1
|
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.
Collapse
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
| |
Collapse
|
2
|
Abadie C, Lalande J, Dourmap C, Limami AM, Tcherkez G. Leaf day respiration involves multiple carbon sources and depends on previous dark metabolism. PLANT, CELL & ENVIRONMENT 2024; 47:2146-2162. [PMID: 38444114 DOI: 10.1111/pce.14871] [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: 10/06/2023] [Revised: 02/06/2024] [Accepted: 02/20/2024] [Indexed: 03/07/2024]
Abstract
Day respiration (Rd) is the metabolic, nonphotorespiratory process by which illuminated leaves liberate CO2 during photosynthesis. Rd is used routinely in photosynthetic models and is thus critical for calculations. However, metabolic details associated with Rd are poorly known, and this can be problematic to predict how Rd changes with environmental conditions and relates to night respiration. It is often assumed that day respiratory CO2 release just reflects 'ordinary' catabolism (glycolysis and Krebs 'cycle'). Here, we carried out a pulse-chase experiment, whereby a 13CO2 pulse in the light was followed by a chase period in darkness and then in the light. We took advantage of nontargeted, isotope-assisted metabolomics to determine non-'ordinary' metabolism, detect carbon remobilisation and compare light and dark 13C utilisation. We found that several concurrent metabolic pathways ('ordinary' catabolism, oxidative pentose phosphates pathway, amino acid production, nucleotide biosynthesis and secondary metabolism) took place in the light and participated in net CO2 efflux associated with day respiration. Flux reconstruction from metabolomics leads to an underestimation of Rd, further suggesting the contribution of a variety of CO2-evolving processes. Also, the cornerstone of the Krebs 'cycle', citrate, is synthetised de novo from photosynthates mostly in darkness, and remobilised or synthesised from stored material in the light. Collectively, our data provides direct evidence that leaf day respiration (i) involves several CO2-producing reactions and (ii) is fed by different carbon sources, including stored carbon disconnected from current photosynthates.
Collapse
Affiliation(s)
- Cyril Abadie
- Institut de recherche en horticulture et semences, INRAe, Université d'Angers, Beaucouzé, France
- Ecophysiologie et génomique fonctionnelle de la vigne, Institut des Sciences de la Vigne et du Vin, INRAe, Université de Bordeaux, Villenave-d'Ornon, France
| | - Julie Lalande
- Institut de recherche en horticulture et semences, INRAe, Université d'Angers, Beaucouzé, France
| | - Corentin Dourmap
- Institut de recherche en horticulture et semences, INRAe, Université d'Angers, Beaucouzé, France
| | - Anis M Limami
- Institut de recherche en horticulture et semences, INRAe, Université d'Angers, Beaucouzé, France
| | - Guillaume Tcherkez
- Institut de recherche en horticulture et semences, INRAe, Université d'Angers, Beaucouzé, France
- Research School of Biology, ANU College of Science, Australian National University, Canberra, Australia
| |
Collapse
|
3
|
Yu YZ, Liu HT, Yang F, Li L, Schäufele R, Tcherkez G, Schnyder H, Gong XY. δ13C of bulk organic matter and cellulose reveal post-photosynthetic fractionation during ontogeny in C4 grass leaves. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:1451-1464. [PMID: 37943576 DOI: 10.1093/jxb/erad445] [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: 06/30/2023] [Accepted: 11/04/2023] [Indexed: 11/10/2023]
Abstract
The 13C isotope composition (δ13C) of leaf dry matter is a useful tool for physiological and ecological studies. However, how post-photosynthetic fractionation associated with respiration and carbon export influences δ13C remains uncertain. We investigated the effects of post-photosynthetic fractionation on δ13C of mature leaves of Cleistogenes squarrosa, a perennial C4 grass, in controlled experiments with different levels of vapour pressure deficit and nitrogen supply. With increasing leaf age class, the 12C/13C fractionation of leaf organic matter relative to the δ13C of atmosphere CO2 (ΔDM) increased while that of cellulose (Δcel) was almost constant. The divergence between ΔDM and Δcel increased with leaf age class, with a maximum value of 1.6‰, indicating the accumulation of post-photosynthetic fractionation. Applying a new mass balance model that accounts for respiration and export of photosynthates, we found an apparent 12C/13C fractionation associated with carbon export of -0.5‰ to -1.0‰. Different ΔDM among leaves, pseudostems, daughter tillers, and roots indicate that post-photosynthetic fractionation happens at the whole-plant level. Compared with ΔDM of old leaves, ΔDM of young leaves and Δcel are more reliable proxies for predicting physiological parameters due to the lower sensitivity to post-photosynthetic fractionation and the similar sensitivity in responses to environmental changes.
Collapse
Affiliation(s)
- Yong Zhi Yu
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Hai Tao Liu
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- College of Resources and Environment, Henan Agricultural University, Zhengzhou 450046, China
| | - Fang Yang
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- College of Resources and Environment, Jilin Agricultural University, Changchun 130117, China
| | - Lei Li
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Guillaume Tcherkez
- Research School of Biology, ANU Joint College of Science, Australian National University, Canberra ACT 0200, Australia
- Institut de Recherche en Horticulture et Semences, INRAe, Université d'Angers, 42 rue Georges Morel, 49070 Beaucouzé, France
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Xiao Ying Gong
- Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, College of Geographical Sciences, Fujian Normal University, Fuzhou, 350007, China
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
- Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, China
| |
Collapse
|
4
|
Ubierna N, Holloway-Phillips MM, Wingate L, Ogée J, Busch FA, Farquhar GD. Using Carbon Stable Isotopes to Study C 3 and C 4 Photosynthesis: Models and Calculations. Methods Mol Biol 2024; 2790:163-211. [PMID: 38649572 DOI: 10.1007/978-1-0716-3790-6_10] [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: 04/25/2024]
Abstract
Stable carbon isotopes are a powerful tool to study photosynthesis. Initial applications consisted of determining isotope ratios of plant biomass using mass spectrometry. Subsequently, theoretical models relating C isotope values to gas exchange characteristics were introduced and tested against instantaneous online measurements of 13C photosynthetic discrimination. Beginning in the twenty-first century, laser absorption spectroscopes with sufficient precision for determining isotope mixing ratios became commercially available. This has allowed collection of large data sets at lower cost and with unprecedented temporal resolution. More data and accompanying knowledge have permitted refinement of 13C discrimination model equations, but often at the expense of increased model complexity and difficult parametrization. This chapter describes instantaneous online measurements of 13C photosynthetic discrimination, provides recommendations for experimental setup, and presents a thorough compilation of equations available to researchers. We update our previous 2018 version of this chapter by including recently improved descriptions of (photo)respiratory processes and associated fractionations. We discuss the capabilities and limitations of the diverse 13C discrimination model equations and provide guidance for selecting the model complexity needed for different applications.
Collapse
Affiliation(s)
- Nerea Ubierna
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Meisha-Marika Holloway-Phillips
- Research Unit of Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmendsorf, Switzerland
| | - Lisa Wingate
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Jérôme Ogée
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Florian A Busch
- School of Biosciences and The Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Busch FA, Holloway-Phillips M, Stuart-Williams H, Farquhar GD. Revisiting carbon isotope discrimination in C 3 plants shows respiration rules when photosynthesis is low. NATURE PLANTS 2020; 6:245-258. [PMID: 32170287 DOI: 10.1038/s41477-020-0606-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 01/23/2020] [Indexed: 05/12/2023]
Abstract
Stable isotopes are commonly used to study the diffusion of CO2 within photosynthetic plant tissues. The standard method used to interpret the observed preference for the lighter carbon isotope in C3 photosynthesis involves the model of Farquhar et al., which relates carbon isotope discrimination to physical and biochemical processes within the leaf. However, under many conditions the model returns unreasonable results for mesophyll conductance to CO2 diffusion (gm), especially when rates of photosynthesis are low. Here, we re-derive the carbon isotope discrimination model using modified assumptions related to the isotope effect of mitochondrial respiration. In particular, we treat the carbon pool associated with respiration as separate from the pool of primary assimilates. We experimentally test the model by comparing gm values measured with different CO2 source gases varying in their isotopic composition, and show that our new model returns matching gm values that are much more reasonable than those obtained with the previous model. We use our results to discuss CO2 diffusion properties within the mesophyll.
Collapse
Affiliation(s)
- Florian A Busch
- Research School of Biology and ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Acton, Australian Capital Territory, Australia.
| | - Meisha Holloway-Phillips
- Research School of Biology and ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Acton, Australian Capital Territory, Australia
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Hilary Stuart-Williams
- Research School of Biology and ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Acton, Australian Capital Territory, Australia
| | - Graham D Farquhar
- Research School of Biology and ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Acton, Australian Capital Territory, Australia
| |
Collapse
|
7
|
Gong XY, Tcherkez G, Wenig J, Schäufele R, Schnyder H. Determination of leaf respiration in the light: comparison between an isotopic disequilibrium method and the Laisk method. THE NEW PHYTOLOGIST 2018; 218:1371-1382. [PMID: 29611899 DOI: 10.1111/nph.15126] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 02/16/2018] [Indexed: 06/08/2023]
Abstract
Quantification of leaf respiration is important for understanding plant physiology and ecosystem biogeochemical processes. Leaf respiration continues in the light (RL ) but supposedly at a lower rate than in the dark (RDk ). However, there is no method for direct measurement of RL and the available methods require nonphysiological measurement conditions. A method based on isotopic disequilibrium quantified RL (RL13C ) and mesophyll conductance of young and old fully expanded leaves of six species. RL13C was compared to RL determined by the Laisk method (RL Laisk ) on the very same leaves with a minimum time lag. RL 13C and RL Laisk were generally lower than RDk , and were not significantly affected by leaf ageing. RL Laisk and RL 13C were positively correlated (r2 = 0.35), and both were positively correlated with RDk (r2 ≥ 0.6). RL Laisk was systematically lower than RL 13C by 0.4 μmol m-2 s-1 . Using A/Cc instead of A/Ci curves, a higher photocompensation point Γ* (by 5 μmol mol-1 ) was found but no influence on RL Laisk estimates was observed. The results imply that the Laisk method underestimates actual RL significantly, probably related to the measurement condition of low CO2 and irradiance. The isotopic disequilibrium method is useful for assessing responses of RL to irradiance and CO2 , improving our mechanistic understanding of RL .
Collapse
Affiliation(s)
- Xiao Ying Gong
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising, Germany
- Department of Ecology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, 510642, China
| | - Guillaume Tcherkez
- Research School of Biology, ANU College of Medicine, Biology and Environment, Australian National University, Canberra, ACT, 0200, Australia
| | - Johannes Wenig
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising, Germany
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising, Germany
| |
Collapse
|
8
|
Ubierna N, Holloway-Phillips MM, Farquhar GD. Using Stable Carbon Isotopes to Study C 3 and C 4 Photosynthesis: Models and Calculations. Methods Mol Biol 2018; 1770:155-196. [PMID: 29978402 DOI: 10.1007/978-1-4939-7786-4_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Stable carbon isotopes are a powerful tool to study photosynthesis. Initial applications consisted of determining isotope ratios of plant biomass using mass spectrometry. Subsequently, theoretical models relating C-isotope values to gas exchange characteristics were introduced and tested against instantaneous online measurements of 13C photosynthetic discrimination. Beginning in the twenty-first century, tunable diode laser spectroscopes with sufficient precision for determining isotope mixing ratios became commercially available. This has allowed collection of large data sets, at low cost and with unprecedented temporal resolution. With more data and accompanying knowledge, it has become apparent that there is a need for increased complexity in models and calculations. This chapter describes instantaneous online measurements of 13C photosynthetic discrimination, provides recommendations for experimental setup, and presents a thorough compilation of equations needed for different applications.
Collapse
Affiliation(s)
- Nerea Ubierna
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, USA.
| | | | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| |
Collapse
|
9
|
Tcherkez G, Gauthier P, Buckley TN, Busch FA, Barbour MM, Bruhn D, Heskel MA, Gong XY, Crous KY, Griffin K, Way D, Turnbull M, Adams MA, Atkin OK, Farquhar GD, Cornic G. Leaf day respiration: low CO 2 flux but high significance for metabolism and carbon balance. THE NEW PHYTOLOGIST 2017; 216:986-1001. [PMID: 28967668 DOI: 10.1111/nph.14816] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/13/2017] [Indexed: 05/04/2023]
Abstract
Contents 986 I. 987 II. 987 III. 988 IV. 991 V. 992 VI. 995 VII. 997 VIII. 998 References 998 SUMMARY: It has been 75 yr since leaf respiratory metabolism in the light (day respiration) was identified as a low-flux metabolic pathway that accompanies photosynthesis. In principle, it provides carbon backbones for nitrogen assimilation and evolves CO2 and thus impacts on plant carbon and nitrogen balances. However, for a long time, uncertainties have remained as to whether techniques used to measure day respiratory efflux were valid and whether day respiration responded to environmental gaseous conditions. In the past few years, significant advances have been made using carbon isotopes, 'omics' analyses and surveys of respiration rates in mesocosms or ecosystems. There is substantial evidence that day respiration should be viewed as a highly dynamic metabolic pathway that interacts with photosynthesis and photorespiration and responds to atmospheric CO2 mole fraction. The view of leaf day respiration as a constant and/or negligible parameter of net carbon exchange is now outdated and it should now be regarded as a central actor of plant carbon-use efficiency.
Collapse
Affiliation(s)
- Guillaume Tcherkez
- Research School of Biology, College of Science, and ARC Center of Excellence for Translational Photosynthesis, Australian National University, Canberra, ACT, 2601, Australia
| | - Paul Gauthier
- Department of Geosciences, Princeton University, Princeton, NJ, 08540, USA
| | - Thomas N Buckley
- IA Watson Grains Research Centre, University of Sydney, 12656 Newell Hwy, Narrabri, NSW, 2390, Australia
| | - Florian A Busch
- Research School of Biology, College of Science, and ARC Center of Excellence for Translational Photosynthesis, Australian National University, Canberra, ACT, 2601, Australia
| | - Margaret M Barbour
- Centre for Carbon, Water and Food, University of Sydney, 380 Werombi Rd, Brownlow Hill, NSW, 2570, Australia
| | - Dan Bruhn
- Section of Biology and Environmental Science, Department of Chemistry and Bioscience, Aalborg University, 9220, Aalborg East, Denmark
| | - Mary A Heskel
- The Ecosystems Center, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA
| | - Xiao Ying Gong
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising, Germany
| | - Kristine Y Crous
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW, 2751, Australia
| | - Kevin Griffin
- Department of Ecology, Evolution and Environmental Biology (E3B), Columbia University, 1200 Amsterdam Avenue, New York, NY, 10027, USA
| | - Danielle Way
- Department of Biology, University of Western Ontario, London, ON, N6A 5B7, Canada
| | - Matthew Turnbull
- Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, PB 4800, Christchurch, New Zealand
| | - Mark A Adams
- Centre for Carbon, Water and Food, University of Sydney, 380 Werombi Rd, Brownlow Hill, NSW, 2570, Australia
| | - Owen K Atkin
- ARC Centre of Excellence in Plant Energy Biology, Division of Plant Science, Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
| | - Graham D Farquhar
- Research School of Biology, College of Science, and ARC Center of Excellence for Translational Photosynthesis, Australian National University, Canberra, ACT, 2601, Australia
| | - Gabriel Cornic
- Ecologie Systématique Evolution, Université Paris-Sud, 91405, Orsay Cedex, France
| |
Collapse
|
10
|
Abadie C, Carroll A, Tcherkez G. Interactions Between Day Respiration, Photorespiration, and N and S Assimilation in Leaves. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2017. [DOI: 10.1007/978-3-319-68703-2_1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
11
|
Barbour MM, Ryazanova S, Tcherkez G. Respiratory Effects on the Carbon Isotope Discrimination Near the Compensation Point. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2017. [DOI: 10.1007/978-3-319-68703-2_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
12
|
Abadie C, Lamothe-Sibold M, Gilard F, Tcherkez G. Isotopic evidence for nitrogen exchange between autotrophic and heterotrophic tissues in variegated leaves. FUNCTIONAL PLANT BIOLOGY : FPB 2016; 43:298-306. [PMID: 32480462 DOI: 10.1071/fp15187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 11/12/2015] [Indexed: 05/15/2023]
Abstract
Many plant species or cultivars form variegated leaves in which blades are made of green and white sectors. On the one hand, there is little photosynthetic CO2 assimilation in white tissue simply because of the lack of functional chloroplasts and thus, leaf white tissue is heterotrophic and fed by photosynthates exported by leaf green tissue. On the other hand, it has been previously shown that the white tissue is enriched in nitrogenous compounds such as amino acids and polyamines, which can, in turn, be remobilised upon nitrogen deficiency. However, the origin of organic nitrogen in leaf white tissue, including the possible requirement for N-reduction in leaf green tissue before export to white tissue, has not been examined. Here, we took advantage of isotopic methods to investigate the source of nitrogen in the white tissue. A survey of natural isotope abundance (δ15N) and elemental composition (%N) in various variegated species shows no visible difference between white and green tissues, suggesting a common N source. However, there is a tendency for N-rich white tissue to be naturally 15N-enriched whereas in the model species Pelargonium×hortorum, white sectors are naturally 15N-depleted, indicating that changes in metabolic composition and/or N-partitioning may occur. Isotopic labelling with 15N-nitrate on illuminated leaf discs clearly shows that the white tissue assimilates little nitrogen and thus relies on nitrate reduction and metabolism in the green tissue. The N-sink represented by the white tissue is considerable, accounting for nearly 50% of total assimilated nitrate.
Collapse
Affiliation(s)
- Cyril Abadie
- Research School of Biology, ANU College of Medicine, Biology and Environment, Australian National University, Canberra, ACT 2601, Australia
| | - Marlène Lamothe-Sibold
- Université Paris-Sud, Institute of Plant Sciences Paris-Saclay IPS2 (Bâtiment 630), UMR CNRS-INRA 9213, Université Paris-Saclay, 91405 Orsay, France
| | - Françoise Gilard
- Université Paris-Sud, Institute of Plant Sciences Paris-Saclay IPS2 (Bâtiment 630), UMR CNRS-INRA 9213, Université Paris-Saclay, 91405 Orsay, France
| | - Guillaume Tcherkez
- Research School of Biology, ANU College of Medicine, Biology and Environment, Australian National University, Canberra, ACT 2601, Australia
| |
Collapse
|
13
|
Lamade E, Tcherkez G, Darlan NH, Rodrigues RL, Fresneau C, Mauve C, Lamothe-Sibold M, Sketriené D, Ghashghaie J. Natural (13) C distribution in oil palm (Elaeis guineensis Jacq.) and consequences for allocation pattern. PLANT, CELL & ENVIRONMENT 2016; 39:199-212. [PMID: 26228944 DOI: 10.1111/pce.12606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 06/26/2015] [Indexed: 06/04/2023]
Abstract
Oil palm has now become one of the most important crops, palm oil representing nearly 25% of global plant oil consumption. Many studies have thus addressed oil palm ecophysiology and photosynthesis-based models of carbon allocation have been used. However, there is a lack of experimental data on carbon fixation and redistribution within palm trees, and important C-sinks have not been fully characterized yet. Here, we carried out extensive measurement of natural (13) C-abundance (δ(13) C) in oil palm tissues, including fruits at different maturation stages. We find a (13) C-enrichment in heterotrophic organs compared to mature leaves, with roots being the most (13) C-enriched. The δ(13) C in fruits decreased during maturation, reflecting the accumulation in (13) C-depleted lipids. We further used observed δ(13) C values to compute plausible carbon fluxes using a steady-state model of (13) C-distribution including metabolic isotope effects ((12) v/(13) v). The results suggest that fruits represent a major respiratory loss (≈39% of total tree respiration) and that sink organs such as fruits are fed by sucrose from leaves. That is, glucose appears to be a quantitatively important compound in palm tissues, but computations indicate that it is involved in dynamic starch metabolism rather that C-exchange between organs.
Collapse
Affiliation(s)
- Emmanuelle Lamade
- UPR34 Performance of Perennial Cropping Systems, CIRAD-PERSYST, Montpellier, 34398, France
| | - Guillaume Tcherkez
- Research School of Biology, College of Medicine, Biology and Environment, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - Nuzul Hijri Darlan
- Indonesian Oil Palm Research Institute, IOPRI, Jl. Brigjen Katamso 51, Medan, North Sumatra, Indonesia
| | | | - Chantal Fresneau
- ESE, Université Paris-Sud, CNRS UMR 8079, Orsay cedex, 91405, France
| | - Caroline Mauve
- Plateforme Métabolisme-Métabolome, Université Paris-Sud, IPS2, Orsay cedex, 91405, France
| | - Marlène Lamothe-Sibold
- Plateforme Métabolisme-Métabolome, Université Paris-Sud, IPS2, Orsay cedex, 91405, France
| | - Diana Sketriené
- ESE, Université Paris-Sud, CNRS UMR 8079, Orsay cedex, 91405, France
| | - Jaleh Ghashghaie
- ESE, Université Paris-Sud, CNRS UMR 8079, Orsay cedex, 91405, France
| |
Collapse
|
14
|
Gong XY, Schäufele R, Feneis W, Schnyder H. (13) CO2 /(12) CO2 exchange fluxes in a clamp-on leaf cuvette: disentangling artefacts and flux components. PLANT, CELL & ENVIRONMENT 2015; 38:2417-2432. [PMID: 25944155 DOI: 10.1111/pce.12564] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 02/19/2015] [Accepted: 04/19/2015] [Indexed: 06/04/2023]
Abstract
Leaks and isotopic disequilibria represent potential errors and artefacts during combined measurements of gas exchange and carbon isotope discrimination (Δ). This paper presents new protocols to quantify, minimize, and correct such phenomena. We performed experiments with gradients of CO2 concentration (up to ±250 μmol mol(-1) ) and δ(13) CCO2 (34‰), between a clamp-on leaf cuvette (LI-6400) and surrounding air, to assess (1) leak coefficients for CO2 , (12) CO2 , and (13) CO2 with the empty cuvette and with intact leaves of Holcus lanatus (C3 ) or Sorghum bicolor (C4 ) in the cuvette; and (2) isotopic disequilibria between net photosynthesis and dark respiration in light. Leak coefficients were virtually identical for (12) CO2 and (13) CO2 , but ∼8 times higher with leaves in the cuvette. Leaks generated errors on Δ up to 6‰ for H. lanatus and 2‰ for S. bicolor in full light; isotopic disequilibria produced similar variation of Δ. Leak errors in Δ in darkness were much larger due to small biological : leak flux ratios. Leak artefacts were fully corrected with leak coefficients determined on the same leaves as Δ measurements. Analysis of isotopic disequilibria enabled partitioning of net photosynthesis and dark respiration, and indicated inhibitions of dark respiration in full light (H. lanatus: 14%, S. bicolor: 58%).
Collapse
Affiliation(s)
- Xiao Ying Gong
- Lehrstuhl für Grünlandlehre, Technische Universität München, 85354, Freising, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, 85354, Freising, Germany
| | - Wolfgang Feneis
- Lehrstuhl für Grünlandlehre, Technische Universität München, 85354, Freising, Germany
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, 85354, Freising, Germany
| |
Collapse
|
15
|
Ubierna N, Farquhar GD. Advances in measurements and models of photosynthetic carbon isotope discrimination in C3 plants. PLANT, CELL & ENVIRONMENT 2014; 37:1494-8. [PMID: 24716900 DOI: 10.1111/pce.12346] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 03/31/2014] [Indexed: 05/08/2023]
Affiliation(s)
- Nerea Ubierna
- Research School of Biology, Australian National University, Canberra, ACT, 0200, Australia
| | | |
Collapse
|
16
|
Gentsch L, Hammerle A, Sturm P, Ogée J, Wingate L, Siegwolf R, Plüss P, Baur T, Buchmann N, Knohl A. Carbon isotope discrimination during branch photosynthesis of Fagus sylvatica: a Bayesian modelling approach. PLANT, CELL & ENVIRONMENT 2014; 37:1516-1535. [PMID: 24372560 DOI: 10.1111/pce.12262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 11/05/2013] [Accepted: 12/04/2013] [Indexed: 06/03/2023]
Abstract
Field measurements of photosynthetic carbon isotope discrimination ((13)Δ) of Fagus sylvatica, conducted with branch bags and laser spectrometry, revealed a high variability of (13)Δ, both on diurnal and day-to-day timescales. We tested the prediction capability of three versions of a commonly used model for (13)Δ [called here comprehensive ((13)(Δcomp)), simplified ((13) Δsimple) and revised ((13)(Δrevised)) versions]. A Bayesian approach was used to calibrate major model parameters. Constrained estimates were found for the fractionation during CO(2) fixation in (13)(Δcomp), but not in (13)(Δsimple), and partially for the mesophyll conductance for CO(2)(gi). No constrained estimates were found for fractionations during mitochondrial and photorespiration, and for a diurnally variable apparent fractionation between current assimilates and mitochondrial respiration, specific to (13)(Δrevised). A quantification of parameter estimation uncertainties and interdependencies further helped explore model structure and behaviour. We found that (13)(Δcomp) usually outperformed (13)(Δsimple) because of the explicit consideration of gi and the photorespiratory fractionation in (13)(Δcomp) that enabled a better description of the large observed diurnal variation (≈9‰) of (13)Δ. Flux-weighted daily means of (13)Δ were also better predicted with (13)(Δcomp) than with (13)(Δsimple).
Collapse
Affiliation(s)
- Lydia Gentsch
- Institute of Agricultural Sciences, ETH Zurich, Universitätsstrasse 2, Zurich, 8092, Switzerland; UR1263 Ephyse, INRA, Villenave d'Ornon, 33140, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Kromdijk J, Ubierna N, Cousins AB, Griffiths H. Bundle-sheath leakiness in C4 photosynthesis: a careful balancing act between CO2 concentration and assimilation. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3443-57. [PMID: 24755278 DOI: 10.1093/jxb/eru157] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Crop species with the C4 photosynthetic pathway are generally characterized by high productivity, especially in environmental conditions favouring photorespiration. In comparison with the ancestral C3 pathway, the biochemical and anatomical modifications of the C4 pathway allow spatial separation of primary carbon acquisition in mesophyll cells and subsequent assimilation in bundle-sheath cells. The CO2-concentrating C4 cycle has to operate in close coordination with CO2 reduction via the Calvin-Benson-Bassham (CBB) cycle in order to keep the C4 pathway energetically efficient. The gradient in CO2 concentration between bundle-sheath and mesophyll cells facilitates diffusive leakage of CO2. This rate of bundle-sheath CO2 leakage relative to the rate of phosphoenolpyruvate carboxylation (termed leakiness) has been used to probe the balance between C4 carbon acquisition and subsequent reduction as a result of environmental perturbations. When doing so, the correct choice of equations to derive leakiness from stable carbon isotope discrimination (Δ(13)C) during gas exchange is critical to avoid biased results. Leakiness responses to photon flux density, either short-term (during measurements) or long-term (during growth and development), can have important implications for C4 performance in understorey light conditions. However, recent reports show leakiness to be subject to considerable acclimation. Additionally, the recent discovery of two decarboxylating C4 cycles operating in parallel in Zea mays suggests that flexibility in the transported C4 acid and associated decarboxylase could also aid in maintaining C4/CBB balance in a changing environment. In this paper, we review improvements in methodology to estimate leakiness, synthesize reports on bundle-sheath leakiness, discuss different interpretations, and highlight areas where future research is necessary.
Collapse
Affiliation(s)
- Johannes Kromdijk
- Institute for Genomic Biology, University of Illinois, 1206W Gregory drive, Urbana, IL 61801, USA
| | - Nerea Ubierna
- Research School of Biology, The Australian National University, Canberra, ACT, Australia
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA99164-4236, USA
| | - Howard Griffiths
- Physiological Ecology Group, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB23EA, UK
| |
Collapse
|
18
|
Ghashghaie J, Badeck FW. Opposite carbon isotope discrimination during dark respiration in leaves versus roots - a review. THE NEW PHYTOLOGIST 2014; 201:751-769. [PMID: 24251924 DOI: 10.1111/nph.12563] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 09/15/2013] [Indexed: 05/13/2023]
Abstract
In general, leaves are (13) C-depleted compared with all other organs (e.g. roots, stem/trunk and fruits). Different hypotheses are formulated in the literature to explain this difference. One of these states that CO2 respired by leaves in the dark is (13) C-enriched compared with leaf organic matter, while it is (13) C-depleted in the case of root respiration. The opposite respiratory fractionation between leaves and roots was invoked as an explanation for the widespread between-organ isotopic differences. After summarizing the basics of photosynthetic and post-photosynthetic discrimination, we mainly review the recent findings on the isotopic composition of CO2 respired by leaves (autotrophic organs) and roots (heterotrophic organs) compared with respective plant material (i.e. apparent respiratory fractionation) as well as its metabolic origin. The potential impact of such fractionation on the isotopic signal of organic matter (OM) is discussed. Some perspectives for future studies are also proposed .
Collapse
Affiliation(s)
- Jaleh Ghashghaie
- Laboratoire d'Ecologie, Systématique et Evolution (ESE), CNRS UMR8079, Bâtiment 362, Université de Paris-Sud (XI), F-91405, Orsay Cedex, France
| | - Franz W Badeck
- Consiglio per la Ricerca e la sperimentazione in Agricoltura, Genomics research centre (CRA - GPG), Via San Protaso, 302, 29017, Fiorenzuola d'Arda (PC), Italy
- Potsdam Institute for Climate Impact Research (PIK), PF 60 12 03, 14412, Potsdam, Germany
| |
Collapse
|
19
|
Cernusak LA, Ubierna N, Winter K, Holtum JAM, Marshall JD, Farquhar GD. Environmental and physiological determinants of carbon isotope discrimination in terrestrial plants. THE NEW PHYTOLOGIST 2013; 200:950-65. [PMID: 23902460 DOI: 10.1111/nph.12423] [Citation(s) in RCA: 232] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Accepted: 06/25/2013] [Indexed: 05/05/2023]
Abstract
Stable carbon isotope ratios (δ(13) C) of terrestrial plants are employed across a diverse range of applications in environmental and plant sciences; however, the kind of information that is desired from the δ(13) C signal often differs. At the extremes, it ranges between purely environmental and purely biological. Here, we review environmental drivers of variation in carbon isotope discrimination (Δ) in terrestrial plants, and the biological processes that can either damp or amplify the response. For C3 plants, where Δ is primarily controlled by the ratio of intercellular to ambient CO2 concentrations (ci /ca ), coordination between stomatal conductance and photosynthesis and leaf area adjustment tends to constrain the potential environmentally driven range of Δ. For C4 plants, variation in bundle-sheath leakiness to CO2 can either damp or amplify the effects of ci /ca on Δ. For plants with crassulacean acid metabolism (CAM), Δ varies over a relatively large range as a function of the proportion of daytime to night-time CO2 fixation. This range can be substantially broadened by environmental effects on Δ when carbon uptake takes place primarily during the day. The effective use of Δ across its full range of applications will require a holistic view of the interplay between environmental control and physiological modulation of the environmental signal.
Collapse
Affiliation(s)
- Lucas A Cernusak
- Department of Marine and Tropical Biology, James Cook University, Cairns, Qld, Australia
| | | | | | | | | | | |
Collapse
|
20
|
Gauthier PPG, Lamothe M, Mahé A, Molero G, Nogués S, Hodges M, Tcherkez G. Metabolic origin of δ15 N values in nitrogenous compounds from Brassica napus L. leaves. PLANT, CELL & ENVIRONMENT 2013; 36:128-37. [PMID: 22709428 DOI: 10.1111/j.1365-3040.2012.02561.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Nitrogen isotope composition (δ(15) N) in plant organic matter is currently used as a natural tracer of nitrogen acquisition efficiency. However, the δ(15) N value of whole leaf material does not properly reflect the way in which N is assimilated because isotope fractionations along metabolic reactions may cause substantial differences among leaf compounds. In other words, any change in metabolic composition or allocation pattern may cause undesirable variability in leaf δ(15) N. Here, we investigated the δ(15) N in different leaf fractions and individual metabolites from rapeseed (Brassica napus) leaves. We show that there were substantial differences in δ(15) N between nitrogenous compounds (up to 30‰) and the content in ((15) N enriched) nitrate had a clear influence on leaf δ(15) N. Using a simple steady-state model of day metabolism, we suggest that the δ(15) N value in major amino acids was mostly explained by isotope fractionation associated with isotope effects on enzyme-catalysed reactions in primary nitrogen metabolism. δ(15) N values were further influenced by light versus dark conditions and the probable occurrence of alternative biosynthetic pathways. We conclude that both biochemical pathways (that fractionate between isotopes) and nitrogen sources (used for amino acid production) should be considered when interpreting the δ(15) N value of leaf nitrogenous compounds.
Collapse
Affiliation(s)
- Paul P G Gauthier
- Institut de Biologie des Plantes, CNRS UMR 8618 Plateforme Métabolisme Métabolome, Université Paris Sud, Orsay Cedex, France.
| | | | | | | | | | | | | |
Collapse
|
21
|
Tcherkez G, Mahé A, Guérard F, Boex-Fontvieille ERA, Gout E, Lamothe M, Barbour MM, Bligny R. Short-term effects of CO(2) and O(2) on citrate metabolism in illuminated leaves. PLANT, CELL & ENVIRONMENT 2012; 35:2208-2220. [PMID: 22646810 DOI: 10.1111/j.1365-3040.2012.02550.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Although there is now a considerable literature on the inhibition of leaf respiration (CO(2) evolution) by light, little is known about the effect of other environmental conditions on day respiratory metabolism. In particular, CO(2) and O(2) mole fractions are assumed to cause changes in the tricarboxylic acid pathway (TCAP) but the amplitude and even the direction of such changes are still a matter of debate. Here, we took advantage of isotopic techniques, new simple equations and instant freeze sampling to follow respiratory metabolism in illuminated cocklebur leaves (Xanthium strumarium L.) under different CO(2) /O(2) conditions. Gas exchange coupled to online isotopic analysis showed that CO(2) evolved by leaves in the light came from 'old' carbon skeletons and there was a slight decrease in (13) C natural abundance when [CO(2) ] increased. This suggested the involvement of enzymatic steps fractionating more strongly against (13) C and thus increasingly limiting for the metabolic respiratory flux as [CO(2) ] increased. Isotopic labelling with (13) C(2) -2,4-citrate lead to (13) C-enriched Glu and 2-oxoglutarate (2OG), clearly demonstrating poor metabolism of citrate by the TCAP. There was a clear relationship between the ribulose-1,5-bisphosphate oxygenation-to-carboxylation ratio (v(o) /v(c) ) and the (13) C commitment to 2OG, demonstrating that 2OG and Glu synthesis via the TCAP is positively influenced by photorespiration.
Collapse
Affiliation(s)
- Guillaume Tcherkez
- Institut de Biologie des Plantes, CNRS UMR8618, Université Paris-Sud, 91405 Orsay Cedex, France.
| | | | | | | | | | | | | | | |
Collapse
|
22
|
Tcherkez G, Gu Rard F, Gilard FO, Lamothe MN, Mauve C, Gout E, Bligny R. Metabolomic characterisation of the functional division of nitrogen metabolism in variegated leaves. FUNCTIONAL PLANT BIOLOGY : FPB 2012; 39:959-967. [PMID: 32480845 DOI: 10.1071/fp12189] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 08/30/2012] [Indexed: 06/11/2023]
Abstract
Many horticultural and natural plant species have variegated leaves, that is, patchy leaves with green and non-green or white areas. Specific studies on the metabolism of variegated leaves are scarce and although white (non-green) areas have been assumed to play the role of a 'nitrogen store', there is no specific studies showing the analysis of nitrogenous metabolites and the dynamics of nitrogen assimilation. Here, we examined the metabolism of variegated leaves of Pelargonium×hortorum. We show that white areas have a larger N:C ratio, more amino acids, with a clear accumulation of arginine. Metabolomic analyses revealed clear differences in the chemical composition, suggesting contrasted metabolic commitments such as an enhancement of alkaloid biosynthesis in white areas. Using isotopic labelling followed by nuclear magnetic resonance or liquid chromatography/mass spectrometry, we further showed that in addition to glutamine, tyrosine and tryptophan, N metabolism forms ornithine in green area and huge amounts of arginine in white areas. Fine isotopic measurements with isotope ratio mass spectrometry indicated that white and green areas exchange nitrogenous molecules but nitrogen export from green areas is quantitatively much more important. The biological significance of the metabolic exchange between leaf areas is briefly discussed.
Collapse
Affiliation(s)
- Guillaume Tcherkez
- Institut de Biologie des Plantes, CNRS UMR8618, Université Paris-Sud, 91405 Orsay cedex, France
| | - Florence Gu Rard
- Plateforme Métabolisme-Métabolome, IFR87, Batiment 630, Université Paris-Sud, 91405 Orsay cedex, France
| | - Fran Oise Gilard
- Plateforme Métabolisme-Métabolome, IFR87, Batiment 630, Université Paris-Sud, 91405 Orsay cedex, France
| | - Marl Ne Lamothe
- Plateforme Métabolisme-Métabolome, IFR87, Batiment 630, Université Paris-Sud, 91405 Orsay cedex, France
| | - Caroline Mauve
- Plateforme Métabolisme-Métabolome, IFR87, Batiment 630, Université Paris-Sud, 91405 Orsay cedex, France
| | - Elisabeth Gout
- Laboratoire de Physiologie Cellulaire Végétale, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble cedex 9, France
| | - Richard Bligny
- Laboratoire de Physiologie Cellulaire Végétale, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble cedex 9, France
| |
Collapse
|
23
|
Gilbert A, Silvestre V, Robins RJ, Remaud GS, Tcherkez G. Biochemical and physiological determinants of intramolecular isotope patterns in sucrose from C3, C4 and CAM plants accessed by isotopic 13C NMR spectrometry: a viewpoint. Nat Prod Rep 2012; 29:476-86. [DOI: 10.1039/c2np00089j] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
24
|
Kodama N, Cousins A, Tu KP, Barbour MM. Spatial variation in photosynthetic CO(2) carbon and oxygen isotope discrimination along leaves of the monocot triticale (Triticum × Secale) relates to mesophyll conductance and the Péclet effect. PLANT, CELL & ENVIRONMENT 2011; 34:1548-62. [PMID: 21707646 DOI: 10.1111/j.1365-3040.2011.02352.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Carbon and oxygen isotope discrimination of CO(2) during photosynthesis (Δ(13)C(obs) and Δ(18)O(obs)) were measured along a monocot leaf, triticale (Triticum × Secale). Both Δ(13)C(obs) and Δ(18)O(obs) increased towards the leaf tip. While this was expected for Δ(18)O(obs) , because of progressive enrichment of leaf water associated with the Péclet effect, the result was surprising for Δ(13) C(obs). To explore parameters determining this pattern, we measured activities of key photosynthetic enzymes [ribulose bis-phosphate carboxylase-oxygenase (Rubisco), phosphoenolpyruvate carboxylase (PEPC) and carbonic anhydrase) as well as maximum carboxylation and electron transport rates (V(cmax) and J(max)) along the leaf. Patterns in leaf internal anatomy along the leaf were also quantified. Mesophyll conductance (g(m)) is known to have a strong influence on Δ(13)C(obs) , so we used three commonly used estimation methods to quantify variation in g(m) along the leaf. Variation in Δ(13)C(obs) was correlated with g(m) and chloroplast surface area facing the intercellular air space, but unrelated to photosynthetic enzyme activity. The observed variation could cause errors at higher scales if the appropriate portion of a leaf is not chosen for leaf-level measurements and model parameterization. Our study shows that one-third of the way from the base of the leaf represents the most appropriate portion to enclose in the leaf chamber.
Collapse
Affiliation(s)
- Naomi Kodama
- Agro-meteorology Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba, Ibaraki 305-8604, Japan.
| | | | | | | |
Collapse
|
25
|
Tcherkez G, Mahé A, Hodges M. (12)C/(13)C fractionations in plant primary metabolism. TRENDS IN PLANT SCIENCE 2011; 16:499-506. [PMID: 21705262 DOI: 10.1016/j.tplants.2011.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 05/18/2011] [Accepted: 05/25/2011] [Indexed: 05/13/2023]
Abstract
Natural (13)C abundance is now an unavoidable tool to study ecosystem and plant carbon economies. A growing number of studies take advantage of isotopic fractionation between carbon pools or (13)C abundance in respiratory CO(2) to examine the carbon source of respiration, plant biomass production or organic matter sequestration in soils. (12)C/(13)C isotope effects associated with plant metabolism are thus essential to understand natural isotopic signals. However, isotope effects of enzymes do not influence metabolites separately, but combine to yield a (12)C/(13)C isotopologue redistribution orchestrated by metabolic flux patterns. In this review, we summarise key metabolic isotope effects and integrate them into the corpus of plant primary carbon metabolism.
Collapse
Affiliation(s)
- Guillaume Tcherkez
- Institut de Biologie des Plantes, CNRS UMR 8618, Université Paris-Sud 11, 91405 Orsay cedex, France
| | | | | |
Collapse
|