Photosynthesis in the fleeting shadows: An overlooked opportunity for increasing crop productivity?

Yu Wang, Steven J. Burgess, Elsa M. de Becker, Stephen P. Long

Research output: Contribution to journalArticle

Abstract

Photosynthesis measurements are traditionally taken under steady-state conditions; however, leaves in crop fields experience frequent fluctuations in light and take time to respond. This slow response reduces the efficiency of carbon assimilation. Transitions from low to high light require photosynthetic induction, including the activation of Rubisco and the opening of stomata, whereas transitions from high to low light require the relaxation of dissipative energy processes, collectively known as non-photochemical quenching (NPQ). Previous attempts to assess the impact of these delays on net carbon assimilation have used simplified models of crop canopies, limiting the accuracy of predictions. Here, we use ray tracing to predict the spatial and temporal dynamics of lighting for a rendered mature Glycine max (soybean) canopy to review the relative importance of these delays on net cumulative assimilation over the course of both a sunny and a cloudy summer day. Combined limitations result in a 13% reduction in crop carbon assimilation on both sunny and cloudy days, with induction being more important on cloudy than on sunny days. Genetic variation in NPQ relaxation rates and photosynthetic induction in parental lines of a soybean nested association mapping (NAM) population was assessed. Short-term NPQ relaxation (<30 min) showed little variation across the NAM lines, but substantial variation was found in the speeds of photosynthetic induction, attributable to Rubisco activation. Over the course of a sunny and an intermittently cloudy day these would translate to substantial differences in total crop carbon assimilation. These findings suggest an unexplored potential for breeding improved photosynthetic potential in our major crops.

Original languageEnglish (US)
Pages (from-to)874-884
Number of pages11
JournalThe Plant Journal
Volume101
Issue number4
DOIs
StatePublished - Feb 1 2020

Keywords

  • photosynthetic induction
  • non-photochemical quenching
  • NPQ
  • food security
  • soybean
  • wheat
  • photosystem II
  • photoinhibition
  • stomata
  • crop breeding
  • leaf canopy
  • Rubisco activase

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

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    Data and code for: Photosynthesis in the fleeting shadows: An overlooked opportunity for increasing crop productivity?

    Wang, Y. (Creator), Burgess, S. J. (Creator), de Becker, E. (Creator) & Long, S. P. (Creator), University of Illinois at Urbana-Champaign, Dec 20 2019

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