1
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Vesala T. Opening Pandora's box of transport phenomena. THE NEW PHYTOLOGIST 2024; 243:1281-1283. [PMID: 38581180 DOI: 10.1111/nph.19749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/08/2024]
Abstract
This article is a Commentary on Griffani et al. (2024), 243: 1301–1311.
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Affiliation(s)
- Timo Vesala
- Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, PO Box 64, FI-00014, Finland
- Institute for Atmospheric and Earth System Research/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Helsinki, PO Box 27, FI-00014, Finland
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2
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Griffani DS, Rognon P, Farquhar GD. The role of thermodiffusion in transpiration. THE NEW PHYTOLOGIST 2024; 243:1301-1311. [PMID: 38453691 DOI: 10.1111/nph.19642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 01/28/2024] [Indexed: 03/09/2024]
Abstract
Plant leaf temperatures can differ from ambient air temperatures. A temperature gradient in a gas mixture gives rise to a phenomenon known as thermodiffusion, which operates in addition to ordinary diffusion. Whilst transpiration is generally understood to be driven solely by the ordinary diffusion of water vapour along a concentration gradient, we consider the implications of thermodiffusion for transpiration. We develop a new modelling framework that introduces the effects of thermodiffusion on the transpiration rate, E. By applying this framework, we quantify the proportion of E attributable to thermodiffusion for a set of physiological and environmental conditions, varied over a wide range. Thermodiffusion is found to be most significant (in some cases > 30% of E) when a leaf-to-air temperature difference coincides with a relatively small water vapour concentration difference across the boundary layer; a boundary layer conductance that is large as compared to the stomatal conductance; or a relatively low transpiration rate. Thermodiffusion also alters the conditions required for the onset of reverse transpiration, and the rate at which this water vapour uptake occurs.
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Affiliation(s)
- Danielle S Griffani
- Faculty of Science and Engineering, Southern Cross University, East Lismore, NSW, 2480, Australia
| | - Pierre Rognon
- School of Civil Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Acton, ACT, 2601, Australia
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3
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Branch HA, Moxley DR, Angert AL. Regional differences in leaf evolution facilitate photosynthesis following severe drought. THE NEW PHYTOLOGIST 2024. [PMID: 39021265 DOI: 10.1111/nph.19963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 06/21/2024] [Indexed: 07/20/2024]
Abstract
Characterizing physiological and anatomical changes that underlie rapid evolution following climatic perturbation can broaden our understanding of how climate change is affecting biodiversity. It can also provide evidence of cryptic adaptation despite stasis at higher levels of biological organization. Here, we compared evolutionary changes in populations of Mimulus cardinalis from historically different climates in the north and south of the species' range following an exceptional drought. We grew seeds produced from predrought ancestral plants alongside peak-drought descendants in a common glasshouse and exposed them to wet and dry conditions. Before the drought, northern ancestral populations expressed traits contributing to drought escape, while southern ancestral populations expressed drought avoidance. Following the drought, both regions evolved to reduce water loss and maintain photosynthesis in dry treatments (drought avoidance), but via different anatomical alterations in stomata, trichomes, and palisade mesophyll. Additionally, southern populations lost the ability to take advantage of wet conditions. These results reveal rapid evolution towards drought avoidance at an anatomical level following an exceptional drought, but suggest that differences in the mechanisms between regions incur different trade-offs. This sheds light on the importance of characterizing underlying mechanisms for downstream life-history and macromorphological traits.
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Affiliation(s)
- Haley A Branch
- Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Dylan R Moxley
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Amy L Angert
- Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Zoology, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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4
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Tholen D. GasanalyzeR: advancing reproducible research using a new R package for photosynthesis data workflows. AOB PLANTS 2024; 16:plae035. [PMID: 39040093 PMCID: PMC11261163 DOI: 10.1093/aobpla/plae035] [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: 04/14/2024] [Accepted: 06/18/2024] [Indexed: 07/24/2024]
Abstract
The analysis of photosynthetic traits has become an integral part of plant (eco-)physiology. Many of these characteristics are not directly measured, but calculated from combinations of several, more direct, measurements. The calculations of such derived variables are based on underlying physical models and may use additional constants or assumed values. Commercially available gas-exchange instruments typically report such derived variables, but the available implementations use different definitions and assumptions. Moreover, no software is currently available to allow a fully scripted and reproducible workflow that includes importing data, pre-processing and recalculating derived quantities. The R package gasanalyzer aims to address these issues by providing methods to import data from different instruments, by translating photosynthetic variables to a standardized nomenclature, and by optionally recalculating derived quantities using standardized equations. In addition, the package facilitates performing sensitivity analyses on variables or assumptions used in the calculations to allow researchers to better assess the robustness of the results. The use of the package and how to perform sensitivity analyses are demonstrated using three different examples.
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Affiliation(s)
- Danny Tholen
- Department of Integrative Biology and Biodiversity Research, Institute of Botany, the University of Natural Resources and Life Sciences, Vienna, 1180 Vienna, Austria
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5
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Ogée J. A step forward in the study of photosynthetic limitation by CO 2 diffusion into the mesophyll. THE NEW PHYTOLOGIST 2024. [PMID: 38887143 DOI: 10.1111/nph.19910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Affiliation(s)
- Jérôme Ogée
- INRAE, Bordeaux Science Agro, UMR 1391 ISPA, Villenave d'Ornon, 33140, France
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6
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Cernusak LA, Wong SC, Stuart-Williams H, Márquez DA, Pontarin N, Farquhar GD. Unsaturation in the air spaces of leaves and its implications. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38867619 DOI: 10.1111/pce.15001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 05/26/2024] [Accepted: 05/31/2024] [Indexed: 06/14/2024]
Abstract
Modern plant physiological theory stipulates that the resistance to water movement from plants to the atmosphere is overwhelmingly dominated by stomata. This conception necessitates a corollary assumption-that the air spaces in leaves must be nearly saturated with water vapour; that is, with a relative humidity that does not decline materially below unity. As this idea became progressively engrained in scientific discourse and textbooks over the last century, observations inconsistent with this corollary assumption were occasionally reported. Yet, evidence of unsaturation gained little traction, with acceptance of the prevailing framework motivated by three considerations: (1) leaf water potentials measured by either thermocouple psychrometry or the Scholander pressure chamber are largely consistent with the framework; (2) being able to assume near saturation of intercellular air spaces was transformational to leaf gas exchange analysis; and (3) there has been no obvious mechanism to explain a variable, liquid-phase resistance in the leaf mesophyll. Here, we review the evidence that refutes the assumption of universal, near saturation of air spaces in leaves. Refining the prevailing paradigm with respect to this assumption provides opportunities for identifying and developing mechanisms for increased plant productivity in the face of increasing evaporative demand imposed by global climate change.
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Affiliation(s)
- Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Queensland, Australia
| | - Suan Chin Wong
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Hilary Stuart-Williams
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Diego A Márquez
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Nicole Pontarin
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
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7
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Tominaga J, Kawamitsu Y. Combined leaf gas-exchange system for model assessment. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:2982-2993. [PMID: 38426531 DOI: 10.1093/jxb/erae081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 02/29/2024] [Indexed: 03/02/2024]
Abstract
Leaf gas-exchange measurements are useful in assessing plant environmental responses. However, uncertainties in the leaf gas-exchange model potentially limit its application. The main challenge in the model-dependent calculations is to detect violations of assumptions. Here, we developed a system that integrates into one instrument the direct measurement of leaf intercellular CO2 concentration and the standard open-flow (OF) and novel open-diffusion (OD) systems for flux measurement. In the OD system, a gas-permeable membrane between the leaf ambient air and outside air creates CO2 and H2O differentials, rather than the air flow in the OF chamber. We measured hypostomatous and amphistomatous leaves of several species with different photosynthetic capacities [sunflower (Helianthus annuus), grape (Vitis vinifera), lemon (Citrus limon), and cherry (Prunus avium)]. The CO2 and H2O differentials in the OD system strictly depend on the flux measured by the OF system. The lower permeability of the membrane resulted in a larger differential per flux, indicating that the OD system can increase the resolution for a small flux. An analysis of the conductance model along with observations suggested that cuticle and leaf intercellular conductances and the unsaturation of leaf humidity contributed to discrepancies between the direct measurement and standard calculation. The combined system developed here provides an opportunity to address these overlooked concepts in leaf gas exchange.
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Affiliation(s)
- Jun Tominaga
- Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima 739-8528, Japan
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8
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Salesse-Smith CE, Lochocki EB, Doran L, Haas BE, Stutz SS, Long SP. Greater mesophyll conductance and leaf photosynthesis in the field through modified cell wall porosity and thickness via AtCGR3 expression in tobacco. PLANT BIOTECHNOLOGY JOURNAL 2024. [PMID: 38687118 DOI: 10.1111/pbi.14364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 04/02/2024] [Accepted: 04/11/2024] [Indexed: 05/02/2024]
Abstract
Mesophyll conductance (gm) describes the ease with which CO2 passes from the sub-stomatal cavities of the leaf to the primary carboxylase of photosynthesis, Rubisco. Increasing gm is suggested as a means to engineer increases in photosynthesis by increasing [CO2] at Rubisco, inhibiting oxygenation and accelerating carboxylation. Here, tobacco was transgenically up-regulated with Arabidopsis Cotton Golgi-related 3 (CGR3), a gene controlling methylesterification of pectin, as a strategy to increase CO2 diffusion across the cell wall and thereby increase gm. Across three independent events in tobacco strongly expressing AtCGR3, mesophyll cell wall thickness was decreased by 7%-13%, wall porosity increased by 75% and gm measured by carbon isotope discrimination increased by 28%. Importantly, field-grown plants showed an average 8% increase in leaf photosynthetic CO2 uptake. Up-regulating CGR3 provides a new strategy for increasing gm in dicotyledonous crops, leading to higher CO2 assimilation and a potential means to sustainable crop yield improvement.
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Affiliation(s)
- Coralie E Salesse-Smith
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Edward B Lochocki
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Lynn Doran
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Benjamin E Haas
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Samantha S Stutz
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Stephen P Long
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Departments of Plant Biology and of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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9
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Mills C, Bartlett MK, Buckley TN. The poorly-explored stomatal response to temperature at constant evaporative demand. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38602407 DOI: 10.1111/pce.14911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 02/13/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
Changes in leaf temperature are known to drive stomatal responses, because the leaf-to-air water vapour gradient (Δw) increases with temperature if ambient vapour pressure is held constant, and stomata respond to changes in Δw. However, the direct response of stomata to temperature (DRST; the response when Δw is held constant by adjusting ambient humidity) has been examined far less extensively. Though the meagre available data suggest the response is usually positive, results differ widely and defy broad generalisation. As a result, little is known about the DRST. This review discusses the current state of knowledge about the DRST, including numerous hypothesised biophysical mechanisms, potential implications of the response for plant adaptation, and possible impacts of the DRST on plant-atmosphere carbon and water exchange in a changing climate.
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Affiliation(s)
- Colleen Mills
- Department of Plant Sciences, University of California, Davis, USA
| | - Megan K Bartlett
- Department of Viticulture and Enology, University of California, Davis, USA
| | - Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, USA
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10
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Jain P, Huber AE, Rockwell FE, Sen S, Holbrook NM, Stroock AD. New approaches to dissect leaf hydraulics reveal large gradients in living tissues of tomato leaves. THE NEW PHYTOLOGIST 2024; 242:453-465. [PMID: 38413216 DOI: 10.1111/nph.19585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 01/22/2024] [Indexed: 02/29/2024]
Abstract
The water status of the living tissue in leaves is critical in determining plant function and global exchange of water and CO2. Despite significant advances in the past two decades, persistent questions remain about the tissue-specific origins of leaf hydraulic properties and their dependence on water status. We use a fluorescent nanoparticle reporter that provides water potential in the mesophyll apoplast adjacent to the epidermis of intact leaves to complement existing methods based on the Scholander Pressure Chamber (SPC). Working in tomato leaves, this approach provides access to the hydraulic conductance of the whole leaf, xylem, and outside-xylem tissues. These measurements show that, as stem water potential decreases, the water potential in the mesophyll apoplast can drop below that assessed with the SPC and can fall significantly below the turgor loss point of the leaf. We find that this drop in potential, dominated by the large loss (10-fold) of hydraulic conductance of the outside-xylem tissue, is not however strong enough to significantly limit transpiration. These observations highlight the need to reassess models of water transfer through the outside-xylem tissues, the potential importance of this tissue in regulating transpiration, and the power of new approaches for probing leaf hydraulics.
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Affiliation(s)
- Piyush Jain
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Annika E Huber
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - Fulton E Rockwell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Sabyasachi Sen
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, 14853, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Abraham D Stroock
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, 14853, USA
- School of Integrative Plant Science, Cornell University, Ithaca, NY, 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY, 14853, USA
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11
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Bourbia I, Brodribb TJ. Stomatal response to VPD is not triggered by changes in soil-leaf hydraulic conductance in Arabidopsis or Callitris. THE NEW PHYTOLOGIST 2024; 242:444-452. [PMID: 38396304 DOI: 10.1111/nph.19607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024]
Abstract
Stomatal closure under high VPDL (leaf to air vapour pressure deficit) is a primary means by which plants prevent large excursions in transpiration rate and leaf water potential (Ψleaf) that could lead to tissue damage. Yet, the drivers of this response remain controversial. Changes in Ψleaf appear to drive stomatal VPDL response, but many argue that dynamic changes in soil-to-leaf hydraulic conductance (Ks-l) make an important contribution to this response pathway, even in well-hydrated soils. Here, we examined whether the regulation of whole plant stomatal conductance (gc) in response to typical changes in daytime VPDL is influenced by dynamic changes in Ks-l. We use well-watered plants of two species with contrasting ecological and physiological features: the herbaceous Arabidopsis thaliana (ecotype Columbia-0) and the dry forest conifer Callitris rhomboidea. The dynamics of Ks-l and gc were continuously monitored by combining concurrent in situ measurements of Ψleaf using an open optical dendrometer and whole plant transpiration using a balance. Large changes in VPDL were imposed to induce stomatal closure and observe the impact on Ks-l. In both species, gc was observed to decline substantially as VPDL increased, while Ks-l remained stable. Our finding suggests that stomatal regulation of transpiration is not contingent on a decrease in Ks-l. Static Ks-l provides a much simpler explanation for transpiration control in hydrated plants and enables simplified modelling and new methods for monitoring plant water use in the field.
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Affiliation(s)
- Ibrahim Bourbia
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas., 7001, Australia
| | - Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, Tas., 7001, Australia
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12
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Kim D, Guadagno CR, Ewers BE, Mackay DS. Combining PSII photochemistry and hydraulics improves predictions of photosynthesis and water use from mild to lethal drought. PLANT, CELL & ENVIRONMENT 2024; 47:1255-1268. [PMID: 38178610 DOI: 10.1111/pce.14806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 12/10/2023] [Accepted: 12/20/2023] [Indexed: 01/06/2024]
Abstract
Rising temperatures and increases in drought negatively impact the efficiency and sustainability of both agricultural and forest ecosystems. Although hydraulic limitations on photosynthesis have been extensively studied, a solid understanding of the links between whole plant hydraulics and photosynthetic processes at the cellular level under changing environmental conditions is still missing, hampering our predictive power for plant mortality. Here, we examined plant hydraulic traits and CO2 assimilation rate under progressive water limitation by implementing Photosystem II (PSII) dynamics with a whole plant process model (TREES). The photosynthetic responses to plant water status were parameterized based on measurements of chlorophyll a fluorescence, gas exchange and water potential for Brassica rapa (R500) grown in a greenhouse under fully watered to lethal drought conditions. The updated model significantly improved predictions of photosynthesis, stomatal conductance and leaf water potential. TREES with PSII knowledge predicted a larger hydraulic safety margin and a decrease in percent loss of conductivity. TREES predicted a slower decrease in leaf water potential, which agreed with measurements. Our results highlight the pressing need for incorporating PSII drought photochemistry into current process models to capture cross-scale plant water dynamics from cell to whole plant level.
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Affiliation(s)
- Dohyoung Kim
- Department of Geography, State University of New York at Buffalo, Buffalo, New York, USA
| | | | - Brent E Ewers
- Department of Botany, University of Wyoming, Laramie, Wyoming, USA
| | - D Scott Mackay
- Department of Geography, State University of New York at Buffalo, Buffalo, New York, USA
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13
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Jain P, Huber AE, Rockwell FE, Sen S, Holbrook NM, Stroock AD. Localized measurements of water potential reveal large loss of conductance in living tissues of maize leaves. PLANT PHYSIOLOGY 2024; 194:2288-2300. [PMID: 38128552 PMCID: PMC10980393 DOI: 10.1093/plphys/kiad679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/25/2023] [Accepted: 11/30/2023] [Indexed: 12/23/2023]
Abstract
The water status of the living tissue in leaves between the xylem and stomata (outside xylem zone (OXZ) plays a critical role in plant function and global mass and energy balance but has remained largely inaccessible. We resolve the local water relations of OXZ tissue using a nanogel reporter of water potential (ψ), AquaDust, that enables an in situ, nondestructive measurement of both ψ of xylem and highly localized ψ at the terminus of transpiration in the OXZ. Working in maize (Zea mays L.), these localized measurements reveal gradients in the OXZ that are several folds larger than those based on conventional methods and values of ψ in the mesophyll apoplast well below the macroscopic turgor loss potential. We find a strong loss of hydraulic conductance in both the bundle sheath and the mesophyll with decreasing xylem potential but not with evaporative demand. Our measurements suggest the OXZ plays an active role in regulating the transpiration path, and our methods provide the means to study this phenomenon.
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Affiliation(s)
- Piyush Jain
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Annika E Huber
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Fulton E Rockwell
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Sabyasachi Sen
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA
| | - Noel Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Abraham D Stroock
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14853, USA
- School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
- Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853, USA
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14
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Busch FA, Ainsworth EA, Amtmann A, Cavanagh AP, Driever SM, Ferguson JN, Kromdijk J, Lawson T, Leakey ADB, Matthews JSA, Meacham-Hensold K, Vath RL, Vialet-Chabrand S, Walker BJ, Papanatsiou M. A guide to photosynthetic gas exchange measurements: Fundamental principles, best practice and potential pitfalls. PLANT, CELL & ENVIRONMENT 2024. [PMID: 38321805 DOI: 10.1111/pce.14815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/31/2023] [Indexed: 02/08/2024]
Abstract
Gas exchange measurements enable mechanistic insights into the processes that underpin carbon and water fluxes in plant leaves which in turn inform understanding of related processes at a range of scales from individual cells to entire ecosytems. Given the importance of photosynthesis for the global climate discussion it is important to (a) foster a basic understanding of the fundamental principles underpinning the experimental methods used by the broad community, and (b) ensure best practice and correct data interpretation within the research community. In this review, we outline the biochemical and biophysical parameters of photosynthesis that can be investigated with gas exchange measurements and we provide step-by-step guidance on how to reliably measure them. We advise on best practices for using gas exchange equipment and highlight potential pitfalls in experimental design and data interpretation. The Supporting Information contains exemplary data sets, experimental protocols and data-modelling routines. This review is a community effort to equip both the experimental researcher and the data modeller with a solid understanding of the theoretical basis of gas-exchange measurements, the rationale behind different experimental protocols and the approaches to data interpretation.
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Affiliation(s)
- Florian A Busch
- School of Biosciences and Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
- Research School of Biology, The Australian National University, Canberra, Australian Captial Territory, Australia
| | | | - Anna Amtmann
- School of Molecular Biosciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - Amanda P Cavanagh
- School of Life Sciences, University of Essex, Colchester, UK
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
| | - Steven M Driever
- Centre for Crop Systems Analysis, Wageningen University & Research, Wageningen, The Netherlands
| | - John N Ferguson
- School of Life Sciences, University of Essex, Colchester, UK
| | - Johannes Kromdijk
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, UK
| | - Andrew D B Leakey
- Departments of Plant Biology and Crop Sciences, University of Illinois Urbana Champaign, Urbana, Illinois, USA
| | | | | | - Richard L Vath
- Department of Plant Sciences, University of Cambridge, Cambridge, UK
- LI-COR Environmental, Lincoln, Nebraska, USA
| | - Silvere Vialet-Chabrand
- Department of Plant Sciences, Horticulture and Product Physiology, Wageningen, The Netherlands
| | - Berkley J Walker
- Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Maria Papanatsiou
- School of Molecular Biosciences, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
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15
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Zhou S, Zhou J, Pan Y, Wu Q, Ping J. Wearable electrochemical sensors for plant small-molecule detection. TRENDS IN PLANT SCIENCE 2024; 29:219-231. [PMID: 38071111 DOI: 10.1016/j.tplants.2023.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 11/07/2023] [Accepted: 11/15/2023] [Indexed: 02/10/2024]
Abstract
Small molecules in plants - such as metabolites, phytohormones, reactive oxygen species (ROS), and inorganic ions - participate in the processes of plant growth and development, physiological metabolism, and stress response. Wearable electrochemical sensors, known for their fast response, high sensitivity, and minimal plant damage, serve as ideal tools for dynamically tracking these small molecules. Such sensors provide producers or agricultural researchers with noninvasive or minimally invasive means of obtaining plant signals. In this review we explore the applications of wearable electrochemical sensors in detecting plant small molecules, enabling scientific assessment of plant conditions, quantification of environmental stresses, and facilitation of plant health monitoring and disease prediction.
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Affiliation(s)
- Shenghan Zhou
- Laboratory of Agricultural Information Intelligent Sensing, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, PR China
| | - Jin Zhou
- Laboratory of Agricultural Information Intelligent Sensing, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, PR China
| | - Yuxiang Pan
- Innovation Platform of Micro/Nano Technology for Biosensing, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, PR China
| | - Qingyu Wu
- State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, The Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China.
| | - Jianfeng Ping
- Laboratory of Agricultural Information Intelligent Sensing, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, PR China; Innovation Platform of Micro/Nano Technology for Biosensing, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, PR China; Key Laboratory of Agricultural Sensors, Ministry of Agriculture and Rural, Anhui Agricultural University, Anhui, PR China.
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16
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Lupo Y, Moshelion M. The balance of survival: Comparative drought response in wild and domesticated tomatoes. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 339:111928. [PMID: 37992898 DOI: 10.1016/j.plantsci.2023.111928] [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: 09/03/2023] [Revised: 11/12/2023] [Accepted: 11/17/2023] [Indexed: 11/24/2023]
Abstract
Plants have the ability to undergo reversible behavioral, morphological, or physiological changes in response to environmental conditions. This plasticity enables plants to cope with uncertain environmental conditions, such as drought. A primary plastic trait is the rate of stomatal response to changes in ambient conditions, which determines the amount of water lost via transpiration, as well as levels of CO2 absorption, growth, and productivity. Here, we examined the differences between domesticated (S. lycopersicum cv. M82) and wild tomato (S. pennellii) species and their responses to drought stress. The plants were grown in pots in a functional phenotyping platform (FPP) in a semi-controlled environment greenhouse. We found that the domesticated tomato had a higher transpiration rate (E) and higher stomatal conductance (gs). The domesticated tomato also had greater biomass and greater leaf area under drought conditions, as compared to the wild tomato. Despite the domesticated tomato's higher E and higher gs, there was no difference between the photosynthetic rates (An) of the two lines. Moreover, the wild tomato had a higher maximum rate of rubisco activity (Vcmax), which might explain its greater leaf level and whole canopy water-use efficiency. The domesticated tomato's higher E and greater leaf area led to its earlier exposure to drought stress, as compared to the wild tomato, which maintained higher levels of soil water, enabling it to maintain steady rates of whole-canopy stomatal conductance (gsc) for extended periods. The wild tomato was also more sensitive to soil water availability and lowered its maximum transpiration rate (Emax) at a higher soil-water-content (SWC) level compared to the domesticated species. Our results suggest that the domestication of tomatoes favored morphological/anatomical performance traits over physiological efficiency.
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Affiliation(s)
- Yaniv Lupo
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel; French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede-Boker, Israel
| | - Menachem Moshelion
- The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
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17
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Binstock BR, Manandhar A, McAdam SAM. Characterizing the breakpoint of stomatal response to vapor pressure deficit in an angiosperm. PLANT PHYSIOLOGY 2024; 194:732-740. [PMID: 37850913 DOI: 10.1093/plphys/kiad560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/21/2023] [Accepted: 10/05/2023] [Indexed: 10/19/2023]
Abstract
Vapor pressure difference between the leaf and atmosphere (VPD) is the most important regulator of daytime transpiration, yet the mechanism driving stomatal responses to an increase in VPD in angiosperms remains unresolved. Here, we sought to characterize the mechanism driving stomatal closure at high VPD in an angiosperm species, particularly testing whether abscisic acid (ABA) biosynthesis could explain the observation of a trigger point for stomatal sensitivity to an increase in VPD. We tracked leaf gas exchange and modeled leaf water potential (Ψl) in leaves exposed to a range of step-increases in VPD in the herbaceous species Senecio minimus Poir. (Asteraceae). We found that mild increases in VPD in this species did not induce stomatal closure because modeled Ψl did not decline below a threshold close to turgor loss point (Ψtlp), but when leaves were exposed to a large increase in VPD, stomata closed as modeled Ψl declined below Ψtlp. Leaf ABA levels were higher in leaves exposed to a step-increase in VPD that caused Ψl to transiently decline below Ψtlp and in which stomata closed compared with leaves in which stomata did not close. We conclude that the stomata of S. minimus are insensitive to VPD until Ψl declines to a threshold that triggers the biosynthesis of ABA and that this mechanism might be common to angiosperms.
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Affiliation(s)
- Benjamin R Binstock
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| | - Anju Manandhar
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
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18
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Waszczak C, Yarmolinsky D, Leal Gavarrón M, Vahisalu T, Sierla M, Zamora O, Carter R, Puukko T, Sipari N, Lamminmäki A, Durner J, Ernst D, Winkler JB, Paulin L, Auvinen P, Fleming AJ, Andersson MX, Kollist H, Kangasjärvi J. Synthesis and import of GDP-l-fucose into the Golgi affect plant-water relations. THE NEW PHYTOLOGIST 2024; 241:747-763. [PMID: 37964509 DOI: 10.1111/nph.19378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 10/13/2023] [Indexed: 11/16/2023]
Abstract
Land plants evolved multiple adaptations to restrict transpiration. However, the underlying molecular mechanisms are not sufficiently understood. We used an ozone-sensitivity forward genetics approach to identify Arabidopsis thaliana mutants impaired in gas exchange regulation. High water loss from detached leaves and impaired decrease of leaf conductance in response to multiple stomata-closing stimuli were identified in a mutant of MURUS1 (MUR1), an enzyme required for GDP-l-fucose biosynthesis. High water loss observed in mur1 was independent from stomatal movements and instead could be linked to metabolic defects. Plants defective in import of GDP-l-Fuc into the Golgi apparatus phenocopied the high water loss of mur1 mutants, linking this phenotype to Golgi-localized fucosylation events. However, impaired fucosylation of xyloglucan, N-linked glycans, and arabinogalactan proteins did not explain the aberrant water loss of mur1 mutants. Partial reversion of mur1 water loss phenotype by borate supplementation and high water loss observed in boron uptake mutants link mur1 gas exchange phenotypes to pleiotropic consequences of l-fucose and boron deficiency, which in turn affect mechanical and morphological properties of stomatal complexes and whole-plant physiology. Our work emphasizes the impact of fucose metabolism and boron uptake on plant-water relations.
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Affiliation(s)
- Cezary Waszczak
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | | | - Marina Leal Gavarrón
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | - Triin Vahisalu
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | - Maija Sierla
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | - Olena Zamora
- Institute of Technology, University of Tartu, 50411, Tartu, Estonia
| | - Ross Carter
- Sainsbury Laboratory, University of Cambridge, CB2 1LR, Cambridge, UK
| | - Tuomas Puukko
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | - Nina Sipari
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
- Viikki Metabolomics Unit, Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014, Helsinki, Finland
| | - Airi Lamminmäki
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
| | - Jörg Durner
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Dieter Ernst
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - J Barbro Winkler
- Research Unit Environmental Simulation, Helmholtz Zentrum München, German Research Center for Environmental Health, 85764, Neuherberg, Germany
| | - Lars Paulin
- Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Petri Auvinen
- Institute of Biotechnology, University of Helsinki, FI-00014, Helsinki, Finland
| | - Andrew J Fleming
- School of Biosciences, University of Sheffield, S10 2TN, Sheffield, UK
| | - Mats X Andersson
- Department of Biological and Environmental Sciences, University of Gothenburg, SE-405 30, Gothenburg, Sweden
| | - Hannes Kollist
- Institute of Technology, University of Tartu, 50411, Tartu, Estonia
| | - Jaakko Kangasjärvi
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, University of Helsinki, FI-00014, Helsinki, Finland
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19
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Burkhardt J, Zinsmeister D, Roth-Nebelsick A, Hüging H, Pariyar S. Ambient aerosols increase stomatal transpiration and conductance of hydroponic sunflowers by extending the hydraulic system to the leaf surface. FRONTIERS IN PLANT SCIENCE 2023; 14:1275358. [PMID: 38098798 PMCID: PMC10720890 DOI: 10.3389/fpls.2023.1275358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/06/2023] [Indexed: 12/17/2023]
Abstract
Introduction Many atmospheric aerosols are hygroscopic and play an important role in cloud formation. Similarly, aerosols become sites of micro-condensation when they deposit to the upper and lower surfaces of leaves. Deposited salts, in particular can trigger condensation at humidities considerably below atmospheric saturation, according to their hygroscopicity and the relative humidity within the leaf boundary layer. Salt induced water potential gradients and the resulting dynamics of concentrated salt solutions can be expected to affect plant water relations. Methods Hydroponic sunflowers were grown in filtered (FA) and unfiltered, ambient air (AA). Sap flow was measured for 18 days and several indicators of incipient drought stress were studied. Results At 2% difference in mean vapor pressure deficit (D), AA sunflowers had 49% higher mean transpiration rates, lower osmotic potential, higher proline concentrations, and different tracer transport patterns in the leaf compared to FA sunflowers. Aerosols increased plant conductance particularly at low D. Discussion The proposed mechanism is that thin aqueous films of salt solutions from deliquescent deposited aerosols enter into stomata and cause an extension of the hydraulic system. This hydraulic connection leads - parallel to stomatal water vapor transpiration - to wick-like stomatal loss of liquid water and to a higher impact of D on plant water loss. Due to ample water supply by hydroponic cultivation, AA plants thrived as well as FA plants, but under more challenging conditions, aerosol deposits may make plants more susceptible to drought stress.
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Affiliation(s)
- Juergen Burkhardt
- Institute of Crop Science and Resource Conservation, Plant Nutrition Group, University of Bonn, Bonn, Germany
| | - Daniel Zinsmeister
- Institute of Crop Science and Resource Conservation, Plant Nutrition Group, University of Bonn, Bonn, Germany
| | - Anita Roth-Nebelsick
- Department Palaeontology, State Museum of Natural History Stuttgart, Stuttgart, Germany
| | - Hubert Hüging
- Institute of Crop Science and Resource Conservation, Crop Science Group, University of Bonn, Bonn, Germany
| | - Shyam Pariyar
- Institute of Crop Science and Resource Conservation, Plant Nutrition Group, University of Bonn, Bonn, Germany
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20
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Wang X, Huang J, Peng S, Xiong D. Leaf rolling precedes stomatal closure in rice (Oryza sativa) under drought conditions. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:6650-6661. [PMID: 37551729 DOI: 10.1093/jxb/erad316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Accepted: 08/05/2023] [Indexed: 08/09/2023]
Abstract
Leaf rolling is a physiological response to drought that may help to reduce water loss, but its significance as a contribution to drought tolerance is uncertain. We scored the leaf rolling of four rice genotypes along an experimental drought gradient using an improved cryo-microscopy method. Leaf water potential (Ψleaf), gas exchange, chlorophyll fluorescence, leaf hydraulic conductance, rehydration capacity, and the bulk turgor loss point were also analysed. During the drought process, stomatal conductance declined sharply to reduce water loss, and leaves rolled up before the stomata completely closed. The leaf water loss rate of rolled leaves was significantly reduced compared with artificially flattened leaves. The Ψleaf threshold of initial leaf rolling ranged from -1.95 to -1.04 MPa across genotypes. When a leaf rolled so that the leaf edges were touching, photosynthetic rate and stomatal conductance declined more than 80%. Across genotypes, leaf hydraulic conductance declined first, followed by gas exchange and chlorophyll fluorescence parameters. However, the Ψleaf threshold for a given functional trait decline differed significantly among genotypes, with the exception of leaf hydraulic conductance. Our results suggested that leaf rolling was mechanistically linked to drought avoidance and tolerance traits and might serve as a useful phenotypic trait for rice breeding in future drought scenarios.
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Affiliation(s)
- Xiaoxiao Wang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Jianliang Huang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Shaobing Peng
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Dongliang Xiong
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
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21
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Scoffoni C, Albuquerque C, Buckley TN, Sack L. The dynamic multi-functionality of leaf water transport outside the xylem. THE NEW PHYTOLOGIST 2023; 239:2099-2107. [PMID: 37386735 DOI: 10.1111/nph.19069] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 05/12/2023] [Indexed: 07/01/2023]
Abstract
A surge of papers have reported low leaf vulnerability to xylem embolism during drought. Here, we focus on the less studied, and more sensitive, outside-xylem leaf hydraulic responses to multiple internal and external conditions. Studies of 34 species have resolved substantial vulnerability to dehydration of the outside-xylem pathways, and studies of leaf hydraulic responses to light also implicate dynamic outside-xylem responses. Detailed experiments suggest these dynamic responses arise at least in part from strong control of radial water movement across the vein bundle sheath. While leaf xylem vulnerability may influence leaf and plant survival during extreme drought, outside-xylem dynamic responses are important for the control and resilience of water transport and leaf water status for gas exchange and growth.
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Affiliation(s)
- Christine Scoffoni
- Department of Biological Sciences, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA
| | - Caetano Albuquerque
- Department of Biological Sciences, California State University Los Angeles, 5151 State University Dr., Los Angeles, CA, 90032, USA
| | - Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, 1 Shields Ave, Davis, CA, 95616, USA
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 612 Charles E. Young Dr., Los Angeles, CA, 90095, USA
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22
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Byrt CS, Zhang RY, Magrath I, Chan KX, De Rosa A, McGaughey S. Exploring aquaporin functions during changes in leaf water potential. FRONTIERS IN PLANT SCIENCE 2023; 14:1213454. [PMID: 37615024 PMCID: PMC10442719 DOI: 10.3389/fpls.2023.1213454] [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: 04/28/2023] [Accepted: 07/04/2023] [Indexed: 08/25/2023]
Abstract
Maintenance of optimal leaf tissue humidity is important for plant productivity and food security. Leaf humidity is influenced by soil and atmospheric water availability, by transpiration and by the coordination of water flux across cell membranes throughout the plant. Flux of water and solutes across plant cell membranes is influenced by the function of aquaporin proteins. Plants have numerous aquaporin proteins required for a multitude of physiological roles in various plant tissues and the membrane flux contribution of each aquaporin can be regulated by changes in protein abundance, gating, localisation, post-translational modifications, protein:protein interactions and aquaporin stoichiometry. Resolving which aquaporins are candidates for influencing leaf humidity and determining how their regulation impacts changes in leaf cell solute flux and leaf cavity humidity is challenging. This challenge involves resolving the dynamics of the cell membrane aquaporin abundance, aquaporin sub-cellular localisation and location-specific post-translational regulation of aquaporins in membranes of leaf cells during plant responses to changes in water availability and determining the influence of cell signalling on aquaporin permeability to a range of relevant solutes, as well as determining aquaporin influence on cell signalling. Here we review recent developments, current challenges and suggest open opportunities for assessing the role of aquaporins in leaf substomatal cavity humidity regulation.
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23
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Orlowski N, Rinderer M, Dubbert M, Ceperley N, Hrachowitz M, Gessler A, Rothfuss Y, Sprenger M, Heidbüchel I, Kübert A, Beyer M, Zuecco G, McCarter C. Challenges in studying water fluxes within the soil-plant-atmosphere continuum: A tracer-based perspective on pathways to progress. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 881:163510. [PMID: 37059146 DOI: 10.1016/j.scitotenv.2023.163510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/04/2023] [Accepted: 04/10/2023] [Indexed: 06/01/2023]
Abstract
Tracing and quantifying water fluxes in the hydrological cycle is crucial for understanding the current state of ecohydrological systems and their vulnerability to environmental change. Especially the interface between ecosystems and the atmosphere that is strongly mediated by plants is important to meaningfully describe ecohydrological system functioning. Many of the dynamic interactions generated by water fluxes between soil, plant and the atmosphere are not well understood, which is partly due to a lack of interdisciplinary research. This opinion paper reflects the outcome of a discussion among hydrologists, plant ecophysiologists and soil scientists on open questions and new opportunities for collaborative research on the topic "water fluxes in the soil-plant-atmosphere continuum" especially focusing on environmental and artificial tracers. We emphasize the need for a multi-scale experimental approach, where a hypothesis is tested at multiple spatial scales and under diverse environmental conditions to better describe the small-scale processes (i.e., causes) that lead to large-scale patterns of ecosystem functioning (i.e., consequences). Novel in-situ, high-frequency measurement techniques offer the opportunity to sample data at a high spatial and temporal resolution needed to understand the underlying processes. We advocate for a combination of long-term natural abundance measurements and event-based approaches. Multiple environmental and artificial tracers, such as stable isotopes, and a suite of experimental and analytical approaches should be combined to complement information gained by different methods. Virtual experiments using process-based models should be used to inform sampling campaigns and field experiments, e.g., to improve experimental designs and to simulate experimental outcomes. On the other hand, experimental data are a pre-requisite to improve our currently incomplete models. Interdisciplinary collaboration will help to overcome research gaps that overlap across different earth system science fields and help to generate a more holistic view of water fluxes between soil, plant and atmosphere in diverse ecosystems.
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Affiliation(s)
- Natalie Orlowski
- Hydrology, Faculty of Environment and Natural Resources, University of Freiburg, Freiburg im Breisgau, Germany.
| | - Michael Rinderer
- Hydrology, Faculty of Environment and Natural Resources, University of Freiburg, Freiburg im Breisgau, Germany; Geo7 AG, Bern, Switzerland
| | - Maren Dubbert
- Isotope Biogeochemistry and Gasfluxes, ZALF, Müncheberg, Germany
| | | | - Markus Hrachowitz
- Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, Stevinweg 1, 2628CN Delft, Netherlands
| | - Arthur Gessler
- Forest Dynamics, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland; Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland
| | - Youri Rothfuss
- Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Jülich, Germany; Terra Teaching and Research Centre, University of Liège, Gembloux, Belgium
| | - Matthias Sprenger
- Earth and Environmental Sciences at the Lawrence Berkeley National Laboratory, Berkeley, USA
| | - Ingo Heidbüchel
- Hydrological Modelling, University of Bayreuth, Bayreuth, Germany; Hydrogeology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Angelika Kübert
- Institute for Atmospheric and Earth System Research (INAR), University of Helsinki, Helsinki, Finland
| | - Matthias Beyer
- Institute for Geoecology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Giulia Zuecco
- Department of Land, Environment, Agriculture and Forestry, University of Padova, Legnaro, Italy; Department of Chemical Sciences, University of Padova, Padova, Italy
| | - Colin McCarter
- Department of Geography, Department of Biology and Chemistry, Nipissing University, North Bay, Ontario, Canada
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24
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Chen J, Yue K, Shen L, Zheng C, Zhu Y, Han K, Kai L. Aquaporins and CO 2 diffusion across biological membrane. Front Physiol 2023; 14:1205290. [PMID: 37383148 PMCID: PMC10293838 DOI: 10.3389/fphys.2023.1205290] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 06/05/2023] [Indexed: 06/30/2023] Open
Abstract
Despite the physiological significance of effective CO2 diffusion across biological membranes, the underlying mechanism behind this process is not yet resolved. Particularly debatable is the existence of CO2-permeable aquaporins. The lipophilic characteristic of CO2 should, according to Overton's rule, result in a rapid flux across lipid bilayers. However, experimental evidence of limited membrane permeability poses a challenge to this idea of free diffusion. In this review, we summarized recent progress with regard to CO2 diffusion, and discussed the physiological effects of altered aquaporin expression, the molecular mechanisms of CO2 transport via aquaporins, and the function of sterols and other membrane proteins in CO2 permeability. In addition, we highlight the existing limits in measuring CO2 permeability and end up with perspectives on resolving such argument either by determining the atomic resolution structure of CO2 permeable aquaporins or by developing new methods for measuring permeability.
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Affiliation(s)
- Junyu Chen
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Ke Yue
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Lulu Shen
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
| | - Chuncui Zheng
- Hangzhou Institute of Test and Calibration for Quality and Technology Supervision, Hangzhou, China
| | - Yiyong Zhu
- Jiangsu Provincial Key Laboratory for Organic Solid Waste Utilization, National Engineering Research Center for Organic-Based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
| | - Kun Han
- Jiangsu Keybio Co., Ltd, Xuzhou, China
| | - Lei Kai
- School of Life Sciences, Jiangsu Normal University, Xuzhou, China
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25
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Scafaro AP, Posch BC, Evans JR, Farquhar GD, Atkin OK. Rubisco deactivation and chloroplast electron transport rates co-limit photosynthesis above optimal leaf temperature in terrestrial plants. Nat Commun 2023; 14:2820. [PMID: 37198175 DOI: 10.1038/s41467-023-38496-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 05/03/2023] [Indexed: 05/19/2023] Open
Abstract
Net photosynthetic CO2 assimilation rate (An) decreases at leaf temperatures above a relatively mild optimum (Topt) in most higher plants. This decline is often attributed to reduced CO2 conductance, increased CO2 loss from photorespiration and respiration, reduced chloroplast electron transport rate (J), or deactivation of Ribulose-1,5-bisphosphate Carboxylase Oxygenase (Rubisco). However, it is unclear which of these factors can best predict species independent declines in An at high temperature. We show that independent of species, and on a global scale, the observed decline in An with rising temperatures can be effectively accounted for by Rubisco deactivation and declines in J. Our finding that An declines with Rubisco deactivation and J supports a coordinated down-regulation of Rubisco and chloroplast electron transport rates to heat stress. We provide a model that, in the absence of CO2 supply limitations, can predict the response of photosynthesis to short-term increases in leaf temperature.
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Affiliation(s)
- Andrew P Scafaro
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia.
- Centre for Entrepreneurial Agri-Technology, Gould Building, Australian National University, Canberra, 2601, Australia.
| | - Bradley C Posch
- Department of Research, Collections and Conservation, Desert Botanical Garden, Phoenix, AZ, USA
| | - John R Evans
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Graham D Farquhar
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
| | - Owen K Atkin
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
- Centre for Entrepreneurial Agri-Technology, Gould Building, Australian National University, Canberra, 2601, Australia
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26
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Márquez DA, Stuart-Williams H, Cernusak LA, Farquhar GD. Assessing the CO 2 concentration at the surface of photosynthetic mesophyll cells. THE NEW PHYTOLOGIST 2023; 238:1446-1460. [PMID: 36751879 DOI: 10.1111/nph.18784] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 01/21/2023] [Indexed: 06/18/2023]
Abstract
We present a robust estimation of the CO2 concentration at the surface of photosynthetic mesophyll cells (cw ), applicable under reasonable assumptions of assimilation distribution within the leaf. We used Capsicum annuum, Helianthus annuus and Gossypium hirsutumas model plants for our experiments. We introduce calculations to estimate cw using independent adaxial and abaxial gas exchange measurements, and accounting for the mesophyll airspace resistances. The cw was lower than adaxial and abaxial estimated intercellular CO2 concentrations (ci ). Differences between cw and the ci of each surface were usually larger than 10 μmol mol-1 . Differences between adaxial and abaxial ci ranged from a few μmol mol-1 to almost 50 μmol mol-1 , where the largest differences were found at high air saturation deficits (ASD). Differences between adaxial and abaxial ci and the ci estimated by mixing both fluxes ranged from -30 to +20 μmol mol-1 , where the largest differences were found under high ASD or high ambient CO2 concentrations. Accounting for cw improves the information that can be extracted from gas exchange experiments, allowing a more detailed description of the CO2 and water vapor gradients within the leaf.
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Affiliation(s)
- Diego A Márquez
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Hilary Stuart-Williams
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Lucas A Cernusak
- College of Science and Engineering, James Cook University, Cairns, Qld, 4878, Australia
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
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Roth-Nebelsick A, Krause M. The Plant Leaf: A Biomimetic Resource for Multifunctional and Economic Design. Biomimetics (Basel) 2023; 8:biomimetics8020145. [PMID: 37092397 PMCID: PMC10123730 DOI: 10.3390/biomimetics8020145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 04/25/2023] Open
Abstract
As organs of photosynthesis, leaves are of vital importance for plants and a source of inspiration for biomimetic developments. Leaves are composed of interconnected functional elements that evolved in concert under high selective pressure, directed toward strategies for improving productivity with limited resources. In this paper, selected basic components of the leaf are described together with biomimetic examples derived from them. The epidermis (the "skin" of leaves) protects the leaf from uncontrolled desiccation and carries functional surface structures such as wax crystals and hairs. The epidermis is pierced by micropore apparatuses, stomata, which allow for regulated gas exchange. Photosynthesis takes place in the internal leaf tissue, while the venation system supplies the leaf with water and nutrients and exports the products of photosynthesis. Identifying the selective forces as well as functional limitations of the single components requires understanding the leaf as an integrated system that was shaped by evolution to maximize carbon gain from limited resource availability. These economic aspects of leaf function manifest themselves as trade-off solutions. Biomimetics is expected to benefit from a more holistic perspective on adaptive strategies and functional contexts of leaf structures.
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Affiliation(s)
| | - Matthias Krause
- State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany
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