1
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Jardine KJ, Som S, Gallo LB, Demus J, Domingues TF, Wistrom CM, Gu L, Tcherkez G, Niinemets Ü. Concurrent Measurement of O 2 Production and Isoprene Emission During Photosynthesis: Pros, Cons and Metabolic Implications of Responses to Light, CO 2 and Temperature. PLANT, CELL & ENVIRONMENT 2024. [PMID: 39248643 DOI: 10.1111/pce.15124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 08/13/2024] [Accepted: 08/17/2024] [Indexed: 09/10/2024]
Abstract
Traditional leaf gas exchange experiments have focused on net CO2 exchange (Anet). Here, using California poplar (Populus trichocarpa), we coupled measurements of net oxygen production (NOP), isoprene emissions and δ18O in O2 to traditional CO2/H2O gas exchange with chlorophyll fluorescence, and measured light, CO2 and temperature response curves. This allowed us to obtain a comprehensive picture of the photosynthetic redox budget including electron transport rate (ETR) and estimates of the mean assimilatory quotient (AQ = Anet/NOP). We found that Anet and NOP were linearly correlated across environmental gradients with similar observed AQ values during light (1.25 ± 0.05) and CO2 responses (1.23 ± 0.07). In contrast, AQ was suppressed during leaf temperature responses in the light (0.87 ± 0.28), potentially due to the acceleration of alternative ETR sinks like lipid synthesis. Anet and NOP had an optimum temperature (Topt) of 31°C, while ETR and δ18O in O2 (35°C) and isoprene emissions (39°C) had distinctly higher Topt. The results confirm a tight connection between water oxidation and ETR and support a view of light-dependent lipid synthesis primarily driven by photosynthetic ATP/NADPH not consumed by the Calvin-Benson cycle, as an important thermotolerance mechanism linked with high rates of (photo)respiration and CO2/O2 recycling.
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Affiliation(s)
- Kolby Jeremiah Jardine
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences Division, Berkeley, California, USA
| | - Suman Som
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences Division, Berkeley, California, USA
| | - Luiza Beraldi Gallo
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Sciences Division, Berkeley, California, USA
- FFCLRP, Departamento de Biologia, Ribeirão Preto, University of São Paulo, São Paulo, Brazil
| | - Jilian Demus
- College of Natural Resources, University of California, Berkeley, Berkeley, California, USA
| | | | | | - Lianhong Gu
- Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, Tennessee, USA
| | - Guillaume Tcherkez
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
- Institut de Recherche en Horticulture et Semences, INRAE, Université d'Angers, Beaucouzé, France
| | - Ülo Niinemets
- Chair of Plant Biology and Crop Science, Estonian University of Life Sciences, Tartu, Estonia
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2
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Márquez DA, Busch FA. The interplay of short-term mesophyll and stomatal conductance responses under variable environmental conditions. PLANT, CELL & ENVIRONMENT 2024; 47:3393-3410. [PMID: 38488802 DOI: 10.1111/pce.14880] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 02/26/2024] [Accepted: 02/29/2024] [Indexed: 08/16/2024]
Abstract
Understanding the short-term responses of mesophyll conductance (gm) and stomatal conductance (gsc) to environmental changes remains a challenging yet central aspect of plant physiology. This review synthesises our current knowledge of these short-term responses, which underpin CO2 diffusion within leaves. Recent methodological advances in measuring gm using online isotopic discrimination and chlorophyll fluorescence have improved our confidence in detecting short-term gm responses, but results need to be carefully evaluated. Environmental factors like vapour pressure deficit and CO2 concentration indirectly impact gm through gsc changes, highlighting some of the complex interactions between the two parameters. Evidence suggests that short-term responses of gm are not, or at least not fully, mechanistically linked to changes in gsc, cautioning against using gsc as a reliable proxy for gm. The overarching challenge lies in unravelling the mechanistic basis of short-term gm responses, which will contribute to the development of accurate models bridging laboratory insights with broader ecological implications. Addressing these gaps in understanding is crucial for refining predictions of gm behaviour under changing environmental conditions.
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Affiliation(s)
- Diego A Márquez
- School of Biosciences and Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
| | - Florian A Busch
- School of Biosciences and Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
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3
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Abadie C, Lalande J, Tcherkez G. Combining Gas Exchange and Rapid Quenching of Leaf Tissue for Mass Spectrometry and NMR Analysis Using an External Chamber. Methods Mol Biol 2024; 2792:195-208. [PMID: 38861089 DOI: 10.1007/978-1-0716-3802-6_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
We describe here a method to study and manipulate photorespiration in intact illuminated leaves. When the CO2/O2 mole fraction ratio changes, instant sampling is critical, to quench leaf metabolism and thus trace rapid metabolic modification due to gaseous conditions. To do so, we combine 13CO2 labeling and gas exchange, using a large custom leaf chamber to facilitate fast sampling by direct liquid nitrogen spraying. Moreover, the use of a high chamber surface area (about 130 cm2) allows one to sample a large amount of leaf material to carry out 13C-nuclear magnetic resonance (NMR) analysis and complementary analyses, such as isotopic analyses by high-resolution mass spectrometry (by both GC and LC-MS). 13C-NMR gives access to absolute 13C amounts at the specific carbon atom position in the labeled molecules and thereby provides an estimate of 13C-flux of photorespiratory intermediates. Since NMR analysis is not very sensitive and can miss minor metabolites, GC or LC-MS analyses are useful to monitor metabolites at low concentrations. Furthermore, 13C-NMR and high-resolution LC-MS allow to estimate isotopologue distribution in response to 13CO2 labeling while modifying photorespiration activity.
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Affiliation(s)
- Cyril Abadie
- Institut de Recherche en Horticulture et Semences, Université d'Angers, Beaucouzé, France
| | - Julie Lalande
- Institut de Recherche en Horticulture et Semences, Université d'Angers, Beaucouzé, France
| | - Guillaume Tcherkez
- Institut de Recherche en Horticulture et Semences, Université d'Angers, Beaucouzé, France.
- Research School of Biology, Australian National University, Canberra, ACT, Australia.
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4
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Yin X, Amthor JS. Estimating leaf day respiration from conventional gas exchange measurements. THE NEW PHYTOLOGIST 2024; 241:52-58. [PMID: 37858976 DOI: 10.1111/nph.19330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 09/21/2023] [Indexed: 10/21/2023]
Abstract
Leaf day respiration (Rd ) strongly influences carbon-use efficiencies of whole plants and the global terrestrial biosphere. It has long been thought that Rd is slower than respiration in the dark at a given temperature, but measuring Rd by gas exchange remains a challenge because leaves in the light are also photosynthesizing. The Kok method and the Laisk method are widely used to estimate Rd . We highlight theoretical limitations of these popular methods, and recent progress toward their improvement by using additional information from chlorophyll fluorescence and by accounting for the photosynthetic reassimilation of respired CO2 . The latest evidence for daytime CO2 and energy release from the oxidative pentose phosphate pathway in chloroplasts appears to be important to understanding Rd .
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Affiliation(s)
- Xinyou Yin
- Centre for Crop Systems Analysis, Department of Plant Sciences, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Jeffrey S Amthor
- Center for Ecosystem Science and Society, Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, 86011, USA
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5
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O’Leary BM, Scafaro AP, York LM. High-throughput, dynamic, multi-dimensional: an expanding repertoire of plant respiration measurements. PLANT PHYSIOLOGY 2023; 191:2070-2083. [PMID: 36638140 PMCID: PMC10069890 DOI: 10.1093/plphys/kiac580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
A recent burst of technological innovation and adaptation has greatly improved our ability to capture respiration rate data from plant sources. At the tissue level, several independent respiration measurement options are now available, each with distinct advantages and suitability, including high-throughput sampling capacity. These advancements facilitate the inclusion of respiration rate data into large-scale biological studies such as genetic screens, ecological surveys, crop breeding trials, and multi-omics molecular studies. As a result, our understanding of the correlations of respiration with other biological and biochemical measurements is rapidly increasing. Difficult questions persist concerning the interpretation and utilization of respiration data; concepts such as allocation of respiration to growth versus maintenance, the unnecessary or inefficient use of carbon and energy by respiration, and predictions of future respiration rates in response to environmental change are all insufficiently grounded in empirical data. However, we emphasize that new experimental designs involving novel combinations of respiration rate data with other measurements will flesh-out our current theories of respiration. Furthermore, dynamic recordings of respiration rate, which have long been used at the scale of mitochondria, are increasingly being used at larger scales of size and time to reflect processes of cellular signal transduction and physiological response to the environment. We also highlight how respiratory methods are being better adapted to different plant tissues including roots and seeds, which have been somewhat neglected historically.
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Affiliation(s)
- Brendan M O’Leary
- Saskatoon Research and Development Centre, Agriculture and Agri-food Canada, Saskatoon S7N 0X2, Canada
| | - Andrew P Scafaro
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Larry M York
- Center for Bioenergy Innovation and Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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6
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Physiological and biochemical responses of selected weed and crop species to the plant-based bioherbicide WeedLock. Sci Rep 2022; 12:19602. [PMID: 36379972 PMCID: PMC9666524 DOI: 10.1038/s41598-022-24144-2] [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: 08/18/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022] Open
Abstract
WeedLock is a broad-spectrum plant-based bioherbicide that is currently on the market as a ready-to-use formulation. In this study, we investigated the physiological and biochemical effects of WeedLock (672.75 L ha-1) on Ageratum conyzoides L., Eleusine indica (L.) Gaertn, Zea mays L., and Amaranthus gangeticus L. at four different time points. WeedLock caused significant reductions in chlorophyll pigment content and disrupted photosynthetic processes in all test plants. The greatest inhibition in photosynthesis was recorded in A. conyzoides at 24 h post-treatment with a 74.88% inhibition. Plants treated with WeedLock showed increased malondialdehyde (MDA) and proline production, which is indicative of phytotoxic stress. Remarkably, MDA contents of all treated plants increased by more than 100% in comparison to untreated. The activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) was elevated following treatment with WeedLock. Significant increases were observed in the SOD activity of A. conyzoides ranging from 69.66 to 118.24% from 6 to 72 h post-treatment. Our findings confirm that WeedLock disrupts the normal physiological and biochemical processes in plants following exposure and that its mode of action is associated with ROS (reactive oxygen species) production, similar to that of PPO (protoporphyrinogen oxidase) inhibitors, although specific site-of-action of this novel bioherbicide warrants further investigation.
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7
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Jardine KJ, Lei J, Som S, Souza D, Clendinen CS, Mehta H, Handakumbura P, Bill M, Young RP. Light-Dependence of Formate (C1) and Acetate (C2) Transport and Oxidation in Poplar Trees. PLANTS 2022; 11:plants11162080. [PMID: 36015384 PMCID: PMC9413118 DOI: 10.3390/plants11162080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/05/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022]
Abstract
Although apparent light inhibition of leaf day respiration is a widespread reported phenomenon, the mechanisms involved, including utilization of alternate respiratory pathways and substrates and light inhibition of TCA cycle enzymes are under active investigation. Recently, acetate fermentation was highlighted as a key drought survival strategy mediated through protein acetylation and jasmonate signaling. Here, we evaluate the light-dependence of acetate transport and assimilation in Populus trichocarpa trees using the dynamic xylem solution injection (DXSI) method developed here for continuous studies of C1 and C2 organic acid transport and light-dependent metabolism. Over 7 days, 1.0 L of [13C]formate and [13C2]acetate solutions were delivered to the stem base of 2-year old potted poplar trees, while continuous diurnal observations were made in the canopy of CO2, H2O, and isoprene gas exchange together with δ13CO2. Stem base injection of 10 mM [13C2]acetate induced an overall pattern of canopy branch headspace 13CO2 enrichment (δ13CO2 +27‰) with a diurnal structure in δ13CO2 reaching a mid-day minimum followed by a maximum shortly after darkening where δ13CO2 values rapidly increased up to +12‰. In contrast, 50 mM injections of [13C]formate were required to reach similar δ13CO2 enrichment levels in the canopy with δ13CO2 following diurnal patterns of transpiration. Illuminated leaves of detached poplar branches pretreated with 10 mM [13C2]acetate showed lower δ13CO2 (+20‰) compared to leaves treated with 10 mM [13C]formate (+320‰), the opposite pattern observed at the whole plant scale. Following dark/light cycles at the leaf-scale, rapid, strong, and reversible enhancements in headspace δ13CO2 by up to +60‰ were observed in [13C2]acetate-treated leaves which showed enhanced dihydrojasmonic acid and TCA cycle intermediate concentrations. The results are consistent with acetate in the transpiration stream as an effective activator of the jasmonate signaling pathway and respiratory substrate. The shorter lifetime of formate relative to acetate in the transpiration stream suggests rapid formate oxidation to CO2 during transport to the canopy. In contrast, acetate is efficiently transported to the canopy where an increased allocation towards mitochondrial dark respiration occurs at night. The results highlight the potential for an effective integration of acetate into glyoxylate and TCA cycles and the light-inhibition of citrate synthase as a potential regulatory mechanism controlling the diurnal allocation of acetate between anabolic and catabolic processes.
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Affiliation(s)
- Kolby J. Jardine
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Science Division, Berkeley, CA 94720, USA
- Correspondence:
| | - Joseph Lei
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Science Division, Berkeley, CA 94720, USA
| | - Suman Som
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Science Division, Berkeley, CA 94720, USA
| | - Daisy Souza
- Forest Management Laboratory, National Institute for Amazon Research, Manaus 69067-375, Brazil
| | - Chaevien S. Clendinen
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Hardeep Mehta
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Pubudu Handakumbura
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Markus Bill
- Lawrence Berkeley National Laboratory, Climate and Ecosystem Science Division, Berkeley, CA 94720, USA
| | - Robert P. Young
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99354, USA
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8
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DiMario RJ, Giuliani R, Ubierna N, Slack AD, Cousins AB, Studer AJ. Lack of leaf carbonic anhydrase activity eliminates the C 4 carbon-concentrating mechanism requiring direct diffusion of CO 2 into bundle sheath cells. PLANT, CELL & ENVIRONMENT 2022; 45:1382-1397. [PMID: 35233800 DOI: 10.1111/pce.14291] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/13/2021] [Accepted: 10/30/2021] [Indexed: 06/14/2023]
Abstract
Carbonic anhydrase (CA) performs the first enzymatic step of C4 photosynthesis by catalysing the reversible hydration of dissolved CO2 that diffuses into mesophyll cells from intercellular airspaces. This CA-catalysed reaction provides the bicarbonate used by phosphoenolpyruvate carboxylase to generate products that flow into the C4 carbon-concentrating mechanism (CCM). It was previously demonstrated that the Zea mays ca1ca2 double mutant lost 97% of leaf CA activity, but there was little difference in the growth phenotype under ambient CO2 partial pressures (pCO2 ). We hypothesise that since CAs are among the fastest enzymes, minimal activity from a third CA, CA8, can provide the inorganic carbon needed to drive C4 photosynthesis. We observed that removing CA8 from the maize ca1ca2 background resulted in plants that had 0.2% of wild-type leaf CA activity. These ca1ca2ca8 plants had reduced photosynthetic parameters and could only survive at elevated pCO2 . Photosynthetic and carbon isotope analysis combined with modelling of photosynthesis and carbon isotope discrimination was used to determine if ca1ca2ca8 plants had a functional C4 cycle or were relying on direct CO2 diffusion to ribulose 1,5-bisphosphate carboxylase/oxygenase within bundle sheath cells. The results suggest that leaf CA activity in ca1ca2ca8 plants was not sufficient to sustain the C4 CCM.
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Affiliation(s)
- Robert J DiMario
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Rita Giuliani
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Nerea Ubierna
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Aaron D Slack
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Anthony J Studer
- Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, Illinois, USA
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9
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Zhao HL, Chang TG, Xiao Y, Zhu XG. Potential metabolic mechanisms for inhibited chloroplast nitrogen assimilation under high CO2. PLANT PHYSIOLOGY 2021; 187:1812-1833. [PMID: 34618071 PMCID: PMC8566258 DOI: 10.1093/plphys/kiab345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 06/28/2021] [Indexed: 05/31/2023]
Abstract
Improving photosynthesis is considered a major and feasible option to dramatically increase crop yield potential. Increased atmospheric CO2 concentration often stimulates both photosynthesis and crop yield, but decreases protein content in the main C3 cereal crops. This decreased protein content in crops constrains the benefits of elevated CO2 on crop yield and affects their nutritional value for humans. To support studies of photosynthetic nitrogen assimilation and its complex interaction with photosynthetic carbon metabolism for crop improvement, we developed a dynamic systems model of plant primary metabolism, which includes the Calvin-Benson cycle, the photorespiration pathway, starch synthesis, glycolysis-gluconeogenesis, the tricarboxylic acid cycle, and chloroplastic nitrogen assimilation. This model successfully captures responses of net photosynthetic CO2 uptake rate (A), respiration rate, and nitrogen assimilation rate to different irradiance and CO2 levels. We then used this model to predict inhibition of nitrogen assimilation under elevated CO2. The potential mechanisms underlying inhibited nitrogen assimilation under elevated CO2 were further explored with this model. Simulations suggest that enhancing the supply of α-ketoglutarate is a potential strategy to maintain high rates of nitrogen assimilation under elevated CO2. This model can be used as a heuristic tool to support research on interactions between photosynthesis, respiration, and nitrogen assimilation. It also provides a basic framework to support the design and engineering of C3 plant primary metabolism for enhanced photosynthetic efficiency and nitrogen assimilation in the coming high-CO2 world.
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Affiliation(s)
- Hong-Long Zhao
- University of Chinese Academy of Sciences, Beijing 100049, China
- National Key Laboratory for Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Tian-Gen Chang
- National Key Laboratory for Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yi Xiao
- National Key Laboratory for Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200031, China
- Department of Crop Sciences, University of Illinois at Urbana Champaign, Urbana, Illinois 61801, USA
- Department of Plant Biology, University of Illinois at Urbana Champaign, Urbana, Illinois 61801, USA
| | - Xin-Guang Zhu
- National Key Laboratory for Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200031, China
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10
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Mellon M, Storti M, Vera-Vives AM, Kramer DM, Alboresi A, Morosinotto T. Inactivation of mitochondrial complex I stimulates chloroplast ATPase in Physcomitrium patens. PLANT PHYSIOLOGY 2021; 187:931-946. [PMID: 34608952 PMCID: PMC8491079 DOI: 10.1093/plphys/kiab276] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 05/18/2021] [Indexed: 06/11/2023]
Abstract
Light is the ultimate source of energy for photosynthetic organisms, but respiration is fundamental for supporting metabolism during the night or in heterotrophic tissues. In this work, we isolated Physcomitrella (Physcomitrium patens) plants with altered respiration by inactivating Complex I (CI) of the mitochondrial electron transport chain by independently targeting on two essential subunits. Inactivation of CI caused a strong growth impairment even in fully autotrophic conditions in tissues where all cells are photosynthetically active, demonstrating that respiration is essential for photosynthesis. CI mutants showed alterations in the stoichiometry of respiratory complexes while the composition of photosynthetic apparatus was substantially unaffected. CI mutants showed altered photosynthesis with high activity of both Photosystems I and II, likely the result of high chloroplast ATPase activity that led to smaller ΔpH formation across thylakoid membranes, decreasing photosynthetic control on cytochrome b6f in CI mutants. These results demonstrate that alteration of respiratory activity directly impacts photosynthesis in P. patens and that metabolic interaction between organelles is essential in their ability to use light energy for growth.
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Affiliation(s)
- Marco Mellon
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Mattia Storti
- Department of Biology, University of Padova, 35121 Padova, Italy
| | | | - David M. Kramer
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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11
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13C Isotope Labelling to Follow the Flux of Photorespiratory Intermediates. PLANTS 2021; 10:plants10030427. [PMID: 33668274 PMCID: PMC7996249 DOI: 10.3390/plants10030427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/18/2021] [Accepted: 02/19/2021] [Indexed: 12/04/2022]
Abstract
Measuring the carbon flux through metabolic pathways in intact illuminated leaves remains challenging because of, e.g., isotopic dilution by endogenous metabolites, the impossibility to reach isotopic steady state, and the occurrence of multiple pools. In the case of photorespiratory intermediates, our knowledge of the partitioning between photorespiratory recycling, storage, and utilization by other pathways is thus rather limited. There has been some controversy as to whether photorespiratory glycine and serine may not be recycled, thus changing the apparent stoichiometric coefficient between photorespiratory O2 fixation and CO2 release. We describe here an isotopic method to trace the fates of glycine, serine and glycerate, taking advantage of positional 13C content with NMR and isotopic analyses by LC–MS. This technique is well-adapted to show that the proportion of glycerate, serine and glycine molecules escaping photorespiratory recycling is very small.
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12
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Ma WT, Tcherkez G, Wang XM, Schäufele R, Schnyder H, Yang Y, Gong XY. Accounting for mesophyll conductance substantially improves 13 C-based estimates of intrinsic water-use efficiency. THE NEW PHYTOLOGIST 2021; 229:1326-1338. [PMID: 32984961 DOI: 10.1111/nph.16958] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 09/14/2020] [Indexed: 05/08/2023]
Abstract
Carbon isotope discrimination (Δ) has been used widely to infer intrinsic water-use efficiency (iWUE) of C3 plants, a key parameter linking carbon and water fluxes. Despite the essential role of mesophyll conductance (gm ) in photosynthesis and Δ, its effect on Δ-based predictions of iWUE has generally been neglected. Here, we derive a mathematical expression of iWUE as a function of Δ that includes gm (iWUEmes ) and exploits the gm -stomatal conductance (gsc ) relationship across drought-stress levels and plant functional groups (deciduous or semideciduous woody, evergreen woody and herbaceous species) in a global database. iWUEmes was further validated with an independent dataset of online-Δ and CO2 and H2 O gas exchange measurements with seven species. Drought stress reduced gsc and gm by nearly one-half across all plant functional groups, but had no significant effect on the gsc : gm ratio, with a well supported value of 0.79 ± 0.07 (95% CI, n = 198). gm was negatively correlated to iWUE. Incorporating the gsc : gm ratio greatly improved estimates of iWUE, compared with calculations that assumed infinite gm . The inclusion of the gsc : gm ratio, fixed at 0.79 when gm was unknown, proved desirable to eliminate significant errors in estimating iWUE from Δ across various C3 vegetation types.
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Affiliation(s)
- Wei Ting Ma
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Guillaume Tcherkez
- Research School of Biology, ANU College of Medicine, Biology and Environment, Australian National University, Canberra, ACT 0200, Australia
- Institut de Recherche en Horticulture et Semences, INRAe, Université d'Angers, 42 rue Georges Morel, Beaucouzé, 49070, France
| | - Xu Ming Wang
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising, 85354, Germany
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, Freising, 85354, Germany
| | - Yusheng Yang
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Xiao Ying Gong
- Key Laboratory for Subtropical Mountain Ecology (Ministry of Science and Technology and Fujian Province Funded), College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
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13
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Gauthier PPG, Saenz N, Griffin KL, Way D, Tcherkez G. Is the Kok effect a respiratory phenomenon? Metabolic insight using 13 C labeling in Helianthus annuus leaves. THE NEW PHYTOLOGIST 2020; 228:1243-1255. [PMID: 32564374 DOI: 10.1111/nph.16756] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
The Kok effect is a well-known phenomenon in which the quantum yield of photosynthesis changes abruptly at low light. This effect has often been interpreted as a shift in leaf respiratory metabolism and thus used widely to measure day respiration. However, there is still no formal evidence that the Kok effect has a respiratory origin. Here, both gas exchange and isotopic labeling were carried out on sunflower leaves, using glucose that was 13 C-enriched at specific C-atom positions. Position-specific decarboxylation measurements and NMR analysis of metabolites were used to trace the fate of C-atoms in metabolism. Decarboxylation rates were significant at low light (including above the Kok break point) and increased with decreasing irradiance below 100 µmol photons m-2 s-1 . The variation in several metabolite pools such as malate, fumarate or citrate, and flux calculations suggest the involvement of several decarboxylating pathways in the Kok effect, including the malic enzyme. Our results show that day respiratory CO2 evolution plays an important role in the Kok effect. However, the increase in the apparent quantum yield of photosynthesis below the Kok break point is also probably related to malate metabolism, which participates in maintaining photosynthetic linear electron flow.
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Affiliation(s)
- Paul P G Gauthier
- Department of Geosciences, Princeton University, Princeton, NJ, 08544, USA
| | - Natalie Saenz
- Department of Chemistry, Columbia University, 3000 Broadway NYC, New York, NY, 10025, USA
| | - Kevin L Griffin
- Department of Ecology, Evolution and Environmental Biology (E3B), Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA
- Department of Earth and Environmental Sciences, Lamont Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY, 10964, USA
| | - Danielle Way
- Department of Biology, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B7, Canada
- Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY, 11973, USA
- Nicholas School of the Environment, Duke University, Durham, NC, 27710, USA
| | - Guillaume Tcherkez
- Research School of Biology, Joint College of Sciences, Australian National University, Canberra, ACT, 2601, Australia
- Seedling Metabolism and Stress, Institut de Recherche en Horticulture et Semences, INRAE Angers, Université d'Angers, 42 rue Georges Morel, Beaucouzé Cedex, 49780, France
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14
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Yin X, Niu Y, van der Putten PEL, Struik PC. The Kok effect revisited. THE NEW PHYTOLOGIST 2020; 227:1764-1775. [PMID: 32369617 PMCID: PMC7497127 DOI: 10.1111/nph.16638] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/24/2020] [Indexed: 05/18/2023]
Abstract
The Kok effect refers to the abrupt decrease around the light compensation point in the slope of net photosynthetic rate vs irradiance. Arguably, this switch arises from light inhibition of respiration, allowing the Kok method to estimate day respiration (Rd ). Recent analysis suggests that increasing proportions of photorespiration (quantified as Γ*/Cc , the ratio of CO2 compensation point Γ* to chloroplast CO2 concentration, Cc ) with irradiance explain much of the Kok effect. Also, the Kok method has been modified to account for the decrease in PSII photochemical efficiency (Φ2 ) with irradiance. Using a model that illustrates how varying Rd , Γ*/Cc , Φ2 and proportions of alternative electron transport could engender the Kok effect, we quantified the contribution of these parameters to the Kok effect measured in sunflower across various O2 and CO2 concentrations and various temperatures. Overall, the decreasing Φ2 with irradiance explained c. 12%, and the varying Γ*/Cc explained c. 25%, of the Kok effect. Maximum real light inhibition of Rd was much lower than the inhibition derived from the Kok method, but still increased with photorespiration. Photorespiration had a dual contribution to the Kok effect, one via the varying Γ*/Cc and the other via its participation in light inhibition of Rd .
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Affiliation(s)
- Xinyou Yin
- Centre for Crop Systems AnalysisDepartment of Plant SciencesWageningen University & ResearchPO Box 430Wageningen6700 AKthe Netherlands
| | - Yuxi Niu
- Centre for Crop Systems AnalysisDepartment of Plant SciencesWageningen University & ResearchPO Box 430Wageningen6700 AKthe Netherlands
| | - Peter E. L. van der Putten
- Centre for Crop Systems AnalysisDepartment of Plant SciencesWageningen University & ResearchPO Box 430Wageningen6700 AKthe Netherlands
| | - Paul C. Struik
- Centre for Crop Systems AnalysisDepartment of Plant SciencesWageningen University & ResearchPO Box 430Wageningen6700 AKthe Netherlands
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15
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Zhu XG, Ort DR, Parry MAJ, von Caemmerer S. A wish list for synthetic biology in photosynthesis research. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:2219-2225. [PMID: 32060550 PMCID: PMC7134917 DOI: 10.1093/jxb/eraa075] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Accepted: 02/12/2020] [Indexed: 05/02/2023]
Abstract
This perspective summarizes the presentations and discussions at the ' International Symposium on Synthetic Biology in Photosynthesis Research', which was held in Shanghai in 2018. Leveraging the current advanced understanding of photosynthetic systems, the symposium brain-stormed about the redesign and engineering of photosynthetic systems for translational goals and evaluated available new technologies/tools for synthetic biology as well as technological obstacles and new tools that would be needed to overcome them. Four major research areas for redesigning photosynthesis were identified: (i) mining natural variations of photosynthesis; (ii) coordinating photosynthesis with pathways utilizing photosynthate; (iii) reconstruction of highly efficient photosynthetic systems in non-host species; and (iv) development of new photosynthetic systems that do not exist in nature. To expedite photosynthesis synthetic biology research, an array of new technologies and community resources need to be developed, which include expanded modelling capacities, molecular engineering toolboxes, model species, and phenotyping tools.
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Affiliation(s)
- Xin-Guang Zhu
- Institute of Plant Physiology and Ecology and Center for Excellence for Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Donald R Ort
- Departments of Plant Biology and Crop Sciences, University of Illinois at Urbana Champaign, Urbana, IL, USA
| | - Martin A J Parry
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Susanne von Caemmerer
- Research School of Biological Sciences, Australian National University, Acton, Australia
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16
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Lundgren MR, Fleming AJ. Cellular perspectives for improving mesophyll conductance. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:845-857. [PMID: 31854030 PMCID: PMC7065256 DOI: 10.1111/tpj.14656] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 12/11/2019] [Indexed: 05/04/2023]
Abstract
After entering the leaf, CO2 faces an intricate pathway to the site of photosynthetic fixation embedded within the chloroplasts. The efficiency of CO2 flux is hindered by a number of structural and biochemical barriers which, together, define the ease of flow of the gas within the leaf, termed mesophyll conductance. Previous authors have identified the key elements of this pathway, raising the prospect of engineering the system to improve CO2 flux and, thus, to increase leaf photosynthetic efficiency. In this review, we provide a perspective on the potential for improving the individual elements that contribute to this complex parameter. We lay particular emphasis on generation of the cellular architecture of the leaf which sets the initial boundaries of a number of mesophyll conductance parameters, incorporating an overview of the molecular transport processes which have been proposed as major facilitators of CO2 flux across structural boundaries along the pathway. The review highlights the research areas where future effort might be invested to increase our fundamental understanding of mesophyll conductance and leaf function and, consequently, to enable translation of these findings to improve the efficiency of crop photosynthesis.
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Affiliation(s)
| | - Andrew J. Fleming
- Department of Animal and Plant SciencesUniversity of SheffieldWestern BankSheffieldS10 2TNUK
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17
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Giuliani R, Karki S, Covshoff S, Lin HC, Coe RA, Koteyeva NK, Evans MA, Quick WP, von Caemmerer S, Furbank RT, Hibberd JM, Edwards GE, Cousins AB. Transgenic maize phosphoenolpyruvate carboxylase alters leaf-atmosphere CO 2 and 13CO 2 exchanges in Oryza sativa. PHOTOSYNTHESIS RESEARCH 2019; 142:153-167. [PMID: 31325077 PMCID: PMC6848035 DOI: 10.1007/s11120-019-00655-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 06/11/2019] [Indexed: 05/07/2023]
Abstract
The engineering process of C4 photosynthesis into C3 plants requires an increased activity of phosphoenolpyruvate carboxylase (PEPC) in the cytosol of leaf mesophyll cells. The literature varies on the physiological effect of transgenic maize (Zea mays) PEPC (ZmPEPC) leaf expression in Oryza sativa (rice). Therefore, to address this issue, leaf-atmosphere CO2 and 13CO2 exchanges were measured, both in the light (at atmospheric O2 partial pressure of 1.84 kPa and at different CO2 levels) and in the dark, in transgenic rice expressing ZmPEPC and wild-type (WT) plants. The in vitro PEPC activity was 25 times higher in the PEPC overexpressing (PEPC-OE) plants (~20% of maize) compared to the negligible activity in WT. In the PEPC-OE plants, the estimated fraction of carboxylation by PEPC (β) was ~6% and leaf net biochemical discrimination against 13CO2[Formula: see text] was ~ 2‰ lower than in WT. However, there were no differences in leaf net CO2 assimilation rates (A) between genotypes, while the leaf dark respiration rates (Rd) over three hours after light-dark transition were enhanced (~ 30%) and with a higher 13C composition [Formula: see text] in the PEPC-OE plants compared to WT. These data indicate that ZmPEPC in the PEPC-OE rice plants contributes to leaf carbon metabolism in both the light and in the dark. However, there are some factors, potentially posttranslational regulation and PEP availability, which reduce ZmPEPC activity in vivo.
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Affiliation(s)
- Rita Giuliani
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA
| | - Shanta Karki
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
| | - Sarah Covshoff
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
| | - Hsiang-Chun Lin
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
| | - Robert A Coe
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
| | - Nuria K Koteyeva
- Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute of the Russian Academy of Sciences, Prof. Popov Street 2, St. Petersburg, Russia, 197376
| | - Marc A Evans
- Department of Mathematics and Statistics, Washington State University, Pullman, WA, 99164-3113, USA
| | - W Paul Quick
- C4 Rice Center, International Rice Research Institute (IRRI), Los Baños, Philippines
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
| | - Susanne von Caemmerer
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
| | - Robert T Furbank
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
| | - Julian M Hibberd
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
| | - Gerald E Edwards
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA
| | - Asaph B Cousins
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA.
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18
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Ye ZP, Liu YG, Kang HJ, Duan HL, Chen XM, Zhou SX. Comparing two measures of leaf photorespiration rate across a wide range of light intensities. JOURNAL OF PLANT PHYSIOLOGY 2019; 240:153002. [PMID: 31254740 DOI: 10.1016/j.jplph.2019.153002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 06/17/2019] [Accepted: 06/17/2019] [Indexed: 06/09/2023]
Abstract
Suppression of photorespiration by low O2 concentrations (Method 1) and simultaneous measurements of gas exchange and chlorophyll fluorescence (Method 2) are often used to estimate leaf photorespiration rate (Rp) of C3 plants. However, it is largely unknown whether Method 1 and Method 2 can be used equivalently in estimating Rp. Using a field experiment on two wheat cultivars (T. aestivum JM22 and T. aestivum Z39-118) whose leaf gas exchange and chlorophyll fluorescence at low and normal O2 concentrations (2% versus 21% O2) were simultaneously measured across a wide range of light intensities (I), this study assessed the impacts of the two measures on Rp and its response under changing irradiance conditions. All the above quantities increased with the increasing I until reaching the cultivar-specific maximum values and the corresponding saturation light intensities. However, there were significant differences between Rp estimated by Method 1 and Method 2 at the I range from 150 to 2000 μmol m-2 s-1 for T. aestivum JM22 and from 150 to 1000 μmol m-2 s-1 for T. aestivum Z39-118. These findings demonstrated that the two methods cannot be used equivalently under changing irradiance conditions.
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Affiliation(s)
- Zi-Piao Ye
- Maths and Physics College, Jinggangshan University, Ji'an 343009, Jiangxi, China
| | - Yu-Guo Liu
- Institute of Desertification Studies, Chinese Academy of Forestry, Beijing 100091, China
| | - Hua-Jing Kang
- Wenzhou Vocational College of Science and Technology, Wenzhou 325006, Zhejiang, China
| | - Hong-Lang Duan
- Jiangxi Provincial Key Laboratory for Restoration of Degraded Ecosystems & Watershed Ecohydrology, Nanchang Institute of Technology, Nanchang 330099, China
| | - Xian-Mao Chen
- Soil Fertilizer and Environmental Resources Institute, Jiangxi Academy of Agricultural Sciences, Nanchang 330200, Jiangxi, China.
| | - Shuang-Xi Zhou
- The New Zealand Institute for Plant and Food Research Limited, Hawke's Bay 4130, New Zealand.
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19
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Berghuijs HNC, Yin X, Ho QT, Retta MA, Nicolaï BM, Struik PC. Using a reaction-diffusion model to estimate day respiration and reassimilation of (photo)respired CO 2 in leaves. THE NEW PHYTOLOGIST 2019; 223:619-631. [PMID: 31002400 PMCID: PMC6618012 DOI: 10.1111/nph.15857] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 04/05/2019] [Indexed: 05/29/2023]
Abstract
Methods using gas exchange measurements to estimate respiration in the light (day respiration R d ) make implicit assumptions about reassimilation of (photo)respired CO2 ; however, this reassimilation depends on the positions of mitochondria. We used a reaction-diffusion model without making these assumptions to analyse datasets on gas exchange, chlorophyll fluorescence and anatomy for tomato leaves. We investigated how R d values obtained by the Kok and the Yin methods are affected by these assumptions and how those by the Laisk method are affected by the positions of mitochondria. The Kok method always underestimated R d . Estimates of R d by the Yin method and by the reaction-diffusion model agreed only for nonphotorespiratory conditions. Both the Yin and Kok methods ignore reassimilation of (photo)respired CO2 , and thus underestimated R d for photorespiratory conditions, but this was less so in the Yin than in the Kok method. Estimates by the Laisk method were affected by assumed positions of mitochondria. It did not work if mitochondria were in the cytosol between the plasmamembrane and the chloroplast envelope. However, mitochondria were found to be most likely between the tonoplast and chloroplasts. Our reaction-diffusion model effectively estimates R d , enlightens the dependence of R d estimates on reassimilation and clarifies (dis)advantages of existing methods.
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Affiliation(s)
- Herman N. C. Berghuijs
- Centre for Crop Systems AnalysisWageningen University & ResearchDroevendaalsesteeg 16708 PBWageningenthe Netherlands
- Flanders Center of Postharvest Technology/BIOSYST‐MeBioSKatholieke Universiteit LeuvenWillem de Croylaan 42LeuvenB‐3001Belgium
- Department of Crop Production EcologySwedish University of Agricultural SciencesUlls väg 16Uppsala75651Sweden
| | - Xinyou Yin
- Centre for Crop Systems AnalysisWageningen University & ResearchDroevendaalsesteeg 16708 PBWageningenthe Netherlands
| | - Q. Tri Ho
- Flanders Center of Postharvest Technology/BIOSYST‐MeBioSKatholieke Universiteit LeuvenWillem de Croylaan 42LeuvenB‐3001Belgium
- Food Chemistry & Technology DepartmentTeagasc Food Research CentreMoorepark, Fermoy, Co.CorkP61 C996Ireland
| | - Moges A. Retta
- Centre for Crop Systems AnalysisWageningen University & ResearchDroevendaalsesteeg 16708 PBWageningenthe Netherlands
- Flanders Center of Postharvest Technology/BIOSYST‐MeBioSKatholieke Universiteit LeuvenWillem de Croylaan 42LeuvenB‐3001Belgium
| | - Bart M. Nicolaï
- Flanders Center of Postharvest Technology/BIOSYST‐MeBioSKatholieke Universiteit LeuvenWillem de Croylaan 42LeuvenB‐3001Belgium
| | - Paul C. Struik
- Centre for Crop Systems AnalysisWageningen University & ResearchDroevendaalsesteeg 16708 PBWageningenthe Netherlands
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20
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Knebl A, Domes R, Yan D, Popp J, Trumbore S, Frosch T. Fiber-Enhanced Raman Gas Spectroscopy for 18O- 13C-Labeling Experiments. Anal Chem 2019; 91:7562-7569. [PMID: 31050402 DOI: 10.1021/acs.analchem.8b05684] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Stable isotopes are used in ecology to track and disentangle different processes and pathways. Especially for studies focused on the gas exchange of plants, sensing techniques that offer oxygen (O2) and carbon dioxide (CO2) sensitivity with isotopic discrimination are highly sought after. Addressing this challenge, fiber-enhanced Raman gas spectroscopy is introduced as a fast optical technique directly combining 13CO2 and 12CO2 as well as 18O2 and 16O2 measurements in one instrument. We demonstrate how a new type of optical hollow-core fiber, the so-called revolver fiber, is utilized for enhanced Raman gas sensing. Carbon dioxide and oxygen isotopologues were measured at concentrations expected when using 13C- and 18O-labeled gases in plant experiments. Limits of detection have been determined to be 25 ppm for CO2 and 150 ppm for O2. The combination of measurements with different integration times allows the creation of highly resolved broadband spectra. With the help of calculations based on density functional theory, the line at 1512 cm-1 occurring in the oxygen spectrum is assigned to 18O16O. The relative abundances of the isotopologues 18O16O and nitrogen 15N14N were in good agreement with typical values. For CO2, fiber-enhanced Raman spectra show the Fermi diad and hotbands of 12C16O2, 13C16O2, and 12C18O16O. Several weak lines were observed, and the line at 1426 cm-1 was identified as originating from the (0 4 0 2) → (0 2 0 2) transition of 12C16O2. With the demonstrated sensitivity and discriminatory power, fiber-enhanced Raman spectroscopy is a possible alternative means to investigate plant metabolism, directly combining 13CO2 and 12CO2 measurements with 18O2 and 16O2 measurements in one instrument. The presented method thus has large potential for basic analytical investigations as well as for applications in the environmental sciences.
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Affiliation(s)
- Andreas Knebl
- Leibniz Institute of Photonic Technology , 07745 Jena , Germany.,Max-Planck-Institute for Biogeochemistry , 07745 Jena , Germany
| | - Robert Domes
- Leibniz Institute of Photonic Technology , 07745 Jena , Germany
| | - Di Yan
- Leibniz Institute of Photonic Technology , 07745 Jena , Germany
| | - Juergen Popp
- Leibniz Institute of Photonic Technology , 07745 Jena , Germany.,Institute of Physical Chemistry & Abbe Center of Photonics , Friedrich Schiller University , 07743 Jena , Germany
| | - Susan Trumbore
- Max-Planck-Institute for Biogeochemistry , 07745 Jena , Germany
| | - Torsten Frosch
- Leibniz Institute of Photonic Technology , 07745 Jena , Germany.,Institute of Physical Chemistry & Abbe Center of Photonics , Friedrich Schiller University , 07743 Jena , Germany
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21
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Way DA, Aspinwall MJ, Drake JE, Crous KY, Campany CE, Ghannoum O, Tissue DT, Tjoelker MG. Responses of respiration in the light to warming in field-grown trees: a comparison of the thermal sensitivity of the Kok and Laisk methods. THE NEW PHYTOLOGIST 2019; 222:132-143. [PMID: 30372524 DOI: 10.1111/nph.15566] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 10/21/2018] [Indexed: 06/08/2023]
Abstract
The Kok and Laisk techniques can both be used to estimate light respiration Rlight . We investigated whether responses of Rlight to short- and long-term changes in leaf temperature depend on the technique used to estimate Rlight . We grew Eucalyptus tereticornis in whole-tree chambers under ambient temperature (AT) or AT + 3°C (elevated temperature, ET). We assessed dark respiration Rdark and light respiration with the Kok (RKok ) and Laisk (RLaisk ) methods at four temperatures to determine the degree of light suppression of respiration using both methods in AT and ET trees. The ET treatment had little impact on Rdark , RKok or RLaisk . Although the thermal sensitivities of RKok or RLaisk were similar, RKok was higher than RLaisk . We found negative values of RLaisk at the lowest measurement temperatures, indicating positive net CO2 uptake, which we propose may be related to phosphoenolpyruvate carboxylase activity. Light suppression of Rdark decreased with increasing leaf temperature, but the degree of suppression depended on the method used. The Kok and Laisk methods do not generate the same estimates of Rlight or light suppression of Rdark between 20 and 35°C. Negative rates of RLaisk imply that this method may become less reliable at low temperatures.
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Affiliation(s)
- Danielle A Way
- Department of Biology, University of Western Ontario, 1151 Richmond Street, London, ON N6A 5B7, Canada
- Nicholas School for the Environment, Duke University, 9 Circuit Drive, Box 90328, Durham, NC, 27708, USA
| | - Michael J Aspinwall
- Hawkesbury Institute of the Environment, Western Sydney University, Locked bag 1797, Penrith, NSW, 2751, Australia
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA
| | - John E Drake
- Hawkesbury Institute of the Environment, Western Sydney University, Locked bag 1797, Penrith, NSW, 2751, Australia
- Forest and Natural Resources Management, SUNY-ESF, 1 Forestry Drive, Syracuse, NY, 13210, USA
| | - Kristine Y Crous
- Hawkesbury Institute of the Environment, Western Sydney University, Locked bag 1797, Penrith, NSW, 2751, Australia
| | - Courtney E Campany
- Hawkesbury Institute of the Environment, Western Sydney University, Locked bag 1797, Penrith, NSW, 2751, Australia
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY, 13346, USA
| | - Oula Ghannoum
- Hawkesbury Institute of the Environment, Western Sydney University, Locked bag 1797, Penrith, NSW, 2751, Australia
| | - David T Tissue
- Hawkesbury Institute of the Environment, Western Sydney University, Locked bag 1797, Penrith, NSW, 2751, Australia
| | - Mark G Tjoelker
- Hawkesbury Institute of the Environment, Western Sydney University, Locked bag 1797, Penrith, NSW, 2751, Australia
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22
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Heskel MA, Tang J. Environmental controls on light inhibition of respiration and leaf and canopy daytime carbon exchange in a temperate deciduous forest. TREE PHYSIOLOGY 2018; 38:1886-1902. [PMID: 30252110 DOI: 10.1093/treephys/tpy103] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/21/2018] [Indexed: 06/08/2023]
Abstract
Uncertainty in the estimation of daytime ecosystem carbon cycling due to the light inhibition of leaf respiration and photorespiration, and how these small fluxes vary through the growing season in the field, remains a confounding element in calculations of gross primary productivity and ecosystem respiration. Our study focuses on how phenology, short-term temperature changes and canopy position influence leaf-level carbon exchange in Quercus rubra L. (red oak) at Harvard Forest in central Massachusetts, USA. Using leaf measurements and eddy covariance, we also quantify the effect of light inhibition on estimates of daytime respiration at leaf and ecosystem scales. Measured rates of leaf respiration in the light and dark were highest in the early growing season and declined in response to 10-day prior air temperatures (P < 0.01), evidence of within-season thermal acclimation. Leaf respiration was significantly inhibited by light (27.1 ± 2.82% inhibited across all measurements), and this inhibition varied with the month of measurement; greater inhibition was observed in mid-summer leaves compared with early- and late-season leaves. Increases in measurement temperature led to higher rates of respiration and photorespiration, though with a less pronounced positive effect on photosynthesis; as a result, carbon-use efficiency declined with increasing leaf temperature. Over the growing season when we account for seasonally variable light inhibition and basal respiration rates, our modeling approaches found a cumulative 12.9% reduction of leaf-level respiration and a 12.8% reduction of canopy leaf respiration, resulting in a 3.7% decrease in total ecosystem respiration compared with estimates that do not account for light inhibition in leaves. Our study sheds light on the environmental controls of the light inhibition of daytime leaf respiration and how integrating this phenomenon and other small fluxes can reduce uncertainty in current and future projections of terrestrial carbon cycling.
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Affiliation(s)
- Mary A Heskel
- The Ecosystems Center, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, USA
- Department of Biology, Macalester College, 1600 Grand Avenue, Saint Paul, MN, USA
| | - Jianwu Tang
- The Ecosystems Center, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, USA
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23
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Holloway-Phillips M. Photosynthetic Oxygen Production: New Method Brings to Light Forgotten Flux. PLANT PHYSIOLOGY 2018; 177:7-9. [PMID: 29720532 PMCID: PMC5933131 DOI: 10.1104/pp.18.00344] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
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