Format

Send to

Choose Destination
See comment in PubMed Commons below
Planta. 2003 Nov;218(1):107-14. Epub 2003 Jul 19.

Down-regulation of linear and activation of cyclic electron transport during drought.

Author information

1
School of Biological Sciences, University of Manchester, 3.164 Stopford Building, Oxford Road, Manchester, M13 9PT, UK.

Erratum in

  • Planta. 2004 Feb;218(4):682.

Abstract

The effects of short-term drought on the regulation of electron transport through photosystems I and II (PSI and PSII) have been studied in Hordeum vulgare L. cv. Chariot. Fluorescence measurements demonstrated that electron flow through PSII decreased in response to both drought and CO2 limitation. This was due to regulation, as opposed to photoinhibition. We demonstrate that this regulation occurs between the two photosystems--in contrast to PSII, PSI became more oxidised and the rate constant for P700 re-reduction decreased under these conditions. Thus, when carbon fixation is inhibited, electron transport is down-regulated to match the reduced requirement for electrons and minimise reactive oxygen production. At the same time non-photochemical quenching (NPQ) increases, alleviating the excitation pressure placed on PSII. We observe an increase in the proportion of PSI centres that are 'active' (i.e. can be oxidised with a saturating flash and then rapidly re-reduced) under the conditions when NPQ is increased. We suggest that these additional centres are primarily involved in cyclic electron transport, which generates the DeltapH to support NPQ and protect PSII.

PMID:
12883889
DOI:
10.1007/s00425-003-1077-5
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Springer
    Loading ...
    Support Center