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Photosynthetic electron transport and specific photoprotective responses in wheat leaves under drought stress.
Photosynth Res. 2013 Nov; 117(1-3):529-46.PR

Abstract

The photosynthetic responses of wheat (Triticum aestivum L.) leaves to different levels of drought stress were analyzed in potted plants cultivated in growth chamber under moderate light. Low-to-medium drought stress was induced by limiting irrigation, maintaining 20 % of soil water holding capacity for 14 days followed by 3 days without water supply to induce severe stress. Measurements of CO2 exchange and photosystem II (PSII) yield (by chlorophyll fluorescence) were followed by simultaneous measurements of yield of PSI (by P700 absorbance changes) and that of PSII. Drought stress gradually decreased PSII electron transport, but the capacity for nonphotochemical quenching increased more slowly until there was a large decrease in leaf relative water content (where the photosynthetic rate had decreased by half or more). We identified a substantial part of PSII electron transport, which was not used by carbon assimilation or by photorespiration, which clearly indicates activities of alternative electron sinks. Decreasing the fraction of light absorbed by PSII and increasing the fraction absorbed by PSI with increasing drought stress (rather than assuming equal absorption by the two photosystems) support a proposed function of PSI cyclic electron flow to generate a proton-motive force to activate nonphotochemical dissipation of energy, and it is consistent with the observed accumulation of oxidized P700 which causes a decrease in PSI electron acceptors. Our results support the roles of alternative electron sinks (either from PSII or PSI) and cyclic electron flow in photoprotection of PSII and PSI in drought stress conditions. In future studies on plant stress, analyses of the partitioning of absorbed energy between photosystems are needed for interpreting flux through linear electron flow, PSI cyclic electron flow, along with alternative electron sinks.

Authors+Show Affiliations

Department of Plant Physiology, Slovak Agricultural University, Tr. A. Hlinku 2, 949 76, Nitra, Slovak Republic, marek.zivcak@uniag.sk.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

23860828

Citation

Zivcak, Marek, et al. "Photosynthetic Electron Transport and Specific Photoprotective Responses in Wheat Leaves Under Drought Stress." Photosynthesis Research, vol. 117, no. 1-3, 2013, pp. 529-46.
Zivcak M, Brestic M, Balatova Z, et al. Photosynthetic electron transport and specific photoprotective responses in wheat leaves under drought stress. Photosynth Res. 2013;117(1-3):529-46.
Zivcak, M., Brestic, M., Balatova, Z., Drevenakova, P., Olsovska, K., Kalaji, H. M., Yang, X., & Allakhverdiev, S. I. (2013). Photosynthetic electron transport and specific photoprotective responses in wheat leaves under drought stress. Photosynthesis Research, 117(1-3), 529-46. https://doi.org/10.1007/s11120-013-9885-3
Zivcak M, et al. Photosynthetic Electron Transport and Specific Photoprotective Responses in Wheat Leaves Under Drought Stress. Photosynth Res. 2013;117(1-3):529-46. PubMed PMID: 23860828.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Photosynthetic electron transport and specific photoprotective responses in wheat leaves under drought stress. AU - Zivcak,Marek, AU - Brestic,Marian, AU - Balatova,Zuzana, AU - Drevenakova,Petra, AU - Olsovska,Katarina, AU - Kalaji,Hazem M, AU - Yang,Xinghong, AU - Allakhverdiev,Suleyman I, Y1 - 2013/07/17/ PY - 2013/03/18/received PY - 2013/07/03/accepted PY - 2013/7/18/entrez PY - 2013/7/19/pubmed PY - 2014/6/6/medline SP - 529 EP - 46 JF - Photosynthesis research JO - Photosynth Res VL - 117 IS - 1-3 N2 - The photosynthetic responses of wheat (Triticum aestivum L.) leaves to different levels of drought stress were analyzed in potted plants cultivated in growth chamber under moderate light. Low-to-medium drought stress was induced by limiting irrigation, maintaining 20 % of soil water holding capacity for 14 days followed by 3 days without water supply to induce severe stress. Measurements of CO2 exchange and photosystem II (PSII) yield (by chlorophyll fluorescence) were followed by simultaneous measurements of yield of PSI (by P700 absorbance changes) and that of PSII. Drought stress gradually decreased PSII electron transport, but the capacity for nonphotochemical quenching increased more slowly until there was a large decrease in leaf relative water content (where the photosynthetic rate had decreased by half or more). We identified a substantial part of PSII electron transport, which was not used by carbon assimilation or by photorespiration, which clearly indicates activities of alternative electron sinks. Decreasing the fraction of light absorbed by PSII and increasing the fraction absorbed by PSI with increasing drought stress (rather than assuming equal absorption by the two photosystems) support a proposed function of PSI cyclic electron flow to generate a proton-motive force to activate nonphotochemical dissipation of energy, and it is consistent with the observed accumulation of oxidized P700 which causes a decrease in PSI electron acceptors. Our results support the roles of alternative electron sinks (either from PSII or PSI) and cyclic electron flow in photoprotection of PSII and PSI in drought stress conditions. In future studies on plant stress, analyses of the partitioning of absorbed energy between photosystems are needed for interpreting flux through linear electron flow, PSI cyclic electron flow, along with alternative electron sinks. SN - 1573-5079 UR - https://www.unboundmedicine.com/medline/citation/23860828/Photosynthetic_electron_transport_and_specific_photoprotective_responses_in_wheat_leaves_under_drought_stress_ L2 - https://dx.doi.org/10.1007/s11120-013-9885-3 DB - PRIME DP - Unbound Medicine ER -