Evidence for alternative electron sinks to photosynthetic carbon assimilation in the high mountain plant species Ranunculus glacialis
| Autor: | Gabriel Cornic, Florence Baptist, Eve-Marie Josse, Peter Streb, Marcel Kuntz, Emily Gallouët |
|---|---|
| Přispěvatelé: | Laboratoire d'Ecophysiologie Végétale, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), School of Biological Sciences, University of Bristol [Bristol], Laboratoire d'Ecologie Alpine (LECA), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Plastes et différenciation cellulaire (PDC), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Guyénon, Yvette |
| Jazyk: | angličtina |
| Rok vydání: | 2005 |
| Předmět: |
SOLDANELLA-ALPINA
0106 biological sciences Photosystem II Physiology over-reduction Plant Science antioxidant levels 01 natural sciences Plastid terminal oxidase Chlorophyll fluorescence [SDV.EE]Life Sciences [q-bio]/Ecology environment 0303 health sciences chlorophyll fluorescence WINTER RYE LEAVES excess electron transport photosystem-ii Photorespiration PHOTOOXIDATIVE STRESS photooxidative stress CHLOROPHYLL FLUORESCENCE NADP-MALATE DEHYDROGENASE PTOX photorespiration PLASTID TERMINAL OXIDASE winter rye leaves arabidopsis-thaliana [SDV.BID]Life Sciences [q-bio]/Biodiversity Biology in-vitro Photosynthesis 03 medical and health sciences nadp-malate dehydrogenase PHOTOSYSTEM-II Botany light stress Ranunculus glacialis 030304 developmental biology soldanella-alpina IN-VITRO Chlororespiration 15. Life on land biology.organism_classification plastid terminal oxidase (PTOX) itemperature and light stress ANTIOXIDANT LEVELS photoprotection Photoprotection plastid terminal oxidase (PTOX) itemperature and ARABIDOPSIS-THALIANA [SDE.BE]Environmental Sciences/Biodiversity and Ecology immutans 010606 plant biology & botany |
| Zdroj: | Plant, Cell and Environment Plant, Cell and Environment, Wiley, 2005, 28 (9), pp.1123-1135. ⟨10.1111/j.1365-3040.2005.01350.x⟩ Plant, Cell and Environment, Wiley, 2005, 28, pp.1123-1135 Streb, P, Josse, E-M, Gallouet, E, Baptist, F, Kuntz, M & Cornic, G 2005, ' Evidence for alternative electron sinks to photosynthetic carbon assimilation in the high mountain plant species Ranunculus glacialis ', Plant, Cell and Environment, vol. 28, no. 9, pp. 1123-1135 . https://doi.org/10.1111/j.1365-3040.2005.01350.x |
| ISSN: | 0140-7791 1365-3040 |
| DOI: | 10.1111/j.1365-3040.2005.01350.x⟩ |
| Popis: | International audience; The high mountain plant species Ranunculus glacialis has a low antioxidative scavenging capacity and a low activity of thermal dissipation of excess light energy despite its growth under conditions of frequent light and cold stress. In order to examine whether this species is protected from over-reduction by matching photosystem II (PSII) electron transport (ETR) and carbon assimilation, both were analysed simultaneously at various temperatures and light intensities using infrared gas absorption coupled with chlorophyll fluorescence. ETR exceeded electron consumption by carbon assimilation at higher light intensities and at all temperatures tested, necessitating alternative electron sinks. As photorespiration might consume the majority of excess electrons, photorespiration was inhibited by either high internal leaf CO2 molar ratio (C-i), low oxygen partial pressure (0.5% oxygen), or both. At 0.5% oxygen ETR was significantly lower than at 21% oxygen. At 21% oxygen, however, ETR still exceeded carbon assimilation at high C-i, suggesting that excess electrons are transferred to another oxygen consuming reaction when photorespiration is blocked. Nevertheless, photorespiration does contribute to electron consumption. While the activity of the water -water cycle to electron consumption is not known in leaves of R. glacialis, indirect evidence such as the high sensitivity to oxidative stress and the low initial NADP-malate dehydrogenase (NADP-MDH) activity suggests only a minor contribution as an alternative electron sink. Alternatively, the plastid terminal oxidase (PTOX) may transfer excess electrons to oxygen. This enzyme is highly abundant in R. glacialis leaves and exceeds the PTOX content of every other plant species so far examined, including those of transgenic tomato leaves overexpressing the PTOX protein. Finally, PTOX contents strongly declined during deacclimation of R. glacialis plants, suggesting their important role in photoprotection. Ranunculus glacialis is the first reported plant species with such a high PTOX protein content. |
| Databáze: | OpenAIRE |
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