Journal Article

PreJuSER-9981

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Altered physiological function, not structure, drives increased radiation-use efficiency of soybean grown at elevated CO2

Rascher, U.FZJ* ; Biskup, B.FZJ* ; Leakey, A. D. B. ; McGrath, J. M. ; Ainsworth, E. A.

2010
Springer Science + Business Media B.V Dordrecht [u.a.]

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Please use a persistent id in citations: doi:10.1007/s11120-010-9548-6

Abstract: Previous studies of elevated carbon dioxide concentration ([CO(2)]) on crop canopies have found that radiation-use efficiency is increased more than radiation-interception efficiency. It is assumed that increased radiation-use efficiency is due to changes in leaf-level physiology; however, canopy structure can affect radiation-use efficiency if leaves are displayed in a manner that optimizes their physiological capacity, even though the canopy intercepts the same amount of light. In order to determine the contributions of physiology and canopy structure to radiation-use and radiation-interception efficiency, this study relates leaf-level physiology and leaf display to photosynthetic rate of the outer canopy. We used a new imaging approach that delivers three-dimensional maps of the outer canopy during the growing season. The 3D data were used to model leaf orientation and mean photosynthetic electron transport of the outer canopy to show that leaf orientation changes did not contribute to increased radiation-use; i.e. leaves of the outer canopy showed similar diurnal leaf movements and leaf orientation in both treatments. Elevated [CO(2)] resulted in an increased maximum electron transport rate (ETR(max)) of light reactions of photosynthesis. Modeling of canopy light interception showed that stimulated leaf-level electron transport at elevated [CO(2)], and not alterations in leaf orientation, was associated with stimulated radiation-use efficiency and biomass production in elevated [CO(2)]. This study provides proof of concept of methodology to quantify structure-function relationships in combination, allowing a quantitative estimate of the contribution of both effects to canopy energy conversion under elevated [CO(2)].

Keyword(s): Carbon Dioxide: pharmacology (MeSH) ; Electron Transport: drug effects (MeSH) ; Photosynthesis: drug effects (MeSH) ; Soybeans: drug effects (MeSH) ; Soybeans: growth & development (MeSH) ; Soybeans: physiology (MeSH) ; Carbon Dioxide ; J ; Three-dimensional canopy surface (auto) ; Photosynthesis (auto) ; Light reactions (auto) ; Chlorophyll fluorescence (auto) ; Elevated CO2 (auto) ; Glycine max (auto) ; Structure-function relations (auto)

Note: We thank Tim Mies for technical assistance, and Steve Long for supporting our research at SoyFACE. SoyFACE was supported by the Illinois Council for Food and Agricultural Research, Archer Daniels Midland Company, the U.S. Department of Agricultural, and the Illinois Agricultural Experiment Station. B. Biskup and U. Rascher were supported by a NSF/DAAD grant (grant PPP D/05/50496). B. Biskup also acknowledges support of his PhD thesis by the Heinrich-Heine University of Dusseldorf, Germany. We thank K.G. Rascher for assistance with the statistical analyses, and D. Ort for valuable discussions. We also greatly thank H. Scharr for supporting the development of the stereo system and the development of the analyses algorithms.

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Research Program(s):

1. Terrestrische Umwelt (P24)

Appears in the scientific report 2010

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