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Rzigui T, De Paepe R, Cornic G, Streb P. In the mitochondrial CMSII mutant of Nicotiana sylvestris photosynthetic activity remains higher than in the WT under persisting mild water stress. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 205-206:20-8. [PMID: 23498859 DOI: 10.1016/j.plantsci.2013.01.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Revised: 01/24/2013] [Accepted: 01/26/2013] [Indexed: 06/01/2023]
Abstract
Photosynthetic responses to persisting mild water stress were compared between the wild type (WT) and the respiratory complex I mutant CMSII of Nicotiana sylvestris. In both genotypes, plants kept at 80% leaf-RWC (WT80 and CMSII80) had lower photosynthetic activity and stomatal/mesophyll conductances compared to well-watered controls. While the stomatal conductance and the chloroplastic CO2 molar ratio were similar in WT80 and CMSII80 leaves, net photosynthesis was higher in CMSII80. Carboxylation efficiency was lowest in WT80 leaves both, on the basis of the same internal and chloroplastic CO2 molar ratio. Photosynthetic and fluorescence parameters indicate that WT80 leaves were only affected in the presence of oxygen. Photorespiration, as estimated by electron flux to oxygen, increased slightly in CMSII80 and WT80 leaves in accordance with increased glycerate contents but maximum photorespiration at low chloroplastic CO2 was markedly lowest in WT80 leaves. This suggests that carbon assimilation of WT80 leaves is impaired by limited photorespiratory activity. The results are discussed with respect to a possible pre-acclimation of complex I deficient leaves in CMSII to drive photosynthesis and photorespiration at low CO2 partial pressure.
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Affiliation(s)
- Touhami Rzigui
- Université Paris-Sud 11, Ecologie, Systématique et Evolution, UMR-CNRS 8079, Bâtiment 362, 91405 Orsay Cedex, France
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Flexas J, Barbour MM, Brendel O, Cabrera HM, Carriquí M, Díaz-Espejo A, Douthe C, Dreyer E, Ferrio JP, Gago J, Gallé A, Galmés J, Kodama N, Medrano H, Niinemets Ü, Peguero-Pina JJ, Pou A, Ribas-Carbó M, Tomás M, Tosens T, Warren CR. Mesophyll diffusion conductance to CO2: an unappreciated central player in photosynthesis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2012; 193-194:70-84. [PMID: 22794920 DOI: 10.1016/j.plantsci.2012.05.009] [Citation(s) in RCA: 358] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 05/08/2012] [Accepted: 05/20/2012] [Indexed: 05/20/2023]
Abstract
Mesophyll diffusion conductance to CO(2) is a key photosynthetic trait that has been studied intensively in the past years. The intention of the present review is to update knowledge of g(m), and highlight the important unknown and controversial aspects that require future work. The photosynthetic limitation imposed by mesophyll conductance is large, and under certain conditions can be the most significant photosynthetic limitation. New evidence shows that anatomical traits, such as cell wall thickness and chloroplast distribution are amongst the stronger determinants of mesophyll conductance, although rapid variations in response to environmental changes might be regulated by other factors such as aquaporin conductance. Gaps in knowledge that should be research priorities for the near future include: how different is mesophyll conductance among phylogenetically distant groups and how has it evolved? Can mesophyll conductance be uncoupled from regulation of the water path? What are the main drivers of mesophyll conductance? The need for mechanistic and phenomenological models of mesophyll conductance and its incorporation in process-based photosynthesis models is also highlighted.
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Affiliation(s)
- Jaume Flexas
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain.
| | - Margaret M Barbour
- Faculty of Agriculture, Food and Natural Resources, The University of Sydney, Private Bag 4011, Narellan, NSW 2567, Australia
| | - Oliver Brendel
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, F-54280 Champenoux, France; Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54500 Vandoeuvre, France
| | - Hernán M Cabrera
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; Centro de Ecología Aplicada Ltda., Av. Suecia 3304, Ñuñoa, Santiago, Chile
| | - Marc Carriquí
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Antonio Díaz-Espejo
- Instituto de Recursos Naturales y Agrobiología, IRNAS-CSIC, Apartado 1052, 41080 Sevilla, Spain
| | - Cyril Douthe
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, F-54280 Champenoux, France; Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54500 Vandoeuvre, France; School of Biological Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Erwin Dreyer
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, F-54280 Champenoux, France; Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54500 Vandoeuvre, France
| | - Juan P Ferrio
- Department of Crop and Forest Sciences, AGROTECNIO Center, Universitat de Lleida, Avda. Rovira Roure 191, 25198 Lleida, Spain
| | - Jorge Gago
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Alexander Gallé
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Jeroni Galmés
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Naomi Kodama
- Agro-Meteorology Division, National Institute for Agro-Environmental Sciences, 3-1-3 Kannondai, Tsukuba 305-8604, Japan
| | - Hipólito Medrano
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
| | - José J Peguero-Pina
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Alicia Pou
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Miquel Ribas-Carbó
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Magdalena Tomás
- Research Group in Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears, Carretera de Valldemossa Km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain
| | - Tiina Tosens
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu 51014, Estonia
| | - Charles R Warren
- School of Biological Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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Abstract
• The quantitative significance of amino acids to plant nutrition remains controversial. This experiment determined whether post-uptake metabolism and root to shoot export differ between glycine and glutamine, and examined implications for estimation of amino acid uptake. • Field soil containing a Eucalyptus pauciflora seedling was injected with uniformly (13)C- and (15)N-labelled glycine or glutamine. I quantified (15)N and (13)C excess in leaves and roots and intact labelled amino acids in leaves, roots and stem xylem sap. A tunable diode laser quantified fluxes of (12)CO(2) and (13)CO(2) from leaves and soil. • 60-360 min after addition of amino acid, intact molecules of U-(13)C,(15)N glutamine were < 5% of (15)N excess in roots, whereas U-(13)C,(15)N glycine was 30-100% of (15)N excess in roots. Intact molecules of glutamine, but not glycine, were exported from roots to shoots. • Post-uptake metabolism and transport complicate interpretation of isotope labelling such that root and shoot contents of intact amino acid, (13)C and (15)N may not reflect rates of uptake. Future experiments should focus on reconciling discrepancies between intact amino acid, (13)C and (15)N by determining the turnover of amino acids within roots. Alternatively, post-uptake metabolism and transport could be minimized by harvesting plants within minutes of isotope addition.
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Affiliation(s)
- Charles R Warren
- School of Biological Sciences, The University of Sydney, Sydney, NSW, Australia.
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