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Joffe R, Tosens T, Berthe A, Jolivet Y, Niinemets Ü, Gandin A. Reduced mesophyll conductance under chronic O 3 exposure in poplar reflects thicker cell walls and increased subcellular diffusion pathway lengths according to the anatomical model. PLANT, CELL & ENVIRONMENT 2024. [PMID: 39101376 DOI: 10.1111/pce.15049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 06/23/2024] [Accepted: 07/04/2024] [Indexed: 08/06/2024]
Abstract
Ozone (O3) is one of the most harmful and widespread air pollutants, affecting crop yield and plant health worldwide. There is evidence that O3 reduces the major limiting factor of photosynthesis, namely CO2 mesophyll conductance (gm), but there is little quantitative information of O3-caused changes in key leaf anatomical traits and their impact on gm. We exposed two O3-responsive clones of the economically important tree species Populus × canadensis Moench to 120 ppb O3 for 21 days. An anatomical diffusion model within the leaf was used to analyse the entire CO2 diffusion pathway from substomatal cavities to carboxylation sites and determine the importance of each structural and subcellular component as a limiting factor. gm decreased substantially under O3 and was found to be the most important limitation of photosynthesis. This decrease was mostly driven by an increased cell wall thickness and length of subcellular diffusion pathway caused by altered interchloroplast spacing and chloroplast positioning. By contrast, the prominent leaf integrative trait leaf dry mass per area was neither affected nor related to gm under O3. The observed relationship between gm and anatomy, however, was clone-dependent, suggesting that mechanisms regulating gm may differ considerably between closely related plant lines. Our results confirm the need for further studies on factors constraining gm under stress conditions.
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Affiliation(s)
- Ricardo Joffe
- Faculté des Sciences et Technologies, Université de Lorraine, AgroParisTech, INRAE, SILVA, Nancy, France
| | - Tiina Tosens
- Department of Crop Science and Plant Biology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Audrey Berthe
- Faculté des Sciences et Technologies, Université de Lorraine, AgroParisTech, INRAE, SILVA, Nancy, France
| | - Yves Jolivet
- Faculté des Sciences et Technologies, Université de Lorraine, AgroParisTech, INRAE, SILVA, Nancy, France
| | - Ülo Niinemets
- Department of Crop Science and Plant Biology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
- Estonian Academy of Sciences, Tallinn, Estonia
| | - Anthony Gandin
- Faculté des Sciences et Technologies, Université de Lorraine, AgroParisTech, INRAE, SILVA, Nancy, France
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2
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Janová J, Kubásek J, Grams TEE, Zeisler-Diehl V, Schreiber L, Šantrůček J. Effect of light-induced changes in leaf anatomy on intercellular and cellular components of mesophyll resistance for CO 2 in Fagus sylvatica. PLANT BIOLOGY (STUTTGART, GERMANY) 2024; 26:842-854. [PMID: 38743618 DOI: 10.1111/plb.13655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 04/15/2024] [Indexed: 05/16/2024]
Abstract
Mesophyll resistance for CO2 diffusion (rm) is one of the main limitations for photosynthesis and plant growth. Breeding new varieties with lower rm requires knowledge of its distinct components. We tested new method for estimating the relative drawdowns of CO2 concentration (c) across hypostomatous leaves of Fagus sylvatica. This technique yields values of the ratio of the internal CO2 concentrations at the adaxial and abaxial leaf side, cd/cb, the drawdown in the intercellular air space (IAS), and intracellular drawdown between IAS and chloroplast stroma, cc/cbd. The method is based on carbon isotope composition of leaf dry matter and epicuticular wax isolated from upper and lower leaf sides. We investigated leaves from tree-canopy profile to analyse the effects of light and leaf anatomy on the drawdowns and partitioning of rm into its inter- (rIAS) and intracellular (rliq) components. Validity of the new method was tested by independent measurements of rm using conventional isotopic and gas exchange techniques. 73% of investigated leaves had adaxial epicuticular wax enriched in 13C compared to abaxial wax (by 0.50‰ on average), yielding 0.98 and 0.70 for average of cd/cb and cc/cbd, respectively. The rIAS to rliq proportion were 5.5:94.5% in sun-exposed and 14.8:85.2% in shaded leaves. cc dropped to less than half of the atmospheric value in the sunlit and to about two-thirds of it in shaded leaves. This method shows that rIAS is minor but not negligible part of rm and reflects leaf anatomy traits, i.e. leaf mass per area and thickness.
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Affiliation(s)
- J Janová
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - J Kubásek
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - T E E Grams
- Ecophysiology of Plants, Technical University of Munich, Freising, Germany
| | - V Zeisler-Diehl
- Institute of Cellular and Molecular Botany, University of Bonn, Bonn, Germany
| | - L Schreiber
- Institute of Cellular and Molecular Botany, University of Bonn, Bonn, Germany
| | - J Šantrůček
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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3
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Xiong D. Leaf anatomy does not explain the large variability of mesophyll conductance across C 3 crop species. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 113:1035-1048. [PMID: 36602006 DOI: 10.1111/tpj.16098] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 12/29/2022] [Accepted: 01/02/2023] [Indexed: 06/17/2023]
Abstract
Increasing mesophyll conductance of CO2 (gm ) is a strategy to improve photosynthesis in C3 crops. However, the relative importance of different anatomical traits in determining gm in crops is unclear. Mesophyll conductance measurements were performed on 10 crops using the online carbon isotope discrimination method and the 'variable J' method in parallel. The influences of crucial leaf anatomical traits on gm were evaluated using a one-dimensional anatomical CO2 diffusion model. The gm values measured using two independent methods were compatible, although significant differences were observed in their absolute values. Quantitative analysis showed that cell wall thickness and chloroplast stroma thickness are the most important elements along the diffusion pathway. Unexpectedly, the large variability of gm across crops was not associated with any investigated leaf anatomical traits except chloroplast thickness. The gm values estimated using the anatomical model differed remarkably from the values measured in vivo in most species. However, when the species-specific effective porosity of the cell wall and the species-specific facilitation effect of CO2 diffusion across the membrane and chloroplast stoma were taken into account, the model could output gm values very similar to those measured in vivo. These results indicate that gm variation across crops is probably also driven by the effective porosity of the cell wall and effects of facilitation of CO2 transport across the membrane and chloroplast stroma in addition to the thicknesses of the elements.
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Affiliation(s)
- Dongliang Xiong
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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4
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Knauer J, Cuntz M, Evans JR, Niinemets Ü, Tosens T, Veromann‐Jürgenson L, Werner C, Zaehle S. Contrasting anatomical and biochemical controls on mesophyll conductance across plant functional types. THE NEW PHYTOLOGIST 2022; 236:357-368. [PMID: 35801854 PMCID: PMC9804998 DOI: 10.1111/nph.18363] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/30/2022] [Indexed: 06/06/2023]
Abstract
Mesophyll conductance (gm ) limits photosynthesis by restricting CO2 diffusion between the substomatal cavities and chloroplasts. Although it is known that gm is determined by both leaf anatomical and biochemical traits, their relative contribution across plant functional types (PFTs) is still unclear. We compiled a dataset of gm measurements and concomitant leaf traits in unstressed plants comprising 563 studies and 617 species from all major PFTs. We investigated to what extent gm limits photosynthesis across PFTs, how gm relates to structural, anatomical, biochemical, and physiological leaf properties, and whether these relationships differ among PFTs. We found that gm imposes a significant limitation to photosynthesis in all C3 PFTs, ranging from 10-30% in most herbaceous annuals to 25-50% in woody evergreens. Anatomical leaf traits explained a significant proportion of the variation in gm (R2 > 0.3) in all PFTs except annual herbs, in which gm is more strongly related to biochemical factors associated with leaf nitrogen and potassium content. Our results underline the need to elucidate mechanisms underlying the global variability of gm . We emphasise the underestimated potential of gm for improving photosynthesis in crops and identify modifications in leaf biochemistry as the most promising pathway for increasing gm in these species.
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Affiliation(s)
- Jürgen Knauer
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityPenrithNSW2751Australia
- Climate Science CentreCSIRO Oceans and AtmosphereCanberraACT2601Australia
- Max Planck Institute for Biogeochemistry07745JenaGermany
| | - Matthias Cuntz
- AgroParisTech, UMR SilvaINRAE, Université de Lorraine54000NancyFrance
| | - John R. Evans
- ARC Centre of Excellence for Translational PhotosynthesisResearch School of BiologyThe Australian National UniversityCanberraACT2601Australia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental SciencesEstonian University of Life Sciences51006TartuEstonia
| | - Tiina Tosens
- Institute of Agricultural and Environmental SciencesEstonian University of Life Sciences51006TartuEstonia
| | | | | | - Sönke Zaehle
- Max Planck Institute for Biogeochemistry07745JenaGermany
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5
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Joffe R, Berthe A, Jolivet Y, Gandin A. The response of mesophyll conductance to ozone-induced oxidative stress is genotype-dependent in poplar. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4850-4866. [PMID: 35429268 DOI: 10.1093/jxb/erac154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 04/14/2022] [Indexed: 06/14/2023]
Abstract
The CO2 diffusion conductance within the leaf mesophyll (gm) is considered a major limiting factor of photosynthesis. However, the effects of the major secondary air pollutant ozone (O3) on gm have been poorly investigated. Eight genotypes of the economically important tree species Populus × canadensis Moench were exposed to 120 ppb O3 for 21 d. gm showed a genotype-dependent response to O3-induced oxidative stress and was a major limiting factor of net assimilation rate (Anet), ahead of stomatal conductance to CO2 (gsc) and of the maximum carboxylation capacity of the Rubisco enzyme (Vcmax) in half of the tested genotypes. Increased leaf dry mass per area (LMA) and decreased chlorophyll content were linked to the observed gm decrease, but this relationship did not entirely explain the different genotypic gm responses. Moreover, the oxidative stress defence metabolites ascorbate and glutathione were not related to O3 tolerance of gm. However, malondialdehyde probably mitigated the observed gm decrease in some genotypes due to its oxidative stress signalling function. The large variation of gm suggests different regulation mechanisms amongst poplar genotypes under oxidative stress.
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Affiliation(s)
- Ricardo Joffe
- Université de Lorraine, AgroParisTech, INRAE, SILVA, F-54000 Nancy, France
| | - Audrey Berthe
- Université de Lorraine, AgroParisTech, INRAE, SILVA, F-54000 Nancy, France
| | - Yves Jolivet
- Université de Lorraine, AgroParisTech, INRAE, SILVA, F-54000 Nancy, France
| | - Anthony Gandin
- Université de Lorraine, AgroParisTech, INRAE, SILVA, F-54000 Nancy, France
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6
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Momayyezi M, Borsuk AM, Brodersen CR, Gilbert ME, Théroux‐Rancourt G, Kluepfel DA, McElrone AJ. Desiccation of the leaf mesophyll and its implications for CO 2 diffusion and light processing. PLANT, CELL & ENVIRONMENT 2022; 45:1362-1381. [PMID: 35141930 PMCID: PMC9314819 DOI: 10.1111/pce.14287] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 01/18/2022] [Accepted: 01/24/2022] [Indexed: 05/09/2023]
Abstract
Leaves balance CO2 and radiative absorption while maintaining water transport to maximise photosynthesis. Related species with contrasting leaf anatomy can provide insights into inherent and stress-induced links between structure and function for commonly measured leaf traits for important crops. We used two walnut species with contrasting mesophyll anatomy to evaluate these integrated exchange processes under non-stressed and drought conditions using a combination of light microscopy, X-ray microCT, gas exchange, hydraulic conductance, and chlorophyll distribution profiles through leaves. Juglans regia had thicker palisade mesophyll, higher fluorescence in the palisade, and greater low-mesophyll porosity that were associated with greater gas-phase diffusion (gIAS ), stomatal and mesophyll (gm ) conductances and carboxylation capacity. More and highly-packed mesophyll cells and bundle sheath extensions (BSEs) in Juglans microcarpa led to higher fluorescence in the spongy and in proximity to the BSEs. Both species exhibited drought-induced reductions in mesophyll cell volume, yet the associated increases in porosity and gIAS were obscured by declines in biochemical activity that decreased gm . Inherent differences in leaf anatomy between the species were linked to differences in gas exchange, light absorption and photosynthetic capacity, and drought-induced changes in leaf structure impacted performance via imposing species-specific limitations to light absorption, gas exchange and hydraulics.
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Affiliation(s)
- Mina Momayyezi
- Department of Viticulture and EnologyUniversity of CaliforniaDavisCaliforniaUSA
| | - Aleca M. Borsuk
- School of the EnvironmentYale UniversityNew HavenConnecticutUSA
| | | | | | | | | | - Andrew J. McElrone
- Department of Viticulture and EnologyUniversity of CaliforniaDavisCaliforniaUSA
- USDA‐ARSCrops Pathology and Genetics Research UnitDavisCaliforniaUSA
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7
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Lei Z, Liu F, Wright IJ, Carriquí M, Niinemets Ü, Han J, Jia M, Atwell BJ, Cai X, Zhang W, Zhou Z, Zhang Y. Comparisons of photosynthetic and anatomical traits between wild and domesticated cotton. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:873-885. [PMID: 34153103 DOI: 10.1093/jxb/erab293] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 06/19/2021] [Indexed: 06/13/2023]
Abstract
Mesophyll conductance (gm) is a crucial leaf trait contributing to the photosynthetic rate (AN). Plant domestication typically leads to an enhancement of AN that is often associated with profound anatomical modifications, but it is unclear which of these structural alterations influence gm. We analyzed the implication of domestication on leaf anatomy and its effect on gm in 26 wild and 31 domesticated cotton genotypes (Gossypium sp.) grown under field conditions. We found that domesticated genotypes had higher AN but similar gm to wild genotypes. Consistent with this, domestication did not translate into significant differences in the fraction of mesophyll occupied by intercellular air spaces (fias) or mesophyll and chloroplast surface area exposed to intercellular air space (Sm/S and Sc/S, respectively). However, leaves of domesticated genotypes were significantly thicker, with larger but fewer mesophyll cells with thinner cell walls. Moreover, domesticated genotypes had higher cell wall conductance (gcw) but smaller cytoplasmic conductance (gcyt) than wild genotypes. It appears that domestication in cotton has not generally led to significant improvement in gm, in part because their thinner mesophyll cell walls (increasing gcw) compensate for their lower gcyt, itself due to larger distance between plasmalemma and chloroplast envelopes.
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Affiliation(s)
- Zhangying Lei
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Fang Liu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, PR China
| | - Ian J Wright
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Marc Carriquí
- School of Natural Sciences, University of Tasmania, Bag 55, 7001 Hobart, Tasmania, Australia
| | - Ülo Niinemets
- Chair of Crop Science and Plant Biology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51006 Tartu, Estonia
| | - Jimei Han
- School of Integrative Plant Science, Soil and Crop Science Section, Cornell University, Ithaca, NY 14850, USA
| | - Mengmeng Jia
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
| | - Brian J Atwell
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Xiaoyan Cai
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, PR China
| | - Wangfeng Zhang
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
| | - Zhongli Zhou
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, PR China
| | - Yali Zhang
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
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8
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Roig-Oliver M, Douthe C, Bota J, Flexas J. Cell wall thickness and composition are related to photosynthesis in Antarctic mosses. PHYSIOLOGIA PLANTARUM 2021; 173:1914-1925. [PMID: 34432898 DOI: 10.1111/ppl.13533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
Cell wall thickness (Tcw ) has been proposed as an important anatomical trait that could determine photosynthesis through land plants' phylogeny, bryophytes being the plant group presenting the thickest walls and the lowest photosynthetic rates. Also, it has recently been suggested that cell wall composition may have the potential to influence both thickness and mesophyll conductance (gm ), representing a novel trait that could ultimately affect photosynthesis. However, only a few studies in spermatophytes have demonstrated this issue. In order to explore the role of cell wall composition in determining both Tcw and gm in mosses, we tested six species grown under field conditions in Antarctica. We performed gas exchange and chlorophyll fluorescence measurements, an anatomical characterization, and a quantitative analysis of cell wall main composition (i.e., cellulose, hemicelluloses and pectins) in these six species. We found the photosynthetic rates to vary between the species, and they also presented differences in anatomical characteristics and in cell wall composition. Whilst gm correlated negatively with Tcw and pectins content, a positive relationship between Tcw and pectins emerged, suggesting that pectins could contribute to determine cell wall porosity. Although our results do not allow us to provide conclusive statements, we suggest for the first time that cell wall composition-with pectins playing a key role-could strongly influence Tcw and gm in Antarctic mosses, ultimately defining photosynthesis.
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Affiliation(s)
- Margalida Roig-Oliver
- Departament de Biologia, Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears (UIB), INAGEA, Palma, Illes Balears, Spain
| | - Cyril Douthe
- Departament de Biologia, Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears (UIB), INAGEA, Palma, Illes Balears, Spain
| | - Josefina Bota
- Departament de Biologia, Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears (UIB), INAGEA, Palma, Illes Balears, Spain
| | - Jaume Flexas
- Departament de Biologia, Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears (UIB), INAGEA, Palma, Illes Balears, Spain
- King Abdulaziz University, Jeddah, Saudi Arabia
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9
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Chen L, Luo W, Huang J, Peng S, Xiong D. Leaf photosynthetic plasticity does not predict biomass responses to growth irradiance in rice. PHYSIOLOGIA PLANTARUM 2021; 173:2155-2165. [PMID: 34537975 DOI: 10.1111/ppl.13564] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 09/08/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
Phenotypic plasticity, the capacity of an organism to generate alternative phenotypes in response to different environments, is a particularly important characteristic to enable sessile plants to adapt to rapid changes in their surroundings. Leaf anatomical and physiological traits exhibit plasticity in response to growth irradiances, but it is relatively unclear if the plasticity varies among genotypes for a species. Equally importantly, empirical results on how leaf-level plasticity influences whole-plant growth are largely absent. We conducted an integrated investigation into the light-introduced plasticity by measuring 48 traits involving plant growth, leaf anatomy, leaf biochemistry, and leaf physiology of five rice genotypes grown under two irradiances. More than half of the estimated traits were significantly affected by growth light intensities, and the sizes of the cumulative effect of growth light ranged from -25.04% (stomatal conductance at high measurement light) to 135.2% (tiller number). Growth irradiance levels dramatically shifted the relationship between photosynthetic rate and stomatal conductance. However, the relationship between photosynthetic rate and mesophyll conductance was rarely influenced by growth light levels. Importantly, the present study highlights the significant variation in trait plasticity across rice genotypes and that the light-introduced biomass changes were rarely predicted by leaf photosynthetic plasticity. Our findings imply that the genotypes with high productivity at the low growth light conditions do not necessarily have high productivity under high light conditions.
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Affiliation(s)
- Lin Chen
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Wanzhen Luo
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Jianliang Huang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Shaobing Peng
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Dongliang Xiong
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, Hubei, China
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10
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Flexas J, Clemente-Moreno MJ, Bota J, Brodribb TJ, Gago J, Mizokami Y, Nadal M, Perera-Castro AV, Roig-Oliver M, Sugiura D, Xiong D, Carriquí M. Cell wall thickness and composition are involved in photosynthetic limitation. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3971-3986. [PMID: 33780533 DOI: 10.1093/jxb/erab144] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
The key role of cell walls in setting mesophyll conductance to CO2 (gm) and, consequently, photosynthesis is reviewed. First, the theoretical properties of cell walls that can affect gm are presented. Then, we focus on cell wall thickness (Tcw) reviewing empirical evidence showing that Tcw varies strongly among species and phylogenetic groups in a way that correlates with gm and photosynthesis; that is, the thicker the mesophyll cell walls, the lower the gm and photosynthesis. Potential interplays of gm, Tcw, dehydration tolerance, and hydraulic properties of leaves are also discussed. Dynamic variations of Tcw in response to the environment and their implications in the regulation of photosynthesis are discussed, and recent evidence suggesting an influence of cell wall composition on gm is presented. We then propose a hypothetical mechanism for the influence of cell walls on photosynthesis, combining the effects of thickness and composition, particularly pectins. Finally, we discuss the prospects for using biotechnology for enhancing photosynthesis by altering cell wall-related genes.
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Affiliation(s)
- Jaume Flexas
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Ctra Valldemossa Km 7.5., 07122, Palma, Illes Balears, Spain
| | - María J Clemente-Moreno
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Ctra Valldemossa Km 7.5., 07122, Palma, Illes Balears, Spain
| | - Josefina Bota
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Ctra Valldemossa Km 7.5., 07122, Palma, Illes Balears, Spain
| | - Tim J Brodribb
- School of Biological Sciences, University of Tasmania, Hobart, TAS, Australia
| | - Jorge Gago
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Ctra Valldemossa Km 7.5., 07122, Palma, Illes Balears, Spain
| | - Yusuke Mizokami
- Laboratory of Applied Ecology, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji-shi, Tokyo, Japan
| | - Miquel Nadal
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Ctra Valldemossa Km 7.5., 07122, Palma, Illes Balears, Spain
| | - Alicia V Perera-Castro
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Ctra Valldemossa Km 7.5., 07122, Palma, Illes Balears, Spain
| | - Margalida Roig-Oliver
- Research Group on Plant Biology under Mediterranean Conditions, Institut d'Investigacions Agroambientals i d'Economia de l'Aigua (INAGEA) - Universitat de les Illes Balears (UIB), Ctra Valldemossa Km 7.5., 07122, Palma, Illes Balears, Spain
| | - Daisuke Sugiura
- Laboratory of Crop Science, Department of Plant Production Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, Japan
| | - Dongliang Xiong
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Marc Carriquí
- School of Biological Sciences, University of Tasmania, Hobart, TAS, Australia
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11
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Muir CD. A Stomatal Model of Anatomical Tradeoffs Between Gas Exchange and Pathogen Colonization. FRONTIERS IN PLANT SCIENCE 2020; 11:518991. [PMID: 33193466 PMCID: PMC7658178 DOI: 10.3389/fpls.2020.518991] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 10/01/2020] [Indexed: 06/11/2023]
Abstract
Stomatal pores control leaf gas exchange and are one route for infection of internal plant tissues by many foliar pathogens, setting up the potential for tradeoffs between photosynthesis and pathogen colonization. Anatomical shifts to lower stomatal density and/or size may also limit pathogen colonization, but such developmental changes could permanently reduce the gas exchange capacity for the life of the leaf. I developed and analyzed a spatially explicit model of pathogen colonization on the leaf as a function of stomatal size and density, anatomical traits which partially determine maximum rates of gas exchange. The model predicts greater stomatal size or density increases the probability of colonization, but the effect is most pronounced when the fraction of leaf surface covered by stomata is low. I also derived scaling relationships between stomatal size and density that preserves a given probability of colonization. These scaling relationships set up a potential anatomical conflict between limiting pathogen colonization and minimizing the fraction of leaf surface covered by stomata. Although a connection between gas exchange and pathogen defense has been suggested empirically, this is the first mathematical model connecting gas exchange and pathogen defense via stomatal anatomy. A limitation of the model is that it does not include variation in innate immunity and stomatal closure in response to pathogens. Nevertheless, the model makes predictions that can be tested with experiments and may explain variation in stomatal size and density among plants. The model is generalizable to many types of pathogens, but lacks significant biological realism that may be needed for precise predictions.
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Crous KY, Campany C, Lopez R, Cano FJ, Ellsworth DS. Canopy position affects photosynthesis and anatomy in mature Eucalyptus trees in elevated CO2. TREE PHYSIOLOGY 2020; 41:tpaa117. [PMID: 32918811 DOI: 10.1093/treephys/tpaa117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 08/26/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
Leaves are exposed to different light conditions according to their canopy position, resulting in structural and anatomical differences with consequences for carbon uptake. While these structure-function relationships have been thoroughly explored in dense forest canopies, such gradients may be diminished in open canopies, and they are often ignored in ecosystem models. We tested within-canopy differences in photosynthetic properties and structural traits in leaves in a mature Eucalyptus tereticornis canopy exposed to long-term elevated CO2 for up to three years. We explored these traits in relation to anatomical variation and diffusive processes for CO2 (i.e., stomatal conductance, gs and mesophyll conductance, gm) in both upper and lower portions of the canopy receiving ambient and elevated CO2. While shade resulted in 13% lower leaf mass per area ratio (MA) in lower versus upper canopy leaves, there was no relationship between leaf Nmass and canopy gap fraction. Both maximum carboxylation capacity (Vcmax) and maximum electron transport (Jmax) were ~ 18% lower in shaded leaves and were also reduced by ~ 22% with leaf aging. In mature leaves, we found no canopy differences for gm or gs, despite anatomical differences in MA, leaf thickness and mean mesophyll thickness between canopy positions. There was a positive relationship between net photosynthesis and gm or gs in mature leaves. Mesophyll conductance was negatively correlated with mean parenchyma length, suggesting that long palisade cells may contribute to a longer CO2 diffusional pathway and more resistance to CO2 transfer to chloroplasts. Few other relationships between gm and anatomical variables were found in mature leaves, which may be due to the open crown of Eucalyptus. Consideration of shade effects and leaf-age dependent responses to photosynthetic capacity and mesophyll conductance are critical to improve canopy photosynthesis models and will improve understanding of long-term responses to elevated CO2 in tree canopies.
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Affiliation(s)
- K Y Crous
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW 2751, Australia
| | - C Campany
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW 2751, Australia
- Department of Biology, Shepherd University, P.O. Box 5000, Shepherdstown, West Virginia, 25443, USA
| | - R Lopez
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW 2751, Australia
- Departamento de Sistemas y Recursos Naturales, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | - F J Cano
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW 2751, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Western Sydney University, Locked Bag 1797, Penrith NSW 2751, Australia
| | - D S Ellsworth
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith NSW 2751, Australia
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Cousins AB, Mullendore DL, Sonawane BV. Recent developments in mesophyll conductance in C3, C4, and crassulacean acid metabolism plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:816-830. [PMID: 31960507 DOI: 10.1111/tpj.14664] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 12/19/2019] [Indexed: 05/24/2023]
Abstract
The conductance of carbon dioxide (CO2 ) from the substomatal cavities to the initial sites of CO2 fixation (gm ) can significantly reduce the availability of CO2 for photosynthesis. There have been many recent reviews on: (i) the importance of gm for accurately modelling net rates of CO2 assimilation, (ii) on how leaf biochemical and anatomical factors influence gm , (iii) the technical limitation of estimating gm , which cannot be directly measured, and (iv) how gm responds to long- and short-term changes in growth and measurement environmental conditions. Therefore, this review will highlight these previous publications but will attempt not to repeat what has already been published. We will instead initially focus on the recent developments on the two-resistance model of gm that describe the potential of photorespiratory and respiratory CO2 released within the mitochondria to diffuse directly into both the chloroplast and the cytosol. Subsequently, we summarize recent developments in the three-dimensional (3-D) reaction-diffusion models and 3-D image analysis that are providing new insights into how the complex structure and organization of the leaf influences gm . Finally, because most of the reviews and literature on gm have traditionally focused on C3 plants we review in the final sections some of the recent developments, current understanding and measurement techniques of gm in C4 and crassulacean acid metabolism (CAM) plants. These plants have both specialized leaf anatomy and either a spatially or temporally separated CO2 concentrating mechanisms (C4 and CAM, respectively) that influence how we interpret and estimate gm compared with a C3 plants.
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Affiliation(s)
- Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Daniel L Mullendore
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Balasaheb V Sonawane
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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Knauer J, Zaehle S, De Kauwe MG, Haverd V, Reichstein M, Sun Y. Mesophyll conductance in land surface models: effects on photosynthesis and transpiration. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:858-873. [PMID: 31659806 DOI: 10.1111/tpj.14587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 10/10/2019] [Accepted: 10/17/2019] [Indexed: 05/08/2023]
Abstract
The CO2 transfer conductance within plant leaves (mesophyll conductance, gm ) is currently not considered explicitly in most land surface models (LSMs), but instead treated implicitly as an intrinsic property of the photosynthetic machinery. Here, we review approaches to overcome this model deficiency by explicitly accounting for gm , which comprises the re-adjustment of photosynthetic parameters and a model describing the variation of gm in dependence of environmental conditions. An explicit representation of gm causes changes in the response of photosynthesis to environmental factors, foremost leaf temperature, and ambient CO2 concentration, which are most pronounced when gm is small. These changes in leaf-level photosynthesis translate into a stronger climate and CO2 response of gross primary productivity (GPP) and transpiration at the global scale. The results from two independent studies show consistent latitudinal patterns of these effects with biggest differences in GPP in the boreal zone (up to ~15%). Transpiration and evapotranspiration show spatially similar, but attenuated, changes compared with GPP. These changes are indirect effects of gm caused by the assumed strong coupling between stomatal conductance and photosynthesis in current LSMs. Key uncertainties in these simulations are the variation of gm with light and the robustness of its temperature response across plant types and growth conditions. Future research activities focusing on the response of gm to environmental factors and its relation to other plant traits have the potential to improve the representation of photosynthesis in LSMs and to better understand its present and future role in the Earth system.
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Affiliation(s)
- Jürgen Knauer
- CSIRO Oceans and Atmosphere, Canberra, ACT, 2601, Australia
- Department of Biogeochemical Integration, Max Planck Institute for Biogeochemistry, 07745, Jena, Germany
| | - Sönke Zaehle
- Department of Biogeochemical Integration, Max Planck Institute for Biogeochemistry, 07745, Jena, Germany
- Michael-Stifel Center Jena for Data-Driven and Simulation Science, 07745, Jena, Germany
| | - Martin G De Kauwe
- ARC Centre of Excellence for Climate Extremes and the Climate Change Research Centre, University of New South Wales, Sydney, 2052, NSW, Australia
| | - Vanessa Haverd
- CSIRO Oceans and Atmosphere, Canberra, ACT, 2601, Australia
| | - Markus Reichstein
- Department of Biogeochemical Integration, Max Planck Institute for Biogeochemistry, 07745, Jena, Germany
- Michael-Stifel Center Jena for Data-Driven and Simulation Science, 07745, Jena, Germany
| | - Ying Sun
- School of Integrative Plant Science, Soil and Crop Sciences Section, Cornell University, Ithaca, NY, 14850, USA
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Cano FJ, Sharwood RE, Cousins AB, Ghannoum O. The role of leaf width and conductances to CO 2 in determining water use efficiency in C 4 grasses. THE NEW PHYTOLOGIST 2019; 223:1280-1295. [PMID: 31087798 DOI: 10.1111/nph.15920] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/28/2019] [Indexed: 05/26/2023]
Abstract
C4 plants achieve higher photosynthesis (An ) and intrinsic water use efficiency (iWUE) than C3 plants, but processes underpinning the variability in An and iWUE across the three C4 subtypes remain unclear, partly because we lack an integrated framework for quantifying the contribution of diffusional and biochemical limitations to C4 photosynthesis. We exploited the natural diversity among C4 grasses to develop an original mathematical approach for estimating eight key processes of C4 photosynthesis and their relative limitations to An . We also developed a new formulation to estimate mesophyll conductance (gm ) based on actual hydration rates of CO2 by carbonic anhydrases. We found a positive relationship between gm and iWUE and an inverse correlation with gsw among C4 grasses. We also revealed subtype-specific regulatory processes of iWUE that may be related to known anatomical traits characterising each C4 subtype. Leaf width was an important determinant of iWUE and showed significant correlations with key limitations of An , especially among NADP-ME species. In conclusion, incorporating leaf width in breeding trials may unlock new opportunities for C4 crops because the revealed negative relationship between leaf width and iWUE may translate into higher crop and canopy WUE.
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Affiliation(s)
- Francisco Javier Cano
- ARC Centre of Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, Sydney, NSW, 2753, Australia
| | - Robert E Sharwood
- ARC Centre of Translational Photosynthesis and Australian National University, Research School of Biology, Acton, ACT, 2601, Australia
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA
| | - Oula Ghannoum
- ARC Centre of Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, Sydney, NSW, 2753, Australia
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