Please use this identifier to cite or link to this item:
Scopus Web of Science® Altmetric
Type: Journal article
Title: Relative enhancement of photosynthesis and growth at elevated CO2 is greater under sunflecks than uniform irradiance in a tropical rain forest tree seedling
Author: Leakey, A.
Press, M.
Scholes, J.
Watling, J.
Citation: Plant, Cell and Environment, 2002; 25(12):1701-1714
Publisher: Blackwell Science Ltd
Issue Date: 2002
ISSN: 0140-7791
Statement of
A. D. B. Leakey, M. C. Press, J. D. Scholes, J. R. Watling
Abstract: The survivorship of dipterocarp seedlings in the deeply shaded understorey of South-east Asian rain forests is limited by their ability to maintain a positive carbon balance. Photosynthesis during sunflecks is an important component of carbon gain. To investigate the effect of elevated CO2 upon photosynthesis and growth under sunflecks, seedlings of Shorealeprosula were grown in controlled environment conditions at ambient or elevated CO2. Equal total daily photon flux density (PFD) (~7·7 mol m 2 d 1) was supplied as either uniform irradiance (~170 µmol m 2 s 1) or shade/fleck sequences (~30 µmol m 2 s 1/~525 µmol m 2 s 1). Photosynthesis and growth were enhanced by elevated CO2 treatments but lower under flecked irradiance treatments. Acclimation of photosynthetic capacity occurred in response to elevated CO2 but not flecked irradiance. Importantly, the relative enhancement effects of elevated CO2 were greater under sunflecks (growth 60%, carbon gain 89%) compared with uniform irradiance (growth 25%, carbon gain 59%). This was driven by two factors: (1) greater efficiency of dynamic photosynthesis (photosynthetic induction gain and loss, post-irradiance gas exchange); and (2) photosynthetic enhancement being greatest at very low PFD. This allowed improved carbon gain during both clusters of lightflecks (73%) and intervening periods of deep shade (99%). The relatively greater enhancement of growth and photosynthesis at elevated CO2 under sunflecks has important potential consequences for seedling regeneration processes and hence forest structure and composition.
Keywords: Shorea leprosula
dynamic photosynthesis
forest understorey
photosynthetic induction
stomatal conductance
Description: The definitive version is available at
DOI: 10.1046/j.1365-3040.2002.00944.x
Published version:
Appears in Collections:Aurora harvest 7
Ecology, Evolution and Landscape Science publications
Environment Institute Leaders publications

Files in This Item:
There are no files associated with this item.

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.