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Jiménez JDLC, Armstrong W, Colmer TD, Pedersen O. Overcoming constraints to measuring O2 diffusivity and consumption of intact roots. Plant Physiol 2024; 195:283-286. [PMID: 38366585 PMCID: PMC11060671 DOI: 10.1093/plphys/kiae046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 01/02/2024] [Indexed: 02/18/2024]
Abstract
A method using O2 microsensors enables detailed quantification of respiratory O2 consumption and diffusive resistance to O2 of individual root cell layers.
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Affiliation(s)
| | - William Armstrong
- Department of Biological Sciences, University of Hull, Hull HU6 7RX, UK
- School of Agriculture and Environment, The University of Western Australia, Crawley, WA 6009, Australia
| | - Timothy D Colmer
- School of Agriculture and Environment, The University of Western Australia, Crawley, WA 6009, Australia
- The UWA Institute of Agriculture, The University of Western Australia, Crawley, WA 6009, Australia
| | - Ole Pedersen
- Department of Biology, University of Copenhagen, Copenhagen 2100, Denmark
- School of Biological Sciences, The University of Western Australia, Crawley, WA 6009, Australia
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2
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Jiménez JDLC, Mustroph A, Pedersen O, Weits DA, Schmidt-Schippers R. Flooding stress and responses to hypoxia in plants. Funct Plant Biol 2024; 51:FP24061. [PMID: 38538565 DOI: 10.1071/fp24061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 03/12/2024] [Indexed: 04/04/2024]
Abstract
In recent years, research on flooding stress and hypoxic responses in plants has gathered increasing attention due to climate change and the important role of O2 in metabolism and signalling. This Collection of Functional Plant Biology on 'Flooding stress and responses to hypoxia in plants' presents key contributions aimed at progressing our current understanding on how plants respond to low-O2 conditions, flooding stress and a combination of stresses commonly found in flooded areas. The Collection emphasises the characterisation of diverse plant responses across different developmental stages, from seed germination to fully developed plants, and under different water stress conditions ranging from waterlogging to complete submergence, or simply low-O2 conditions resulting from limited O2 diffusivity in bulky tissues. Additionally, this Collection highlights diverse approaches, including eco-physiological characterisation of plant responses, detailed descriptions of root anatomical characteristics and their surrounding microenvironments, evaluation of the seed microbiota under flooding stress, the modification of gene expression, and evaluations of diverse germplasm collections.
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Affiliation(s)
- Juan de la Cruz Jiménez
- Department of Biology, University of Copenhagen, Universitetsparken 4, Copenhagen 2100, Denmark
| | - Angelika Mustroph
- Plant Physiology, University Bayreuth, Universitaetsstr. 30, Bayreuth 95440, Germany
| | - Ole Pedersen
- Department of Biology, University of Copenhagen, Universitetsparken 4, Copenhagen 2100, Denmark; and School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Daan A Weits
- Experimental and Computational Plant Development, Institute of Environment Biology, Utrecht University, Padualaan 8, Utrecht 3584 CH, Netherlands
| | - Romy Schmidt-Schippers
- Department of Plant Biotechnology, Faculty of Biology, University of Bielefeld, Bielefeld D-33615, Germany; and Center for Biotechnology, University of Bielefeld, Bielefeld 33615, Germany
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Peralta Ogorek LL, Jiménez JDLC, Visser EJW, Takahashi H, Nakazono M, Shabala S, Pedersen O. Outer apoplastic barriers in roots: prospects for abiotic stress tolerance. Funct Plant Biol 2024; 51:NULL. [PMID: 37814289 DOI: 10.1071/fp23133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/25/2023] [Indexed: 10/11/2023]
Abstract
Floods and droughts are becoming more frequent as a result of climate change and it is imperative to find ways to enhance the resilience of staple crops to abiotic stresses. This is crucial to sustain food production during unfavourable conditions. Here, we analyse the current knowledge about suberised and lignified outer apoplastic barriers, focusing on the functional roles of the barrier to radial O2 loss formed as a response to soil flooding and we discuss whether this trait also provides resilience to multiple abiotic stresses. The barrier is composed of suberin and lignin depositions in the exodermal and/or sclerenchyma cell walls. In addition to the important role during soil flooding, the barrier can also restrict radial water loss, prevent phytotoxin intrusion, salt intrusion and the main components of the barrier can impede invasion of pathogens in the root. However, more research is needed to fully unravel the induction pathway of the outer apoplastic barriers and to address potential trade-offs such as reduced nutrient or water uptake. Nevertheless, we suggest that the outer apoplastic barriers might act as a jack of all trades providing tolerance to multiple abiotic and/or biotic stressors.
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Affiliation(s)
- Lucas León Peralta Ogorek
- The Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Copenhagen 2100, Denmark; and School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK
| | - Juan de la Cruz Jiménez
- The Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Copenhagen 2100, Denmark
| | - Eric J W Visser
- Department of Experimental Plant Ecology, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Heyendaalseweg 135, Nijmegen 6525 AJ, Netherlands
| | - Hirokazu Takahashi
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Mikio Nakazono
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan; and School of Biological Sciences, University of Western Australia, Crawley WA 6009, Australia
| | - Sergey Shabala
- School of Biological Sciences, University of Western Australia, Crawley WA 6009, Australia; and International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, China
| | - Ole Pedersen
- The Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Copenhagen 2100, Denmark; and School of Biological Sciences, University of Western Australia, Crawley WA 6009, Australia
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Jiménez JDLC, Pedersen O. Mitigation of Greenhouse Gas Emissions from Rice via Manipulation of Key Root Traits. Rice (N Y) 2023; 16:24. [PMID: 37160782 PMCID: PMC10169991 DOI: 10.1186/s12284-023-00638-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 04/18/2023] [Indexed: 05/11/2023]
Abstract
Rice production worldwide represents a major anthropogenic source of greenhouse gas emissions. Nitrogen fertilization and irrigation practices have been fundamental to achieve optimal rice yields, but these agricultural practices together with by-products from plants and microorganisms, facilitate the production, accumulation and venting of vast amounts of CO2, CH4 and N2O. We propose that the development of elite rice varieties should target root traits enabling an effective internal O2 diffusion, via enlarged aerenchyma channels. Moreover, gas tight barriers impeding radial O2 loss in basal parts of the roots will increase O2 diffusion to the root apex where molecular O2 diffuses into the rhizosphere. These developments result in plants with roots penetrating deeper into the flooded anoxic soils, producing higher volumes of oxic conditions in the interface between roots and rhizosphere. Molecular O2 in these zones promotes CH4 oxidation into CO2 by methanotrophs and nitrification (conversion of NH4+ into NO3-), reducing greenhouse gas production and at the same time improving plant nutrition. Moreover, roots with tight barriers to radial O2 loss will have restricted diffusional entry of CH4 produced in the anoxic parts of the rhizosphere and therefore plant-mediated diffusion will be reduced. In this review, we describe how the exploitation of these key root traits in rice can potentially reduce greenhouse gas emissions from paddy fields.
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Affiliation(s)
- Juan de la Cruz Jiménez
- Department of Biology, University of Copenhagen, Universitetsparken 4, 3rd floor, Copenhagen, 2100, Denmark.
| | - Ole Pedersen
- Department of Biology, University of Copenhagen, Universitetsparken 4, 3rd floor, Copenhagen, 2100, Denmark.
- School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
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Dalle Carbonare L, Jiménez JDLC, Lichtenauer S, van Veen H. Plant responses to limited aeration: Advances and future challenges. Plant Direct 2023; 7:e488. [PMID: 36993903 PMCID: PMC10040318 DOI: 10.1002/pld3.488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 06/19/2023]
Abstract
Limited aeration that is caused by tissue geometry, diffusion barriers, high elevation, or a flooding event poses major challenges to plants and is often, but not exclusively, associated with low oxygen. These processes span a broad interest in the research community ranging from whole plant and crop responses, post-harvest physiology, plant morphology and anatomy, fermentative metabolism, plant developmental processes, oxygen sensing by ERF-VIIs, gene expression profiles, the gaseous hormone ethylene, and O2 dynamics at cellular resolution. The International Society for Plant Anaerobiosis (ISPA) gathers researchers from all over the world contributing to understand the causes, responses, and consequences of limited aeration in plants. During the 14th ISPA meeting, major research progress was related to the evolution of O2 sensing mechanisms and the intricate network that balances low O2 signaling. Here, the work moved beyond flooding stress and emphasized novel underexplored roles of low O2 and limited aeration in altitude adaptation, fruit development and storage, and the vegetative development of growth apices. Regarding tolerance towards flooding, the meeting stressed the relevance and regulation of developmental plasticity, aerenchyma, and barrier formation to improve internal aeration. Additional newly explored flood tolerance traits concerned resource balance, senescence, and the exploration of natural genetic variation for novel tolerance loci. In this report, we summarize and synthesize the major progress and future challenges for low O2 and aeration research presented at the conference.
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Affiliation(s)
| | | | - Sophie Lichtenauer
- Institute of Plant Biology and BiotechnologyUniversity of MünsterMünsterGermany
| | - Hans van Veen
- Plant Stress Resilience, Institute of Environmental BiologyUtrecht UniversityUtrechtThe Netherlands
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
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Jiménez JDLC, Pellegrini E, Pedersen O, Nakazono M. Radial Oxygen Loss from Plant Roots—Methods. Plants 2021; 10:plants10112322. [PMID: 34834684 PMCID: PMC8622749 DOI: 10.3390/plants10112322] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 11/16/2022]
Abstract
In flooded soils, an efficient internal aeration system is essential for root growth and plant survival. Roots of many wetland species form barriers to restrict radial O2 loss (ROL) to the rhizosphere. The formation of such barriers greatly enhances longitudinal O2 diffusion from basal parts towards the root tip, and the barrier also impedes the entry of phytotoxic compounds produced in flooded soils into the root. Nevertheless, ROL from roots is an important source of O2 for rhizosphere oxygenation and the oxidation of toxic compounds. In this paper, we review the methodological aspects for the most widely used techniques for the qualitative visualization and quantitative determination of ROL from roots. Detailed methodological approaches, practical set-ups and examples of ROL from roots with or without barriers to ROL are included. This paper provides practical knowledge relevant to several disciplines, including plant–soil interactions, biogeochemistry and eco-physiological aspects of roots and soil biota.
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Affiliation(s)
- Juan de la Cruz Jiménez
- Laboratory of Plant Genetics and Breeding, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan;
- Correspondence:
| | - Elisa Pellegrini
- Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, Via delle Scienze 206, 33100 Udine, Italy;
- The Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Universitetsparken 4, DK2100 Copenhagen, Denmark;
| | - Ole Pedersen
- The Freshwater Biological Laboratory, Department of Biology, University of Copenhagen, Universitetsparken 4, DK2100 Copenhagen, Denmark;
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Perth, WA 6009, Australia
| | - Mikio Nakazono
- Laboratory of Plant Genetics and Breeding, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan;
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Perth, WA 6009, Australia
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Jiménez JDLC, Clode PL, Signorelli S, Veneklaas EJ, Colmer TD, Kotula L. The barrier to radial oxygen loss impedes the apoplastic entry of iron into the roots of Urochloa humidicola. J Exp Bot 2021; 72:3279-3293. [PMID: 33543268 DOI: 10.1093/jxb/erab043] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 02/01/2021] [Indexed: 05/25/2023]
Abstract
Lack of O2 and high concentrations of iron (Fe) and manganese (Mn) commonly occur in waterlogged soils. The development of a barrier to impede radial O2 loss (ROL) is a key trait improving internal O2 transport and waterlogging tolerance in plants. We evaluated the ability of the barrier to ROL to impede the entry of excess Fe into the roots of the waterlogging-tolerant grass Urochloa humidicola. Plants were grown in aerated or stagnant deoxygenated nutrient solution with 5 µM or 900 µM Fe. Quantitative X-ray microanalysis was used to determine cell-specific Fe concentrations at two positions behind the root apex in relation to ROL and the formation of apoplastic barriers. At a mature zone of the root, Fe was 'excluded' at the exodermis where a suberized lamella was evident, a feature also associated with a strong barrier to ROL. In contrast, the potassium (K) concentration was similar in all root cells, indicating that K uptake was not affected by apoplastic barriers. The hypothesis that the formation of a tight barrier to ROL impedes the apoplastic entry of toxic concentrations of Fe into the mature zones of roots was supported by the significantly higher accumulation of Fe on the outer side of the exodermis.
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Affiliation(s)
- Juan de la Cruz Jiménez
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
| | - Peta L Clode
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Perth, WA, Australia
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
| | - Santiago Signorelli
- Laboratorio de Bioquímica, Departamento de Biología Vegetal, Facultad de Agronomía, Universidad de la República, CP 12900 Montevideo, Uruguay
| | - Erik J Veneklaas
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
- The Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
| | - Timothy D Colmer
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
- The Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
| | - Lukasz Kotula
- UWA School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
- The Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
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de la Cruz Jiménez J, Cardoso JA, Kotula L, Veneklaas EJ, Pedersen O, Colmer TD. Root length is proxy for high-throughput screening of waterlogging tolerance in Urochloa spp. grasses. Funct Plant Biol 2021; 48:411-421. [PMID: 33287947 DOI: 10.1071/fp20200] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 11/10/2020] [Indexed: 06/12/2023]
Abstract
C4 perennial Urochloa spp. grasses are widely planted in extensive areas in the tropics. These areas are continuously facing waterlogging events, which limits plant growth and production. However, no commercial cultivar combining excellent waterlogging tolerance with superior biomass production and nutritional quality is available. The objective of this study was to identify root traits that can be used for selecting waterlogging tolerant species of Urochloa. Root respiration, root morphological, architectural and anatomical traits were evaluated in eight contrasting Urochloa spp. genotypes grown under aerated or deoxygenated stagnant solutions. Moreover, modelling of internal aeration was used to relate differences in root traits and root growth in waterlogged soils. Increased aerenchyma formation in roots, reduced stele area and development of a fully suberised exodermis are characteristics improving internal aeration of roots and therefore determining waterlogging tolerance in these C4 forage grasses. Waterlogging-tolerant genotypes had steeper root angles and greater root lengths than the waterlogging-sensitive genotypes. In stagnant conditions, waterlogging-tolerant genotypes had a greater proportion of aerenchyma and reduced stele area in root cross-sections, had deeper roots, steeper root angle and larger root biomass, which in turn, allowed for greater shoot biomass. Total root length had the strongest positive influence on shoot dry mass and can therefore be used as proxy for selecting waterlogging tolerant Urochloa genotypes.
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Affiliation(s)
- Juan de la Cruz Jiménez
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; and Corresponding author.
| | - Juan A Cardoso
- International Center for Tropical Agriculture (CIAT), Km 17 Recta Cali - Palmira, Colombia
| | - Lukasz Kotula
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Erik J Veneklaas
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; and UWA School of Biological Sciences, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; and The Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Ole Pedersen
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; and Department of Biology, University of Copenhagen, Universitetsparken 4, 3rd floor, 2100 Copenhagen, Denmark
| | - Timothy D Colmer
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia; and The Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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Jiménez JDLC, Kotula L, Veneklaas EJ, Colmer TD. Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions. Ann Bot 2019; 124:1019-1032. [PMID: 31152584 PMCID: PMC6881221 DOI: 10.1093/aob/mcz071] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 04/27/2019] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND AIMS The perennial C4 grass Urochloa humidicola is widely planted on infertile acidic and waterlogging-prone soils of tropical America. Waterlogging results in soil anoxia, and O2 deficiency can reduce nutrient uptake by roots. Interestingly, both nutrient deficiencies and soil waterlogging can enhance root cortical cell senescence, and the increased gas-filled porosity facilitates internal aeration of roots. We tested the influence of nutrient supply and root-zone O2 on root traits, leaf nutrient concentrations and growth of U. humidicola. METHODS Plants were grown in pots in a completely randomized design under aerated or stagnant deoxygenated hydroponic conditions and six nutrient regimes, with low to high concentrations of all essential elements, for 28 d in a controlled-temperature greenhouse. The standard acid solution (SAS) used was previously designed based on infertile acidic soils of the tropical America savannas, and step increases in the concentration of SAS were used in aerated or deoxygenated 0.1 % agar solution, which mimics changes in gas composition in waterlogged soils. Measurements included shoot and root growth, root porosity, root anatomy, radial O2 loss, and leaf tissue nutrient concentrations. KEY RESULTS Shoot dry mass was reduced for plants in stagnant compared with aerated conditions at high, but not at low, levels of mineral nutrition. In low-nutrition stagnant solution, roots were shorter, of greater porosity and had smaller radial thickness of the stele. Suberized lamellae and lignified sclerenchyma, as well as a strong barrier to radial O2 loss, were documented for roots from all treatments. Leaf nutrient concentrations of K, Mg and Ca (but not N, P and S) were higher in aerated than in stagnant conditions. CONCLUSIONS Under low-nutrient conditions, plant growth in stagnant solution was equal to that in aerated solution, whereas under higher-nutrient regimes growth increased but dry mass in stagnant solution was less than in aerated solution. Slow growth in low-nutrient conditions limited any further response to the low O2 treatment, and greater porosity and smaller stele size in roots would enhance internal O2 movement within roots in the nutrient-limited stagnant conditions. A constitutive barrier to radial O2 loss and aerenchyma facilitates O2 movement to the tips of roots, which presumably contributes to maintaining nutrient uptake and the tolerance of U. humidicola to low O2 in the root-zone.
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Affiliation(s)
- Juan de la Cruz Jiménez
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Crawley, WA, Australia
- International Center for Tropical Agriculture (CIAT), Palmira, Colombia
| | - Lukasz Kotula
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Crawley, WA, Australia
| | - Erik J Veneklaas
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Crawley, WA, Australia
- School of Biological Sciences, Faculty of Science, The University of Western Australia, Crawley, WA, Australia
- The Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
| | - Timothy D Colmer
- UWA School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Crawley, WA, Australia
- The Institute of Agriculture, The University of Western Australia, Crawley, WA, Australia
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Jiménez JDLC, Cardoso JA, Leiva LF, Gil J, Forero MG, Worthington ML, Miles JW, Rao IM. Non-destructive Phenotyping to Identify Brachiaria Hybrids Tolerant to Waterlogging Stress under Field Conditions. Front Plant Sci 2017; 8:167. [PMID: 28243249 PMCID: PMC5303708 DOI: 10.3389/fpls.2017.00167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 01/26/2017] [Indexed: 05/10/2023]
Abstract
Brachiaria grasses are sown in tropical regions around the world, especially in the Neotropics, to improve livestock production. Waterlogging is a major constraint to the productivity and persistence of Brachiaria grasses during the rainy season. While some Brachiaria cultivars are moderately tolerant to seasonal waterlogging, none of the commercial cultivars combines superior yield potential and nutritional quality with a high level of waterlogging tolerance. The Brachiaria breeding program at the International Center for Tropical Agriculture, has been using recurrent selection for the past two decades to combine forage yield with resistance to biotic and abiotic stress factors. The main objective of this study was to test the suitability of normalized difference vegetation index (NDVI) and image-based phenotyping as non-destructive approaches to identify Brachiaria hybrids tolerant to waterlogging stress under field conditions. Nineteen promising hybrid selections from the breeding program and three commercial checks were evaluated for their tolerance to waterlogging under field conditions. The waterlogging treatment was imposed by applying and maintaining water to 3 cm above soil surface. Plant performance was determined non-destructively using proximal sensing and image-based phenotyping and also destructively via harvesting for comparison. Image analysis of projected green and dead areas, NDVI and shoot biomass were positively correlated (r ≥ 0.8). Our results indicate that image analysis and NDVI can serve as non-destructive screening approaches for the identification of Brachiaria hybrids tolerant to waterlogging stress.
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Affiliation(s)
- Juan de la Cruz Jiménez
- School of Plant Biology, The University of Western Australia, CrawleyWA, Australia
- International Center for Tropical AgricultureCali, Colombia
| | | | - Luisa F. Leiva
- Semillero de Investigación LÚN, Grupo D+TEC, Universidad de IbaguéIbagué, Colombia
| | - Juanita Gil
- International Center for Tropical AgricultureCali, Colombia
| | - Manuel G. Forero
- Semillero de Investigación LÚN, Grupo D+TEC, Universidad de IbaguéIbagué, Colombia
| | - Margaret L. Worthington
- International Center for Tropical AgricultureCali, Colombia
- Department of Horticulture, University of Arkansas, FayettevilleAR, USA
| | - John W. Miles
- International Center for Tropical AgricultureCali, Colombia
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Cardoso JA, Pineda M, Jiménez JDLC, Vergara MF, Rao IM. Contrasting strategies to cope with drought conditions by two tropical forage C4 grasses. AoB Plants 2015; 7:plv107. [PMID: 26333827 PMCID: PMC4595746 DOI: 10.1093/aobpla/plv107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 08/26/2015] [Indexed: 05/16/2023]
Abstract
Drought severely limits forage productivity of C4 grasses across the tropics. The avoidance of water deficit by increasing the capacity for water uptake or by controlling water loss are common responses in forage C4 grasses. Napier grass (Pennisetum purpureum) and Brachiaria hybrid cv. Mulato II are tropical C4 grasses used for livestock production due to their reputed resistance to drought conditions. However, there is scant information on the mechanisms used by these grasses to overcome water-limited conditions. Therefore, assessments of cumulative transpired water, shoot growth, leaf rolling, leaf gas exchange, dry mass production and a number of morpho-physiological traits were recorded over a period of 21 days under well-watered or drought conditions. Drought reduced shoot dry mass of both grasses by 35 %, yet each grass exhibited contrasting strategies to cope with water shortage. Napier grass transpired most available water by the end of the drought treatment, whereas a significant amount of water was still available for Mulato II. Napier grass maintained carbon assimilation until the soil was fairly dry, whereas Mulato II restricted water loss by early stomatal closure at relatively wet soil conditions. Our results suggest that Napier grass exhibits a 'water-spending' behaviour that might be targeted to areas with intermittent drought stress, whereas Mulato II displays a 'water-saving' nature that could be directed to areas with longer dry periods.
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Affiliation(s)
- Juan Andrés Cardoso
- Tropical Forages Program, International Center for Tropical Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia
| | - Marcela Pineda
- Tropical Forages Program, International Center for Tropical Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia Facultad de Ciencias Agrarias, Universidad Nacional de Colombia, Carrera 30 No. 45-03, Bogotá, Colombia
| | - Juan de la Cruz Jiménez
- Tropical Forages Program, International Center for Tropical Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia
| | - Manuel Fernando Vergara
- Facultad de Ciencias Agrarias, Universidad Nacional de Colombia, Carrera 30 No. 45-03, Bogotá, Colombia
| | - Idupulapati M Rao
- Tropical Forages Program, International Center for Tropical Agriculture (CIAT), Apartado Aéreo 6713, Cali, Colombia
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Cardoso JA, Jiménez JDLC, Rao IM. Waterlogging-induced changes in root architecture of germplasm accessions of the tropical forage grass Brachiaria humidicola. AoB Plants 2014; 6:plu017. [PMID: 24876299 PMCID: PMC4038435 DOI: 10.1093/aobpla/plu017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/24/2014] [Indexed: 05/10/2023]
Abstract
Waterlogging is one of the major factors limiting the productivity of pastures in the humid tropics. Brachiaria humidicola is a forage grass commonly used in zones prone to temporary waterlogging. Brachiaria humidicola accessions adapt to waterlogging by increasing aerenchyma in nodal roots above constitutive levels to improve oxygenation of root tissues. In some accessions, waterlogging reduces the number of lateral roots developed from main root axes. Waterlogging-induced reduction of lateral roots could be of adaptive value as lateral roots consume oxygen supplied from above ground via their parent root. However, a reduction in lateral root development could also be detrimental by decreasing the surface area for nutrient and water absorption. To examine the impact of waterlogging on lateral root development, an outdoor study was conducted to test differences in vertical root distribution (in terms of dry mass and length) and the proportion of lateral roots to the total root system (sum of nodal and lateral roots) down the soil profile under drained or waterlogged soil conditions. Plant material consisted of 12 B. humidicola accessions from the gene bank of the International Center for Tropical Agriculture, Colombia. Rooting depth was restricted by 21 days of waterlogging and confined to the first 30 cm below the soil surface. Although waterlogging reduced the overall proportion of lateral roots, its proportion significantly increased in the top 10 cm of the soil. This suggests that soil flooding increases lateral root proliferation of B. humidicola in the upper soil layers. This may compensate for the reduction of root surface area brought about by the restriction of root growth at depths below 30 cm. Further work is needed to test the relative efficiency of nodal and lateral roots for nutrient and water uptake under waterlogged soil conditions.
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Affiliation(s)
- Juan Andrés Cardoso
- Centro Internacional de Agricultura Tropical (CIAT), Apartado Aéreo 6713, Cali, Colombia Programa de doctorado Biología Agraria y Acuicultura, Universidad de Granada, Avenida de Fuente Nueva s/n, Granada 18071, Spain
| | | | - Idupulapati M Rao
- Centro Internacional de Agricultura Tropical (CIAT), Apartado Aéreo 6713, Cali, Colombia
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Cardoso JA, Rincón J, Jiménez JDLC, Noguera D, Rao IM. Morpho-anatomical adaptations to waterlogging by germplasm accessions in a tropical forage grass. AoB Plants 2013. [PMCID: PMC4455694 DOI: 10.1093/aobpla/plt047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Brachiaria humidicola, a tropical forage grass, is recognized for its tolerance to temporary waterlogging. Waterlogged soils are characterized by slow movement of gases and oxygen defficiency. B. humidicola accessions showed adaptations common to wetland species, including a ventilation system (aerenchyma) from shoot to root that might facilitate O2 transport and the escape of gases that usually accumulate in roots under waterlogging. Of 12 accessions tested, one accession (CIAT 26570) showed greater aerenchyma formation. Quicker growth under waterlogging of CIAT 26570 might be associated with greater aerenchyma formation. Soil waterlogging reduces gas exchange between the soil and the atmosphere, leading to oxygen deprivation in the rhizosphere. Brachiaria spp. are the most widely sown forage grasses in tropical America. Among commercial Brachiaria grasses, B. humidicola shows superior tolerance to waterlogged soils based on maintenance of growth and reduced leaf chlorophyll loss and senescence. However, little is known about the underlying traits of waterlogging tolerance in B. humidicola or their intraspecific variation. For this purpose, an outdoor study was conducted using 12 germplasm accessions of B. humidicola that were grown in soil cylinders under drained or waterlogged soil conditions for 21 days. Dry mass production and morpho-anatomical responses (aerenchyma in shoots and roots, root diameter, proportional area of stele in roots, number of nodal and lateral roots, and length of the longest root) were determined. All accessions showed shorter roots and reduced root dry mass under waterlogged soil conditions. All accessions showed aerenchyma in shoots and roots under drained conditions but were further increased under waterlogging. All accessions showed a reduction in the proportional area of stele of roots in response to waterlogging. The accession (CIAT 26570) that showed a higher proportion of aerenchyma in shoots and roots and an increased number of nodal roots (with higher diameter and a reduction in the number of lateral roots) showed longer roots, less reduction in root dry mass and increased shoot growth under waterlogged conditions. We conclude that superior growth of one accession (CIAT 26570) under waterlogged soil conditions is probably a result of morpho-anatomical traits acting together to enhance root aeration and shoot ventilation. Further research is needed to test the ability to recover from waterlogging in B. humidicola accessions.
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Affiliation(s)
- Juan Andrés Cardoso
- Centro Internacional de Agricultura Tropical (CIAT), Apartado Aéreo 6713, Cali, Colombia
- Programa de doctorado Biología Agraria y Acuicultura, Universidad de Granada, Avenida de Fuente Nueva s/n, Granada 18071, Spain
- Corresponding author's e-mail address:
| | - Joisse Rincón
- Centro Internacional de Agricultura Tropical (CIAT), Apartado Aéreo 6713, Cali, Colombia
| | | | - Diana Noguera
- BIO UPMC—Bioemco (UMR CNRS 7618), 32 Avenue Henri Varagnat, Bondy Cedex 93143, France
- Laboratori de Cartografia i SIG, Facultat de Geografia i Història, Universitat de Barcelona, Montalegre 6, Barcelona 08001, Spain
| | - Idupulapati M. Rao
- Centro Internacional de Agricultura Tropical (CIAT), Apartado Aéreo 6713, Cali, Colombia
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