Skip Navigation


JXB Advance Access originally published online on February 24, 2009
Journal of Experimental Botany 2009 60(4):1179-1190; doi:10.1093/jxb/ern364
This Article
Right arrow Full Text Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow Supplementary Data
Right arrowOA All Versions of this Article:
60/4/1179    most recent
ern364v1
Right arrow E-letters: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when E-letters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (2)
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Boonman, A.
Right arrow Articles by Pons, T. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Boonman, A.
Right arrow Articles by Pons, T. L.
Agricola
Right arrow Articles by Boonman, A.
Right arrow Articles by Pons, T. L.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2009 The Author(s).
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details)

RESEARCH PAPER

Redundant roles of photoreceptors and cytokinins in regulating photosynthetic acclimation to canopy density

A. Boonman1 *, E. Prinsen2, L. A. C. J. Voesenek1 and T. L. Pons1,{dagger}

1Plant Ecophysiology Group, Institute of Environmental Biology, Utrecht University, 3584 CA, Utrecht, The Netherlands
2Department of Biology, Laboratory for Plant Biochemistry and Physiology, University of Antwerpen, B-2020 Antwerpen, Belgium

{dagger} To whom correspondence should be addressed. E-mail: t.l.pons{at}uu.nl.

The regulation of photosynthetic acclimation to canopy density was investigated in tobacco canopies and in tobacco and Arabidopsis plants with part of their foliage experimentally shaded. Both species acclimated to canopy light gradients and partial shading by allocating photosynthetic capacity to leaves in high light and adjusting chloroplast organization to the local light conditions. An investigation was carried out to determine whether signalling mediated by photoreceptors, sugars, cytokinin, and nitrate is involved in and necessary for proper photosynthetic acclimation. No evidence was found for a role for sugars, or for nitrate. The distribution of cytokinins in tobacco stands of contrasting density could be explained in part by irradiance-dependent delivery of cytokinins through the transpiration stream. Functional studies using a comprehensive selection of Arabidopsis mutants and transgenics showed that normal wild-type responses to partial shading were retained when signalling mediated by photoreceptors or cytokinins was disrupted. This indicates that these pathways probably operate in a redundant manner. However, the reduction of the chlorophyll a/b ratio in response to local shade was completely absent in the Arabidopsis Ws-2 accession mutated in PHYTOCHROME D and in the triple phyAphyCphyD mutant. Moreover, cytokinin receptor mutants also showed a reduced response, suggesting a previously unrecognized function of phyD and cytokinins.

Key words: Arabidopsis mutants, cytokinin, environmental signalling, photoreceptors, photosynthetic acclimation, tobacco

* Present address: Experimental Plant Systematics, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, PO Box 94062, 1090 GB Amsterdam, The Netherlands.

Received 10 December 2008; Accepted 22 December 2008


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.