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von Caemmerer S. Updating the steady-state model of C4 photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6003-6017. [PMID: 34173821 PMCID: PMC8411607 DOI: 10.1093/jxb/erab266] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 06/06/2021] [Indexed: 05/22/2023]
Abstract
C4 plants play a key role in world agriculture. For example, C4 crops such as maize and sorghum are major contributors to food production in both developed and developing countries, and the C4 grasses sugarcane, miscanthus, and switchgrass are major plant sources of bioenergy. In the challenge to manipulate and enhance C4 photosynthesis, steady-state models of leaf photosynthesis provide an important tool for gas exchange analysis and thought experiments that can explore photosynthetic pathway changes. Here a previous C4 photosynthetic model developed by von Caemmerer and Furbank has been updated with new kinetic parameterization and temperature dependencies added. The parameterization was derived from experiments on the C4 monocot, Setaria viridis, which for the first time provides a cohesive parameterization. Mesophyll conductance and its temperature dependence have also been included, as this is an important step in the quantitative correlation between the initial slope of the CO2 response curve of CO2 assimilation and in vitro phosphoenolpyruvate carboxylase activity. Furthermore, the equations for chloroplast electron transport have been updated to include cyclic electron transport flow, and equations have been added to calculate the electron transport rate from measured CO2 assimilation rates.
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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
- Correspondence:
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2
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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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Pignon CP, Long SP. Retrospective analysis of biochemical limitations to photosynthesis in 49 species: C 4 crops appear still adapted to pre-industrial atmospheric [CO 2 ]. PLANT, CELL & ENVIRONMENT 2020; 43:2606-2622. [PMID: 32743797 DOI: 10.1111/pce.13863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 06/23/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
Leaf CO2 uptake (A) in C4 photosynthesis is limited by the maximum apparent rate of PEPc carboxylation (Vpmax ) at low intercellular [CO2 ] (ci ) with a sharp transition to a ci -saturated rate (Vmax ) due to co-limitation by ribulose-1:5-bisphosphate carboxylase/oxygenase (Rubisco) and regeneration of PEP. The response of A to ci has been widely used to determine these two parameters. Vmax and Vpmax depend on different enzymes but draw on a shared pool of leaf resources, such that resource distribution is optimized, and A maximized, when Vmax and Vpmax are co-limiting. We collected published A/ci curves in 49 C4 species and assessed variation in photosynthetic traits between phylogenetic groups, and as a function of atmospheric [CO2 ]. The balance of Vmax -Vpmax varied among evolutionary lineages and C4 subtypes. Operating A was strongly Vmax -limited, such that re-allocation of resources from Vpmax towards Vmax was predicted to improve A by 12% in C4 crops. This would not require additional inputs but rather altered partitioning of existing leaf nutrients, resulting in increased water and nutrient-use efficiency. Optimal partitioning was achieved only in plants grown at pre-industrial atmospheric [CO2 ], suggesting C4 crops have not adjusted to the rapid increase in atmospheric [CO2 ] of the past few decades.
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Affiliation(s)
- Charles P Pignon
- Carl Woese Institute for Genomic Biology and Departments of Crop Sciences and Plant Biology, University of Illinois, Urbana, Illinois, USA
| | - Stephen P Long
- Carl Woese Institute for Genomic Biology and Departments of Crop Sciences and Plant Biology, University of Illinois, Urbana, Illinois, USA
- Lancaster Environment Centre, University of Lancaster, UK
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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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Ellsworth PZ, Feldman MJ, Baxter I, Cousins AB. A genetic link between leaf carbon isotope composition and whole-plant water use efficiency in the C 4 grass Setaria. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:1234-1248. [PMID: 31968138 DOI: 10.1111/tpj.14696] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 12/18/2019] [Accepted: 01/02/2020] [Indexed: 05/13/2023]
Abstract
Genetic selection for whole-plant water use efficiency (yield per transpiration; WUEplant ) in any crop-breeding programme requires high-throughput phenotyping of component traits of WUEplant such as intrinsic water use efficiency (WUEi ; CO2 assimilation rate per stomatal conductance). Measuring WUEi by gas exchange measurements is laborious and time consuming and may not reflect an integrated WUEi over the life of the leaf. Alternatively, leaf carbon stable isotope composition (δ13 Cleaf ) has been suggested as a potential time-integrated proxy for WUEi that may provide a tool to screen for WUEplant . However, a genetic link between δ13 Cleaf and WUEplant in a C4 species has not been well established. Therefore, to determine if there is a genetic relationship in a C4 plant between δ13 Cleaf and WUEplant under well watered and water-limited growth conditions, a high-throughput phenotyping facility was used to measure WUEplant in a recombinant inbred line (RIL) population created between the C4 grasses Setaria viridis and S. italica. Three quantitative trait loci (QTL) for δ13 Cleaf were found and co-localized with transpiration, biomass accumulation, and WUEplant . Additionally, WUEplant for each of the δ13 Cleaf QTL allele classes was negatively correlated with δ13 Cleaf , as would be predicted when WUEi influences WUEplant . These results demonstrate that δ13 Cleaf is genetically linked to WUEplant , likely to be through their relationship with WUEi , and can be used as a high-throughput proxy to screen for WUEplant in these C4 species.
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Affiliation(s)
- Patrick Z Ellsworth
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Max J Feldman
- Donald Danforth Plant Sciences Center, St. Louis, MO, USA
| | - Ivan Baxter
- Donald Danforth Plant Sciences Center, St. Louis, MO, USA
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA, USA
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Gao J, Liu Z, Zhao B, Liu P, Zhang JW. Physiological and comparative proteomic analysis provides new insights into the effects of shade stress in maize (Zea mays L.). BMC PLANT BIOLOGY 2020; 20:60. [PMID: 32024458 PMCID: PMC7003340 DOI: 10.1186/s12870-020-2264-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/23/2020] [Indexed: 05/08/2023]
Abstract
BACKGROUND Shade stress, a universal abiotic stress, suppresses plant growth and production seriously. However, little is known regarding the protein regulatory networks under shade stress. To better characterize the proteomic changes of maize leaves under shade stress, 60% shade (S) and supplementary lighting (L) on cloudy daylight from tasseling stage to physiological maturity stage were designed, the ambient sunlight treatment was used as control (CK). Isobaric tag for relative and absolute quantification (iTRAQ) technology was used to determine the proteome profiles in leaves. RESULTS Shading significantly decreased the SPAD value, net photosynthetic rate, and grain yield. During two experimental years, grain yields of S were reduced by 48 and 47%, and L increased by 6 and 11%, compared to CK. In total, 3958 proteins were identified by iTRAQ, and 2745 proteins were quantified including 349 proteins showed at least 1.2-fold changes in expression levels between treatments and CK. The differentially expressed proteins were classified into photosynthesis, stress defense, energy production, signal transduction, and protein and amino acid metabolism using the Web Gene Ontology Annotation Plot online tool. In addition, these proteins showed significant enrichment of the chloroplasts (58%) and cytosol (21%) for subcellular localization. CONCLUSIONS 60% shade induced the expression of proteins involved in photosynthetic electron transport chain (especially light-harvesting complex) and stress/defense/detoxification. However, the proteins related to calvin cycle, starch and sucrose metabolisms, glycolysis, TCA cycle, and ribosome and protein synthesis were dramatically depressed. Together, our results might help to provide a valuable resource for protein function analysis and also clarify the proteomic and physiological mechanism of maize underlying shade stress.
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Affiliation(s)
- Jia Gao
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, Shandong 271018 People’s Republic of China
| | - Zheng Liu
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, Shandong 271018 People’s Republic of China
| | - Bin Zhao
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, Shandong 271018 People’s Republic of China
| | - Peng Liu
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, Shandong 271018 People’s Republic of China
| | - Ji-Wang Zhang
- State Key Laboratory of Crop Biology and College of Agronomy, Shandong Agricultural University, Taian, Shandong 271018 People’s Republic of China
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Sonawane BV, Sharwood RE, Whitney S, Ghannoum O. Shade compromises the photosynthetic efficiency of NADP-ME less than that of PEP-CK and NAD-ME C4 grasses. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3053-3068. [PMID: 29659931 PMCID: PMC5972597 DOI: 10.1093/jxb/ery129] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 03/19/2018] [Indexed: 05/18/2023]
Abstract
The high energy cost and apparently low plasticity of C4 photosynthesis compared with C3 photosynthesis may limit the productivity and distribution of C4 plants in low light (LL) environments. C4 photosynthesis evolved numerous times, but it remains unclear how different biochemical subtypes perform under LL. We grew eight C4 grasses belonging to three biochemical subtypes [NADP-malic enzyme (NADP-ME), NAD-malic enzyme (NAD-ME), and phosphoenolpyruvate carboxykinase (PEP-CK)] under shade (16% sunlight) or control (full sunlight) conditions and measured their photosynthetic characteristics at both low and high light. We show for the first time that LL (during measurement or growth) compromised the CO2-concentrating mechanism (CCM) to a greater extent in NAD-ME than in PEP-CK or NADP-ME C4 grasses by virtue of a greater increase in carbon isotope discrimination (∆P) and bundle sheath CO2 leakiness (ϕ), and a greater reduction in photosynthetic quantum yield (Φmax). These responses were partly explained by changes in the ratios of phosphoenolpyruvate carboxylase (PEPC)/initial Rubisco activity and dark respiration/photosynthesis (Rd/A). Shade induced a greater photosynthetic acclimation in NAD-ME than in NADP-ME and PEP-CK species due to a greater Rubisco deactivation. Shade also reduced plant dry mass to a greater extent in NAD-ME and PEP-CK relative to NADP-ME grasses. In conclusion, LL compromised the co-ordination of the C4 and C3 cycles and, hence, the efficiency of the CCM to a greater extent in NAD-ME than in PEP-CK species, while CCM efficiency was less impacted by LL in NADP-ME species. Consequently, NADP-ME species are more efficient at LL, which could explain their agronomic and ecological dominance relative to other C4 grasses.
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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, NSW, Australia
- School of Biological Sciences, Washington State University, Pullman, WA, USA
- Correspondence:
| | - Robert E Sharwood
- ARC Centre of Excellence for Translational Photosynthesis and Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Spencer 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, NSW, Australia
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Zhong S, Chai H, Xu Y, Li Y, Ma JY, Sun W. Drought Sensitivity of the Carbon Isotope Composition of Leaf Dark-Respired CO 2 in C 3 ( Leymus chinensis) and C 4 ( Chloris virgata and Hemarthria altissima) Grasses in Northeast China. FRONTIERS IN PLANT SCIENCE 2017; 8:1996. [PMID: 29375587 PMCID: PMC5770615 DOI: 10.3389/fpls.2017.01996] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 11/07/2017] [Indexed: 05/13/2023]
Abstract
Whether photosynthetic pathway differences exist in the amplitude of nighttime variations in the carbon isotope composition of leaf dark-respired CO2 (δ13Cl) and respiratory apparent isotope fractionation relative to biomass (ΔR,biomass) in response to drought stress is unclear. These differences, if present, would be important for the partitioning of C3-C4 mixed ecosystem C fluxes. We measured δ13Cl, the δ13C of biomass and of potential respiratory substrates and leaf gas exchange in one C3 (Leymus chinensis) and two C4 (Chloris virgata and Hemarthria altissima) grasses during a manipulated drought period. For all studied grasses, δ13Cl decreased from 21:00 to 03:00 h. The magnitude of the nighttime shift in δ13Cl decreased with increasing drought stress. The δ13Cl values were correlated with the δ13C of respiratory substrates, whereas the magnitude of the nighttime shift in δ13Cl strongly depended on the daytime carbon assimilation rate and the range of nighttime variations in the respiratory substrate content. The ΔR,biomass in the C3 and C4 grasses varied in opposite directions with the intensification of the drought stress. The contribution of C4 plant-associated carbon flux is likely to be overestimated if carbon isotope signatures are used for the partitioning of ecosystem carbon exchange and the δ13C of biomass is used as a substitute for leaf dark-respired CO2. The detected drought sensitivities in δ13Cl and differences in respiratory apparent isotope fractionation between C3 and C4 grasses have marked implications for isotope partitioning studies at the ecosystem level.
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Affiliation(s)
- Shangzhi Zhong
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Hua Chai
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Yueqiao Xu
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
| | - Yan Li
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Jian-Ying Ma
- State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
| | - Wei Sun
- Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast Normal University, Changchun, China
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Lanoue J, Leonardos ED, Ma X, Grodzinski B. The Effect of Spectral Quality on Daily Patterns of Gas Exchange, Biomass Gain, and Water-Use-Efficiency in Tomatoes and Lisianthus: An Assessment of Whole Plant Measurements. FRONTIERS IN PLANT SCIENCE 2017; 8:1076. [PMID: 28676816 PMCID: PMC5477295 DOI: 10.3389/fpls.2017.01076] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 06/06/2017] [Indexed: 05/18/2023]
Abstract
Advancements in light-emitting diode (LED) technology have made them a viable alternative to current lighting systems for both sole and supplemental lighting requirements. Understanding how wavelength specific LED lighting can affect plants is thus an area of great interest. Much research is available on the wavelength specific responses of leaves from multiple crops when exposed to long-term wavelength specific lighting. However, leaf measurements do not always extrapolate linearly to the complexities which are found within a whole plant canopy, namely mutual shading and leaves of different ages. Taken together, both tomato (Solanum lycopersicum) leaves under short-term illumination and lisianthus (Eustoma grandiflorum) and tomato whole plant diurnal patterns of plants acclimated to specific lighting indicate wavelength specific responses of both H2O and CO2 gas exchanges involved in the major growth parameters of a plant. Tomato leaves grown under a white light source indicated an increase in transpiration rate and internal CO2 concentration and a subsequent decrease in water-use-efficiency (WUE) when exposed to a blue LED light source compared to a green LED light source. Interestingly, the maximum photosynthetic rate was observed to be similar. Using plants grown under wavelength specific supplemental lighting in a greenhouse, a decrease in whole plant WUE was seen in both crops under both red-blue (RB) and red-white (RW) LEDs when compared to a high pressure sodium (HPS) light. Whole plant WUE was decreased by 31% under the RB LED treatment for both crops compared to the HPS treatment. Tomato whole plant WUE was decreased by 25% and lisianthus whole plant WUE was decreased by 15% when compared to the HPS treatment when grown under RW LED. The understanding of the effects of wavelength specific lighting on both leaf and whole plant gas exchange has significant implications on basic academic research as well as commercial greenhouse production.
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Affiliation(s)
- Jason Lanoue
- Department of Plant Agriculture, University of GuelphGuelph, ON, Canada
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10
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Ellsworth PZ, Ellsworth PV, Cousins AB. Relationship of leaf oxygen and carbon isotopic composition with transpiration efficiency in the C4 grasses Setaria viridis and Setaria italica. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3513-3528. [PMID: 28859378 PMCID: PMC5853516 DOI: 10.1093/jxb/erx185] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 05/26/2017] [Indexed: 05/20/2023]
Abstract
Leaf carbon and oxygen isotope ratios can potentially provide a time-integrated proxy for stomatal conductance (gs) and transpiration rate (E), and can be used to estimate transpiration efficiency (TE). In this study, we found significant relationships of bulk leaf carbon isotopic signature (δ13CBL) and bulk leaf oxygen enrichment above source water (Δ18OBL) with gas exchange and TE in the model C4 grasses Setaria viridis and S. italica. Leaf δ13C had strong relationships with E, gs, water use, biomass, and TE. Additionally, the consistent difference in δ13CBL between well-watered and water-limited plants suggests that δ13CBL is effective in separating C4 plants with different availability of water. Alternatively, the use of Δ18OBL as a proxy for E and TE in S. viridis and S. italica was problematic. First, the oxygen isotopic composition of source water, used to calculate leaf water enrichment (Δ18OLW), was variable with time and differed across water treatments. Second, water limitations changed leaf size and masked the relationship of Δ18OLW and Δ18OBL with E. Therefore, the data collected here suggest that δ13CBL but not Δ18OBL may be an effective proxy for TE in C4 grasses.
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Affiliation(s)
- Patrick Z Ellsworth
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | | | - Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA, USA
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11
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Ma JY, Sun W, Koteyeva NK, Voznesenskaya E, Stutz SS, Gandin A, Smith-Moritz AM, Heazlewood JL, Cousins AB. Influence of light and nitrogen on the photosynthetic efficiency in the C 4 plant Miscanthus × giganteus. PHOTOSYNTHESIS RESEARCH 2017; 131:1-13. [PMID: 27531584 DOI: 10.1007/s11120-016-0281-7] [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: 08/05/2015] [Accepted: 05/26/2016] [Indexed: 06/06/2023]
Abstract
There are numerous studies describing how growth conditions influence the efficiency of C4 photosynthesis. However, it remains unclear how changes in the biochemical capacity versus leaf anatomy drives this acclimation. Therefore, the aim of this study was to determine how growth light and nitrogen availability influence leaf anatomy, biochemistry and the efficiency of the CO2 concentrating mechanism in Miscanthus × giganteus. There was an increase in the mesophyll cell wall surface area but not cell well thickness in the high-light (HL) compared to the low-light (LL) grown plants suggesting a higher mesophyll conductance in the HL plants, which also had greater photosynthetic capacity. Additionally, the HL plants had greater surface area and thickness of bundle-sheath cell walls compared to LL plants, suggesting limited differences in bundle-sheath CO2 conductance because the increased area was offset by thicker cell walls. The gas exchange estimates of phosphoenolpyruvate carboxylase (PEPc) activity were significantly less than the in vitro PEPc activity, suggesting limited substrate availability in the leaf due to low mesophyll CO2 conductance. Finally, leakiness was similar across all growth conditions and generally did not change under the different measurement light conditions. However, differences in the stable isotope composition of leaf material did not correlate with leakiness indicating that dry matter isotope measurements are not a good proxy for leakiness. Taken together, these data suggest that the CO2 concentrating mechanism in Miscanthus is robust under low-light and limited nitrogen growth conditions, and that the observed changes in leaf anatomy and biochemistry likely help to maintain this efficiency.
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Affiliation(s)
- Jian-Ying Ma
- Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- School of Biological Science, Washington State University, Pullman, WA, 99163, USA
| | - Wei Sun
- School of Biological Science, Washington State University, Pullman, WA, 99163, USA
- Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun, 130024, China
| | - Nuria K Koteyeva
- Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Elena Voznesenskaya
- Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Samantha S Stutz
- School of Biological Science, Washington State University, Pullman, WA, 99163, USA
| | - Anthony Gandin
- School of Biological Science, Washington State University, Pullman, WA, 99163, USA
| | - Andreia M Smith-Moritz
- Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Joshua L Heazlewood
- Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- ARC Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Asaph B Cousins
- School of Biological Science, Washington State University, Pullman, WA, 99163, USA.
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12
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Studer AJ, Schnable JC, Weissmann S, Kolbe AR, McKain MR, Shao Y, Cousins AB, Kellogg EA, Brutnell TP. The draft genome of the C 3 panicoid grass species Dichanthelium oligosanthes. Genome Biol 2016; 17:223. [PMID: 27793170 PMCID: PMC5084476 DOI: 10.1186/s13059-016-1080-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 10/05/2016] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Comparisons between C3 and C4 grasses often utilize C3 species from the subfamilies Ehrhartoideae or Pooideae and C4 species from the subfamily Panicoideae, two clades that diverged over 50 million years ago. The divergence of the C3 panicoid grass Dichanthelium oligosanthes from the independent C4 lineages represented by Setaria viridis and Sorghum bicolor occurred approximately 15 million years ago, which is significantly more recent than members of the Bambusoideae, Ehrhartoideae, and Pooideae subfamilies. D. oligosanthes is ideally placed within the panicoid clade for comparative studies of C3 and C4 grasses. RESULTS We report the assembly of the nuclear and chloroplast genomes of D. oligosanthes, from high-throughput short read sequencing data and a comparative transcriptomics analysis of the developing leaf of D. oligosanthes, S. viridis, and S. bicolor. Physiological and anatomical characterizations verified that D. oligosanthes utilizes the C3 pathway for carbon fixation and lacks Kranz anatomy. Expression profiles of transcription factors along developing leaves of D. oligosanthes and S. viridis were compared with previously published data from S. bicolor, Zea mays, and Oryza sativa to identify a small suite of transcription factors that likely acquired functions specifically related to C4 photosynthesis. CONCLUSIONS The phylogenetic location of D. oligosanthes makes it an ideal C3 plant for comparative analysis of C4 evolution in the panicoid grasses. This genome will not only provide a better C3 species for comparisons with C4 panicoid grasses, but also highlights the power of using high-throughput sequencing to address questions in evolutionary biology.
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Affiliation(s)
- Anthony J. Studer
- Donald Danforth Plant Science Center, St. Louis, MO 63132 USA
- Present address: Department of Crop Sciences, University of Illinois Urbana-Champaign, Urbana, IL 61801 USA
| | - James C. Schnable
- Donald Danforth Plant Science Center, St. Louis, MO 63132 USA
- Present address: Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE 68588 USA
| | - Sarit Weissmann
- Donald Danforth Plant Science Center, St. Louis, MO 63132 USA
| | - Allison R. Kolbe
- School of Biological Sciences, Washington State University, Pullman, WA 99164 USA
| | | | - Ying Shao
- Donald Danforth Plant Science Center, St. Louis, MO 63132 USA
- St. Jude Children’s Research Hospital, Pediatric Cancer Genome Project, Memphis, TN USA
| | - Asaph B. Cousins
- School of Biological Sciences, Washington State University, Pullman, WA 99164 USA
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13
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Bellasio C, Lundgren MR. Anatomical constraints to C4 evolution: light harvesting capacity in the bundle sheath. THE NEW PHYTOLOGIST 2016; 212:485-496. [PMID: 27375085 DOI: 10.1111/nph.14063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 05/10/2016] [Indexed: 06/06/2023]
Abstract
In C4 photosynthesis CO2 assimilation and reduction are typically coordinated across mesophyll (M) and bundle sheath (BS) cells, respectively. This system consequently requires sufficient light to reach BS to generate enough ATP to allow ribulose-1,5-bisphosphate (RuBP) regeneration in BS. Leaf anatomy influences BS light penetration and therefore constrains C4 cycle functionality. Using an absorption scattering model (coded in Excel, and freely downloadable) we simulate light penetration profiles and rates of ATP production in BS across the C3 , C3 -C4 and C4 anatomical continua. We present a trade-off for light absorption between BS pigment concentration and space allocation. C3 BS anatomy limits light absorption and benefits little from high pigment concentrations. Unpigmented BS extensions increase BS light penetration. C4 and C3 -C4 anatomies have the potential to generate sufficient ATP in the BS, whereas typical C3 anatomy does not, except some C3 taxa closely related to C4 groups. Insufficient volume of BS, relative to M, will hamper a C4 cycle via insufficient BS light absorption. Thus, BS ATP production and RuBP regeneration, coupled with increased BS investments, allow greater operational plasticity. We propose that larger BS in C3 lineages may be co-opted for C3 -C4 and C4 biochemistry requirements.
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Affiliation(s)
- Chandra Bellasio
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK.
| | - Marjorie R Lundgren
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, UK
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14
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Effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of summer maize. Naturwissenschaften 2016; 103:67. [PMID: 27437706 DOI: 10.1007/s00114-016-1392-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 06/28/2016] [Accepted: 07/01/2016] [Indexed: 10/21/2022]
Abstract
A field experiment was conducted to study the effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of two summer maize hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking (R1) to physiological maturity (R6) (S1), from the sixth leaf stage (V6) to R1 (S2), and from seeding to R6 (S3), respectively. The net photosynthetic rate (P n) was significantly decreased after shading. The greatest reduction of P n was found at S3 treatment, followed by S1 and S2 treatments. P n of S3 was decreased by 59 and 48 % for DH605, and 39 and 43 % for ZD958 at tasseling and milk-ripe stages, respectively, compared to that of CK. Additionally, leaf area index (LAI) and chlorophyll content decreased after shading. In terms of mesophyll cell ultrastructure, chloroplast configuration of mesophyll cells dispersed, and part of chloroplast swelled and became circular. Meanwhile, the major characteristics of chloroplasts showed poorly developed thylakoid structure at the early growth stage, blurry lamellar structure, loose grana, and a large gap between slices and warping granum. Then, plasmolysis occurred in mesophyll cells and the endomembrane system was destroyed, which resulted in the dissolution of cell membrane, karyotheca, mitochondria, and some membrane structures. The damaged mesophyll cell ultrastructure led to the decrease of photosynthetic capacity, and thus resulted in significant yield reduction by 45, 11, and 84 % in S1, S2, and S3 treatments, respectively, compared to that of CK.
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15
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Ellsworth PZ, Cousins AB. Carbon isotopes and water use efficiency in C4 plants. CURRENT OPINION IN PLANT BIOLOGY 2016; 31:155-61. [PMID: 27155062 DOI: 10.1016/j.pbi.2016.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/07/2016] [Accepted: 04/14/2016] [Indexed: 05/13/2023]
Abstract
Drought is a major agricultural problem worldwide. Therefore, selection for increased water use efficiency (WUE) in food and biofuel crop species will be an important trait in plant breeding programs. The leaf carbon isotopic composition (δ(13)Cleaf) has been suggested to serve as a rapid and effective high throughput phenotyping method for WUE in both C3 and C4 species. This is because WUE, leaf carbon discrimination (Δ(13)Cleaf), and δ(13)Cleaf are correlated through their relationships with intercellular to ambient CO2 partial pressures (Ci/Ca). However, in C4 plants, changing environmental conditions may influence photosynthetic efficiency (bundle-sheath leakiness) and post-photosynthetic fractionation that will potentially alter the relationship between δ(13)Cleaf and Ci/Ca. Here we discuss how these factors influence the relationship between δ(13)Cleaf and WUE, and the potential of using δ(13)Cleaf as a meaningful proxy for WUE.
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Affiliation(s)
| | - Asaph B Cousins
- Washington State University, Pullman, WA 99163, United States.
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16
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Xing S, Kang L, Xu Q, Fan Y, Liu W, Zhu C, Song Z, Wang Q, Yan J, Li J, Sang T. The Coordination of Gene Expression within Photosynthesis Pathway for Acclimation of C4 Energy Crop Miscanthus lutarioriparius. FRONTIERS IN PLANT SCIENCE 2016; 7:109. [PMID: 26904072 PMCID: PMC4746358 DOI: 10.3389/fpls.2016.00109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 01/21/2016] [Indexed: 05/27/2023]
Abstract
As a promising candidate for the second-generation C4 energy crop, Miscanthus lutarioriparius has well acclimated to the water-limited and high-light Loess Plateau in China by improving photosynthesis rate and water use efficiency (WUE) compared to its native habitat along Yangtze River. Photosynthetic genes were demonstrated as one major category of the candidate genes underlying the physiological superiority. To further study how photosynthetic genes interact to improve the acclimation potential of M. lutarioriparius, population expression patterns within photosynthesis pathway were explored between one mild environment and one harsh environment. We found that 108 transcripts in assembled transcriptome of M. lutarioriparius were highly similar to genes in three Kyoto Encyclopedia of Genes and Genomes (KEGG) photosynthesis pathways of sorghum and maize. Phylogenetic analyses using sorghum, maize, rice, and Arabidopsis genes of dark reaction identified 23 orthologs and 30 paralogs of M. lutarioriparius photosynthetic genes. These genes were also clustered into two kinds of expression pattern. 87% of transcripts in dark reaction were up-regulated and all 14 chloroplast-encoded transcripts in light reaction increased degradation in the harsh environment compared to the mild environment. Moreover, 80.8% of photosynthetic transcripts were coordinated at transcription level under the two environments. Interestingly, LHCI and PSI were significantly correlated with F-ATPase and C4 cycle. Overall, this study indicates the coordinated expression between cyclic electron transport (consisting of LHCI, PSI, and ATPase) and CO2-concentrating mechanism (C4 cycle) could account for photosynthesis plasticity on M. lutarioriparius acclimation potential.
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Affiliation(s)
- Shilai Xing
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of SciencesBeijing, China
- University of Chinese Academy of SciencesBeijing, China
| | - Lifang Kang
- Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of SciencesBeijing, China
| | - Qin Xu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of SciencesBeijing, China
| | - Yangyang Fan
- University of Chinese Academy of SciencesBeijing, China
- Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of SciencesBeijing, China
| | - Wei Liu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of SciencesBeijing, China
| | - Caiyun Zhu
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of SciencesBeijing, China
- University of Chinese Academy of SciencesBeijing, China
| | - Zhihong Song
- University of Chinese Academy of SciencesBeijing, China
- Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of SciencesBeijing, China
| | - Qian Wang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of SciencesBeijing, China
- University of Chinese Academy of SciencesBeijing, China
| | - Juan Yan
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of SciencesWuhan, China
| | - Jianqiang Li
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of SciencesWuhan, China
| | - Tao Sang
- State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of SciencesBeijing, China
- Key Laboratory of Plant Resources and Beijing Botanical Garden, Institute of Botany, Chinese Academy of SciencesBeijing, China
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17
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Cui H, Camberato JJ, Jin L, Zhang J. Effects of shading on spike differentiation and grain yield formation of summer maize in the field. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2015; 59:1189-200. [PMID: 25380975 DOI: 10.1007/s00484-014-0930-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 10/16/2014] [Accepted: 10/28/2014] [Indexed: 05/20/2023]
Abstract
A field experiment was conducted to study the effects of shading on tassel and ear development and yield formation of three summer maize hybrids Zhenjie 2 (ZJ2), Denghai 605 (DH605), and Zhengdan 958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking stage (R1) to physiological maturity stage (R6) (treatment S1), from the sixth extended leaf stage (V6) to R1 (treatment S2) and from seeding to R6 (treatment S3). Shading had no significant effect on the time from seeding to shoot emergence (VE); however, subsequent growth and development were delayed with shading beyond this point. The differentiation time of both tassel and ear delayed, and female spike (tassel) floret differentiation, sexual organ formation time, and anthesis-silking interval (ASI) were lengthened. After shading, the total number of floret, silk, and fertilization floret reduced significantly; the number of abortive seeds increased, and the total setting percentage among different treatments showed that CK>S2>S1>S3; and the total setting percentages in S1, S2, and S3 of ZD958 were 44, 72, and 15 % respectively. The total floret number of tassel primordium differentiation, fertility rate, and seed setting rate of florets in S3 treatment was the minimum; kernels per ear decreased seriously and single ear setting percentage was only 16 %; although floret degeneration number of S2 during ear differentiation stages increased and floret fertility rate reduced than that of CK, fertilization flower seed production increased and abortive seed decreased after canceling shading. Aborted kernel of S1 increased and kernel dry weight reduced, resulting in a significant decrease of kernel number per ear and kernel weight, and the grain abortive rate of 40-62 %. In conclusion, shading changed the growth and development process and caused infertility of tassel and ear; tassel branches decreased, reducing pollen vitality and silks differentiation cut down; and grain dry matter accumulation and setting percentage decreased, causing yield reduction. Grain yield and biomass reduced 66, 36, and 93 % compared to the control by shading treatments of S1, S2, and S3, respectively.
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Affiliation(s)
- Haiyan Cui
- State Key Laboratory of Crop Biology, Agronomy College of Shandong Agricultural University, Taian, Shandong, 271018, People's Republic of China
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18
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von Caemmerer S, Ghannoum O, Pengelly JJL, Cousins AB. Carbon isotope discrimination as a tool to explore C4 photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3459-70. [PMID: 24711615 DOI: 10.1093/jxb/eru127] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Photosynthetic carbon isotope discrimination is a non-destructive tool for investigating C4 metabolism. Tuneable diode laser absorption spectroscopy provides new opportunities for making rapid, concurrent measurements of carbon isotope discrimination and CO2 assimilation over a range of environmental conditions, and this has facilitated the use of carbon isotope discrimination as a probe of C4 metabolism. In spite of the significant progress made in recent years, understanding how photosynthetic carbon isotope discrimination measured concurrently with gas exchange relates to carbon isotope composition of leaf and plant dry matter remains a challenge that requires resolution if this technique is to be successfully applied as a screening tool in crop breeding and phylogenetic research. In this review, we update our understanding of the factors and assumptions that underlie variations in photosynthetic carbon isotope discrimination in C4 leaves. Closing the main gaps in our understanding of carbon isotope discrimination during C4 photosynthesis may help advance research aimed at developing higher productivity and efficiency in key C4 food, feed, and biofuel crops.
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Affiliation(s)
- Susanne von Caemmerer
- Research School of Biology, The Australian National University, Canberra ACT 0200, Australia
| | - Oula Ghannoum
- Hawkesbury Institute for the Environment, University of Western Sydney, Hawkesbury campus, Locked Bag 1797, Penrith 2751, NSW, Australia
| | - Jasper J L Pengelly
- Research School of Biology, The Australian National University, Canberra ACT 0200, Australia
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
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19
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Bellasio C, Griffiths H. Acclimation of C4 metabolism to low light in mature maize leaves could limit energetic losses during progressive shading in a crop canopy. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3725-36. [PMID: 24591058 PMCID: PMC4085954 DOI: 10.1093/jxb/eru052] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
C4 plants have a biochemical carbon-concentrating mechanism that increases CO2 concentration around Rubisco in the bundle sheath. Under low light, the activity of the carbon-concentrating mechanism generally decreases, associated with an increase in leakiness (ϕ), the ratio of CO2 retrodiffusing from the bundle sheath relative to C4 carboxylation. This increase in ϕ had been theoretically associated with a decrease in biochemical operating efficiency (expressed as ATP cost of gross assimilation, ATP/GA) under low light and, because a proportion of canopy photosynthesis is carried out by shaded leaves, potential productivity losses at field scale. Maize plants were grown under light regimes representing the cycle that leaves undergo in the canopy, whereby younger leaves initially developed under high light and were then re-acclimated to low light (600 to 100 μE·m(-2)·s(-1) photosynthetically active radiation) for 3 weeks. Following re-acclimation, leaves reduced rates of light-respiration and reached a status of lower ϕ, effectively optimizing the limited ATP resources available under low photosynthetically active radiation. Direct estimates of respiration in the light, and ATP production rate, allowed an empirical estimate of ATP production rate relative to gross assimilation to be derived. These values were compared to modelled ATP/GA which was predicted using leakiness as the sole proxy for ATP/GA, and, using a novel comprehensive biochemical model, showing that irrespective of whether leaves are acclimated to very low or high light intensity, the biochemical efficiency of the C4 cycle does not decrease at low photosynthetically active radiation.
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Affiliation(s)
- Chandra Bellasio
- Physiological Ecology Group, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
| | - Howard Griffiths
- Physiological Ecology Group, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
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20
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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.
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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
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21
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Wang Y, Bräutigam A, Weber APM, Zhu XG. Three distinct biochemical subtypes of C4 photosynthesis? A modelling analysis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:3567-78. [PMID: 24609651 PMCID: PMC4085956 DOI: 10.1093/jxb/eru058] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
C4 photosynthesis has higher light-use, nitrogen-use, and water-use efficiencies than C3 photosynthesis. Historically, most of C4 plants were classified into three subtypes (NADP-malic enzyme (ME), NAD-ME, or phosphoenolpyruvate carboxykinase (PEPCK) subtypes) according to their major decarboxylation enzyme. However, a wealth of historic and recent data indicates that flexibility exists between different decarboxylation pathways in many C4 species, and this flexibility might be controlled by developmental and environmental cues. This work used systems modelling to theoretically explore the significance of flexibility in decarboxylation mechanisms and transfer acids utilization. The results indicate that employing mixed C4 pathways, either the NADP-ME type with the PEPCK type or the NAD-ME type with the PEPCK type, effectively decreases the need to maintain high concentrations and concentration gradients of transport metabolites. Further, maintaining a mixture of C4 pathways robustly affords high photosynthetic efficiency under a broad range of light regimes. A pure PEPCK-type C4 photosynthesis is not beneficial because the energy requirements in bundle sheath cells cannot be fulfilled due to them being shaded by mesophyll cells. Therefore, only two C4 subtypes should be considered as distinct subtypes, the NADP-ME type and NAD-ME types, which both inherently involve a supplementary PEPCK cycle.
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Affiliation(s)
- Yu Wang
- State Key Laboratory for Hybrid Rice, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Andrea Bräutigam
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences (CEPLAS), Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Xin-Guang Zhu
- State Key Laboratory for Hybrid Rice, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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22
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Bellasio C, Griffiths H. Acclimation to low light by C4 maize: implications for bundle sheath leakiness. PLANT, CELL & ENVIRONMENT 2014; 37:1046-58. [PMID: 24004447 DOI: 10.1111/pce.12194] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
C4 plants have a biochemical carbon concentrating mechanism (CCM) that increases CO2 concentration around ribulose bisphosphate carboxylase oxygenase (Rubisco) in the bundle sheath (BS). Under limiting light, the activity of the CCM generally decreases, causing an increase in leakiness, (Φ), the ratio of CO2 retrodiffusing from the BS relative to C4 carboxylation processes. Maize plants were grown under high and low light regimes (respectively HL, 600 versus LL, 100 μE m(-2) s(-1) ). Short-term acclimation of Φ was compared from isotopic discrimination (Δ), gas exchange and photochemistry. Direct measurement of respiration in the light, and ATP production rate (JATP ), allowed us use a novel approach to derive Φ, compared with the conventional fitting of measured and predicted Δ. HL grown plants responded to decreasing light intensities with the well-documented increase in Φ. Conversely, LL plants showed a constant Φ, which has not been observed previously. We explain the pattern by two contrasting acclimation strategies: HL plants maintained a high CCM activity at LL, resulting in high CO2 overcycling and increased Φ; LL plants acclimated by down-regulating the CCM, effectively optimizing scarce ATP supply. This surprising plasticity may limit the impact of Φ-dependent carbon losses in leaves becoming shaded within developing canopies.
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Affiliation(s)
- Chandra Bellasio
- Physiological Ecology Group, Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
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23
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Stutz SS, Edwards GE, Cousins AB. Single-cell C(4) photosynthesis: efficiency and acclimation of Bienertia sinuspersici to growth under low light. THE NEW PHYTOLOGIST 2014; 202:220-232. [PMID: 24384064 DOI: 10.1111/nph.12648] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 11/13/2013] [Indexed: 06/03/2023]
Abstract
Traditionally, it was believed that C(4) photosynthesis required two types of chlorenchyma cells to concentrate CO(2) within the leaf. However, several species have been identified that perform C(4) photosynthesis using dimorphic chloroplasts within an individual cell. The goal of this research was to determine how growth under limited light affects leaf structure, biochemistry and efficiency of the single-cell CO(2) -concentrating mechanism in Bienertia sinuspersici. Measurements of rates of CO(2) assimilation and CO(2) isotope exchange in response to light intensity and O(2) were used to determine the efficiency of the CO(2) -concentrating mechanism in plants grown under moderate and low light. In addition, enzyme assays, chlorophyll content and light microscopy of leaves were used to characterize acclimation to light-limited growth conditions. There was acclimation to growth under low light with a decrease in capacity for photosynthesis when exposed to high light. This was associated with a decreased investment in biochemistry for carbon assimilation with only subtle changes in leaf structure and anatomy. The capture and assimilation of CO(2) delivered by the C(4) cycle was lower in low-light-grown plants. Low-light-grown plants were able to acclimate to maintain structural and functional features for the performance of efficient single-cell C(4) photosynthesis.
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Affiliation(s)
- Samantha S Stutz
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Gerald E Edwards
- 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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Sun W, Ubierna N, Ma JY, Walker BJ, Kramer DM, Cousins AB. The coordination of C4 photosynthesis and the CO2-concentrating mechanism in maize and Miscanthus x giganteus in response to transient changes in light quality. PLANT PHYSIOLOGY 2014; 164:1283-92. [PMID: 24488966 PMCID: PMC3938620 DOI: 10.1104/pp.113.224683] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 01/12/2014] [Indexed: 05/07/2023]
Abstract
Unequal absorption of photons between photosystems I and II, and between bundle-sheath and mesophyll cells, are likely to affect the efficiency of the CO2-concentrating mechanism in C4 plants. Under steady-state conditions, it is expected that the biochemical distribution of energy (ATP and NADPH) and photosynthetic metabolite concentrations will adjust to maintain the efficiency of C4 photosynthesis through the coordination of the C3 (Calvin-Benson-Bassham) and C4 (CO2 pump) cycles. However, under transient conditions, changes in light quality will likely alter the coordination of the C3 and C4 cycles, influencing rates of CO2 assimilation and decreasing the efficiency of the CO2-concentrating mechanism. To test these hypotheses, we measured leaf gas exchange, leaf discrimination, chlorophyll fluorescence, electrochromatic shift, photosynthetic metabolite pools, and chloroplast movement in maize (Zea mays) and Miscanthus × giganteus following transitional changes in light quality. In both species, the rate of net CO2 assimilation responded quickly to changes in light treatments, with lower rates of net CO2 assimilation under blue light compared with red, green, and blue light, red light, and green light. Under steady state, the efficiency of CO2-concentrating mechanisms was similar; however, transient changes affected the coordination of C3 and C4 cycles in M. giganteus but to a lesser extent in maize. The species differences in the ability to coordinate the activities of C3 and C4 cycles appear to be related to differences in the response of cyclic electron flux around photosystem I and potentially chloroplast rearrangement in response to changes in light quality.
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Affiliation(s)
- Wei Sun
- Institute of Grassland Science, Northeast Normal University, Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun, Jilin 130024, China (W.S.)
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, Washington 99164 (W.S., N.U., B.J.W., A.B.C.)
- Key Laboratory of Biogeography and Bioresource in Arid Land, Chinese Academy of Sciences, Urumqi 830011, China (J.-Y.M.); and
- Biochemistry and Molecular Biology and Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 (D.M.K.)
| | | | - Jian-Ying Ma
- Institute of Grassland Science, Northeast Normal University, Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun, Jilin 130024, China (W.S.)
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, Washington 99164 (W.S., N.U., B.J.W., A.B.C.)
- Key Laboratory of Biogeography and Bioresource in Arid Land, Chinese Academy of Sciences, Urumqi 830011, China (J.-Y.M.); and
- Biochemistry and Molecular Biology and Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 (D.M.K.)
| | - Berkley J. Walker
- Institute of Grassland Science, Northeast Normal University, Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun, Jilin 130024, China (W.S.)
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, Washington 99164 (W.S., N.U., B.J.W., A.B.C.)
- Key Laboratory of Biogeography and Bioresource in Arid Land, Chinese Academy of Sciences, Urumqi 830011, China (J.-Y.M.); and
- Biochemistry and Molecular Biology and Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 (D.M.K.)
| | - David M. Kramer
- Institute of Grassland Science, Northeast Normal University, Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun, Jilin 130024, China (W.S.)
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, Washington 99164 (W.S., N.U., B.J.W., A.B.C.)
- Key Laboratory of Biogeography and Bioresource in Arid Land, Chinese Academy of Sciences, Urumqi 830011, China (J.-Y.M.); and
- Biochemistry and Molecular Biology and Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824 (D.M.K.)
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Walker B, Ariza LS, Kaines S, Badger MR, Cousins AB. Temperature response of in vivo Rubisco kinetics and mesophyll conductance in Arabidopsis thaliana: comparisons to Nicotiana tabacum. PLANT, CELL & ENVIRONMENT 2013; 36:2108-19. [PMID: 23869820 DOI: 10.1111/pce.12166] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 07/03/2013] [Accepted: 07/08/2013] [Indexed: 05/19/2023]
Abstract
Biochemical models are used to predict and understand the response of photosynthesis to rising temperatures and CO2 partial pressures. These models require the temperature dependency of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) kinetics and mesophyll conductance to CO2 (g(m)). However, it is not known how the temperature response of Rubisco kinetics differs between species, and comprehensive in vivo Rubisco kinetics that include gm have only been determined in the warm-adapted Nicotiana tabacum. Here, we measured the temperature response of Rubisco kinetics and gm in N. tabacum and the cold-adapted Arabidopsis thaliana using gas exchange and (13)CO2 isotopic discrimination on plants with genetically reduced levels of Rubisco. While the individual Rubisco kinetic parameters in N. tabacum and A. thaliana were similar across temperatures, they collectively resulted in significantly different modelled rates of photosynthesis. Additionally, gm increased with temperature in N. tabacum but not in A. thaliana. These findings highlight the importance of considering species-dependent differences in Rubisco kinetics and gm when modelling the temperature response of photosynthesis.
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Affiliation(s)
- Berkley Walker
- Molecular Plant Sciences, Washington State University, Pullman, WA, 99164, USA
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von Caemmerer S. Steady-state models of photosynthesis. PLANT, CELL & ENVIRONMENT 2013; 36:1617-30. [PMID: 23496792 DOI: 10.1111/pce.12098] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 03/07/2013] [Accepted: 03/12/2013] [Indexed: 05/19/2023]
Abstract
In the challenge to increase photosynthetic rate per leaf area mathematical models of photosynthesis can be used to help interpret gas exchange measurements made under different environmental conditions and predict underlying photosynthetic biochemistry. To do this successfully it is important to improve the modelling of temperature dependencies of CO₂ assimilation and gain better understanding of internal CO₂ diffusion limitations. Despite these shortcomings steady-state models of photosynthesis provide simple easy to use tools for thought experiments to explore photosynthetic pathway changes such as redirecting photorespiratory CO₂, inserting bicarbonate pumps into C₃ chloroplasts or inserting C₄ photosynthesis into rice. Here a number of models derived from the C₃ model by Farquhar, von Caemmerer and Berry are discussed and compared.
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Affiliation(s)
- Susanne von Caemmerer
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia.
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Ubierna N, Sun W, Kramer DM, Cousins AB. The efficiency of C4 photosynthesis under low light conditions in Zea mays, Miscanthus x giganteus and Flaveria bidentis. PLANT, CELL & ENVIRONMENT 2013; 36:365-81. [PMID: 22812384 DOI: 10.1111/j.1365-3040.2012.02579.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The efficiency of C(4) photosynthesis in Zea mays, Miscanthus x giganteus and Flaveria bidentis in response to light was determined using measurements of gas exchange, (13) CO(2) photosynthetic discrimination, metabolite pools and spectroscopic assays, with models of C(4) photosynthesis and leaf (13) CO(2) discrimination. Spectroscopic and metabolite assays suggested constant energy partitioning between the C(4) and C(3) cycles across photosynthetically active radiation (PAR). Leakiness (φ), modelled using C(4) light-limited photosynthesis equations (φ(mod)), matched values from the isotope method without simplifications (φ(is)) and increased slightly from high to low PAR in all species. However, simplifications of bundle-sheath [CO(2)] and respiratory fractionation lead to large overestimations of φ at low PAR with the isotope method. These species used different strategies to maintain similar φ. For example, Z. mays had large rates of the C(4) cycle and low bundle-sheath cells CO(2 ) conductance (g(bs)). While F. bidentis had larger g(bs) but lower respiration rates and M. giganteus had less C(4) cycle capacity but low g(bs), which resulted in similar φ. This demonstrates that low g(bs) is important for efficient C(4) photosynthesis but it is not the only factor determining φ. Additionally, these C(4) species are able to optimize photosynthesis and minimize φ over a range of PARs, including low light.
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Affiliation(s)
- Nerea Ubierna
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA 99164-4236, USA
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