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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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Luo D, Huang G, Zhang Q, Zhou G, Peng S, Li Y. Plasticity of mesophyll cell density and cell wall thickness and composition play a pivotal role in regulating plant growth and photosynthesis under shading in rapeseed. ANNALS OF BOTANY 2023; 132:963-978. [PMID: 37739395 PMCID: PMC10808032 DOI: 10.1093/aob/mcad140] [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: 07/06/2023] [Accepted: 09/20/2023] [Indexed: 09/24/2023]
Abstract
BACKGROUND AND AIMS Plasticity of leaf growth and photosynthesis is an important strategy of plants to adapt to shading stress; however, their strategy of leaf development to achieve a simultaneous increase in leaf area and photosynthesis under shading remains unknown. METHODS In the present study, a pot experiment was conducted using three rapeseed genotypes of Huayouza 50 (HYZ50), Zhongshuang 11 (ZS11) and Huayouza 62 (HYZ62), and the responses of plant growth, leaf morphoanatomical traits, cell wall composition and photosynthesis to shading were investigated. KEY RESULTS Shading significantly increased leaf area per plant (LAplant) in all genotypes, but the increase in HYZ62 was greater than that in HYZ50 and ZS11. The greater increment of LAplant in HYZ62 was related to the larger decrease in leaf mass per area (LMA) and leaf density (LD), which were in turn related to less densely packed mesophyll cells and thinner cell walls (Tcw). Moreover, shading significantly increased photosynthesis in HYZ62 but significantly decreased it in HYZ50. The enhanced photosynthesis in HYZ62 was related to increased mesophyll conductance (gm) due primarily to thinner cell walls. CONCLUSIONS The data presented indicate that the different plasticity of mesophyll cell density, cell wall thickness and cell wall composition in response to shading can dramatically affect leaf growth and photosynthesis.
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Affiliation(s)
- Dongxu Luo
- Ministry of Agriculture 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, 430070, China
| | - Guanjun Huang
- Ministry of Agriculture 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, 430070, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Qiangqiang Zhang
- Rice Ecophysiology and Precise Management Laboratory, College of Agronomy, Anhui Agricultural University, Anhui 230036, China
| | - Guangsheng Zhou
- Ministry of Agriculture 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, 430070, China
| | - Shaobing Peng
- Ministry of Agriculture 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, 430070, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yong Li
- Ministry of Agriculture 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, 430070, China
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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Zhang SY, Zhao BG, Shen Z, Mei YC, Li G, Dong FQ, Zhang J, Chao Q, Wang BC. Integrating ATAC-seq and RNA-seq to identify differentially expressed genes with chromatin-accessible changes during photosynthetic establishment in Populus leaves. PLANT MOLECULAR BIOLOGY 2023; 113:59-74. [PMID: 37634200 DOI: 10.1007/s11103-023-01375-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 08/03/2023] [Indexed: 08/29/2023]
Abstract
Leaves are the primary photosynthetic organs, providing essential substances for tree growth. It is important to obtain an anatomical understanding and regulatory network analysis of leaf development. Here, we studied leaf development in Populus Nanlin895 along a development gradient from the newly emerged leaf from the shoot apex to the sixth leaf (L1 to L6) using anatomical observations and RNA-seq analysis. It indicated that mesophyll cells possess obvious vascular, palisade, and spongy tissue with distinct intercellular spaces after L3. Additionally, vacuoles fuse while epidermal cells expand to form pavement cells. RNA-seq analysis indicated that genes highly expressed in L1 and L2 were related to cell division and differentiation, while those highly expressed in L3 were enriched in photosynthesis. Therefore, we selected L1 and L3 to integrate ATAC-seq and RNA-seq and identified 735 differentially expressed genes (DEGs) with changes in chromatin accessibility regions within their promoters, of which 87 were transcription factors (TFs), such as ABI3VP1, AP-EREBP, MYB, NAC, and GRF. Motif enrichment analysis revealed potential regulatory functions for the DEGs through upstream TFs including TCP, bZIP, HD-ZIP, Dof, BBR-BPC, and MYB. Overall, our research provides a potential molecular foundation for regulatory network exploration in leaf development during photosynthesis establishment.
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Affiliation(s)
- Sheng-Ying Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Biligen-Gaowa Zhao
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhuo Shen
- Guangdong Key Laboratory for New Technology Research of Vegetables, Vegetable Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin, 150040, China
| | - Ying-Chang Mei
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guo Li
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Feng-Qin Dong
- University of Chinese Academy of Sciences, Beijing, 100049, China
- The Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Jiao Zhang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qing Chao
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Bai-Chen Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Pang Y, Liao Q, Peng H, Qian C, Wang F. CO 2 mesophyll conductance regulated by light: a review. PLANTA 2023; 258:11. [PMID: 37289402 DOI: 10.1007/s00425-023-04157-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 04/17/2023] [Indexed: 06/09/2023]
Abstract
MAIN CONCLUSION Light quality and intensity regulate plant mesophyll conductance, which has played an essential role in photosynthesis by controlling leaf structural and biochemical properties. Mesophyll conductance (gm), a crucial physiological factor influencing the photosynthetic rate of leaves, is used to describe the resistance of CO2 from the sub-stomatal cavity into the chloroplast up to the carboxylation site. Leaf structural and biochemical components, as well as external environmental factors such as light, temperature, and water, all impact gm. As an essential factor of plant photosynthesis, light affects plant growth and development and plays a vital role in regulating gm as well as determining photosynthesis and yield. This review aimed to summarize the mechanisms of gm response to light. Both structural and biochemical perspectives were combined to reveal the effects of light quality and intensity on the gm, providing a guide for selecting the optimal conditions for intensifying photosynthesis in plants.
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Affiliation(s)
- Yadan Pang
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, 610213, China
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400712, China
| | - Qiuhong Liao
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, 610213, China
| | - Honggui Peng
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400712, China
| | - Chun Qian
- College of Horticulture and Landscape Architecture, Southwest University, Chongqing, 400712, China
| | - Fang Wang
- Institute of Urban Agriculture, Chinese Academy of Agricultural Sciences, Chengdu, 610213, China.
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Abstract
When microscopy meets modelling the exciting concept of a 'virtual leaf' is born. The goal of a 'virtual leaf' is to capture complex physiology in a virtual environment, resulting in the capacity to run experiments computationally. One example of a 'virtual leaf' application is capturing 3D anatomy from volume microscopy data and estimating where water evaporates in the leaf and the proportions of apoplastic, symplastic and gas phase water transport. The same 3D anatomy could then be used to improve established 3D reaction-diffusion models, providing a better understanding of the transport of CO2 across the stomata, through the airspace and across the mesophyll cell wall. This viewpoint discusses recent progress that has been made in transitioning from a bulk leaf approach to a 3D understanding of leaf physiology, in particular, the movement of CO2 and H2O within the leaf.
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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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7
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Zou QQ, Liu DH, Sang M, Jiang CD. Sunflower Leaf Structure Affects Chlorophyll a Fluorescence Induction Kinetics In Vivo. Int J Mol Sci 2022; 23:ijms232314996. [PMID: 36499324 PMCID: PMC9738131 DOI: 10.3390/ijms232314996] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 12/05/2022] Open
Abstract
Chlorophyll a fluorescence induction kinetics (CFI) is an important tool that reflects the photosynthetic function of leaves, but it remains unclear whether it is affected by leaf structure. Therefore, in this study, the leaf structure and CFI curves of sunflower and sorghum seedlings were analyzed. Results revealed that there was a significant difference between the structures of palisade and spongy tissues in sunflower leaves. Their CFI curves, measured on both the adaxial and abaxial sides, also differed significantly. However, the differences in the leaf structures and CFI curves between both sides of sorghum leaves were not significant. Further analysis revealed that the differences in the CFI curves between the adaxial and abaxial sides of sunflower leaves almost disappeared due to reduced incident light scattering and refraction in the leaf tissues; more importantly, changes in the CFI curves of the abaxial side were greater than the adaxial side. Compared to leaves grown under full sunlight, weak light led to decreased differences in the CFI curves between the adaxial and abaxial sides of sunflower leaves; of these, changes in the CFI curves and palisade tissue structure on the adaxial side were more obvious than on the abaxial side. Therefore, it appears that large differences in sunflower leaf structures may affect the shape of CFI curves. These findings lay a foundation for enhancing our understanding of CFI from a new perspective.
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Affiliation(s)
- Qing-Qing Zou
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dong-Huan Liu
- China National Botanical Garden, Beijing 100093, China
- Beijing Botanical Garden, Beijing Floriculture Engineering Technology Research Centre, Beijing 100093, China
| | - Min Sang
- China National Botanical Garden, Beijing 100093, China
- Beijing Botanical Garden, Beijing Floriculture Engineering Technology Research Centre, Beijing 100093, China
| | - Chuang-Dao Jiang
- Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
- Correspondence:
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8
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Lei Z, Westerband AC, Wright IJ, He Y, Zhang W, Cai X, Zhou Z, Liu F, Zhang Y. Leaf trait covariation and controls on leaf mass per area (LMA) following cotton domestication. ANNALS OF BOTANY 2022; 130:231-243. [PMID: 35849070 PMCID: PMC9445596 DOI: 10.1093/aob/mcac086] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 07/05/2022] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS The process of domestication has driven dramatic shifts in plant functional traits, including leaf mass per area (LMA). It remains unclear whether domestication has produced concerted shifts in the lower-level anatomical traits that underpin LMA and how these traits in turn affect photosynthesis. METHODS In this study we investigated controls of LMA and leaf gas exchange by leaf anatomical properties at the cellular, tissue and whole-leaf levels, comparing 26 wild and 31 domesticated genotypes of cotton (Gossypium). KEY RESULTS As expected, domesticated plants expressed lower LMA, higher photosynthesis and higher stomatal conductance, suggesting a shift towards the 'faster' end of the leaf economics spectrum. At whole-leaf level, variation in LMA was predominantly determined by leaf density (LD) both in wild and domesticated genotypes. At tissue level, higher leaf volume per area (Vleaf) in domesticated genotypes was driven by a simultaneous increase in the volume of epidermal, mesophyll and vascular bundle tissue and airspace, while lower LD resulted from a lower volume of palisade tissue and vascular bundles (which are of high density), paired with a greater volume of epidermis and airspace, which are of low density. The volume of spongy mesophyll exerted direct control on photosynthesis in domesticated genotypes but only indirect control in wild genotypes. At cellular level, a shift to larger but less numerous cells with thinner cell walls underpinned a lower proportion of cell wall mass, and thus a reduction in LD. CONCLUSIONS Taken together, cotton domestication has triggered synergistic shifts in the underlying determinants of LMA but also photosynthesis, at cell, tissue and whole-leaf levels, resulting in a marked shift in plant ecological strategy.
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Affiliation(s)
- Zhangying Lei
- Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Corps, Shihezi University, Shihezi, P.R. China
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, NSW, Australia
| | - Andrea C Westerband
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, NSW, Australia
| | - Ian J Wright
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, NSW, Australia
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
- ARC Centre for Plant Success in Nature & Agriculture, Western Sydney University, Penrith, NSW 2751, Australia
| | - Yang He
- Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Corps, Shihezi University, Shihezi, P.R. China
| | - Wangfeng Zhang
- Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Corps, Shihezi University, Shihezi, P.R. China
| | - Xiaoyan Cai
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, P.R. China
| | - Zhongli Zhou
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, P.R. China
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Momayyezi M, Rippner DA, Duong FV, Raja PV, Brown PJ, Kluepfel DA, Earles JM, Forrestel EJ, Gilbert ME, McElrone AJ. Structural and functional leaf diversity lead to variability in photosynthetic capacity across a range of Juglans regia genotypes. PLANT, CELL & ENVIRONMENT 2022; 45:2351-2365. [PMID: 35642731 PMCID: PMC9543909 DOI: 10.1111/pce.14370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 05/17/2022] [Accepted: 05/28/2022] [Indexed: 06/15/2023]
Abstract
Similar to other cropping systems, few walnut cultivars are used as scion in commercial production. Germplasm collections can be used to diversify cultivar options and hold potential for improving crop productivity, disease resistance and stress tolerance. In this study, we explored the anatomical and biochemical bases of photosynthetic capacity and response to water stress in 11 Juglans regia accessions in the U.S. department of agriculture, agricultural research service (USDA-ARS) National Clonal Germplasm. Net assimilation rate (An ) differed significantly among accessions and was greater in lower latitudes coincident with higher stomatal and mesophyll conductances, leaf thickness, mesophyll porosity, gas-phase diffusion, leaf nitrogen and lower leaf mass and stomatal density. High CO2 -saturated assimilation rates led to increases in An under diffusional and biochemical limitations. Greater An was found in lower-latitude accessions native to climates with more frost-free days, greater precipitation seasonality and lower temperature seasonality. As expected, water stress consistently impaired photosynthesis with the highest % reductions in lower-latitude accessions (A3, A5 and A9), which had the highest An under well-watered conditions. However, An for A3 and A5 remained among the highest under dehydration. J. regia accessions, which have leaf structural traits and biochemistry that enhance photosynthesis, could be used as commercial scions or breeding parents to enhance productivity.
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Affiliation(s)
- Mina Momayyezi
- Department of Viticulture and EnologyUniversity of CaliforniaDavisCaliforniaUSA
| | | | - Fiona V. Duong
- Department of Viticulture and EnologyUniversity of CaliforniaDavisCaliforniaUSA
| | - Pranav V. Raja
- Department of Viticulture and EnologyUniversity of CaliforniaDavisCaliforniaUSA
| | - Patrick J. Brown
- Department of Plant SciencesUniversity of CaliforniaDavisCaliforniaUSA
| | | | - J. Mason Earles
- Department of Viticulture and EnologyUniversity of CaliforniaDavisCaliforniaUSA
| | | | | | - Andrew J. McElrone
- Department of Viticulture and EnologyUniversity of CaliforniaDavisCaliforniaUSA
- USDA‐ARS, Crops Pathology and Genetics Research UnitDavisCaliforniaUSA
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10
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Perera-Castro AV, Waterman MJ, Robinson SA, Flexas J. Limitations to photosynthesis in bryophytes: certainties and uncertainties regarding methodology. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:4592-4604. [PMID: 35524766 DOI: 10.1093/jxb/erac189] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 05/05/2022] [Indexed: 06/14/2023]
Abstract
Bryophytes are the group of land plants with the lowest photosynthetic rates, which was considered to be a consequence of their higher anatomical CO2 diffusional limitation compared with tracheophytes. However, the most recent studies assessing limitations due to biochemistry and mesophyll conductance in bryophytes reveal discrepancies based on the methodology used. In this study, we compared data calculated from two different methodologies for estimating mesophyll conductance: variable J and the curve-fitting method. Although correlated, mesophyll conductance estimated by the curve-fitting method was on average 4-fold higher than the conductance obtained by the variable J method; a large enough difference to account for the scale of differences previously shown between the biochemical and diffusional limitations to photosynthesis. Biochemical limitations were predominant when the curve-fitting method was used. We also demonstrated that variations in bryophyte relative water content during measurements can also introduce errors in the estimation of mesophyll conductance, especially for samples which are overly desiccated. Furthermore, total chlorophyll concentration and soluble proteins were significantly lower in bryophytes than in tracheophytes, and the percentage of proteins quantified as Rubisco was also significantly lower in bryophytes (<6.3% in all studied species) than in angiosperms (>16% in all non-stressed cases). Photosynthetic rates normalized by Rubisco were not significantly different between bryophytes and angiosperms. Our data suggest that the biochemical limitation to photosynthesis in bryophytes is more relevant than so far assumed.
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Affiliation(s)
- Alicia V Perera-Castro
- Universitat de les Illes Balears, Department of Biology, INAGEA, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Illes Balears, Spain
- Universidad de La Laguna, Department of Botany, Ecology and Plant Physiology, Av. Astrofísico Francisco Sánchez, S/N, 38200 La Laguna, Canary Islands, Spain
| | - Melinda J Waterman
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmosphere and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
- Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, NSW, Australia
| | - Sharon A Robinson
- Centre for Sustainable Ecosystem Solutions, School of Earth, Atmosphere and Life Sciences, University of Wollongong, Wollongong, NSW, Australia
- Securing Antarctica's Environmental Future, University of Wollongong, Wollongong, NSW, Australia
| | - Jaume Flexas
- Universitat de les Illes Balears, Department of Biology, INAGEA, Carretera de Valldemossa Km 7.5, 07122, Palma de Mallorca, Illes Balears, Spain
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11
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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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12
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Sun H, Zhang YQ, Zhang SB, Huang W. Photosynthetic Induction Under Fluctuating Light Is Affected by Leaf Nitrogen Content in Tomato. FRONTIERS IN PLANT SCIENCE 2022; 13:835571. [PMID: 35251106 PMCID: PMC8891375 DOI: 10.3389/fpls.2022.835571] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/17/2022] [Indexed: 06/09/2023]
Abstract
The response of photosynthetic CO2 assimilation to changes of illumination affects plant growth and crop productivity under natural fluctuating light conditions. However, the effects of nitrogen (N) supply on photosynthetic physiology after transition from low to high light are seldom studied. To elucidate this, we measured gas exchange and chlorophyll fluorescence under fluctuating light in tomato (Solanum lycopersicum) seedlings grown with different N conditions. After transition from low to high light, the induction speeds of net CO2 assimilation (A N ), stomatal conductance (g s ), and mesophyll conductance (g m ) delayed with the decline in leaf N content. The time to reach 90% of maximum A N , g s and g m was negatively correlated with leaf N content. This delayed photosynthetic induction in plants grown under low N concentration was mainly caused by the slow induction response of g m rather than that of g s . Furthermore, the photosynthetic induction upon transfer from low to high light was hardly limited by photosynthetic electron flow. These results indicate that decreased leaf N content declines carbon gain under fluctuating light in tomato. Increasing the induction kinetics of g m has the potential to enhance the carbon gain of field crops grown in infertile soil.
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Affiliation(s)
- Hu Sun
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yu-Qi Zhang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agriculture Sciences, Beijing, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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Zait Y, Ferrero‐Serrano Á, Assmann SM. The α subunit of the heterotrimeric G protein regulates mesophyll CO 2 conductance and drought tolerance in rice. THE NEW PHYTOLOGIST 2021; 232:2324-2338. [PMID: 34515342 PMCID: PMC9293471 DOI: 10.1111/nph.17730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 09/01/2021] [Indexed: 05/03/2023]
Abstract
Mesophyll conductance gm determines CO2 diffusion rates from mesophyll intercellular air spaces to the chloroplasts and is an important factor limiting photosynthesis. Increasing gm in cultivated plants is a potential strategy to increase photosynthesis and intrinsic water use efficiency (WUEi ). The anatomy of the leaf and metabolic factors such as aquaporins and carbonic anhydrases have been identified as important determinants of gm . However, genes involved in the regulation and modulation of gm remain largely unknown. In this work, we investigated the role of heterotrimeric G proteins in gm and drought tolerance in rice d1 mutants, which harbor a null mutation in the Gα subunit gene, RGA1. d1 mutants in both cv Nipponbare and cv Taichung 65 exhibited increased gm , fostering improvement in photosynthesis, WUEi , and drought tolerance compared with wild-type. The increased surface area of mesophyll cells and chloroplasts exposed to intercellular airspaces and the reduced cell wall and chloroplast thickness in the d1 mutant are evident contributors to the increase in gm . Our results indicate that manipulation of heterotrimeric G protein signaling has the potential to improve crop WUEi and productivity under drought.
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Affiliation(s)
- Yotam Zait
- Biology DepartmentPenn State University208 Mueller LaboratoryUniversity ParkPA16802USA
| | - Ángel Ferrero‐Serrano
- Biology DepartmentPenn State University208 Mueller LaboratoryUniversity ParkPA16802USA
| | - Sarah M. Assmann
- Biology DepartmentPenn State University208 Mueller LaboratoryUniversity ParkPA16802USA
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14
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Stitt M, Luca Borghi G, Arrivault S. Targeted metabolite profiling as a top-down approach to uncover interspecies diversity and identify key conserved operational features in the Calvin-Benson cycle. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5961-5986. [PMID: 34473300 PMCID: PMC8411860 DOI: 10.1093/jxb/erab291] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/21/2021] [Indexed: 05/02/2023]
Abstract
Improving photosynthesis is a promising avenue to increase crop yield. This will be aided by better understanding of natural variance in photosynthesis. Profiling of Calvin-Benson cycle (CBC) metabolites provides a top-down strategy to uncover interspecies diversity in CBC operation. In a study of four C4 and five C3 species, principal components analysis separated C4 species from C3 species and also separated different C4 species. These separations were driven by metabolites that reflect known species differences in their biochemistry and pathways. Unexpectedly, there was also considerable diversity between the C3 species. Falling atmospheric CO2 and changing temperature, nitrogen, and water availability have driven evolution of C4 photosynthesis in multiple lineages. We propose that analogous selective pressures drove lineage-dependent evolution of the CBC in C3 species. Examples of species-dependent variation include differences in the balance between the CBC and the light reactions, and in the balance between regulated steps in the CBC. Metabolite profiles also reveal conserved features including inactivation of enzymes in low irradiance, and maintenance of CBC metabolites at relatively high levels in the absence of net CO2 fixation. These features may be important for photosynthetic efficiency in low light, fluctuating irradiance, and when stomata close due to low water availability.
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Affiliation(s)
- Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Gian Luca Borghi
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
| | - Stéphanie Arrivault
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, D-14476 Potsdam-Golm, Germany
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15
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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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Gimeno TE, Campany CE, Drake JE, Barton CVM, Tjoelker MG, Ubierna N, Marshall JD. Whole-tree mesophyll conductance reconciles isotopic and gas-exchange estimates of water-use efficiency. THE NEW PHYTOLOGIST 2021; 229:2535-2547. [PMID: 33217000 DOI: 10.1111/nph.17088] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 11/07/2020] [Indexed: 06/11/2023]
Abstract
Photosynthetic water-use efficiency (WUE) describes the link between terrestrial carbon (C) and water cycles. Estimates of intrinsic WUE (iWUE) from gas exchange and C isotopic composition (δ13 C) differ due to an internal conductance in the leaf mesophyll (gm ) that is variable and seldom computed. We present the first direct estimates of whole-tree gm , together with iWUE from whole-tree gas exchange and δ13 C of the phloem (δ13 Cph ). We measured gas exchange, online 13 C-discrimination, and δ13 Cph monthly throughout spring, summer, and autumn in Eucalyptus tereticornis grown in large whole-tree chambers. Six trees were grown at ambient temperatures and six at a 3°C warmer air temperature; a late-summer drought was also imposed. Drought reduced whole-tree gm . Warming had few direct effects, but amplified drought-induced reductions in whole-tree gm . Whole-tree gm was similar to leaf gm for these same trees. iWUE estimates from δ13 Cph agreed with iWUE from gas exchange, but only after incorporating gm . δ13 Cph was also correlated with whole-tree 13 C-discrimination, but offset by -2.5 ± 0.7‰, presumably due to post-photosynthetic fractionations. We conclude that δ13 Cph is a good proxy for whole-tree iWUE, with the caveats that post-photosynthetic fractionations and intrinsic variability of gm should be incorporated to provide reliable estimates of this trait in response to abiotic stress.
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Affiliation(s)
- Teresa E Gimeno
- Basque Centre for Climate Change (BC3), Leioa, 48940, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, 48008, Spain
| | - Courtney E Campany
- Department of Biology, Shepherd University, Shepherdstown, WV, 25443, USA
| | - John E Drake
- Forest and Natural Resources Management, SUNY-ESF, Syracuse, NY, 132110, USA
| | - Craig V M Barton
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Mark G Tjoelker
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Nerea Ubierna
- Research School of Biology, The Australian National University, Acton, ACT, 2601, Australia
| | - John D Marshall
- Department of Forest Ecology and Management, Swedish University of Agricultural Sciences (SLU), Skogsmarksgränd 17, 907 36, Umeå, Sweden
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17
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Sakoda K, Yamori W, Groszmann M, Evans JR. Stomatal, mesophyll conductance, and biochemical limitations to photosynthesis during induction. PLANT PHYSIOLOGY 2021; 185:146-160. [PMID: 33631811 PMCID: PMC8133641 DOI: 10.1093/plphys/kiaa011] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 10/22/2020] [Indexed: 05/07/2023]
Abstract
The dynamics of leaf photosynthesis in fluctuating light affects carbon gain by plants. Mesophyll conductance (gm) limits CO2 assimilation rate (A) under the steady state, but the extent of this limitation under non-steady-state conditions is unknown. In the present study, we aimed to characterize the dynamics of gm and the limitations to A imposed by gas diffusional and biochemical processes under fluctuating light. The induction responses of A, stomatal conductance (gs), gm, and the maximum rate of RuBP carboxylation (Vcmax) or electron transport (J) were investigated in Arabidopsis (Arabidopsis thaliana (L.)) and tobacco (Nicotiana tabacum L.). We first characterized gm induction after a change from darkness to light. Each limitation to A imposed by gm, gs and Vcmax or J was significant during induction, indicating that gas diffusional and biochemical processes limit photosynthesis. Initially, gs imposed the greatest limitation to A, showing the slowest response under high light after long and short periods of darkness, assuming RuBP-carboxylation limitation. However, if RuBP-regeneration limitation was assumed, then J imposed the greatest limitation. gm did not vary much following short interruptions to light. The limitation to A imposed by gm was the smallest of all the limitations for most of the induction phase. This suggests that altering induction kinetics of mesophyll conductance would have little impact on A following a change in light. To enhance the carbon gain by plants under naturally dynamic light environments, attention should therefore be focused on faster stomatal opening or activation of electron transport.
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Affiliation(s)
- Kazuma Sakoda
- Graduate School of Agricultural and Life Sciences, University of Tokyo, Nishitokyo 188-0002, Tokyo, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Wataru Yamori
- Graduate School of Agricultural and Life Sciences, University of Tokyo, Nishitokyo 188-0002, Tokyo, Japan
| | - Michael Groszmann
- Division of Plant Science, Research School of Biology, The Australian National University, Canberra, Territory 2601, Australia
| | - John R Evans
- Division of Plant Science, Research School of Biology, The Australian National University, Canberra, Territory 2601, Australia
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18
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Evans JR. Mesophyll conductance: walls, membranes and spatial complexity. THE NEW PHYTOLOGIST 2021; 229:1864-1876. [PMID: 33135193 DOI: 10.1111/nph.16968] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/28/2020] [Indexed: 06/11/2023]
Abstract
A significant resistance to CO2 diffusion is imposed by mesophyll tissue inside leaves. Mesophyll resistance, rm (or its reciprocal, mesophyll conductance, gm ), reduces the rate at which Rubisco can fix CO2 , increasing the water and nitrogen costs of carbon acquisition. gm varies in proportion to the surface area of chloroplasts exposed to intercellular airspace per unit leaf area. It also depends on the thickness and effective porosity of the cell wall and the CO2 permeabilities of membranes. As no measurements exist for the effective porosity of mesophyll cell walls, and CO2 permeability values are too low to account for observed rates of CO2 assimilation, conclusions from modelling must be treated with caution. There is great variation in the mesophyll resistance per unit chloroplast area for a given cell wall thickness, which may reflect differences in effective porosity. While apparent gm can vary with CO2 and irradiance, the underlying conductance at the cellular level may remain unchanged. Dynamic changes in apparent gm arise for spatial reasons and because chloroplasts differ in their photosynthetic composition and operate in different light environments. Measurements of the temperature sensitivity of membrane CO2 permeability are urgently needed to explain variation in temperature responses of gm .
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Affiliation(s)
- John R Evans
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Canberra, ACT, 2601, Australia
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19
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Yang YJ, Hu H, Huang W. The Light Dependence of Mesophyll Conductance and Relative Limitations on Photosynthesis in Evergreen Sclerophyllous Rhododendron Species. PLANTS (BASEL, SWITZERLAND) 2020; 9:plants9111536. [PMID: 33182785 PMCID: PMC7697185 DOI: 10.3390/plants9111536] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/23/2020] [Accepted: 10/30/2020] [Indexed: 06/09/2023]
Abstract
Mesophyll conductance (gm) limits CO2 diffusion from sub-stomatal internal cavities to the sites of RuBP carboxylation. However, the response of gm to light intensity remains controversial. Furthermore, little is known about the light response of relative mesophyll conductance limitation (lm) and its effect on photosynthesis. In this study, we measured chlorophyll fluorescence and gas exchange in nine evergreen sclerophyllous Rhododendron species. gm was maintained stable across light intensities from 300 to 1500 μmol photons m-2 s-1 in all these species, indicating that gm did not respond to the change in illumination in them. With an increase in light intensity, lm gradually increased, making gm the major limiting factor for area-based photosynthesis (AN) under saturating light. A strong negative relationship between lm and AN was found at 300 μmol photons m-2 s-1 but disappeared at 1500 μmol photons m-2 s-1, suggesting an important role for lm in determining AN at sub-saturating light. Furthermore, the light-dependent increase in lm led to a decrease in chloroplast CO2 concentration (Cc), inducing the gradual increase of photorespiration. A higher lm under saturating light made AN more limited by RuBP carboxylation. These results indicate that the light response of lm plays significant roles in determining Cc, photorespiration, and the rate-limiting step of AN.
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Affiliation(s)
- Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China;
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Hu
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China;
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China;
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20
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Veromann-Jürgenson LL, Brodribb TJ, Niinemets Ü, Tosens T. Variability in the chloroplast area lining the intercellular airspace and cell walls drives mesophyll conductance in gymnosperms. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:4958-4971. [PMID: 32392579 DOI: 10.1093/jxb/eraa231] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 05/05/2020] [Indexed: 06/11/2023]
Abstract
The photosynthetic efficiency of plants in different environments is controlled by stomata, hydraulics, biochemistry, and mesophyll conductance (gm). Recently, gm was demonstrated to be the key limitation of photosynthesis in gymnosperms. Values of gm across gymnosperms varied over 20-fold, but this variation was poorly explained by robust structure-bound integrated traits such as leaf dry mass per area. Understanding how the component structural traits control gm is central for identifying the determinants of variability in gm across plant functional and phylogenetic groups. Here, we investigated the structural traits responsible for gm in 65 diverse gymnosperms. Although the integrated morphological traits, shape, and anatomical characteristics varied widely across species, the distinguishing features of all gymnosperms were thick mesophyll cell walls and low chloroplast area exposed to intercellular airspace (Sc/S) compared with angiosperms. Sc/S and cell wall thickness were the fundamental traits driving variations in gm across gymnosperm species. Chloroplast thickness was the strongest limitation of gm among liquid-phase components. The variation in leaf dry mass per area was not correlated with the key ultrastructural traits determining gm. Thus, given the absence of correlating integrated easy-to-measure traits, detailed knowledge of underlying component traits controlling gm across plant taxa is necessary to understand the photosynthetic limitations across ecosystems.
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Affiliation(s)
| | - Timothy J Brodribb
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
- Estonian Academy of Sciences, Tallinn, Estonia
| | - Tiina Tosens
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
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21
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Yin X, van der Putten PEL, Belay D, Struik PC. Using photorespiratory oxygen response to analyse leaf mesophyll resistance. PHOTOSYNTHESIS RESEARCH 2020; 144:85-99. [PMID: 32040701 PMCID: PMC7113236 DOI: 10.1007/s11120-020-00716-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 01/27/2020] [Indexed: 05/12/2023]
Abstract
Classical approaches to estimate mesophyll conductance ignore differences in resistance components for CO2 from intercellular air spaces (IAS) and CO2 from photorespiration (F) and respiration (Rd). Consequently, mesophyll conductance apparently becomes sensitive to (photo)respiration relative to net photosynthesis, (F + Rd)/A. This sensitivity depends on several hard-to-measure anatomical properties of mesophyll cells. We developed a method to estimate the parameter m (0 ≤ m ≤ 1) that lumps these anatomical properties, using gas exchange and chlorophyll fluorescence measurements where (F + Rd)/A ratios vary. This method was applied to tomato and rice leaves measured at five O2 levels. The estimated m was 0.3 for tomato but 0.0 for rice, suggesting that classical approaches implying m = 0 work well for rice. The mesophyll conductance taking the m factor into account still responded to irradiance, CO2, and O2 levels, similar to response patterns of stomatal conductance to these variables. Largely due to different m values, the fraction of (photo)respired CO2 being refixed within mesophyll cells was lower in tomato than in rice. But that was compensated for by the higher fraction via IAS, making the total re-fixation similar for both species. These results, agreeing with CO2 compensation point estimates, support our method of effectively analysing mesophyll resistance.
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Affiliation(s)
- Xinyou Yin
- Centre for Crop Systems Analysis, Wageningen University & Research, P.O. Box 430, 6700 AK, Wageningen, The Netherlands.
| | - Peter E L van der Putten
- Centre for Crop Systems Analysis, Wageningen University & Research, P.O. Box 430, 6700 AK, Wageningen, The Netherlands
| | - Daniel Belay
- Selale University, P.O. Box 245, Fiche, Ethiopia
| | - Paul C Struik
- Centre for Crop Systems Analysis, Wageningen University & Research, P.O. Box 430, 6700 AK, Wageningen, The Netherlands
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22
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Mesophyll conductance: the leaf corridors for photosynthesis. Biochem Soc Trans 2020; 48:429-439. [DOI: 10.1042/bst20190312] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/25/2020] [Accepted: 01/30/2020] [Indexed: 12/15/2022]
Abstract
Besides stomata, the photosynthetic CO2 pathway also involves the transport of CO2 from the sub-stomatal air spaces inside to the carboxylation sites in the chloroplast stroma, where Rubisco is located. This pathway is far to be a simple and direct way, formed by series of consecutive barriers that the CO2 should cross to be finally assimilated in photosynthesis, known as the mesophyll conductance (gm). Therefore, the gm reflects the pathway through different air, water and biophysical barriers within the leaf tissues and cell structures. Currently, it is known that gm can impose the same level of limitation (or even higher depending of the conditions) to photosynthesis than the wider known stomata or biochemistry. In this mini-review, we are focused on each of the gm determinants to summarize the current knowledge on the mechanisms driving gm from anatomical to metabolic and biochemical perspectives. Special attention deserve the latest studies demonstrating the importance of the molecular mechanisms driving anatomical traits as cell wall and the chloroplast surface exposed to the mesophyll airspaces (Sc/S) that significantly constrain gm. However, even considering these recent discoveries, still is poorly understood the mechanisms about signaling pathways linking the environment a/biotic stressors with gm responses. Thus, considering the main role of gm as a major driver of the CO2 availability at the carboxylation sites, future studies into these aspects will help us to understand photosynthesis responses in a global change framework.
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23
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Harwood R, Goodman E, Gudmundsdottir M, Huynh M, Musulin Q, Song M, Barbour MM. Cell and chloroplast anatomical features are poorly estimated from 2D cross-sections. THE NEW PHYTOLOGIST 2020; 225:2567-2578. [PMID: 31553810 DOI: 10.1111/nph.16219] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Leaf function is intimately related to the size, shape, abundance and position of cells and chloroplasts. Anatomy has long been assessed and quantified in two dimensions with 3D structure inferred from 2D micrographs. Serial block face scanning electron microscopy (SBF-SEM) was used to reconstruct 95 cells and 1173 chloroplasts from three wheat and nine chickpea leaves (three samples each from three chickpea genotypes). Wheat chloroplast volume was underestimated by 61% in mesophyll cells and 45% in bundle sheath cells from 2D micrographs, whereas chickpea mesophyll chloroplast volume was underestimated by 60% using simple geometrical models. Models of chickpea spongy and palisade cells both under- and overestimated surface area and volume by varying degrees. These models did not adequately capture irregular shapes such as flattening of chloroplasts or lobed spongy mesophyll cells. It is concluded that simple geometrical models to estimate chloroplast and cell 3D volume and surface area from 2D micrographs are inadequate, and that SBF-SEM has strong potential to contribute to improved understanding of leaf form and function.
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Affiliation(s)
- Richard Harwood
- School of Life and Environmental Sciences, The University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia
| | - Elinor Goodman
- School of Life and Environmental Sciences, The University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia
| | - Marin Gudmundsdottir
- School of Life and Environmental Sciences, The University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia
| | - Minh Huynh
- Australian Centre for Microscopy and Microanalysis, The University of Sydney, City Road, Sydney, NSW, 2006, Australia
| | - Quinn Musulin
- School of Life and Environmental Sciences, The University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia
| | - Magnolia Song
- School of Life and Environmental Sciences, The University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia
| | - Margaret M Barbour
- School of Life and Environmental Sciences, The University of Sydney, Private Bag 4011, Narellan, NSW, 2567, Australia
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Xiong D, Nadal M. Linking water relations and hydraulics with photosynthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:800-815. [PMID: 31677190 DOI: 10.1111/tpj.14595] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 10/16/2019] [Accepted: 10/24/2019] [Indexed: 05/28/2023]
Abstract
For land plants, water is the principal governor of growth. Photosynthetic performance is highly dependent on the stable and suitable water status of leaves, which is balanced by the water transport capacity, the water loss rate as well as the water capacitance of the plant. This review discusses the links between leaf water status and photosynthesis, specifically focussing on the coordination of CO2 and water transport within leaves, and the potential role of leaf capacitance and elasticity on CO2 and water transport.
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Affiliation(s)
- 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, 430070, China
| | - Miquel Nadal
- Research Group on Plant Biology under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears (UIB) - Institute of Agro-Environmental Research and Water Economy (INAGEA), Carretera de Valldemossa, 07122, Palma, Spain
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25
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Momayyezi M, McKown AD, Bell SCS, Guy RD. Emerging roles for carbonic anhydrase in mesophyll conductance and photosynthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:831-844. [PMID: 31816145 DOI: 10.1111/tpj.14638] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 11/17/2019] [Accepted: 11/25/2019] [Indexed: 05/24/2023]
Abstract
Carbonic anhydrase (CA) is an abundant protein in most photosynthesizing organisms and higher plants. This review paper considers the physiological importance of the more abundant CA isoforms in photosynthesis, through their effects on CO2 diffusion and other processes in photosynthetic organisms. In plants, CA has multiple isoforms in three different families (α, β and γ) and is mainly known to catalyze the CO2↔HCO3- equilibrium. This reversible conversion has a clear role in photosynthesis, primarily through sustaining the CO2 concentration at the site of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). Despite showing the same major reaction mechanism, the three main CA families are evolutionarily distinct. For different CA isoforms, cellular localization and total gene expression as a function of developmental stage are predicted to determine the role of each family in relation to the net assimilation rate. Reaction-diffusion modeling and observational evidence support a role for CA activity in reducing resistance to CO2 diffusion inside mesophyll cells by facilitating CO2 transfer in both gas and liquid phases. In addition, physical and/or biochemical interactions between CAs and other membrane-bound compartments, for example aquaporins, are suggested to trigger a CO2 -sensing response by stomatal movement. In response to environmental stresses, changes in the expression level of CAs and/or stimulated deactivation of CAs may correspond with lower photosynthetic capacity. We suggest that further studies should focus on the dynamics of the relationship between the activity of CAs (with different subcellular localization, abundance and gene expression) and limitations due to CO2 diffusivity through the mesophyll and supply of CO2 to photosynthetic reactions.
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Affiliation(s)
- Mina Momayyezi
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
- Department of Viticulture and Enology, University of California, Davis, CA, 95616, USA
| | - Athena D McKown
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Shannon C S Bell
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Robert D Guy
- Department of Forest and Conservation Sciences, Faculty of Forestry, University of British Columbia, Forest Sciences Centre, 2424 Main Mall, Vancouver, BC, V6T 1Z4, Canada
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26
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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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Du T, Meng P, Huang J, Peng S, Xiong D. Fast photosynthesis measurements for phenotyping photosynthetic capacity of rice. PLANT METHODS 2020; 16:6. [PMID: 31998402 PMCID: PMC6979334 DOI: 10.1186/s13007-020-0553-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/10/2020] [Indexed: 06/10/2023]
Abstract
BACKGROUND Over the past decades, the structural and functional genomics of rice have been deeply studied, and high density of molecular genetic markers have been developed. However, the genetic variation in leaf photosynthesis, the most important trait for rice yield improvement, was rarely studied. The lack of photosynthesis phenotyping tools is one of the bottlenecks, as traditional direct photosynthesis measurements are very low-throughput, and recently developed high-throughput methods are indirect measurements. Hence, there is an urgent need for a fast, accurate and direct measurement approach. RESULT We reported a fast photosynthesis measurement (FPM) method for phenotyping photosynthetic capacity of rice, which measures photosynthesis of excised tillers in environment-controlled lab conditions. The light response curves measured using FPM approach coped well with that the curves measured using traditional gas exchange approach. Importantly, the FPM technique achieved an average throughput of 5.4 light response curves per hour, which was 3 times faster than the 1.8 light response curves per hour using the traditional method. Tillers sampled at early morning had the highest photosynthesis, stomatal conductance and the lowest variability. In addition, even 12 h after sampling, there was no significant difference of photosynthesis rate between excised tillers and in situ. We finally investigated the genetic variations of photosynthetic traits across 568 F2 lines using the FPM technique and discussed the logistics of screening several hundred samples per day per instrumental unit using FPM to generate a wealth of photosynthetic phenotypic data, which might help to improve the selection power in large populations of rice with the ultimate aim of improving yield through improved photosynthesis. CONCLUSIONS Here we developed a high-throughput method that can measure the rice leaf photosynthetic capacity approximately 10 times faster than traditional gas exchange approaches. Importantly, this method can overcome measurement errors caused by environmental heterogeneity under field conditions, and it is possible to measure 12 or more hours per day under lab conditions.
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Affiliation(s)
- Tingting Du
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Ping Meng
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Jianliang Huang
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - Shaobing Peng
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, Huazhong Agricultural University, Wuhan, 430070 Hubei China
| | - 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, Huazhong Agricultural University, Wuhan, 430070 Hubei China
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Knauer J, Zaehle S, De Kauwe MG, Bahar NHA, Evans JR, Medlyn BE, Reichstein M, Werner C. Effects of mesophyll conductance on vegetation responses to elevated CO 2 concentrations in a land surface model. GLOBAL CHANGE BIOLOGY 2019; 25:1820-1838. [PMID: 30809890 PMCID: PMC6487956 DOI: 10.1111/gcb.14604] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/26/2019] [Indexed: 05/13/2023]
Abstract
Mesophyll conductance (gm ) is known to affect plant photosynthesis. However, gm is rarely explicitly considered in land surface models (LSMs), with the consequence that its role in ecosystem and large-scale carbon and water fluxes is poorly understood. In particular, the different magnitudes of gm across plant functional types (PFTs) are expected to cause spatially divergent vegetation responses to elevated CO2 concentrations. Here, an extensive literature compilation of gm across major vegetation types is used to parameterize an empirical model of gm in the LSM JSBACH and to adjust photosynthetic parameters based on simulated An - Ci curves. We demonstrate that an explicit representation of gm changes the response of photosynthesis to environmental factors, which cannot be entirely compensated by adjusting photosynthetic parameters. These altered responses lead to changes in the photosynthetic sensitivity to atmospheric CO2 concentrations which depend both on the magnitude of gm and the climatic conditions, particularly temperature. We then conducted simulations under ambient and elevated (ambient + 200 μmol/mol) CO2 concentrations for contrasting ecosystems and for historical and anticipated future climate conditions (representative concentration pathways; RCPs) globally. The gm -explicit simulations using the RCP8.5 scenario resulted in significantly higher increases in gross primary productivity (GPP) in high latitudes (+10% to + 25%), intermediate increases in temperate regions (+5% to + 15%), and slightly lower to moderately higher responses in tropical regions (-2% to +5%), which summed up to moderate GPP increases globally. Similar patterns were found for transpiration, but with a lower magnitude. Our results suggest that the effect of an explicit representation of gm is most important for simulated carbon and water fluxes in the boreal zone, where a cold climate coincides with evergreen vegetation.
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Affiliation(s)
- Jürgen Knauer
- Department of Biogeochemical IntegrationMax Planck Institute for BiogeochemistryJenaGermany
- International Max Planck Research School for Global Biogeochemical Cycles (IMPRS gBGC)JenaGermany
| | - Sönke Zaehle
- Department of Biogeochemical IntegrationMax Planck Institute for BiogeochemistryJenaGermany
- Michael‐Stifel Center Jena for Data‐Driven and Simulation ScienceJenaGermany
| | - Martin G. De Kauwe
- ARC Centre of Excellence for Climate Extremes and the Climate Change Research CentreUniversity of New South WalesSydneyNSWAustralia
| | - Nur H. A. Bahar
- ARC Centre of Excellence in Plant Energy Biology, Division of Plant SciencesResearch School of Biology, Australian National UniversityCanberraACTAustralia
| | - John R. Evans
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant SciencesResearch School of Biology, Australian National UniversityCanberraACTAustralia
| | - Belinda E. Medlyn
- Hawkesbury Institute for the EnvironmentWestern Sydney UniversityRichmondNSWAustralia
| | - Markus Reichstein
- Department of Biogeochemical IntegrationMax Planck Institute for BiogeochemistryJenaGermany
- Michael‐Stifel Center Jena for Data‐Driven and Simulation ScienceJenaGermany
| | - Christiane Werner
- Department of Ecosystem PhysiologyUniversity of FreiburgFreiburgGermany
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30
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Carriquí M, Douthe C, Molins A, Flexas J. Leaf anatomy does not explain apparent short-term responses of mesophyll conductance to light and CO 2 in tobacco. PHYSIOLOGIA PLANTARUM 2019; 165:604-618. [PMID: 29744895 DOI: 10.1111/ppl.12755] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/03/2018] [Accepted: 05/07/2018] [Indexed: 06/08/2023]
Abstract
Mesophyll conductance to CO2 (gm ), a key photosynthetic trait, is strongly constrained by leaf anatomy. Leaf anatomical parameters such as cell wall thickness and chloroplast area exposed to the mesophyll intercellular airspace have been demonstrated to determine gm in species with diverging phylogeny, leaf structure and ontogeny. However, the potential implication of leaf anatomy, especially chloroplast movement, on the short-term response of gm to rapid changes (i.e. seconds to minutes) under different environmental conditions (CO2 , light or temperature) has not been examined. The aim of this study was to determine whether the observed rapid variations of gm in response to variations of light and CO2 could be explained by changes in any leaf anatomical arrangements. When compared to high light and ambient CO2 , the values of gm estimated by chlorophyll fluorescence decreased under high CO2 and increased at low CO2 , while it decreased with decreasing light. Nevertheless, no changes in anatomical parameters, including chloroplast distribution, were found. Hence, the gm estimated by analytical models based on anatomical parameters was constant under varying light and CO2 . Considering this discrepancy between anatomy and chlorophyll fluorescence estimates, it is concluded that apparent fast gm variations should be due to artefacts in its estimation and/or to changes in the biochemical components acting on diffusional properties of the leaf (e.g. aquaporins and carbonic anhydrase).
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Affiliation(s)
- Marc Carriquí
- Research Group on Plant Biology Under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears - Instituto de investigaciones Agroambientales y de la Economía del Agua (INAGEA), Palma, 07122, Spain
| | - Cyril Douthe
- Research Group on Plant Biology Under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears - Instituto de investigaciones Agroambientales y de la Economía del Agua (INAGEA), Palma, 07122, Spain
| | - Arántzazu Molins
- Departament de Botànica, ICBIBE & Jardí Botànic, Facultat de Ciències Biològiques, Universitat de València, Valencia, 46100, Spain
| | - Jaume Flexas
- Research Group on Plant Biology Under Mediterranean Conditions, Departament de Biologia, Universitat de les Illes Balears - Instituto de investigaciones Agroambientales y de la Economía del Agua (INAGEA), Palma, 07122, Spain
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31
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Ren T, Weraduwage SM, Sharkey TD. Prospects for enhancing leaf photosynthetic capacity by manipulating mesophyll cell morphology. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:1153-1165. [PMID: 30590670 DOI: 10.1093/jxb/ery448] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 12/25/2018] [Indexed: 06/09/2023]
Abstract
Leaves are beautifully specialized organs designed to maximize the use of light and CO2 for photosynthesis. Engineering leaf anatomy therefore holds great potential to enhance photosynthetic capacity. Here we review the effect of the dominant leaf anatomical traits on leaf photosynthesis and confirm that a high chloroplast surface area exposed to intercellular airspace per unit leaf area (Sc) is critical for efficient photosynthesis. The possibility of improving Sc through appropriately increasing mesophyll cell density is further analyzed. The potential influences of modifying mesophyll cell morphology on CO2 diffusion, light distribution within the leaf, and other physiological processes are also discussed. Some potential target genes regulating leaf mesophyll cell proliferation and expansion are explored. Indeed, more comprehensive research is needed to understand how manipulating mesophyll cell morphology through editing the potential target genes impacts leaf photosynthetic capacity and related physiological processes. This will pinpoint the targets for engineering leaf anatomy to maximize photosynthetic capacity.
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Affiliation(s)
- Tao Ren
- College of Resources and Environment, Huazhong Agricultural University, China
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, USA
| | - Sarathi M Weraduwage
- Department of Energy Plant Research Laboratory and Plant Resiience Institute, Michigan State University, East Lansing, USA
| | - Thomas D Sharkey
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, USA
- Department of Energy Plant Research Laboratory and Plant Resiience Institute, Michigan State University, East Lansing, USA
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32
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Shrestha A, Buckley TN, Lockhart EL, Barbour MM. The response of mesophyll conductance to short- and long-term environmental conditions in chickpea genotypes. AOB PLANTS 2019; 11:ply073. [PMID: 30680087 PMCID: PMC6340285 DOI: 10.1093/aobpla/ply073] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 12/07/2018] [Indexed: 05/23/2023]
Abstract
. Mesophyll conductance (g m) has been shown to vary between genotypes of a number of species and with growth environments, including nitrogen availability, but understanding of g m variability in legumes is limited. We might expect g m in legumes to respond differently to limited nitrogen availability, due to their ability to fix atmospheric N2. Using online stable carbon isotope discrimination method, we quantified genetic variability in g m under ideal conditions, investigated g m response to N source (N2-fixation or inorganic N) and determined the effects of N source and water availability on the rapid response of g m to photosynthetic photon flux density (PPFD) and radiation wavelength in three genotypes of chickpea (Cicer arietinum). Genotypes varied 2-fold in g m under non-limiting environments. N-fed plants had higher g m than N2-fixing plants in one genotype, while g m in the other two genotypes was unaffected. g m response to PPFD was altered by N source in one of three genotypes, in which the g m response to PPFD was statistically significant in N-fed plants but not in N2-fixing plants. There was no clear effect of moderate water stress on the g m response to PPFD and radiation wavelength. Genotypes of a single legume species differ in the sensitivity of g m to both long- and short-term environmental conditions, precluding utility in crop breeding programmes.
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Affiliation(s)
- Arjina Shrestha
- The Centre for Carbon, Water and Food, Faculty of Science, The University of Sydney, Sydney, Australia
| | - Thomas N Buckley
- The Centre for Carbon, Water and Food, Faculty of Science, The University of Sydney, Sydney, Australia
- Department of Plant Sciences, University of California, Davis, CA, USA
| | - Erin L Lockhart
- The Centre for Carbon, Water and Food, Faculty of Science, The University of Sydney, Sydney, Australia
| | - Margaret M Barbour
- The Centre for Carbon, Water and Food, Faculty of Science, The University of Sydney, Sydney, Australia
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33
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Earles JM, Buckley TN, Brodersen CR, Busch FA, Cano FJ, Choat B, Evans JR, Farquhar GD, Harwood R, Huynh M, John GP, Miller ML, Rockwell FE, Sack L, Scoffoni C, Struik PC, Wu A, Yin X, Barbour MM. Embracing 3D Complexity in Leaf Carbon-Water Exchange. TRENDS IN PLANT SCIENCE 2019; 24:15-24. [PMID: 30309727 DOI: 10.1016/j.tplants.2018.09.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 09/06/2018] [Accepted: 09/11/2018] [Indexed: 06/08/2023]
Abstract
Leaves are a nexus for the exchange of water, carbon, and energy between terrestrial plants and the atmosphere. Research in recent decades has highlighted the critical importance of the underlying biophysical and anatomical determinants of CO2 and H2O transport, but a quantitative understanding of how detailed 3D leaf anatomy mediates within-leaf transport has been hindered by the lack of a consensus framework for analyzing or simulating transport and its spatial and temporal dynamics realistically, and by the difficulty of measuring within-leaf transport at the appropriate scales. We discuss how recent technological advancements now make a spatially explicit 3D leaf analysis possible, through new imaging and modeling tools that will allow us to address long-standing questions related to plant carbon-water exchange.
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Affiliation(s)
- J Mason Earles
- School of Forestry & Environmental Studies, Yale University, New Haven, CT 06511, USA; Equal contribution
| | - Thomas N Buckley
- Department of Plant Sciences, University of California Davis, CA 95916, USA; Equal contribution
| | - Craig R Brodersen
- School of Forestry & Environmental Studies, Yale University, New Haven, CT 06511, USA
| | - Florian A Busch
- Research School of Biology, Australian National University, Action, ACT 0200, Australia
| | - F Javier Cano
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW 2753, Australia
| | - Brendan Choat
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW 2753, Australia
| | - John R Evans
- Research School of Biology, Australian National University, Action, ACT 0200, Australia
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Action, ACT 0200, Australia
| | | | - Minh Huynh
- University of Sydney, Sydney, NSW 2006, Australia
| | - Grace P John
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, CA 90095, USA
| | - Megan L Miller
- College of Natural Resources, University of Idaho, Moscow, ID 83844, USA
| | - Fulton E Rockwell
- Department of Organism and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, CA 90095, USA
| | - Christine Scoffoni
- Department of Biological Sciences, California State University Los Angeles, CA 90032, USA
| | - Paul C Struik
- Department of Plant Sciences, Wageningen University, Centre for Crop Systems Analysis, 6700 AK Wageningen, The Netherlands
| | - Alex Wu
- Centre for Plant Science, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Xinyou Yin
- Department of Plant Sciences, Wageningen University, Centre for Crop Systems Analysis, 6700 AK Wageningen, The Netherlands
| | - Margaret M Barbour
- University of Sydney, Sydney, NSW 2006, Australia; www.sydney.edu.au/science/people/margaret.barbour.
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34
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Flexas J, Cano FJ, Carriquí M, Coopman RE, Mizokami Y, Tholen D, Xiong D. CO2 Diffusion Inside Photosynthetic Organs. THE LEAF: A PLATFORM FOR PERFORMING PHOTOSYNTHESIS 2018. [DOI: 10.1007/978-3-319-93594-2_7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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35
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Pleban JR, Mackay DS, Aston TL, Ewers BE, Weinig C. Phenotypic Trait Identification Using a Multimodel Bayesian Method: A Case Study Using Photosynthesis in Brassica rapa Genotypes. FRONTIERS IN PLANT SCIENCE 2018; 9:448. [PMID: 29719545 PMCID: PMC5913710 DOI: 10.3389/fpls.2018.00448] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 03/22/2018] [Indexed: 05/21/2023]
Abstract
Agronomists have used statistical crop models to predict yield on a genotype-by-genotype basis. Mechanistic models, based on fundamental physiological processes common across plant taxa, will ultimately enable yield prediction applicable to diverse genotypes and crops. Here, genotypic information is combined with multiple mechanistically based models to characterize photosynthetic trait differentiation among genotypes of Brassica rapa. Infrared leaf gas exchange and chlorophyll fluorescence observations are analyzed using Bayesian methods. Three advantages of Bayesian approaches are employed: a hierarchical model structure, the testing of parameter estimates with posterior predictive checks and a multimodel complexity analysis. In all, eight models of photosynthesis are compared for fit to data and penalized for complexity using deviance information criteria (DIC) at the genotype scale. The multimodel evaluation improves the credibility of trait estimates using posterior distributions. Traits with important implications for yield in crops, including maximum rate of carboxylation (Vcmax ) and maximum rate of electron transport (Jmax ) show genotypic differentiation. B. rapa shows phenotypic diversity in causal traits with the potential for genetic enhancement of photosynthesis. This multimodel screening represents a statistically rigorous method for characterizing genotypic differences in traits with clear biophysical consequences to growth and productivity within large crop breeding populations with application across plant processes.
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Affiliation(s)
- Jonathan R. Pleban
- Department of Geography, University at Buffalo, Buffalo, NY, United States
- *Correspondence: Jonathan R. Pleban
| | - D. Scott Mackay
- Department of Geography, University at Buffalo, Buffalo, NY, United States
| | - Timothy L. Aston
- Department of Botany, University of Wyoming, Laramie, WY, United States
| | - Brent E. Ewers
- Department of Botany, University of Wyoming, Laramie, WY, United States
- Program in Ecology, University of Wyoming, Laramie, WY, United States
| | - Cynthia Weinig
- Department of Botany, University of Wyoming, Laramie, WY, United States
- Program in Ecology, University of Wyoming, Laramie, WY, United States
- Department of Molecular Biology, University of Wyoming, Laramie, WY, United States
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Xiao Y, Zhu XG. Components of mesophyll resistance and their environmental responses: A theoretical modelling analysis. PLANT, CELL & ENVIRONMENT 2017; 40:2729-2742. [PMID: 28743156 DOI: 10.1111/pce.13040] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 07/12/2017] [Accepted: 07/14/2017] [Indexed: 05/12/2023]
Abstract
Mesophyll resistance (rm ), stomatal resistance, and biochemical limitations are recognized as three critical factors limiting leaf photosynthesis. Contrary to the expectation of being a constant, rm not only varies with light and CO2 conditions but also shows different responses among species. To elucidate the mechanistic basis of these responses, we derived an analytical model of rm , which incorporates various anatomical and biochemical factors including permeabilities of cell wall and chloroplast envelope to CO2 and HCO3- , carbonic anhydrase activities in cytosol and stroma, Rubisco activities, and relative location of mitochondria and chloroplast. The robustness of this model was confirmed by comparing the predicted rm and its components to numerical models developed at cell and leaf levels, which incorporate detailed 3-dimensional cell and leaf anatomies, CO2 hydration and diffusion processes from intercellular air space to stroma, and CO2 fixation by Rubisco. A combination of these model analyses shows that the varying rm is influenced by four biochemical factors: (a) nonuniform photosynthesis status across the leaf, (b) photorespiration and respiration, (c) bicarbonate leakage on the chloroplast envelope, and (d) hydration activity in cytosol and stroma. This study provides a theoretical framework to study components of rm and their responses to environmental perturbations.
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Affiliation(s)
- Yi Xiao
- Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xin-Guang Zhu
- Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, China
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Evans JR, Morgan PB, von Caemmerer S. Light Quality Affects Chloroplast Electron Transport Rates Estimated from Chl Fluorescence Measurements. PLANT & CELL PHYSIOLOGY 2017; 58:1652-1660. [PMID: 29016964 DOI: 10.1093/pcp/pcx103] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 07/09/2017] [Indexed: 05/23/2023]
Abstract
Chl fluorescence has been used widely to calculate photosynthetic electron transport rates. Portable photosynthesis instruments allow for combined measurements of gas exchange and Chl fluorescence. We analyzed the influence of spectral quality of actinic light on Chl fluorescence and the calculated electron transport rate, and compared this with photosynthetic rates measured by gas exchange in the absence of photorespiration. In blue actinic light, the electron transport rate calculated from Chl fluorescence overestimated the true rate by nearly a factor of two, whereas there was closer agreement under red light. This was consistent with the prediction made with a multilayer leaf model using profiles of light absorption and photosynthetic capacity. Caution is needed when interpreting combined measurements of Chl fluorescence and gas exchange, such as the calculation of CO2 partial pressure in leaf chloroplasts.
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Affiliation(s)
- John R Evans
- 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
| | - Patrick B Morgan
- LI-COR Inc., Lincoln, NE 68504, USA
- School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE 68504, USA
| | - 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
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Théroux-Rancourt G, Earles JM, Gilbert ME, Zwieniecki MA, Boyce CK, McElrone AJ, Brodersen CR. The bias of a two-dimensional view: comparing two-dimensional and three-dimensional mesophyll surface area estimates using noninvasive imaging. THE NEW PHYTOLOGIST 2017; 215:1609-1622. [PMID: 28691233 DOI: 10.1111/nph.14687] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 06/05/2017] [Indexed: 05/22/2023]
Abstract
The mesophyll surface area exposed to intercellular air space per leaf area (Sm ) is closely associated with CO2 diffusion and photosynthetic rates. Sm is typically estimated from two-dimensional (2D) leaf sections and corrected for the three-dimensional (3D) geometry of mesophyll cells, leading to potential differences between the estimated and actual cell surface area. Here, we examined how 2D methods used for estimating Sm compare with 3D values obtained from high-resolution X-ray microcomputed tomography (microCT) for 23 plant species, with broad phylogenetic and anatomical coverage. Relative to 3D, uncorrected 2D Sm estimates were, on average, 15-30% lower. Two of the four 2D Sm methods typically fell within 10% of 3D values. For most species, only a few 2D slices were needed to accurately estimate Sm within 10% of the whole leaf sample median. However, leaves with reticulate vein networks required more sections because of a more heterogeneous vein coverage across slices. These results provide the first comparison of the accuracy of 2D methods in estimating the complex 3D geometry of internal leaf surfaces. Because microCT is not readily available, we provide guidance for using standard light microscopy techniques, as well as recommending standardization of reporting Sm values.
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Affiliation(s)
| | - J Mason Earles
- School of Forestry & Environmental Studies, Yale University, New Haven, CT, 06511, USA
| | - Matthew E Gilbert
- Department of Plant Sciences, University of California Davis, Davis, CA, 95616, USA
| | - Maciej A Zwieniecki
- Department of Plant Sciences, University of California Davis, Davis, CA, 95616, USA
| | - C Kevin Boyce
- Department of Geological Sciences, Stanford University, Stanford, CA, 94305, USA
| | - Andrew J McElrone
- USDA-Agricultural Research Service, Davis, CA, 95616, USA
- Deparment of Viticulture and Enology, University of California, Davis, CA, 95616, USA
| | - Craig R Brodersen
- School of Forestry & Environmental Studies, Yale University, New Haven, CT, 06511, USA
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