Altered physiological function, not structure, drives increased radiation-use efficiency of soybean grown at elevated CO2

Uwe Rascher, Bernhard Biskup, Andrew Leakey, Justin M. McGrath, Elizabeth Ainsworth

Research output: Contribution to journalArticle

Abstract

Previous studies of elevated carbon dioxide concentration ([CO2]) 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 [CO2] resulted in an increased maximum electron transport rate (ETRmax) of light reactions of photosynthesis. Modeling of canopy light interception showed that stimulated leaf-level electron transport at elevated [CO2], and not alterations in leaf orientation, was associated with stimulated radiation-use efficiency and biomass production in elevated [CO2]. 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 [CO2].

Original languageEnglish (US)
Pages (from-to)15-25
Number of pages11
JournalPhotosynthesis research
Volume105
Issue number1
DOIs
StatePublished - Jun 24 2010

Fingerprint

radiation use efficiency
Soybeans
carbon dioxide
Radiation
soybeans
canopy
leaves
Physiology
Electron Transport
electron transfer
Light
physiology
forest canopy
Photosynthesis
Energy conversion
Carbon Dioxide
Biomass
Crops
energy conversion
structure-activity relationships

Keywords

  • Chlorophyll fluorescence
  • Elevated CO
  • Glycine max
  • Light reactions
  • Photosynthesis
  • Structure-function relations
  • Three-dimensional canopy surface

ASJC Scopus subject areas

  • Biochemistry
  • Plant Science
  • Cell Biology

Cite this

Altered physiological function, not structure, drives increased radiation-use efficiency of soybean grown at elevated CO2. / Rascher, Uwe; Biskup, Bernhard; Leakey, Andrew; McGrath, Justin M.; Ainsworth, Elizabeth.

In: Photosynthesis research, Vol. 105, No. 1, 24.06.2010, p. 15-25.

Research output: Contribution to journalArticle

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