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Slow induction of photosynthesis on shade to sun transitions in wheat may cost at least 21% of productivity

Wheat is the second most important direct source of food calories in the world. After considerable improvement during the Green Revolution, increase in genetic yield potential appears to have stalled. Improvement of photosynthetic efficiency now appears a major opportunity in addressing the sustaina...

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Autores principales: Taylor, Samuel H., Long, Stephen P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5566890/
https://www.ncbi.nlm.nih.gov/pubmed/28808109
http://dx.doi.org/10.1098/rstb.2016.0543
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author Taylor, Samuel H.
Long, Stephen P.
author_facet Taylor, Samuel H.
Long, Stephen P.
author_sort Taylor, Samuel H.
collection PubMed
description Wheat is the second most important direct source of food calories in the world. After considerable improvement during the Green Revolution, increase in genetic yield potential appears to have stalled. Improvement of photosynthetic efficiency now appears a major opportunity in addressing the sustainable yield increases needed to meet future food demand. Effort, however, has focused on increasing efficiency under steady-state conditions. In the field, the light environment at the level of individual leaves is constantly changing. The speed of adjustment of photosynthetic efficiency can have a profound effect on crop carbon gain and yield. Flag leaves of wheat are the major photosynthetic organs supplying the grain of wheat, and will be intermittently shaded throughout a typical day. Here, the speed of adjustment to a shade to sun transition in these leaves was analysed. On transfer to sun conditions, the leaf required about 15 min to regain maximum photosynthetic efficiency. In vivo analysis based on the responses of leaf CO(2) assimilation (A) to intercellular CO(2) concentration (c(i)) implied that the major limitation throughout this induction was activation of the primary carboxylase of C3 photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). This was followed in importance by stomata, which accounted for about 20% of the limitation. Except during the first few seconds, photosynthetic electron transport and regeneration of the CO(2) acceptor molecule, ribulose-1,5-bisphosphate (RubP), did not affect the speed of induction. The measured kinetics of Rubisco activation in the sun and de-activation in the shade were predicted from the measurements. These were combined with a canopy ray tracing model that predicted intermittent shading of flag leaves over the course of a June day. This indicated that the slow adjustment in shade to sun transitions could cost 21% of potential assimilation. This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement’.
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spelling pubmed-55668902017-08-27 Slow induction of photosynthesis on shade to sun transitions in wheat may cost at least 21% of productivity Taylor, Samuel H. Long, Stephen P. Philos Trans R Soc Lond B Biol Sci Articles Wheat is the second most important direct source of food calories in the world. After considerable improvement during the Green Revolution, increase in genetic yield potential appears to have stalled. Improvement of photosynthetic efficiency now appears a major opportunity in addressing the sustainable yield increases needed to meet future food demand. Effort, however, has focused on increasing efficiency under steady-state conditions. In the field, the light environment at the level of individual leaves is constantly changing. The speed of adjustment of photosynthetic efficiency can have a profound effect on crop carbon gain and yield. Flag leaves of wheat are the major photosynthetic organs supplying the grain of wheat, and will be intermittently shaded throughout a typical day. Here, the speed of adjustment to a shade to sun transition in these leaves was analysed. On transfer to sun conditions, the leaf required about 15 min to regain maximum photosynthetic efficiency. In vivo analysis based on the responses of leaf CO(2) assimilation (A) to intercellular CO(2) concentration (c(i)) implied that the major limitation throughout this induction was activation of the primary carboxylase of C3 photosynthesis, ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). This was followed in importance by stomata, which accounted for about 20% of the limitation. Except during the first few seconds, photosynthetic electron transport and regeneration of the CO(2) acceptor molecule, ribulose-1,5-bisphosphate (RubP), did not affect the speed of induction. The measured kinetics of Rubisco activation in the sun and de-activation in the shade were predicted from the measurements. These were combined with a canopy ray tracing model that predicted intermittent shading of flag leaves over the course of a June day. This indicated that the slow adjustment in shade to sun transitions could cost 21% of potential assimilation. This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement’. The Royal Society 2017-09-26 2017-08-14 /pmc/articles/PMC5566890/ /pubmed/28808109 http://dx.doi.org/10.1098/rstb.2016.0543 Text en © 2017 The Authors. http://creativecommons.org/licenses/by/4.0/ Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
spellingShingle Articles
Taylor, Samuel H.
Long, Stephen P.
Slow induction of photosynthesis on shade to sun transitions in wheat may cost at least 21% of productivity
title Slow induction of photosynthesis on shade to sun transitions in wheat may cost at least 21% of productivity
title_full Slow induction of photosynthesis on shade to sun transitions in wheat may cost at least 21% of productivity
title_fullStr Slow induction of photosynthesis on shade to sun transitions in wheat may cost at least 21% of productivity
title_full_unstemmed Slow induction of photosynthesis on shade to sun transitions in wheat may cost at least 21% of productivity
title_short Slow induction of photosynthesis on shade to sun transitions in wheat may cost at least 21% of productivity
title_sort slow induction of photosynthesis on shade to sun transitions in wheat may cost at least 21% of productivity
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5566890/
https://www.ncbi.nlm.nih.gov/pubmed/28808109
http://dx.doi.org/10.1098/rstb.2016.0543
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