomas SC. A second dimension to the leaf economics spectrum predicts edaphic habitat association in a tropical forest. PLoS One 2010; 5. [PMID: 20957212 PMCID: PMC2948525 DOI: 10.1371/journal.pone.0013163] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Accepted: 09/01/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Strong patterns of habitat association are frequent among tropical forest trees and contribute to the maintenance of biodiversity. The relation of edaphic differentiation to tradeoffs among leaf functional traits is less clear, but may provide insights into mechanisms of habitat partitioning in these species rich assemblages. METHODOLOGY/PRINCIPAL FINDINGS We quantify the leaf economics spectrum (LES) for 16 tree species within a Bornean forest characterized by highly pronounced habitat specialization. Our findings suggest that the primary axis of trait variation in light-limited, lowland tropical forests was identical to the LES and corresponds with the shade tolerance continuum. There was no separation with respect to edaphic variation along this primary axis of trait variation. However, a second orthogonal axis determined largely by foliar P concentrations resulted in a near-perfect separation of species occupying distinct soil types within the forest. CONCLUSIONS/SIGNIFICANCE We suggest that this second axis of leaf trait variation represents a "leaf edaphic habitat spectrum" related to foliar P and potentially other nutrients closely linked to geological substrate, and may generally occur in plant communities characterized by strong edaphic resource gradients.
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Affiliation(s)
- Jennifer L Baltzer
- Biology Department, Mount Allison University, Sackville, New Brunswick, Canada.
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Quan X, Wang C, Zhang Q, Wang X, Luo Y, Bond-Lamberty B. Dynamics of fine roots in five Chinese temperate forests. JOURNAL OF PLANT RESEARCH 2010; 123:497-507. [PMID: 20217175 DOI: 10.1007/s10265-010-0322-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 01/07/2010] [Indexed: 05/28/2023]
Abstract
We used a minirhizotron method to investigate spatial and temporal dynamics of fine roots (diameter < or =2 mm) in five Chinese temperate forests: Mongolian oak forest, aspen-birch forest, hardwood forest, Korean pine plantation and Dahurian larch plantation. Fine root dynamics were significantly influenced by forest type, soil layer, and sampling time. The grand mean values varied from 1.99 to 3.21 mm cm(-2) (root length per minirhizotron viewing area) for the fine root standing crop; from 6.7 to 11.6 microm cm(-2) day(-1) for the production; and from 3.2 to 6.1 microm cm(-2) day(-1) for the mortality. All forests had a similar seasonal "sinusoidal" pattern of standing crop, and a "unimodal" pattern of production. However, the seasonal dynamics of the mortality were largely unsynchronized with those of the production. The minimum values of standing crop, production and mortality occurred in March for all forests, whereas the maximum values and occurrence time differed among forest types. The standing crop, production and mortality tended to decrease with soil depth. The different spatiotemporal patterns of fine roots among the forests highlight the need for forest-specific measurements and modeling of fine root dynamics and forest carbon allocation.
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Affiliation(s)
- Xiankuai Quan
- College of Forestry, Northeast Forestry University, 26 Hexing Road, Harbin, 150040, China
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