Format

Send to

Choose Destination
See comment in PubMed Commons below
Curr Opin Plant Biol. 2002 Jun;5(3):193-8.

A photoprotective role for O(2) as an alternative electron sink in photosynthesis?

Author information

1
Photosynthesis Research Unit, USDA/ARS & Department of Plant Biology, University of Illinois, Urbana, Illinois 61801, USA.

Abstract

Photoprotection of the photosynthetic apparatus has two essential elements: first, the thermal dissipation of excess excitation energy in the photosystem II antennae (i.e. non-photochemical quenching), and second, the ability of photosystem II to transfer electrons to acceptors within the chloroplast (i.e. photochemical quenching). Recent studies indicate that the proportion of absorbed photons that are thermally dissipated through the non-photochemical pathway often reaches a maximum well before saturating irradiances are reached. Hence, photochemical quenching is crucial for photoprotection at saturating light intensities. When plants are exposed to environmental stresses and the availability of CO(2) within the leaf is restricted, the reduction of oxygen by both the photorespiratory and the Mehler ascorbate peroxidase pathways appears to play a critical photoprotective role, substituting for CO(2) in sustaining electron flow. Induction of high activity of the Mehler ascorbate peroxidase pathway may be associated with acclimation to environmental stress.

PMID:
11960735
[Indexed for MEDLINE]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Support Center