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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.
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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
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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.
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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
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Arslan AM, Wang X, Liu BY, Xu YN, Li L, Gong XY. Photosynthetic resource-use efficiency trade-offs triggered by vapour pressure deficit and nitrogen supply in a C 4 species. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 197:107666. [PMID: 37001304 DOI: 10.1016/j.plaphy.2023.107666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 02/19/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
Trade-offs in resource-use efficiency (including water-, nitrogen-, and light-use efficiency, i.e., WUE, NUE, and LUE) are an important acclimation strategy of plants to environmental stresses. C4 photosynthesis, featured by a CO2 concentrating mechanism, is believed to be more efficient in using resources compared to C3 photosynthesis. However, response of photosynthetic resource-use efficiency trade-offs in C4 plants to vapour pressure deficit (VPD) and N supply has rarely been studied. Here, we studied the photosynthetic acclimation of Cleistogenes squarrosa, a perennial C4 grass, to controlled growth conditions with high or low VPD and N supply. High VPD increased WUE by 12% and decreased NUE by 16%, the ratio of net photosynthetic rate (A) to electron transport rate (J) (A/J) by 7% and the apparent quantum yield by 6%. High N supply tended to reduce NUE and increased maximum phosphoenol pyruvate carboxylation rate by 71% and slightly increased WUE. Stomatal conductance showed acclimation to VPD according to the Ball-Berry model, while a balanced cost of carboxylation and transpiration capacity was found across VPD and N treatments based on the least-cost model. WUE correlated negatively with NUE and LUE indicating that there was a trade-off between them, which is likely associated with acclimations in stomatal conductance and CO2 concentrating mechanisms.
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Affiliation(s)
- Ashraf Muhammad Arslan
- 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
| | - Xuming 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; Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou, 350007, China; Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, 350007, China.
| | - Bo Ya Liu
- 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
| | - Yi Ning Xu
- 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
| | - Lei Li
- 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; Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, Fujian Normal University, Fuzhou, 350007, China; Fujian Provincial Key Laboratory for Plant Eco-physiology, Fuzhou, 350007, China.
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Responses of Carbon Isotope Composition of Common C3 and C4 Plants to Climatic Factors in Temperate Grasslands. SUSTAINABILITY 2022. [DOI: 10.3390/su14127311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Investigating relationships between climatic factors and plant δ13C of both C3 and C4 plants simultaneously is critical for accurately predicting the effects of climate change on plant ecophysiology and ecosystem functioning and reconstructing past vegetation and climate conditions. We selected common C3 and C4 plants in temperate grasslands in Inner Mongolia, China, i.e., Stipa spp., Carex spp., Leymus chinensis and Cleistogenes spp., and investigated the relationships between climatic factors and plant δ13C of each genus/species. The results showed that precipitation, especially growing season precipitation (GSP), was the dominant factor affecting plant δ13C in this region. For C3 plants, there were significantly negative relationships between precipitation and plant δ13C. For C4 plants, plant δ13C of Cleistogenes spp. firstly increased, then decreased with precipitation at a breakpoint GSP 204.84 mm. Our findings emphasize that C4 plant δ13C is sensitive to precipitation, but responses are species-specific and environment-specific, and suggest that C4 plant δ13C can be used as a proxy for water use efficiency (WUE), but care should be taken in evaluating WUE. Moreover, our findings provide basic information for accurately predicting the effects of climate change on ecosystem structure and function and reconstructing past vegetation and climate conditions from bulk materials in arid and semiarid regions.
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Eggels S, Blankenagel S, Schön CC, Avramova V. The carbon isotopic signature of C 4 crops and its applicability in breeding for climate resilience. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2021; 134:1663-1675. [PMID: 33575820 PMCID: PMC8205923 DOI: 10.1007/s00122-020-03761-3] [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: 09/05/2020] [Accepted: 12/30/2020] [Indexed: 05/04/2023]
Abstract
KEY MESSAGE Carbon isotope discrimination is a promising trait for indirect screening for improved water use efficiency of C4 crops. In the context of a changing climate, drought is one of the major factors limiting plant growth and yield. Hence, breeding efforts are directed toward improving water use efficiency (WUE) as a key factor in climate resilience and sustainability of crop production. As WUE is a complex trait and its evaluation is rather resource consuming, proxy traits, which are easier to screen and reliably reflect variation in WUE, are needed. In C3 crops, a trait established to be indicative for WUE is the carbon isotopic composition (δ13C) of plant material, which reflects the preferential assimilation of the lighter carbon isotope 12C over 13C during photosynthesis. In C4 crops, carbon fixation is more complex and δ13C thus depends on many more factors than in C3 crops. Recent physiological and genetic studies indicate a correlation between δ13C and WUE also in C4 crops, as well as a colocalization of quantitative trait loci for the two traits. Moreover, significant intraspecific variation as well as a medium to high heritability of δ13C has been shown in some of the main C4 crops, such as maize, sorghum and sugarcane, indicating its potential for indirect selection and breeding. Further research on physiological, genetic and environmental components influencing δ13C is needed to support its application in improving WUE and making C4 crops resilient to climate change.
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Affiliation(s)
- Stella Eggels
- Plant Breeding, TUM School of Life Sciences, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Sonja Blankenagel
- Plant Breeding, TUM School of Life Sciences, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Chris-Carolin Schön
- Plant Breeding, TUM School of Life Sciences, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany
| | - Viktoriya Avramova
- Plant Breeding, TUM School of Life Sciences, Technical University of Munich, Liesel-Beckmann-Straße 2, 85354, Freising, Germany.
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6
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Sonawane BV, Cousins AB. Mesophyll CO 2 conductance and leakiness are not responsive to short- and long-term soil water limitations in the C 4 plant Sorghum bicolor. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1590-1602. [PMID: 32438487 DOI: 10.1111/tpj.14849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 05/13/2023]
Abstract
Breeding economically important C4 crops for enhanced whole-plant water-use efficiency (WUEplant ) is needed for sustainable agriculture. WUEplant is a complex trait and an efficient phenotyping method that reports on components of WUEplant , such as intrinsic water-use efficiency (WUEi , the rate of leaf CO2 assimilation relative to water loss via stomatal conductance), is needed. In C4 plants, theoretical models suggest that leaf carbon isotope composition (δ13 C), when the efficiency of the CO2 -concentrating mechanism (leakiness, ϕ) remains constant, can be used to screen for WUEi . The limited information about how ϕ responds to water limitations confines the application of δ13 C for WUEi screening of C4 crops. The current research aimed to test the response of ϕ to short- or long-term moderate water limitations, and the relationship of δ13 C with WUEi and WUEplant , by addressing potential mesophyll CO2 conductance (gm ) and biochemical limitations in the C4 plant Sorghum bicolor. We demonstrate that gm and ϕ are not responsive to short- or long-term water limitations. Additionally, δ13 C was not correlated with gas-exchange estimates of WUEi under short- and long-term water limitations, but showed a significant negative relationship with WUEplant . The observed association between the δ13 C and WUEplant suggests an intrinsic link of δ13 C with WUEi in this C4 plant, and can potentially be used as a screening tool for WUEplant in sorghum.
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Affiliation(s)
- Balasaheb V Sonawane
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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7
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Retta MA, Abera MK, Berghuijs HN, Verboven P, Struik PC, Nicolaï BM. In silico study of the role of cell growth factors in photosynthesis using a virtual leaf tissue generator coupled to a microscale photosynthesis gas exchange model. JOURNAL OF EXPERIMENTAL BOTANY 2020. [PMID: 31616944 DOI: 10.5061/dryad.46h5nc0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Computational tools that allow in silico analysis of the role of cell growth and division on photosynthesis are scarce. We present a freely available tool that combines a virtual leaf tissue generator and a two-dimensional microscale model of gas transport during C3 photosynthesis. A total of 270 mesophyll geometries were generated with varying degrees of growth anisotropy, growth extent, and extent of schizogenous airspace formation in the palisade mesophyll. The anatomical properties of the virtual leaf tissue and microscopic cross-sections of actual leaf tissue of tomato (Solanum lycopersicum L.) were statistically compared. Model equations for transport of CO2 in the liquid phase of the leaf tissue were discretized over the geometries. The virtual leaf tissue generator produced a leaf anatomy of tomato that was statistically similar to real tomato leaf tissue. The response of photosynthesis to intercellular CO2 predicted by a model that used the virtual leaf tissue geometry compared well with measured values. The results indicate that the light-saturated rate of photosynthesis was influenced by interactive effects of extent and directionality of cell growth and degree of airspace formation through the exposed surface of mesophyll per leaf area. The tool could be used further in investigations of improving photosynthesis and gas exchange in relation to cell growth and leaf anatomy.
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Affiliation(s)
- Moges A Retta
- Division BIOSYST-MeBioS, KU Leuven-University of Leuven, Willem de Croylaan 42, B-3001 Leuven, Belgium
| | - Metadel K Abera
- Division BIOSYST-MeBioS, KU Leuven-University of Leuven, Willem de Croylaan 42, B-3001 Leuven, Belgium
| | - Herman Nc Berghuijs
- Centre for Crop Systems Analysis, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- BioSolar Cells, 6700 AB Wageningen, The Netherlands
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Ulls väg 16, 75651 Uppsala, Sweden
| | - Pieter Verboven
- Division BIOSYST-MeBioS, KU Leuven-University of Leuven, Willem de Croylaan 42, B-3001 Leuven, Belgium
| | - Paul C Struik
- Centre for Crop Systems Analysis, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- BioSolar Cells, 6700 AB Wageningen, The Netherlands
| | - Bart M Nicolaï
- Division BIOSYST-MeBioS, KU Leuven-University of Leuven, Willem de Croylaan 42, B-3001 Leuven, Belgium
- Flanders Centre of Postharvest Technology, Willem de Croylaan 42, B-3001 Leuven, Belgium
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8
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Retta MA, Abera MK, Berghuijs HN, Verboven P, Struik PC, Nicolaï BM. In silico study of the role of cell growth factors in photosynthesis using a virtual leaf tissue generator coupled to a microscale photosynthesis gas exchange model. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:997-1009. [PMID: 31616944 PMCID: PMC6977192 DOI: 10.1093/jxb/erz451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/30/2019] [Indexed: 06/10/2023]
Abstract
Computational tools that allow in silico analysis of the role of cell growth and division on photosynthesis are scarce. We present a freely available tool that combines a virtual leaf tissue generator and a two-dimensional microscale model of gas transport during C3 photosynthesis. A total of 270 mesophyll geometries were generated with varying degrees of growth anisotropy, growth extent, and extent of schizogenous airspace formation in the palisade mesophyll. The anatomical properties of the virtual leaf tissue and microscopic cross-sections of actual leaf tissue of tomato (Solanum lycopersicum L.) were statistically compared. Model equations for transport of CO2 in the liquid phase of the leaf tissue were discretized over the geometries. The virtual leaf tissue generator produced a leaf anatomy of tomato that was statistically similar to real tomato leaf tissue. The response of photosynthesis to intercellular CO2 predicted by a model that used the virtual leaf tissue geometry compared well with measured values. The results indicate that the light-saturated rate of photosynthesis was influenced by interactive effects of extent and directionality of cell growth and degree of airspace formation through the exposed surface of mesophyll per leaf area. The tool could be used further in investigations of improving photosynthesis and gas exchange in relation to cell growth and leaf anatomy.
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Affiliation(s)
- Moges A Retta
- Division BIOSYST-MeBioS, KU Leuven-University of Leuven, Willem de Croylaan 42, B-3001 Leuven, Belgium
| | - Metadel K Abera
- Division BIOSYST-MeBioS, KU Leuven-University of Leuven, Willem de Croylaan 42, B-3001 Leuven, Belgium
| | - Herman Nc Berghuijs
- Centre for Crop Systems Analysis, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- BioSolar Cells, 6700 AB Wageningen, The Netherlands
- Department of Crop Production Ecology, Swedish University of Agricultural Sciences, Ulls väg 16, 75651 Uppsala, Sweden
| | - Pieter Verboven
- Division BIOSYST-MeBioS, KU Leuven-University of Leuven, Willem de Croylaan 42, B-3001 Leuven, Belgium
| | - Paul C Struik
- Centre for Crop Systems Analysis, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- BioSolar Cells, 6700 AB Wageningen, The Netherlands
| | - Bart M Nicolaï
- Division BIOSYST-MeBioS, KU Leuven-University of Leuven, Willem de Croylaan 42, B-3001 Leuven, Belgium
- Flanders Centre of Postharvest Technology, Willem de Croylaan 42, B-3001 Leuven, Belgium
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Yang F, Schäufele R, Liu HT, Ostler U, Schnyder H, Gong XY. Gross and net nitrogen export from leaves of a vegetative C 4 grass. JOURNAL OF PLANT PHYSIOLOGY 2020; 244:153093. [PMID: 31841951 DOI: 10.1016/j.jplph.2019.153093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/31/2019] [Accepted: 11/29/2019] [Indexed: 06/10/2023]
Abstract
Nitrogen (N) mobilization from mature leaves plays a key role in supplying amino acids to vegetative and reproductive sinks. However, it is unknown if the mobilized N is predominantly sourced by net N-export (a senescence-related process) or other source of N-export from leaves. We used a new approach to partition gross and net N-export from leaf blades at different developmental stages in Cleistogenes squarrosa (a perennial C4 grass). Net N-export was determined as net loss of leaf N with age, while gross N-export was quantified from isotopic mass balances obtained following 24 h-long 15N-labeling with nitrate on 10-12 developmentally distinct (mature and senescing) leaves of individual major tillers. Net N-export was apparent only in older leaves (leaf no. > 7, with leaves numbered basipetally from the tip of the tiller and leaf no. 2 the youngest fully-expanded leaf), while gross N-export was largely independent of leaf age category and was ∼8.4 times greater than the net N-export of a tiller. At whole-tiller level, N import compensated 88 ± 14 (SE) % of gross N-export of all mature blades leading to a net N-export of 0.51 ± 0.07 (SE) μg h-1 tiller-1. N-import was equivalent to 0.09 ± 0.01 (SE) d-1 of total leaf N, similar to reported rates of leaf protein turnover. Gross N-export from all mature blades of a tiller was ∼1.9-times the total demand of the immature tissues of the same (vegetative) tiller. Significant N-export is evident in all mature blades, and is not limited to senescence conditions, implying a much shorter mean residence time of leaf N than that calculated from net N-export. Gross N-export contributes not only to the N demand of the immature tissues of the same tiller but also to N supply of other sinks, such as newly formed tillers. N dynamics at tiller level is integrated with that of the remainder of the shoot, thus highlights the importance of integration of leaf-, tiller-, and plant-scale N dynamics.
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Affiliation(s)
- Fang Yang
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Rudi Schäufele
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Hai Tao Liu
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Ulrike Ostler
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Hans Schnyder
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Xiao Ying Gong
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany.
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10
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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 .
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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
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11
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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.
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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
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Sonawane BV, Sharwood RE, von Caemmerer S, Whitney SM, Ghannoum O. Short-term thermal photosynthetic responses of C4 grasses are independent of the biochemical subtype. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:5583-5597. [PMID: 29045727 PMCID: PMC5853683 DOI: 10.1093/jxb/erx350] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/14/2017] [Indexed: 05/20/2023]
Abstract
C4 photosynthesis evolved independently many times, resulting in multiple biochemical pathways; however, little is known about how these different pathways respond to temperature. We investigated the photosynthetic responses of eight C4 grasses belonging to three biochemical subtypes (NADP-ME, PEP-CK, and NAD-ME) to four leaf temperatures (18, 25, 32, and 40 °C). We also explored whether the biochemical subtype influences the thermal responses of (i) in vitro PEPC (Vpmax) and Rubisco (Vcmax) maximal activities, (ii) initial slope (IS) and CO2-saturated rate (CSR) derived from the A-Ci curves, and (iii) CO2 leakage out of the bundle sheath estimated from carbon isotope discrimination. We focussed on leakiness and the two carboxylases because they determine the coordination of the CO2-concentrating mechanism and are important for parameterizing the semi-mechanistic C4 photosynthesis model. We found that the thermal responses of Vpmax and Vcmax, IS, CSR, and leakiness varied among the C4 species independently of the biochemical subtype. No correlation was observed between Vpmax and IS or between Vcmax and CSR; while the ratios Vpmax/Vcmax and IS/CSR did not correlate with leakiness among the C4 grasses. Determining mesophyll and bundle sheath conductances in diverse C4 grasses is required to further elucidate how C4 photosynthesis responds to temperature.
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Affiliation(s)
- Balasaheb V Sonawane
- ARC Centre of Excellence for Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, Richmond NSW, Australia
| | - Robert E Sharwood
- ARC Centre of Excellence for Translational Photosynthesis and Research School of Biology, Australian National University, Canberra ACT, Australia
| | - Susanne von Caemmerer
- ARC Centre of Excellence for Translational Photosynthesis and Research School of Biology, Australian National University, Canberra ACT, Australia
| | - Spencer M Whitney
- ARC Centre of Excellence for Translational Photosynthesis and Research School of Biology, Australian National University, Canberra ACT, Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, Richmond NSW, Australia
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Wu F, Ma J, Meng Y, Zhang D, Pascal Muvunyi B, Luo K, Di H, Guo W, Wang Y, Feng B, Zhang J. Potential DNA barcodes for Melilotus species based on five single loci and their combinations. PLoS One 2017; 12:e0182693. [PMID: 28910286 PMCID: PMC5598934 DOI: 10.1371/journal.pone.0182693] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Accepted: 07/21/2017] [Indexed: 01/13/2023] Open
Abstract
Melilotus, an annual or biennial herb, belongs to the tribe Trifolieae (Leguminosae) and consists of 19 species. As an important green manure crop, diverse Melilotus species have different values as feed and medicine. To identify different Melilotus species, we examined the efficiency of five candidate regions as barcodes, including the internal transcribed spacer (ITS) and two chloroplast loci, rbcL and matK, and two non-coding loci, trnH-psbA and trnL-F. In total, 198 individuals from 98 accessions representing 18 Melilotus species were sequenced for these five potential barcodes. Based on inter-specific divergence, we analysed sequences and confirmed that each candidate barcode was able to identify some of the 18 species. The resolution of a single barcode and its combinations ranged from 33.33% to 88.89%. Analysis of pairwise distances showed that matK+rbcL+trnL-F+trnH-psbA+ITS (MRTPI) had the greatest value and rbcL the least. Barcode gap values and similarity value analyses confirmed these trends. The results indicated that an ITS region, successfully identifying 13 of 18 species, was the most appropriate single barcode and that the combination of all five potential barcodes identified 16 of the 18 species. We conclude that MRTPI is the most effective tool for Melilotus species identification. Taking full advantage of the barcode system, a clear taxonomic relationship can be applied to identify Melilotus species and enhance their practical production.
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Affiliation(s)
- Fan Wu
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Jinxing Ma
- National Quality Control & Inspection Centre for Grassland Industry Products, National Animal Husbandry Service, Ministry of Agriculture, Beijing, China
| | - Yuqin Meng
- China Agricultural Veterinarian Biology Science and Technology Co. Ltd, Lanzhou, China
| | - Daiyu Zhang
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Blaise Pascal Muvunyi
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Kai Luo
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Hongyan Di
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Wenli Guo
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Yanrong Wang
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
| | - Baochang Feng
- National Quality Control & Inspection Centre for Grassland Industry Products, National Animal Husbandry Service, Ministry of Agriculture, Beijing, China
- * E-mail: (BCF); (JYZ)
| | - Jiyu Zhang
- State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China
- * E-mail: (BCF); (JYZ)
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Yang H, Yu Q, Sheng WP, Li SG, Tian J. Determination of leaf carbon isotope discrimination in C4 plants under variable N and water supply. Sci Rep 2017; 7:351. [PMID: 28336951 PMCID: PMC5428480 DOI: 10.1038/s41598-017-00498-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 03/02/2017] [Indexed: 11/09/2022] Open
Abstract
Understanding the mechanisms underlying variations in carbon isotope discrimination (Δ) in C4 plants is critical for predicting the C3/C4 ratio in C3/C4 mixed grassland. The value of Δ is determined by bundle sheath leakiness (Ф) and the ratio of intercellular to ambient CO2 concentration (C i /C a ). Leaf nitrogen concentration (N leaf ) is considered a driver of Δ in C4 plants. However, little is known about how N leaf affects Ф and C i /C a , and subsequently Δ. Here leaf carbon isotope composition, N leaf , Ф, and leaf gas exchange were measured in Cleistogenes squarrosa, a dominant C4 species in the Inner Mongolia grassland. Δ remained relatively stable under variable N and water supply. Higher N supply and lower water supply increased N leaf , stimulated photosynthesis and further decreased C i /C a . High N supply increased Ф, which responded weakly to water supply. N leaf exerted similar effects on C i /C a and on Ф in the field and pot experiments. Pooling all the data, N leaf explained 73% of the variation in C i /C a . Overall, both Ф and C i /C a determined Δ; however, the contribution of Ф was stronger. N leaf influenced Δ primarily though C i /C a , rather than Ф. Ф should be considered in estimating Δ of C4 endmember.
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Affiliation(s)
- Hao Yang
- Key Laboratory of Ecosystem Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Qiang Yu
- National Hulunber Grassland Ecosystem Observation and Research Station, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
| | - Wen-Ping Sheng
- Key Laboratory of Ecosystem Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Sheng-Gong Li
- Key Laboratory of Ecosystem Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jing Tian
- Key Laboratory of Ecosystem Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China
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Gong XY, Schäufele R, Lehmeier CA, Tcherkez G, Schnyder H. Atmospheric CO 2 mole fraction affects stand-scale carbon use efficiency of sunflower by stimulating respiration in light. PLANT, CELL & ENVIRONMENT 2017; 40:401-412. [PMID: 28024100 DOI: 10.1111/pce.12886] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 12/02/2016] [Accepted: 12/11/2016] [Indexed: 05/26/2023]
Abstract
Plant carbon-use-efficiency (CUE), a key parameter in carbon cycle and plant growth models, quantifies the fraction of fixed carbon that is converted into net primary production rather than respired. CUE has not been directly measured, partly because of the difficulty of measuring respiration in light. Here, we explore if CUE is affected by atmospheric CO2 . Sunflower stands were grown at low (200 μmol mol-1 ) or high CO2 (1000 μmol mol-1 ) in controlled environment mesocosms. CUE of stands was measured by dynamic stand-scale 13 C labelling and partitioning of photosynthesis and respiration. At the same plant age, growth at high CO2 (compared with low CO2 ) led to 91% higher rates of apparent photosynthesis, 97% higher respiration in the dark, yet 143% higher respiration in light. Thus, CUE was significantly lower at high (0.65) than at low CO2 (0.71). Compartmental analysis of isotopic tracer kinetics demonstrated a greater commitment of carbon reserves in stand-scale respiratory metabolism at high CO2 . Two main processes contributed to the reduction of CUE at high CO2 : a reduced inhibition of leaf respiration by light and a diminished leaf mass ratio. This work highlights the relevance of measuring respiration in light and assessment of the CUE response to environment conditions.
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Affiliation(s)
- Xiao Ying Gong
- 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
| | | | - Guillaume Tcherkez
- Research School of Biology, ANU College of Medicine, Biology and Environment, Australian National University, Canberra, Australian Capital Territory, 0200, Australia
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354, Freising, Germany
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Yang F, Gong XY, Liu HT, Schäufele R, Schnyder H. Effects of nitrogen and vapour pressure deficit on phytomer growth and development in a C4 grass. AOB PLANTS 2017; 8:plw075. [PMID: 27810947 PMCID: PMC5206350 DOI: 10.1093/aobpla/plw075] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 10/19/2016] [Indexed: 05/12/2023]
Abstract
Phytomers are basic morphological units of plants. Knowledge of phytomer development is essential for understanding morphological plasticity, functional-structural modelling of plant growth and the usage of leaf characteristics to indicate growth conditions at the time of production (e.g. stable isotope signals). Yet, systematic analysis on the process of phytomer development is unavailable for wild or perennial C4 grasses. Also, effects of environmental factors, such as nitrogen nutrition or vapour pressure deficit (VPD), on coordination events of developmental processes of C4 grasses have not been studied. This study investigates phytomer growth and development in Cleistogenes squarrosa, a predominant C4 grass in the Eurasian steppe, grown at low (0.63 kPa) or high (1.58 kPa) VPD with low or high nitrogen supply in controlled environments. Elongation of phytomers on marked tillers was measured daily for 13 days. Then lengths of immature and mature phytomer components (blade, sheath and internode) of all phytomers were measured following dissection. Nitrogen nutrition and VPD had no effects on coordination of growth within and between phytomers: phytomer tips emerged when phytomers reached 26 % of their final length, coincident with the acceleration phase of its elongation; blade elongation stopped when phytomers reached ∼75 % of their final length and elongation of the preceding phytomer was confined to the internode. The relationship between fraction of final phytomer length and days after tip emergence for all treatments was well described by a sigmoidal function: y = 1/{1 + exp[(1.82 - x)/1.81]}. C. squarrosa exhibited little morphological plasticity at phytomer-level in response to nitrogen supply and VPD, but a clear increase in tillering under high N supply. Also, the invariant coordination of elongation within and between phytomers was a stable developmental feature, thus the quantitative coordination rules are applicable for predicting morphological development of C. squarrosa under contrasting levels of nitrogen nutrition or VPD.
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Affiliation(s)
- Fang Yang
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Xiao Ying Gong
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Hai Tao Liu
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
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von Caemmerer S, Ghannoum O, Furbank RT. C4 photosynthesis: 50 years of discovery and innovation. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:97-102. [PMID: 28110274 PMCID: PMC5444450 DOI: 10.1093/jxb/erw491] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
It is now over half a century since the biochemical characterization of the C4 photosynthetic pathway, and this special issue highlights the sheer breadth of current knowledge. New genomic and transcriptomic information shows that multi-level regulation of gene expression is required for the pathway to function, yet we know it to be one of the most dynamic examples of convergent evolution. Now, a focus on the molecular transition from C3-C4 intermediates, together with improved mathematical models, experimental tools and transformation systems, holds great promise for improving C4 photosynthesis in crops.
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Affiliation(s)
- Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, Richmond NSW 2753, Australia
| | - Robert T Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
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