The Importance of Non-Diffusional Factors in Determining Photosynthesis of Two Contrasting Quinoa Ecotypes (<i>Chenopodium quinoa</i> Willd.) Subjected to Salinity Conditions
The broad distribution of quinoa in saline and non-saline environments is reflected in variations in the photosynthesis-associated mechanisms of different ecotypes. The aim of this study was to characterize the photosynthetic response to high salinity (0.4 M NaCl) of two contrasting Chilean genotype...
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MDPI AG
2021-05-01
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| Series: | Plants |
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| Online Access: | https://www.mdpi.com/2223-7747/10/5/927 |
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| author | José Delatorre-Herrera Karina B. Ruiz Manuel Pinto |
| author_facet | José Delatorre-Herrera Karina B. Ruiz Manuel Pinto |
| author_sort | José Delatorre-Herrera |
| collection | DOAJ |
| description | The broad distribution of quinoa in saline and non-saline environments is reflected in variations in the photosynthesis-associated mechanisms of different ecotypes. The aim of this study was to characterize the photosynthetic response to high salinity (0.4 M NaCl) of two contrasting Chilean genotypes, Amarilla (salt-tolerant, <i>salares</i> ecotype) and Hueque (salt-sensitive, coastal ecotype). Our results show that saline stress induced a significant decrease in the K<sup>+</sup>/Na<sup>+</sup> ratio in roots and an increase in glycine betaine in leaves, particularly in the sensitive genotype (Hueque). Measurement of the photosynthesis-related parameters showed that maximum CO<sub>2</sub> assimilation (A<sub>max</sub>) in control plants was comparable between genotypes (ca. 9–10 μmol CO<sub>2</sub> m<sup>−2</sup> s<sup>−1</sup>). However, salt treatment produced different responses, with A<sub>max</sub> values decreasing by 65.1% in the sensitive ecotype and 37.7% in the tolerant one. Although both genotypes maintained mesophyll conductance when stomatal restrictions were removed, the biochemical components of Amarilla were impaired to a lesser extent under salt stress conditions: for example, the maximum rate of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO; V<sub>cmax</sub>) was not as affected in Amarilla, revealing that this enzyme has a higher affinity for its substrate in this genotype and, thus, a better carboxylation efficiency. The present results show that the higher salinity tolerance of Amarilla was also due to its ability to control non-diffusional components, indicating its superior photosynthetic capacity compared to Hueque, particularly under salt stress conditions. |
| first_indexed | 2024-03-10T11:39:06Z |
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| language | English |
| last_indexed | 2024-03-10T11:39:06Z |
| publishDate | 2021-05-01 |
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| spelling | doaj.art-0a361be8d0104e8086a56e13850e3cc52023-11-21T18:36:45ZengMDPI AGPlants2223-77472021-05-0110592710.3390/plants10050927The Importance of Non-Diffusional Factors in Determining Photosynthesis of Two Contrasting Quinoa Ecotypes (<i>Chenopodium quinoa</i> Willd.) Subjected to Salinity ConditionsJosé Delatorre-Herrera0Karina B. Ruiz1Manuel Pinto2Doctoral Program in Agriculture for Arid-Desert Environments, Faculty of Renewable Natural Resources, Desert Agriculture Area, Universidad Arturo Prat, Iquique 1100000, ChileFacultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique 2120, ChilePlant Physiology Laboratory, Institute of Agronomic and Veterinary Sciences, Universidad de O´Higgins, Rancagua 2820000, ChileThe broad distribution of quinoa in saline and non-saline environments is reflected in variations in the photosynthesis-associated mechanisms of different ecotypes. The aim of this study was to characterize the photosynthetic response to high salinity (0.4 M NaCl) of two contrasting Chilean genotypes, Amarilla (salt-tolerant, <i>salares</i> ecotype) and Hueque (salt-sensitive, coastal ecotype). Our results show that saline stress induced a significant decrease in the K<sup>+</sup>/Na<sup>+</sup> ratio in roots and an increase in glycine betaine in leaves, particularly in the sensitive genotype (Hueque). Measurement of the photosynthesis-related parameters showed that maximum CO<sub>2</sub> assimilation (A<sub>max</sub>) in control plants was comparable between genotypes (ca. 9–10 μmol CO<sub>2</sub> m<sup>−2</sup> s<sup>−1</sup>). However, salt treatment produced different responses, with A<sub>max</sub> values decreasing by 65.1% in the sensitive ecotype and 37.7% in the tolerant one. Although both genotypes maintained mesophyll conductance when stomatal restrictions were removed, the biochemical components of Amarilla were impaired to a lesser extent under salt stress conditions: for example, the maximum rate of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO; V<sub>cmax</sub>) was not as affected in Amarilla, revealing that this enzyme has a higher affinity for its substrate in this genotype and, thus, a better carboxylation efficiency. The present results show that the higher salinity tolerance of Amarilla was also due to its ability to control non-diffusional components, indicating its superior photosynthetic capacity compared to Hueque, particularly under salt stress conditions.https://www.mdpi.com/2223-7747/10/5/927Na<sup>+</sup>, K<sup>+</sup>, CO<sub>2</sub> assimilationstomatal restrictionsnon-diffusionaldiffusionalRubisCO activity |
| spellingShingle | José Delatorre-Herrera Karina B. Ruiz Manuel Pinto The Importance of Non-Diffusional Factors in Determining Photosynthesis of Two Contrasting Quinoa Ecotypes (<i>Chenopodium quinoa</i> Willd.) Subjected to Salinity Conditions Plants Na<sup>+</sup>, K<sup>+</sup>, CO<sub>2</sub> assimilation stomatal restrictions non-diffusional diffusional RubisCO activity |
| title | The Importance of Non-Diffusional Factors in Determining Photosynthesis of Two Contrasting Quinoa Ecotypes (<i>Chenopodium quinoa</i> Willd.) Subjected to Salinity Conditions |
| title_full | The Importance of Non-Diffusional Factors in Determining Photosynthesis of Two Contrasting Quinoa Ecotypes (<i>Chenopodium quinoa</i> Willd.) Subjected to Salinity Conditions |
| title_fullStr | The Importance of Non-Diffusional Factors in Determining Photosynthesis of Two Contrasting Quinoa Ecotypes (<i>Chenopodium quinoa</i> Willd.) Subjected to Salinity Conditions |
| title_full_unstemmed | The Importance of Non-Diffusional Factors in Determining Photosynthesis of Two Contrasting Quinoa Ecotypes (<i>Chenopodium quinoa</i> Willd.) Subjected to Salinity Conditions |
| title_short | The Importance of Non-Diffusional Factors in Determining Photosynthesis of Two Contrasting Quinoa Ecotypes (<i>Chenopodium quinoa</i> Willd.) Subjected to Salinity Conditions |
| title_sort | importance of non diffusional factors in determining photosynthesis of two contrasting quinoa ecotypes i chenopodium quinoa i willd subjected to salinity conditions |
| topic | Na<sup>+</sup>, K<sup>+</sup>, CO<sub>2</sub> assimilation stomatal restrictions non-diffusional diffusional RubisCO activity |
| url | https://www.mdpi.com/2223-7747/10/5/927 |
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