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Castillo-Argaez R, Sapes G, Mallen N, Lippert A, John GP, Zare A, Hammond WM. Spectral ecophysiology: hyperspectral pressure-volume curves to estimate leaf turgor loss. New Phytol 2024; 242:935-946. [PMID: 38482720 DOI: 10.1111/nph.19669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 02/19/2024] [Indexed: 04/12/2024]
Abstract
Turgor loss point (TLP) is an important proxy for plant drought tolerance, species habitat suitability, and drought-induced plant mortality risk. Thus, TLP serves as a critical tool for evaluating climate change impacts on plants, making it imperative to develop high-throughput and in situ methods to measure TLP. We developed hyperspectral pressure-volume curves (PV curves) to estimate TLP using leaf spectral reflectance. We used partial least square regression models to estimate water potential (Ψ) and relative water content (RWC) for two species, Frangula caroliniana and Magnolia grandiflora. RWC and Ψ's model for each species had R2 ≥ 0.7 and %RMSE = 7-10. We constructed PV curves with model estimates and compared the accuracy of directly measured and spectra-predicted TLP. Our findings indicate that leaf spectral measurements are an alternative method for estimating TLP. F. caroliniana TLP's values were -1.62 ± 0.15 (means ± SD) and -1.62 ± 0.34 MPa for observed and reflectance predicted, respectively (P > 0.05), while M. grandiflora were -1.78 ± 0.34 and -1.66 ± 0.41 MPa (P > 0.05). The estimation of TLP through leaf reflectance-based PV curves opens a broad range of possibilities for future research aimed at understanding and monitoring plant water relations on a large scale with spectral ecophysiology.
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Affiliation(s)
| | - Gerard Sapes
- Agronomy Department, University of Florida, Gainesville, FL, 32611, USA
| | - Nicole Mallen
- Agronomy Department, University of Florida, Gainesville, FL, 32611, USA
| | - Alston Lippert
- Agronomy Department, University of Florida, Gainesville, FL, 32611, USA
| | - Grace P John
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Alina Zare
- Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - William M Hammond
- Agronomy Department, University of Florida, Gainesville, FL, 32611, USA
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2
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Fabricant AM, Put P, Barskiy DA. Proton relaxometry of tree leaves at hypogeomagnetic fields. Front Plant Sci 2024; 15:1352282. [PMID: 38525149 PMCID: PMC10957608 DOI: 10.3389/fpls.2024.1352282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/21/2024] [Indexed: 03/26/2024]
Abstract
We report on a cross-species proton-relaxometry study in ex vivo tree leaves using nuclear magnetic resonance (NMR) at 7µT. Apart from the intrinsic interest of probing nuclear-spin relaxation in biological tissues at magnetic fields below Earth field, our setup enables comparative analysis of plant water dynamics without the use of expensive commercial spectrometers. In this work, we focus on leaves from common Eurasian evergreen and deciduous tree families: Pinaceae (pine, spruce), Taxaceae (yew), Betulaceae (hazel), Prunus (cherry), and Fagaceae (beech, oak). Using a nondestructive protocol, we measure their effective proton T 2 relaxation times as well as track the evolution of water content associated with leaf dehydration. Newly developed "gradiometric quadrature" detection and data-processing techniques are applied in order to increase the signal-to-noise ratio (SNR) of the relatively weak measured signals. We find that while measured relaxation times do not vary significantly among tree genera, they tend to increase as leaves dehydrate. Such experimental modalities may have particular relevance for future drought-stress research in ecology, agriculture, and space exploration.
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Affiliation(s)
- Anne M. Fabricant
- Institute of Physics, Johannes Gutenberg University of Mainz, Mainz, Germany
- Helmholtz Institute Mainz, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
| | - Piotr Put
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University in Kraków, Kraków, Poland
| | - Danila A. Barskiy
- Institute of Physics, Johannes Gutenberg University of Mainz, Mainz, Germany
- Helmholtz Institute Mainz, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
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3
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Zhang D, Tian C, Mai W. Exogenous Sodium and Calcium Alleviate Drought Stress by Promoting the Succulence of Suaeda salsa. Plants (Basel) 2024; 13:721. [PMID: 38475566 DOI: 10.3390/plants13050721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 02/27/2024] [Accepted: 02/29/2024] [Indexed: 03/14/2024]
Abstract
Succulence is a key trait involved in the response of Suaeda salsa to salt stress. However, few studies have investigated the effects of the interaction between salt and drought stress on S. salsa growth and succulence. In this study, the morphology and physiology of S. salsa were examined under different salt ions (Na+, Ca2+, Mg2+, Cl-, and SO42-) and simulated drought conditions using different polyethylene glycol concentrations (PEG; 0%, 5%, 10%, and 15%). The results demonstrate that Na+ and Ca2+ significantly increased leaf succulence by increasing leaf water content and enlarging epidermal cell size compared to Mg2+, Cl-, and SO42-. Under drought (PEG) stress, with an increase in drought stress, the biomass, degree of leaf succulence, and water content of S. salsa decreased significantly in the non-salt treatment. However, with salt treatment, the results indicated that Na+ and Ca2+ could reduce water stress due to drought by stimulating the succulence of S. salsa. In addition, Na+ and Ca2+ promoted the activity of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), which could reduce oxidative stress. In conclusion, Na+ and Ca2+ are the main factors promoting succulence and can effectively alleviate drought stress in S. salsa.
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Affiliation(s)
- Dong Zhang
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changyan Tian
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
| | - Wenxuan Mai
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China
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4
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Nadal M, Clemente-Moreno MJ, Perera-Castro AV, Roig-Oliver M, Onoda Y, Gulías J, Flexas J. Incorporating pressure-volume traits into the leaf economics spectrum. Ecol Lett 2023; 26:549-562. [PMID: 36750322 DOI: 10.1111/ele.14176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 02/09/2023]
Abstract
In recent years, attempts have been made in linking pressure-volume parameters and the leaf economics spectrum to expand our knowledge of the interrelationships among leaf traits. We provide theoretical and empirical evidence for the coordination of the turgor loss point and associated traits with net CO2 assimilation (An ) and leaf mass per area (LMA). We measured gas exchange, pressure-volume curves and leaf structure in 45 ferns and angiosperms, and explored the anatomical and chemical basis of the key traits. We propose that the coordination observed between mass-based An , capacitance and the turgor loss point (πtlp ) emerges from their shared link with leaf density (one of the components of LMA) and, specially, leaf saturated water content (LSWC), which in turn relates to cell size and nitrogen and carbon content. Thus, considering the components of LMA and LSWC in ecophysiological studies can provide a broader perspective on leaf structure and function.
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Affiliation(s)
- Miquel Nadal
- Departamento de Sistemas Agrícolas, Forestales y Medio Ambiente, Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Zaragoza, Spain
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Palma, Spain
| | - María J Clemente-Moreno
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Palma, Spain
| | - Alicia V Perera-Castro
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Palma, Spain
- Department of Botany, Ecology and Plant Physiology, Universidad de La Laguna (ULL), La Laguna, Spain
| | - Margalida Roig-Oliver
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Palma, Spain
| | - Yusuke Onoda
- Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Javier Gulías
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Palma, Spain
| | - Jaume Flexas
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Palma, Spain
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Junttila S, Sugano J, Vastaranta M, Linnakoski R, Kaartinen H, Kukko A, Holopainen M, Hyyppä H, Hyyppä J. Can Leaf Water Content Be Estimated Using Multispectral Terrestrial Laser Scanning? A Case Study With Norway Spruce Seedlings. Front Plant Sci 2018; 9:299. [PMID: 29568306 PMCID: PMC5853165 DOI: 10.3389/fpls.2018.00299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 02/21/2018] [Indexed: 06/08/2023]
Abstract
Changing climate is increasing the amount and intensity of forest stress agents, such as drought, pest insects, and pathogens. Leaf water content, measured here in terms of equivalent water thickness (EWT), is an early indicator of tree stress that provides timely information about the health status of forests. Multispectral terrestrial laser scanning (MS-TLS) measures target geometry and reflectance simultaneously, providing spatially explicit reflectance information at several wavelengths. EWT and leaf internal structure affect leaf reflectance in the shortwave infrared region that can be used to predict EWT with MS-TLS. A second wavelength that is sensitive to leaf internal structure but not affected by EWT can be used to normalize leaf internal effects on the shortwave infrared region and improve the prediction of EWT. Here we investigated the relationship between EWT and laser intensity features using multisensor MS-TLS at 690, 905, and 1,550 nm wavelengths with both drought-treated and Endoconidiophora polonica inoculated Norway spruce seedlings to better understand how MS-TLS measurements can explain variation in EWT. In our study, a normalized ratio of two wavelengths at 905 and 1,550 nm and length of seedling explained 91% of the variation (R2) in EWT as the respective prediction accuracy for EWT was 0.003 g/cm2 in greenhouse conditions. The relation between EWT and the normalized ratio of 905 and 1,550 nm wavelengths did not seem sensitive to a decreased point density of the MS-TLS data. Based on our results, different EWTs in Norway spruce seedlings show different spectral responses when measured using MS-TLS. These results can be further used when developing EWT monitoring for improving forest health assessments.
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Affiliation(s)
- Samuli Junttila
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
- Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute (FGI), Masala, Finland
| | - Junko Sugano
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
| | - Mikko Vastaranta
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
- Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute (FGI), Masala, Finland
- School of Forest Sciences, University of Eastern Finland, Joensuu, Finland
| | - Riikka Linnakoski
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
- Natural Resources Institute Finland (Luke), Helsinki, Finland
| | - Harri Kaartinen
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute (FGI), Masala, Finland
- Department of Geography and Geology, University of Turku, Turku, Finland
| | - Antero Kukko
- Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute (FGI), Masala, Finland
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute (FGI), Masala, Finland
| | - Markus Holopainen
- Department of Forest Sciences, University of Helsinki, Helsinki, Finland
- Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute (FGI), Masala, Finland
| | - Hannu Hyyppä
- Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute (FGI), Masala, Finland
- Department of Built Environment, Aalto University, Aalto, Finland
| | - Juha Hyyppä
- Centre of Excellence in Laser Scanning Research, Finnish Geospatial Research Institute (FGI), Masala, Finland
- Department of Remote Sensing and Photogrammetry, Finnish Geospatial Research Institute (FGI), Masala, Finland
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Dubbert M, Kübert A, Werner C. Impact of Leaf Traits on Temporal Dynamics of Transpired Oxygen Isotope Signatures and Its Impact on Atmospheric Vapor. Front Plant Sci 2017; 8:5. [PMID: 28149303 PMCID: PMC5241305 DOI: 10.3389/fpls.2017.00005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 01/03/2017] [Indexed: 05/27/2023]
Abstract
Oxygen isotope signatures of transpiration (δ E ) are powerful tracers of water movement from plant to global scale. However, a mechanistic understanding of how leaf morphological/physiological traits effect δ E is missing. A laser spectrometer was coupled to a leaf-level gas-exchange system to measure fluxes and isotopic signatures of plant transpiration under controlled conditions in seven distinct species (Fagus sylvatica, Pinus sylvestris, Acacia longifolia, Quercus suber, Coffea arabica, Plantago lanceolata, Oxalis triangularis). We analyzed the role of stomatal conductance (gs ) and leaf water content (W) on the temporal dynamics of δ E following changes in relative humidity (rH). Changes in rH were applied from 60 to 30% and from 30 to 60%, which is probably more than covering the maximum step changes occurring under natural conditions. Further, the impact of gs and W on isotopic non-steady state isofluxes was analyzed. Following changes in rH, temporal development of δ E was well described by a one-pool modeling approach for most species. Isofluxes of δ E were dominantly driven by stomatal control on E, particularly for the initial period of 30 min following a step change. Hence, the deviation of isofluxes from isotopic steady state can be large, even though plants transpire near to isotopic steady state. Notably, not only transpiration rate and stomatal conductance, but also the leaf traits stomatal density (as a measure of gmax) and leaf water content are significantly related to the time constant (τ) and non-steady-state isofluxes. This might provide an easy-to-access means of a priori assumptions for the impact of isotopic non-steady-state transpiration in various ecosystems. We discuss the implications of our results from leaf to ecosystem scale.
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7
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Jin X, Shi C, Yu CY, Yamada T, Sacks EJ. Determination of Leaf Water Content by Visible and Near-Infrared Spectrometry and Multivariate Calibration in Miscanthus. Front Plant Sci 2017; 8:721. [PMID: 28579992 PMCID: PMC5437372 DOI: 10.3389/fpls.2017.00721] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 04/19/2017] [Indexed: 05/19/2023]
Abstract
Leaf water content is one of the most common physiological parameters limiting efficiency of photosynthesis and biomass productivity in plants including Miscanthus. Therefore, it is of great significance to determine or predict the water content quickly and non-destructively. In this study, we explored the relationship between leaf water content and diffuse reflectance spectra in Miscanthus. Three multivariate calibrations including partial least squares (PLS), least squares support vector machine regression (LSSVR), and radial basis function (RBF) neural network (NN) were developed for the models of leaf water content determination. The non-linear models including RBF_LSSVR and RBF_NN showed higher accuracy than the PLS and Lin_LSSVR models. Moreover, 75 sensitive wavelengths were identified to be closely associated with the leaf water content in Miscanthus. The RBF_LSSVR and RBF_NN models for predicting leaf water content, based on 75 characteristic wavelengths, obtained the high determination coefficients of 0.9838 and 0.9899, respectively. The results indicated the non-linear models were more accurate than the linear models using both wavelength intervals. These results demonstrated that visible and near-infrared (VIS/NIR) spectroscopy combined with RBF_LSSVR or RBF_NN is a useful, non-destructive tool for determinations of the leaf water content in Miscanthus, and thus very helpful for development of drought-resistant varieties in Miscanthus.
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Affiliation(s)
- Xiaoli Jin
- Department of Agronomy and the Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang UniversityHangzhou, China
- *Correspondence: Xiaoli Jin
| | - Chunhai Shi
- Department of Agronomy and the Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang UniversityHangzhou, China
| | - Chang Yeon Yu
- Division of Bioresource Sciences, Kangwon National UniversityChuncheon, South Korea
| | - Toshihiko Yamada
- Field Science Center for Northern Biosphere, Hokkaido UniversitySapporo, Japan
| | - Erik J. Sacks
- Department of Crop Sciences, University of Illinois, Urbana-ChampaignUrbana, IL, USA
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8
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Martins SCV, McAdam SAM, Deans RM, DaMatta FM, Brodribb TJ. Stomatal dynamics are limited by leaf hydraulics in ferns and conifers: results from simultaneous measurements of liquid and vapour fluxes in leaves. Plant Cell Environ 2016; 39:694-705. [PMID: 26510650 DOI: 10.1111/pce.12668] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/16/2015] [Accepted: 10/18/2015] [Indexed: 06/05/2023]
Abstract
Stomatal responsiveness to vapour pressure deficit (VPD) results in continuous regulation of daytime gas-exchange directly influencing leaf water status and carbon gain. Current models can reasonably predict steady-state stomatal conductance (gs ) to changes in VPD but the gs dynamics between steady-states are poorly known. Here, we used a diverse sample of conifers and ferns to show that leaf hydraulic architecture, in particular leaf capacitance, has a major role in determining the gs response time to perturbations in VPD. By using simultaneous measurements of liquid and vapour fluxes into and out of leaves, the in situ fluctuations in leaf water balance were calculated and appeared to be closely tracked by changes in gs thus supporting a passive model of stomatal control. Indeed, good agreement was found between observed and predicted gs when using a hydropassive model based on hydraulic traits. We contend that a simple passive hydraulic control of stomata in response to changes in leaf water status provides for efficient stomatal responses to VPD in ferns and conifers, leading to closure rates as fast or faster than those seen in most angiosperms.
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Affiliation(s)
- Samuel C V Martins
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania, 7001, Australia
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil
| | - Scott A M McAdam
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania, 7001, Australia
| | - Ross M Deans
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania, 7001, Australia
| | - Fábio M DaMatta
- Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-000, Viçosa, MG, Brazil
| | - Tim J Brodribb
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania, 7001, Australia
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Larcher L, Hara-Nishimura I, Sternberg L. Effects of stomatal density and leaf water content on the ¹⁸O enrichment of leaf water. New Phytol 2015; 206:141-151. [PMID: 25408145 DOI: 10.1111/nph.13154] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 10/07/2014] [Indexed: 06/04/2023]
Abstract
Leaf water isotopic composition is imprinted in several biomarkers of interest and it is imperative that we understand the isotopic enrichment of leaf water. Here, we test the effect of stomatal density and leaf water content on the oxygen isotopic composition of leaf water in transgenic Arabidopsis plants expressing different stomatal densities, and several other species showing a range of stomatal density. We grew Arabidopsis plants hydroponically and collected other species in the field. Stomatal density and leaf water content were determined for each plant. We measured transpiration and extracted leaf water for isotopic determination. Using these measurements and the current leaf water isotope model, we calculated several of the parameters related to leaf water isotopic enrichment. High stomatal density promoted leaf water isotope enrichment. No conclusion, however, can be drawn regarding the effect of leaf water content on leaf water isotope enrichment. Factors such as transpiration might mask the effect of stomatal density on leaf water isotopic enrichment. We propose a method by which stomatal density can be incorporated in the current Peclet model of leaf water isotope enrichment. These findings have important applications in the use of plant-based metabolic proxies in paleoclimate studies.
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Affiliation(s)
- Leticia Larcher
- Programa de Pós Graduação em Ecologia e Conservação, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Ikuko Hara-Nishimura
- Graduate School of Science, Department of Botany, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Leonel Sternberg
- Department of Biology, University of Miami, 1301 Memorial Drive, Coral Gables, FL, 33124, USA
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Yu X, Bai G, Liu S, Luo N, Wang Y, Richmond DS, Pijut PM, Jackson SA, Yu J, Jiang Y. Association of candidate genes with drought tolerance traits in diverse perennial ryegrass accessions. J Exp Bot 2013; 64:1537-51. [PMID: 23386684 PMCID: PMC3617828 DOI: 10.1093/jxb/ert018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Drought is a major environmental stress limiting growth of perennial grasses in temperate regions. Plant drought tolerance is a complex trait that is controlled by multiple genes. Candidate gene association mapping provides a powerful tool for dissection of complex traits. Candidate gene association mapping of drought tolerance traits was conducted in 192 diverse perennial ryegrass (Lolium perenne L.) accessions from 43 countries. The panel showed significant variations in leaf wilting, leaf water content, canopy and air temperature difference, and chlorophyll fluorescence under well-watered and drought conditions across six environments. Analysis of 109 simple sequence repeat markers revealed five population structures in the mapping panel. A total of 2520 expression-based sequence readings were obtained for a set of candidate genes involved in antioxidant metabolism, dehydration, water movement across membranes, and signal transduction, from which 346 single nucleotide polymorphisms were identified. Significant associations were identified between a putative LpLEA3 encoding late embryogenesis abundant group 3 protein and a putative LpFeSOD encoding iron superoxide dismutase and leaf water content, as well as between a putative LpCyt Cu-ZnSOD encoding cytosolic copper-zinc superoxide dismutase and chlorophyll fluorescence under drought conditions. Four of these identified significantly associated single nucleotide polymorphisms from these three genes were also translated to amino acid substitutions in different genotypes. These results indicate that allelic variation in these genes may affect whole-plant response to drought stress in perennial ryegrass.
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Affiliation(s)
- Xiaoqing Yu
- Department of Agronomy, Purdue University, West Lafayette, IN 47907, USA
| | - Guihua Bai
- USDA-ARS Hard Winter Wheat Genetics Research Unit, Manhattan, KS 66506, USA
| | - Shuwei Liu
- School of Life Science, Shandong University, Jinan 250100, China
| | - Na Luo
- College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Ying Wang
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN 47907, USA
| | | | - Paula M. Pijut
- USDA-Forest Service, Northern Research Station, Hardwood Tree Improvement and Regeneration Center, West Lafayette, IN 47907, USA
| | - Scott A. Jackson
- Center for Applied Genetic Technologies, The University of Georgia, Athens, GA 30602, USA
| | - Jianming Yu
- Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA
| | - Yiwei Jiang
- Department of Agronomy, Purdue University, West Lafayette, IN 47907, USA
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Herppich WB, Herppich M. Influence of leaf water content on the C 3 -CAM transition in Mesembryanthemum crystallinum. New Phytol 1997; 136:425-432. [PMID: 33863001 DOI: 10.1046/j.1469-8137.1997.00762.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Changes in leaf water content, night-time accumulation of malic (δ-malate) and citric acid (δ-citrate) and phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) activity were followed for 60 d after germination in well watered and salt-stressed plants of the facultatively halophytic ephemeral Mesembryanthemum crystallinum L. To separate the effects of development, salt stress and water deficit on crassulacean acid metabolism (CAM) induction plants were stressed initially 10 d after germination and then successively at 1-wk intervals (five sets). Related to dry mass or organic matter (i.e. dry mass corrected for the mass of inorganic ions) water content started to decrease during the late embryonal phase of the life cycle. Water content on a dry mass basis was always lower in salt-stressed than in well watered individuals. However, on an organic matter basis no difference was detectable. This indicated that salt treatment did not reduce leaf water content but falsified the basis (dry mass). Increases in leaf succulence and in pressure potential prevented long-term water deficit in well watered and in salt-stressed plants. Instead, these changes displayed enhanced vacuolisation, which is an essential prerequisite for the development of CAM. The end of that differentiation process might allow the initiation of nocturnal malic acid accumulation in a threshold response. At the onset of each salt treatment, short-term water deficits occurred due to an incomplete osmotic adaptation independent of plant age. As δ-malate only appeared when plants were c. 35 d old this water deficit was unlikely to be a decisive CAM-inducing factor. About 2 wk after germination water content began to decline during the light periods in plants of all treatments. This pattern disappeared again when CAM had been fully established. Daytime transpirational water loss is therefore unlikely to be the decisive factor because it failed to induce the metabolic shift in young plants. Environmental stress (e.g. salt or drought) can therefore only induce δ-malate when leaf and plant differentiation has reached a certain stage.
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Affiliation(s)
- Werner B Herppich
- Institut für Ökologie der Pflanzen, Westfälische Wilhelms-Universität Münster, D-48143 Münster, Germany
| | - Margaretha Herppich
- Institut für Ökologie der Pflanzen, Westfälische Wilhelms-Universität Münster, D-48143 Münster, Germany
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