Plant Physiol. Illumina
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Plant Physiology Preview
Published on September 11, 2003; 10.1104/pp.103.026567

This Article
Right arrow Full Text (Plant Physiology Preview (PDF))
Right arrow All Versions of this Article:
133/2/803    most recent
pp.103.026567v1
Right arrow Alert me when this article is cited
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 Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Web of Science (9)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Osborne, C. P.
Right arrow Articles by Beerling, D. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Osborne, C. P.
Right arrow Articles by Beerling, D. J.
Agricola
Right arrow Articles by Osborne, C. P.
Right arrow Articles by Beerling, D. J.

Received May 7, 2003
Returned for revision June 4, 2003
Accepted June 23, 2003

The Penalty of a Long, Hot Summer. Photosynthetic Acclimation to High CO2 and Continuous Light in "Living Fossil" Conifers

Colin P. Osborne * and David J. Beerling

Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom

* Corresponding author; email: c.p.osborne{at}sheffield.ac.uk.

Deciduous forests covered the ice-free polar regions 280 to 40 million years ago under warm "greenhouse" climates and high atmospheric pCO2. Their deciduous habit is frequently interpreted as an adaptation for minimizing carbon losses during winter, but experiments with "living fossils" in a simulated warm polar environment refute this explanation. Measured carbon losses through leaf abscission of deciduous trees are significantly greater than losses through winter respiration in evergreens, yet annual rates of primary productivity are similar in all species. Here, we investigate mechanisms underlying this apparent paradox by measuring the seasonal patterns of leaf photosynthesis (A) under pCO2 enrichment in the same trees. During spring, A increased significantly in coastal redwood (Sequoia sempervirens), dawn redwood (Metasequoia glyptostroboides), and swamp cypress (Taxodium distichum) at an elevated pCO2 of 80 Pa compared with controls at 40 Pa. However, strong acclimation in Rubisco carboxylation capacity (Vc,max) completely offset the CO2 response of A in all species by the end of 6 weeks of continuous illumination in the simulated polar summer. Further measurements demonstrated the temporary nature of acclimation, with increases in Vc,max during autumn restoring the CO2 sensitivity of A. Contrary to expectations, the acclimation of Vc,max was not always accompanied by accumulation of leaf carbohydrates, but was associated with a decline in leaf nitrogen in summer, suggesting an alteration of the balance in plant sources and sinks for carbon and nitrogen. Preliminary calculations using A indicated that winter carbon losses through deciduous leaf abscission and respiration were recovered by 10 to 25 d of canopy carbon fixation during summer, thereby explaining the productivity paradox.




This article has been cited by other articles:


Home page
 ANN BOT (LOND)Home page
L. Llorens, C. P. Osborne, and D. J. Beerling
Water-use responses of 'living fossil' conifers to CO2 enrichment in a simulated Cretaceous polar environment
Ann. Bot., July 1, 2009; 104(1): 179 - 188.
[Abstract] [Full Text] [PDF]

Home page
 PaleobiologyHome page
Contrasting seasonal patterns of carbon gain in evergreen and deciduous trees of ancient polar forests
Paleobiology, January 1, 2005; 31(1): 141 - 150.



HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
ASPB Publications PLANT PHYSIOLOGY® THE PLANT CELL
Copyright © 2003 by the American Society of Plant Biologists