Photosynthesis Research

, Volume 117, Issue 1–3, pp 529–546

Photosynthetic electron transport and specific photoprotective responses in wheat leaves under drought stress

  • Marek Zivcak
  • Marian Brestic
  • Zuzana Balatova
  • Petra Drevenakova
  • Katarina Olsovska
  • Hazem M. Kalaji
  • Xinghong Yang
  • Suleyman I. Allakhverdiev
Regular Paper

DOI: 10.1007/s11120-013-9885-3

Cite this article as:
Zivcak, M., Brestic, M., Balatova, Z. et al. Photosynth Res (2013) 117: 529. doi:10.1007/s11120-013-9885-3

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.

Keywords

Drought stress Wheat Photosynthetic electron transport Cyclic electron transport around PSI Photosystem stoichiometry Chlorophyll fluorescence Alternative electron sinks 

Abbreviations

\( A_{{{\text{CO}}_{ 2} }} \)

CO2 assimilation rate

Cyt b6/f

Cytochrome b6/f

gm

Mesophyll conductance

gs

Stomatal conductance

LED

Light emitting diode

LHC

Light harvesting complex

NPQ

Nonphotochemical quenching

P700

Primary electron donor of PSI (reduced form)

P700+

Primary electron donor of PSI (oxidized form)

PAR

Photosynthetic active radiation

PQ

Plastoquinone

PSI

Photosystem I

PSII

Photosystem II

QA

Primary PSII acceptor

qE

pH-dependent energy dissipation

RuBP

Ribulose 1,5-bisphosphate

RWC

Relative water content

ΔpH

Transthylakoid pH gradient

ΨW

Water potential

Supplementary material

11120_2013_9885_MOESM1_ESM.pdf (208 kb)
Supplementary material 1 (PDF 208 kb)

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Marek Zivcak
    • 1
  • Marian Brestic
    • 1
  • Zuzana Balatova
    • 1
  • Petra Drevenakova
    • 1
  • Katarina Olsovska
    • 1
  • Hazem M. Kalaji
    • 2
  • Xinghong Yang
    • 3
  • Suleyman I. Allakhverdiev
    • 4
    • 5
  1. 1.Department of Plant PhysiologySlovak Agricultural UniversityNitraSlovak Republic
  2. 2.Department of Plant Physiology, Faculty of Agriculture and BiologyWarsaw Agricultural University SGGWWarsawPoland
  3. 3.State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop BiologyCollege of Life Sciences, Shandong Agricultural UniversityTaianChina
  4. 4.Institute of Plant Physiology, Russian Academy of SciencesMoscowRussia
  5. 5.Institute of Basic Biological ProblemsRussian Academy of SciencesMoscow RegionRussia

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