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7 results on '"light excess"'

1. Photosynthetic heat tolerance in plants with different foliar water ‐uptake strategies.

Author

Boanares, Daniela, Lemos‐Filho, José P., Isaias, Rosy M. S., and França, Marcel G. C.

Subjects
*PLANT capacity, *PLANT species, *PHOTOSYSTEMS, *WATER efficiency, *LIGHT intensity, *GLOBAL warming, *METHANE hydrates, *CLIMATE change
Abstract

Premise: The distribution and even the survival of plant species are influenced by temperature. In an old climatically buffered infertile landscape (OCBIL) in Brazil, we previously characterized different strategies for foliar water uptake (FWU). It is possible that photosystem II tolerance to heat and excessive light intensity varies among species with different FWU capacities. Methods: The relationship between FWU, photoinhibition, and thermotolerance was investigated in seven species from this ecosystem. Results: The species with slow water absorption and high water absorption are those that presented less photoinhibition. Contrastingly, the species that have fast and low water absorption presented greater thermotolerance when their leaves are totally hydrated. However, when there is greater leaf dehydration, the most thermotolerant species were those with slow but high water absorption. Conclusions: Foliar water uptake is an important trait for plants to tolerate excessive light intensity and higher temperatures. Plants in this OCBIL may be differentially affected by future global warming, and the best strategy to deal with this expected climate change is with slow and high absorption of water. [ABSTRACT FROM AUTHOR]

Published
2021
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2. Photosynthetic performance and light response of two olive cultivars under different water and light regimes.

Author

SOFO, A., DICHIO, B., MONTANARO, G., and XILOYANNIS, C.

Subjects
*PHOTOSYNTHESIS, *CULTIVARS, *OLIVE, *PLANT photoinhibition, *DROUGHTS
Abstract

The olive tree (Olea europaea L.) is commonly grown in the Mediterranean area, where it is adapted to resist periods characterized by severe drought and high irradiance levels. Photosynthetic efficiency (in terms of Fv/Fm and ΦPSII), photochemical (qP) and nonphotochemical quenching (NPQ) were determined in two-year-old olive plants (cultivars Coratina and Biancolilla) grown under two different light levels (exposed plants, EP, and shaded plants, SP) during a 21-day controlled water deficit. After reaching the maximum level of drought stress, plants were rewatered for 23 days. During the experimental period, measurements of gas exchange and chlorophyll (Chl) fluorescence were carried out to study the photosynthetic performance of olive plants. The synergical effect of drought stress and high irradiance levels caused a reduction of gas exchange and photosynthetic efficiency and these decreases were more marked in EP. EP showed a higher degree of photoinhibition, a higher NPQ and a lower qP if compared to SP. Coratina was more sensitive to high light and drought stress but also showed a slower recovery during rewatering, whereas Biancolilla showed a less marked photosynthesis depression during drought and a considerable resilience during rewatering. The results confirm that photoinhibition due to high light intensity and water deficit can be an important factor that affects photosynthetic productivity in this species. [ABSTRACT FROM AUTHOR]

Published
2009
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3. Shade effect on photosynthesis and photoinhibition in olive during drought and rewatering

Author

Sofo, Adriano, Dichio, Bartolomeo, Montanaro, Giuseppe, and Xiloyannis, Cristos

Subjects
*PLANT-water relationships, *PHOTOSYNTHESIS, *PLANT photoinhibition, *SHADES & shadows, *OLIVE, *BOTANY experiments, *EFFECT of drought on plants, *WATER efficiency
Abstract

Abstract: Olive tree (Olea europaea L.) is commonly grown under environmental conditions characterised by water deficit, high temperatures and irradiance levels typical of Mediterranean semi-arid regions. Measurement of gas exchange, chlorophyll content, chlorophyll fluorescence and photoinhibition was carried out on two-year-old olive trees (cv. ‘Coratina’) subjected to a 21-day period of water deficit followed by 23 days of rewatering. At the beginning of the experiment, plants were divided in to two groups and subjected to different light regimes: exposed plants (EP) under a mean photosynthetically active radiation (PAR) at mid-day of 1800μmolm−2 s−1 and shaded plants (SP) under a mean PAR of 1200μmolm−2 s−1. The effect of drought and high irradiance levels caused a reduction of gas exchange and photosystem 2 (PSII) efficiency, in terms of quantum yield of PSII (Φ PSII) both in EP and SP. Shading conditions allowed plants to maintain a high photosynthetic activity at low values of stomatal conductance, whereas in EP the reductions in photosynthetic efficiency and intrinsic water efficiency were due to non-stomatal components of photosynthesis. The decrease in photosynthetic activity and the increase of photoinhibition under drought were more marked in EP than in SP. Full sunlight caused in EP a higher non-photochemical quenching, whereas SP showed a better photochemical efficiency. The information here obtained can be important to understand the mechanisms by which olive plants can minimize photoinhibition when subjected to simultaneous abiotic stresses. [Copyright &y& Elsevier]

Published
2009
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5. A dual strategy to cope with high light in Chlamydomonas reinhardtii

Author

Jun Minagawa, Thomas Roach, Daphné Seigneurin-Berny, Ryutaro Tokutsu, Krishna K. Niyogi, Dimitris Petroutsos, Jacqueline Girard-Bascou, Francis-André Wollman, Graham Peers, Giovanni Finazzi, Marcel Kuntz, Guillaume Allorent, Pierre Cardol, Anja Krieger-Liszkay, Cécile Breyton, Fabrice Franck, Laboratoire de physiologie cellulaire végétale (LPCV), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Division of Environmental Photobiology, National Institute for Basic Biology [Okazaki], Service de Bioénergétique, Biologie Stucturale, et Mécanismes (SB2SM), Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Intégrative de la Cellule (I2BC), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Institut de Biologie et de Technologies de Saclay (IBITECS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Biology [Fort Collins], Colorado State University [Fort Collins] (CSU), Laboratoire de Génétique des Microorganismes, Université de Liège, Physiologie membranaire et moléculaire du chloroplaste (PMMC), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut de biologie structurale (IBS - UMR 5075), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Bioénergétique, Howard Hughes Medical Institute, Department of Plant and Microbial Biology, NEXT Program initiated by the Council for Science and Technology Policy Grant (GS026). - Grant from the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy (Field Work Proposal number 449B) - Fonds de la Recherche Scientifique grants (MIS F.4520 and FRFC 2.4597), National Institute for Basic Biology Cooperative Research Program for the Okazaki Large Spectrograph number 12-513, Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Recherche Agronomique (INRA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de biologie structurale (IBS - UMR 5075 ), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National de la Recherche Agronomique (INRA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Laboratoire de physiologie cellulaire végétale ( LPCV ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut National de la Recherche Agronomique ( INRA ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Centre National de la Recherche Scientifique ( CNRS ), Service de Bioénergétique, Biologie Stucturale, et Mécanismes ( SB2SM ), Centre National de la Recherche Scientifique ( CNRS ) -Institut de Biologie Intégrative de la Cellule ( I2BC ), Université Paris-Sud - Paris 11 ( UP11 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ) -Université Paris-Sud - Paris 11 ( UP11 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Institut de Biologie et de Technologies de Saclay ( IBITECS ), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ), Department of Biology, Colorado State University, University of Colorado Boulder [Boulder], Physiologie membranaire et moléculaire du chloroplaste ( PMMC ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de biologie structurale ( IBS - UMR 5075 ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), and University of California [Berkeley]

Subjects
0106 biological sciences, Photosystem II, Algae, Light, Molecular Sequence Data, Light-Harvesting Protein Complexes, Chlamydomonas reinhardtii, Plant Science, macromolecular substances, Protein Serine-Threonine Kinases, 01 natural sciences, Energy quenching, Fluorescence, 03 medical and health sciences, light acclimation, light excess, Botany, state transitions, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Photosynthesis, [ SDV.BBM ] Life Sciences [q-bio]/Biochemistry, Molecular Biology, Research Articles, 030304 developmental biology, Photosystem, Plant Proteins, 0303 health sciences, Quenching (fluorescence), biology, Photosystem I Protein Complex, Non-photochemical quenching, Chlamydomonas, Photosystem II Protein Complex, Cell Biology, biology.organism_classification, photoprotection, energy quenching, Nigericin, Photoprotection, Mutation, Biophysics, 010606 plant biology & botany
Abstract

Absorption of light in excess of the capacity for photosynthetic electron transport is damaging to photosynthetic organisms. Several mechanisms exist to avoid photodamage, which are collectively referred to as nonphotochemical quenching. This term comprises at least two major processes. State transitions (qT) represent changes in the relative antenna sizes of photosystems II and I. High energy quenching (qE) is the increased thermal dissipation of light energy triggered by lumen acidification. To investigate the respective roles of qE and qT in photoprotection, a mutant (npq4 stt7-9) was generated in Chlamydomonas reinhardtii by crossing the state transition–deficient mutant (stt7-9) with a strain having a largely reduced qE capacity (npq4). The comparative phenotypic analysis of the wild type, single mutants, and double mutants reveals that both state transitions and qE are induced by high light. Moreover, the double mutant exhibits an increased photosensitivity with respect to the single mutants and the wild type. Therefore, we suggest that besides qE, state transitions also play a photoprotective role during high light acclimation of the cells, most likely by decreasing hydrogen peroxide production. These results are discussed in terms of the relative photoprotective benefit related to thermal dissipation of excess light and/or to the physical displacement of antennas from photosystem II.

Published
2013

6. Gestione dell’energia radiante nelle piante da frutto: utilizzazione, foto-protezione e foto-danno. Quali implicazioni per la produttività?

Author

LOSCIALE, PASQUALE, PIERPAOLI, EMANUELE, CORELLI GRAPPADELLI, LUCA, P. Losciale, E. Pierpaoli, and L. Corelli Grappadelli

Subjects
ELECTRON ALTERNATIVE TRANSPORTS, NON PHOTOCHEMICAL QUENCHING, PHOTOSYNTHESIS, LIGHT EXCESS, PHOTO-DAMAGE
Abstract

The energetic basis of orchard productivity lies in the interaction between the tree and sunlight. The light intercepted by a plant is linearly related to the amount of dry matter it produces. This concept drew the evolution of the new, intensive orchard planting systems, although this dependence seems to be more subordinate to planting system rather than light intensity. At whole plant level not always the increase of irradiance determines productivity improvement. One of the reasons can be the plant intrinsic un-efficiency in using energy. Generally in full light only the 5–10% of the total incoming photosynthetic photon flux density (PPFD) is allocated to net photosynthesis. Therefore preserving or improving this efficiency becomes pivotal for scientist and fruit growers. Net photosynthesis increases with light until the saturation point and additional PPFD doesn’t improve carboxylation. In several parts of the world, under clear sky the PPFD reaches commonly 2000 μmol photons m-2 s-1 or above, and about 50% of the incoming light is enough for reaching the saturating point in most plant species. On the other hand, about half of the available light may be in excess. Even tough a conspicuous energy amount is reflected or transmitted, plants can not avoid to absorb photons in excess. The chlorophyll over-excitation promotes the reactive oxygen species (ROS) production increasing the photoinhibition (photo-damage) risks. The dangerous consequences of photoinhibition forced plants to evolve a complex and multilevel machine able to dissipate the energy excess quenching heat (Non Photochemical Quenching), moving electrons (water-water cycle, cyclic transport around PSI, glutathione-ascorbate cycle and photorespiration) and scavenging the generated ROS. The price plants must pay for this equipment is the use of CO2 and reducing power with a consequent decrease of the photosynthetic efficiency, both because some photons are not used for carboxylation and an effective CO2 and reducing power loss occurs. The wide photo-protective apparatus, although is not able to cope with the excessive incoming energy, therefore photo-damage occurs. Each event increasing the photon pressure and/or decreasing the efficiency of the described photo-protective mechanisms (i.e. thermal stress, water and nutritional deficiency) can emphasize the photoinhibition. Likely in nature a small amount of not damaged photo-systems is found because of the effective, efficient and energy consuming recovery system. Since the damaged PSII is quickly repaired with energy expense, it would be interesting to investigate how much PSII recovery costs to plant productivity. This review purposes to improve the knowledge about the several strategies accomplished for managing the incoming energy and the light excess implication on photo-damage in plants. Furthermore the chlorophyll fluorescence measure technique is described. This is the most useful method, particularly because it can be used in vivo as well and it is possible to quantify and discriminate the contribution of pathways in which the incoming photon pressure is engaged. Finally some cases of light excess linked with abiotic stresses and particular physiological condition on fruit species are reported.

Published
2009

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