During photosynthetic induction, biochemical and stomatal limitations differ between Brassica crops

Samuel H. Taylor, Douglas J. Orr, Elizabete Carmo-Silva, Stephen P. Long

Research output: Contribution to journalArticle

Abstract

Interventions to increase crop radiation use efficiency rely on understanding of how biochemical and stomatal limitations affect photosynthesis. When leaves transition from shade to high light, slow increases in maximum Rubisco carboxylation rate and stomatal conductance limit net CO2 assimilation for several minutes. However, as stomata open intercellular [CO2] increases, so electron transport rate could also become limiting. Photosynthetic limitations were evaluated in three important Brassica crops: Brassica rapa, Brassica oleracea and Brassica napus. Measurements of induction after a period of shade showed that net CO2 assimilation by B. rapa and B. napus saturated by 10 min. A new method of analyzing limitations to induction by varying intercellular [CO2] showed this was due to co-limitation by Rubisco and electron transport. By contrast, in B. oleracea persistent Rubisco limitation meant that CO2 assimilation was still recovering 15 min after induction. Correspondingly, B. oleracea had the lowest Rubisco total activity. The methodology developed, and its application here, shows a means to identify the basis of variation in photosynthetic efficiency in fluctuating light, which could be exploited in breeding and bioengineering to improve crop productivity.

Original languageEnglish (US)
JournalPlant Cell and Environment
DOIs
StateAccepted/In press - 2020

Keywords

  • Brassica napus
  • Brassica oleracea
  • Brassica rapa
  • CO response
  • Rubisco
  • crop improvement
  • dynamic photosynthesis
  • photosynthetic electron transport
  • photosynthetic induction
  • stomata

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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