Age-Specific Physiological Adjustments of <i>Spirodela polyrhiza</i> to Sulfur Deficiency
<i>Spirodela polyrhiza</i> is a suitable model organism for investigating plant developmental influences due to its intracolonial variations in response to various environmental fluctuations, like nutrient deficiency. In this study, transmission electron microscopy was used to examine ag...
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2025-06-01
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| author | Vesna Peršić Anja Melnjak Lucija Domjan Günther Zellnig Jasenka Antunović Dunić |
| author_facet | Vesna Peršić Anja Melnjak Lucija Domjan Günther Zellnig Jasenka Antunović Dunić |
| author_sort | Vesna Peršić |
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| description | <i>Spirodela polyrhiza</i> is a suitable model organism for investigating plant developmental influences due to its intracolonial variations in response to various environmental fluctuations, like nutrient deficiency. In this study, transmission electron microscopy was used to examine age-dependent variation in chloroplast ultrastructure, while pigment levels (chlorophyll and anthocyanins), starch accumulation, and metabolic activity (photosynthetic and respiratory rates) were measured to determine metabolic responses to sulfur deficiency. For a comprehensive insight into electron transport efficiency and the redox states of the photosynthetic apparatus, rapid light curves, chlorophyll fluorescence (JIP test parameters), and modulated reflection at 820 nm were analyzed. Under S deficit, mother fronds relied on stored reserves to maintain functional PSII but accumulated reduced PQ pools, slowing electron flow beyond PSII. The first-generation daughter fronds, despite having higher baseline photosynthetic capacity, exhibited the largest decline in photosynthetic indicators (e.g., rETR fell about 50%), limitations in the water-splitting complex, and reduced PSI end-acceptor capacity that resulted in donor- and acceptor-side bottlenecks of electron transport. The youngest granddaughter fronds avoided these bottlenecks by absorbing less light per PSII, channeling electrons through the alternative pathway to balance PQ pools and redox-stable PSI while diverting more carbon into starch and anthocyanin production up to 5-fold for both. These coordinated and age-specific adjustments that provide response flexibility may help maintain photosynthetic function of the colony and facilitate rapid recovery when sulfur becomes available again. |
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| institution | Kabale University |
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| publishDate | 2025-06-01 |
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| spelling | doaj-art-d1e1f6a58dd643c98cecac275fe147bf2025-08-20T03:28:26ZengMDPI AGPlants2223-77472025-06-011413190710.3390/plants14131907Age-Specific Physiological Adjustments of <i>Spirodela polyrhiza</i> to Sulfur DeficiencyVesna Peršić0Anja Melnjak1Lucija Domjan2Günther Zellnig3Jasenka Antunović Dunić4Department of Biology, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, CroatiaDepartment of Biology, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, CroatiaDepartment of Biology, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, CroatiaInstitute of Biology, University of Graz, 8010 Graz, AustriaDepartment of Biology, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia<i>Spirodela polyrhiza</i> is a suitable model organism for investigating plant developmental influences due to its intracolonial variations in response to various environmental fluctuations, like nutrient deficiency. In this study, transmission electron microscopy was used to examine age-dependent variation in chloroplast ultrastructure, while pigment levels (chlorophyll and anthocyanins), starch accumulation, and metabolic activity (photosynthetic and respiratory rates) were measured to determine metabolic responses to sulfur deficiency. For a comprehensive insight into electron transport efficiency and the redox states of the photosynthetic apparatus, rapid light curves, chlorophyll fluorescence (JIP test parameters), and modulated reflection at 820 nm were analyzed. Under S deficit, mother fronds relied on stored reserves to maintain functional PSII but accumulated reduced PQ pools, slowing electron flow beyond PSII. The first-generation daughter fronds, despite having higher baseline photosynthetic capacity, exhibited the largest decline in photosynthetic indicators (e.g., rETR fell about 50%), limitations in the water-splitting complex, and reduced PSI end-acceptor capacity that resulted in donor- and acceptor-side bottlenecks of electron transport. The youngest granddaughter fronds avoided these bottlenecks by absorbing less light per PSII, channeling electrons through the alternative pathway to balance PQ pools and redox-stable PSI while diverting more carbon into starch and anthocyanin production up to 5-fold for both. These coordinated and age-specific adjustments that provide response flexibility may help maintain photosynthetic function of the colony and facilitate rapid recovery when sulfur becomes available again.https://www.mdpi.com/2223-7747/14/13/1907chloroplast ultrastructureanthocyaninsstarch accumulationoxygen evolution rateschlorophyll <i>a</i> fluorescence kineticsrapid light curve |
| spellingShingle | Vesna Peršić Anja Melnjak Lucija Domjan Günther Zellnig Jasenka Antunović Dunić Age-Specific Physiological Adjustments of <i>Spirodela polyrhiza</i> to Sulfur Deficiency Plants chloroplast ultrastructure anthocyanins starch accumulation oxygen evolution rates chlorophyll <i>a</i> fluorescence kinetics rapid light curve |
| title | Age-Specific Physiological Adjustments of <i>Spirodela polyrhiza</i> to Sulfur Deficiency |
| title_full | Age-Specific Physiological Adjustments of <i>Spirodela polyrhiza</i> to Sulfur Deficiency |
| title_fullStr | Age-Specific Physiological Adjustments of <i>Spirodela polyrhiza</i> to Sulfur Deficiency |
| title_full_unstemmed | Age-Specific Physiological Adjustments of <i>Spirodela polyrhiza</i> to Sulfur Deficiency |
| title_short | Age-Specific Physiological Adjustments of <i>Spirodela polyrhiza</i> to Sulfur Deficiency |
| title_sort | age specific physiological adjustments of i spirodela polyrhiza i to sulfur deficiency |
| topic | chloroplast ultrastructure anthocyanins starch accumulation oxygen evolution rates chlorophyll <i>a</i> fluorescence kinetics rapid light curve |
| url | https://www.mdpi.com/2223-7747/14/13/1907 |
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