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Verbeke S, Padilla-Díaz CM, Martínez-Arias C, Goossens W, Haesaert G, Steppe K. Mechanistic modeling reveals the importance of turgor-driven apoplastic water transport in wheat stem parenchyma during carbohydrate mobilization. THE NEW PHYTOLOGIST 2023; 237:423-440. [PMID: 36259090 DOI: 10.1111/nph.18547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
During stem elongation, wheat (Triticum aestivum) increases its stem carbohydrate content before anthesis as a reserve for grain filling. Hydraulic functioning during this mobilization process is not well understood, and contradictory results exist on the direct effect of drought on carbohydrate mobilization. In a dedicated experiment, wheat plants were subjected to drought stress during carbohydrate mobilization. Measurements, important to better understand stem physiology, showed some unexpected patterns that could not be explained by our current knowledge on water transport. Traditional water flow and storage models failed to properly describe the drought response in wheat stems during carbohydrate mobilization. To explain the measured patterns, hypotheses were formulated and integrated in a dedicated model for wheat. The new mechanistic model simulates two hypothetical water storage compartments: one where water is quickly exchanged with the xylem and one that contains the carbohydrate storage. Water exchange between these compartments is turgor-driven. The model was able to simulate the measured increase in stored carbohydrate concentrations with a decrease in water content and stem diameter. Calibration of the model showed the importance of turgor-driven apoplastic water flow during carbohydrate mobilization. This resulted in an increase in stem hydraulic capacitance, which became more important under drought stress.
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Affiliation(s)
- Sarah Verbeke
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Carmen María Padilla-Díaz
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Clara Martínez-Arias
- Departamento de Sistemas y Recursos Naturales, ETSI Montes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, 28040, Madrid, Spain
| | - Willem Goossens
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Geert Haesaert
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000, Ghent, Belgium
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Verbeke S, Padilla-Díaz CM, Haesaert G, Steppe K. Osmotic Adjustment in Wheat ( Triticum aestivum L.) During Pre- and Post-anthesis Drought. FRONTIERS IN PLANT SCIENCE 2022; 13:775652. [PMID: 35173756 PMCID: PMC8841719 DOI: 10.3389/fpls.2022.775652] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 01/10/2022] [Indexed: 05/20/2023]
Abstract
Pre-anthesis drought is expected to greatly increase yield losses in wheat (Triticum aestivum L.), one of the most important crops worldwide. Most studies investigate the effects of pre-anthesis drought only at maturity. The physiology of the plant before anthesis and how it is affected during drought is less studied. Our study focused on physiological patterns in wheat plants during pre- and post-anthesis drought. To this end, we measured leaf xylem water potential, osmotic potential and water content in different plant parts at a high temporal frequency: every 3 days, three times a day. The experiment started just before booting until 2 weeks after flowering. Drought stress was induced by withholding irrigation with rewatering upon turgor loss, which occurred once before and once after anthesis. The goal was to investigate the patterns of osmotic adjustment, when it is used for protection against drought, and if the strategy changes during the phenological development of the plant. Our data gave no indication of daily osmotic adjustment, but did show a delicate control of the osmotic potential during drought in both leaves and stem. Under high drought stress, osmotic potential decreased to avoid further water loss. Before anthesis, rewatering restored leaf water potential and osmotic potential quickly. After anthesis, rewatering restored water potential in the flag leaves, but the osmotic potential in the stem and flag leaf remained low longer. Osmotic adjustment was thus maintained longer after anthesis, showing that the plants invest more energy in the osmotic adjustment after anthesis than before anthesis. We hypothesize that this is because the plants consider the developing ear after anthesis a more important carbohydrate sink than the stem, which is a carbohydrate sink before anthesis, to be used later as a reserve. Low osmotic potential in the stem allowed turgor maintenance, while the low osmotic potential in the flag leaf led to an increase in leaf turgor beyond the level of the control plants. This allowed leaf functioning under drought and assured that water was redirected to the flag leaf and not used to refill the stem storage.
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Affiliation(s)
- Sarah Verbeke
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- *Correspondence: Sarah Verbeke
| | - Carmen María Padilla-Díaz
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- Department of Plant Envirogenetics, Faculty of Science and Engineering, Maastricht University, Maastricht, Netherlands
| | - Geert Haesaert
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Kathy Steppe
- Laboratory of Plant Ecology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Dong X, Peng B, Sieckenius S, Raman R, Conley MM, Leskovar DI. Leaf water potential of field crops estimated using NDVI in ground-based remote sensing-opportunities to increase prediction precision. PeerJ 2021; 9:e12005. [PMID: 34466291 PMCID: PMC8380031 DOI: 10.7717/peerj.12005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 07/27/2021] [Indexed: 11/20/2022] Open
Abstract
Remote-sensing using normalized difference vegetation index (NDVI) has the potential of rapidly detecting the effect of water stress on field crops. However, this detection has typically been accomplished only after the stress effect led to significant changes in crop green biomass, leaf area index, angle and position, and few studies have attempted to estimate the uncertainties of the regression models. These have limited the informed interpretation of NDVI data in agricultural applications. We built a ground-based sensing cart and used it to calibrate the relationships between NDVI and leaf water potential (LWP) for wheat, corn, and cotton growing under field conditions. Both the methods of ordinary least-squares (OLS) and weighted least-squares (WLS) were employed in data analysis, and measurement errors in both LWP and NDVI were considered. We also used statistical resampling to test the effect of measurement errors of LWP on the uncertainties of model coefficients. Our data showed that obtaining a high value of the coefficient of determination did not guarantee a high prediction precision in the obtained regression models. Large prediction uncertainties were estimated for all three crops, and the regressions obtained were not always significant. The best models were obtained for cotton with a prediction uncertainty of 27%. We found that considering measurement errors for both LWP and NDVI led to reduced uncertainties in model coefficients. Also, reducing the sample size of LWP measurement led to significantly increased uncertainties in the coefficients of the linear models describing the LWP-NDVI relationship. Finally, potential strategies for reducing the uncertainty relative to the range of NDVI measurement are discussed.
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Affiliation(s)
- Xuejun Dong
- Texas A&M AgriLife Research and Extension Center at Uvalde, Uvalde, TX, United States
| | - Bin Peng
- Yancheng Institute of Technology, Yancheng City, Jiangsu, China
| | - Shane Sieckenius
- Texas A&M AgriLife Research and Extension Center at Uvalde, Uvalde, TX, United States
| | - Rahul Raman
- Texas A&M AgriLife Research and Extension Center at Uvalde, Uvalde, TX, United States.,Department of Soil and Crop Sciences, Texas A&M University, College Station, TX, United States
| | - Matthew M Conley
- USDA-ARS, U.S. Arid-Land Agricultural Research Center, Maricopa, AZ, United States
| | - Daniel I Leskovar
- Texas A&M AgriLife Research and Extension Center at Uvalde, Uvalde, TX, United States
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Tricker PJ, ElHabti A, Schmidt J, Fleury D. The physiological and genetic basis of combined drought and heat tolerance in wheat. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3195-3210. [PMID: 29562265 DOI: 10.1093/jxb/ery081] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 03/14/2018] [Indexed: 05/03/2023]
Abstract
Drought and heat stress cause losses in wheat productivity in major growing regions worldwide, and both the occurrence and the severity of these events are likely to increase with global climate change. Water deficits and high temperatures frequently occur simultaneously at sensitive growth stages, reducing wheat yields by reducing grain number or weight. Although genetic variation and underlying quantitative trait loci for either individual stress are known, the combination of the two stresses has rarely been studied. Complex and often antagonistic physiology means that genetic loci underlying tolerance to the combined stress are likely to differ from those for drought or heat stress tolerance alone. Here, we review what is known of the physiological traits and genetic control of drought and heat tolerance in wheat and discuss potential physiological traits to study for combined tolerance. We further place this knowledge in the context of breeding for new, more tolerant varieties and discuss opportunities and constraints. We conclude that a fine control of water relations across the growing cycle will be beneficial for combined tolerance and might be achieved through fine management of spatial and temporal gas exchange.
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Affiliation(s)
- Penny J Tricker
- School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, Australia
| | - Abdeljalil ElHabti
- School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, Australia
| | - Jessica Schmidt
- School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, Australia
| | - Delphine Fleury
- School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, Australia
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Soil Water Extraction Monitored Per Plot Across a Field Experiment Using Repeated Electromagnetic Induction Surveys. SOIL SYSTEMS 2018. [DOI: 10.3390/soilsystems2010011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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