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Jhaveri R, Cannanbilla L, Bhat KSA, Sankaran M, Krishnadas M. Anatomical traits explain drought response of seedlings from wet tropical forests. Ecol Evol 2024; 14:e70155. [PMID: 39224158 PMCID: PMC11366499 DOI: 10.1002/ece3.70155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 07/08/2024] [Accepted: 07/29/2024] [Indexed: 09/04/2024] Open
Abstract
Water availability regulates plant community dynamics but the drought response of seedlings remains poorly known, despite their vulnerability, especially for the Asian tropics. In particular, discerning how functional traits of seedlings mediate drought response can aid generalizable predictions of tree responses to global environmental change. We assessed interspecific variation in drought response explained by above- and below-ground seedling traits. We conducted a dry-down experiment in the greenhouse using 16 tree species from the humid forests of Western Ghats in southern India, chosen to represent differences in affinity to conditions of high and low seasonal drought (seasonality affiliation). We compared survival, growth, and photosynthetic performance under drought and well-watered conditions and assessed the extent to which species' responses were explained by seasonality affiliation and 12 traits of root, stem and leaf. We found that the species from seasonally dry forest reduced photosynthetic rate in drought compared with well-watered conditions, but seasonality affiliation did not explain differences in growth and survival. Performance in drought vs well-watered conditions were best explained by anatomical traits of xylem, veins and stomata. Species with larger xylem reduced their growth and photosynthesis to tolerate desiccation. In drought, species with smaller stomata correlated with lower survival even though photosynthetic activity decreased by a larger extent with larger stomata. Overall, anatomical traits of xylem and stomata, directly related to water transport and gas-exchange, played a more prominent role than commonly used traits (e.g., specific leaf area, leaf dry matter content) in explaining species response to drought, and may offer a good proxy for physiological traits related to drought tolerance of seedlings.
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Affiliation(s)
- Rishiddh Jhaveri
- CSIR – Centre for Cellular and Molecular BiologyHyderabadIndia
- Academy of Scientific and Innovative Research (AcSIR)GhaziabadIndia
| | - Lakshmipriya Cannanbilla
- CSIR – Centre for Cellular and Molecular BiologyHyderabadIndia
- Chair of Plant EcologyUniversity of BayreuthBayreuthGermany
| | - K. S. Arpitha Bhat
- Department of Life ScienceBangalore UniversityBangaloreIndia
- Ashoka Trust for Research in Ecology and the Environment (ATREE)BangaloreIndia
| | | | - Meghna Krishnadas
- CSIR – Centre for Cellular and Molecular BiologyHyderabadIndia
- National Centre for Biological Sciences, TIFRBangaloreIndia
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He R, Shi H, Hu M, Zhou Q, Dang H, Zhang Q. Differential phenotypic plasticity of subalpine trees predicts trait integration under climate warming. THE NEW PHYTOLOGIST 2024. [PMID: 39155709 DOI: 10.1111/nph.20067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Accepted: 08/05/2024] [Indexed: 08/20/2024]
Abstract
Understanding limiting factors of phenotypic plasticity is essential given its critical role in shaping biological adaptation and evolution in changing environments. It has been proposed that the pattern of phenotypic correlation could constrain trait plasticity. However, the interplay between phenotypic plasticity and integration has remained contentious. We experimentally simulated climate warming in juveniles of three subalpine tree species by exposing them to three-year in situ open-top chambers (OTCs), and then measured functional plasticity of 72 eco-physiological traits to evaluate whether phenotypic integration constituted an intrinsic constraint to plasticity. We also tested the relationship between the differences in plasticity and maintenance in trait integration. Phenotypic plasticity was positively associated with integration in deciduous tree species under warming. The difference in the plasticity of two paired traits could predict their integration in different environments, where traits displaying more similar plasticity were more likely to be correlated. Our study showed no indication that phenotypic integration constrained plasticity. More importantly, we demonstrated that differential plasticity between traits might result in a notable reorganization of the trait associations, and that warming commonly induced a tighter phenotype. Our study provides new insights into the interplay between phenotypic plasticity and integration in subalpine trees under climate warming.
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Affiliation(s)
- Rui He
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Danjiangkou Wetland Ecosystem Field Scientific Observation and Research Station, Chinese Academy of Sciences & Hubei Province, Wuhan, 430074, China
| | - Hang Shi
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China
- Danjiangkou Wetland Ecosystem Field Scientific Observation and Research Station, Chinese Academy of Sciences & Hubei Province, Wuhan, 430074, China
| | - Man Hu
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China
- Danjiangkou Wetland Ecosystem Field Scientific Observation and Research Station, Chinese Academy of Sciences & Hubei Province, Wuhan, 430074, China
| | - Quan Zhou
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China
| | - Haishan Dang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China
- Danjiangkou Wetland Ecosystem Field Scientific Observation and Research Station, Chinese Academy of Sciences & Hubei Province, Wuhan, 430074, China
| | - Quanfa Zhang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China
- Danjiangkou Wetland Ecosystem Field Scientific Observation and Research Station, Chinese Academy of Sciences & Hubei Province, Wuhan, 430074, China
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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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Carmona CP. Harnessing traits for ecology: a counter perspective. Trends Ecol Evol 2023; 38:1012-1013. [PMID: 37474447 DOI: 10.1016/j.tree.2023.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/27/2023] [Accepted: 06/30/2023] [Indexed: 07/22/2023]
Affiliation(s)
- Carlos P Carmona
- Institute of Ecology and Earth Sciences, University of Tartu, Juhan Liivi 2, 50409 Tartu, Estonia.
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Zhang Y, Cao JJ, Yang QP, Wu MZ, Zhao Y, Kong DL. The worldwide allometric relationship in anatomical structures for plant roots. PLANT DIVERSITY 2023; 45:621-629. [PMID: 38197011 PMCID: PMC10772186 DOI: 10.1016/j.pld.2023.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 04/15/2023] [Accepted: 05/25/2023] [Indexed: 01/11/2024]
Abstract
The cortex (i.e., absorptive tissue) and stele (transportive vascular tissue) are fundamental to the function of plant roots. Unraveling how these anatomical structures are assembled in absorptive roots is essential for our understanding of plant ecology, physiology, and plant responses to global environmental changes. In this review, we first compile a large data set on anatomical traits in absorptive roots, including cortex thickness and stele radius, across 698 observations and 512 species. Using this data set, we reveal a common root allometry in absorptive root structures, i.e., cortex thickness increases much faster than stele radius with increasing root diameter (hereafter, root allometry). Root allometry is further validated within and across plant growth forms (woody, grass, and liana species), mycorrhiza types (arbuscular mycorrhiza, ectomycorrhiza, and orchid mycorrhizas), phylogenetic gradients (from ferns to Orchidaceae), and environmental change scenarios (e.g., elevation of atmospheric CO2 concentration and nitrogen fertilization). These findings indicate that root allometry is common in plants. Importantly, root allometry varies greatly across species. We then summarize recent research on the mechanisms of root allometry and potential issues regarding these mechanisms. We further discuss ecological and evolutionary implications of root allometry. Finally, we propose several important research directions that should be pursued regarding root allometry.
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Affiliation(s)
- Yue Zhang
- College of Forestry, Henan Agricultural University, Zhengzhou 450002, China
| | - Jing-Jing Cao
- College of Forestry, Henan Agricultural University, Zhengzhou 450002, China
| | - Qing-Pei Yang
- College of Forestry, Henan Agricultural University, Zhengzhou 450002, China
| | - Ming-Zuo Wu
- College of Forestry, Henan Agricultural University, Zhengzhou 450002, China
| | - Yong Zhao
- College of Forestry, Henan Agricultural University, Zhengzhou 450002, China
| | - De-Liang Kong
- College of Forestry, Henan Agricultural University, Zhengzhou 450002, China
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Schönauer M, Hietz P, Schuldt B, Rewald B. Root and branch hydraulic functioning and trait coordination across organs in drought-deciduous and evergreen tree species of a subtropical highland forest. FRONTIERS IN PLANT SCIENCE 2023; 14:1127292. [PMID: 37377798 PMCID: PMC10291250 DOI: 10.3389/fpls.2023.1127292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 04/26/2023] [Indexed: 06/29/2023]
Abstract
Vessel traits are key in understanding trees' hydraulic efficiency, and related characteristics like growth performance and drought tolerance. While most plant hydraulic studies have focused on aboveground organs, our understanding of root hydraulic functioning and trait coordination across organs remains limited. Furthermore, studies from seasonally dry (sub-)tropical ecosystems and mountain forests are virtually lacking and uncertainties remain regarding potentially different hydraulic strategies of plants differing in leaf habit. Here, we compared wood anatomical traits and specific hydraulic conductivities between coarse roots and small branches of five drought-deciduous and eight evergreen angiosperm tree species in a seasonally dry subtropical Afromontane forest in Ethiopia. We hypothesized that largest vessels and highest hydraulic conductivities are found in roots, with greater vessel tapering between roots and equally-sized branches in evergreen angiosperms due to their drought-tolerating strategy. We further hypothesized that the hydraulic efficiencies of root and branches cannot be predicted from wood density, but that wood densities across organs are generally related. Root-to-branch ratios of conduit diameters varied between 0.8 and 2.8, indicating considerable differences in tapering from coarse roots to small branches. While deciduous trees showed larger branch xylem vessels compared to evergreen angiosperms, root-to-branch ratios were highly variable within both leaf habit types, and evergreen species did not show a more pronounced degree of tapering. Empirically determined hydraulic conductivity and corresponding root-to-branch ratios were similar between both leaf habit types. Wood density of angiosperm roots was negatively related to hydraulic efficiency and vessel dimensions; weaker relationships were found in branches. Wood density of small branches was neither related to stem nor coarse root wood densities. We conclude that in seasonally dry subtropical forests, similar-sized coarse roots hold larger xylem vessels than small branches, but the degree of tapering from roots to branches is highly variable. Our results indicate that leaf habit does not necessarily influence the relationship between coarse root and branch hydraulic traits. However, larger conduits in branches and a low carbon investment in less dense wood may be a prerequisite for high growth rates of drought-deciduous trees during their shortened growing season. The correlation of stem and root wood densities with root hydraulic traits but not branch wood points toward large trade-offs in branch xylem towards mechanical properties.
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Affiliation(s)
- Marian Schönauer
- Department of Forest and Soil Sciences, Institute of Forest Ecology, University of Natural Resources and Life Sciences, Vienna, Austria
- Department of Forest Work Science and Engineering, Department of Forest Sciences and Forest Ecology, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Peter Hietz
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, University of Natural Resources and Life Sciences Vienna, Vienna, Austria
| | - Bernhard Schuldt
- Chair of Forest Botany, Institute of Forest Botany and Forest Zoology, Technical University of Dresden, Tharandt, Germany
| | - Boris Rewald
- Department of Forest and Soil Sciences, Institute of Forest Ecology, University of Natural Resources and Life Sciences, Vienna, Austria
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