Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions
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 so...
| Autores principales: | , , , |
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| Formato: | Journal Article |
| Lenguaje: | Inglés |
| Publicado: |
Oxford University Press
2019
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| Materias: | |
| Acceso en línea: | https://hdl.handle.net/10568/106600 |
| _version_ | 1855541294487568384 |
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| author | Jiménez Serna, Juan de la Cruz Kotula, Lukasz Veneklaas, Erik Jan Colmer, Timothy D. |
| author_browse | Colmer, Timothy D. Jiménez Serna, Juan de la Cruz Kotula, Lukasz Veneklaas, Erik Jan |
| author_facet | Jiménez Serna, Juan de la Cruz Kotula, Lukasz Veneklaas, Erik Jan Colmer, Timothy D. |
| author_sort | Jiménez Serna, Juan de la Cruz |
| collection | Repository of Agricultural Research Outputs (CGSpace) |
| description | 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. |
| format | Journal Article |
| id | CGSpace106600 |
| institution | CGIAR Consortium |
| language | Inglés |
| publishDate | 2019 |
| publishDateRange | 2019 |
| publishDateSort | 2019 |
| publisher | Oxford University Press |
| publisherStr | Oxford University Press |
| record_format | dspace |
| spelling | CGSpace1066002025-03-13T09:45:42Z Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions Jiménez Serna, Juan de la Cruz Kotula, Lukasz Veneklaas, Erik Jan Colmer, Timothy D. feed crops forage mineral nutrients water tolerance roots 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. 2019-11-27 2020-01-16T15:10:40Z 2020-01-16T15:10:40Z Journal Article https://hdl.handle.net/10568/106600 en Open Access Oxford University Press Jiménez, Juan de la Cruz; Kotula, Lukasz; Veneklaas, Erik J. & Colmer, Timothy D. (2019). Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions. Annals of Botany. 124: 1019-1032. |
| spellingShingle | feed crops forage mineral nutrients water tolerance roots Jiménez Serna, Juan de la Cruz Kotula, Lukasz Veneklaas, Erik Jan Colmer, Timothy D. Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions |
| title | Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions |
| title_full | Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions |
| title_fullStr | Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions |
| title_full_unstemmed | Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions |
| title_short | Root-zone hypoxia reduces growth of the tropical forage grass Urochloa humidicola in high-nutrient but not low-nutrient conditions |
| title_sort | root zone hypoxia reduces growth of the tropical forage grass urochloa humidicola in high nutrient but not low nutrient conditions |
| topic | feed crops forage mineral nutrients water tolerance roots |
| url | https://hdl.handle.net/10568/106600 |
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