Impairment of C 4 photosynthesis by drought is exacerbated by limiting nitrogen and ameliorated by elevated [CO 2] in maize

R. J.Cody Markelz, Reid S. Strellner, Andrew D.B. Leakey

Research output: Contribution to journalArticle

Abstract

Predictions of future ecosystem function and food supply from staple C 4 crops, such as maize, depend on elucidation of the mechanisms by which environmental change and growing conditions interact to determine future plant performance. To test the interactive effects of elevated [CO 2], drought, and nitrogen (N) supply on net photosynthetic CO 2 uptake (A) in the world's most important C 4 crop, maize (Zea mays) was grown at ambient [CO 2] (∼385 ppm) and elevated [CO 2] (550 ppm) with either high N supply (168 kg N ha -1 fertilizer) or limiting N (no fertilizer) at a site in the US Corn Belt. A mid-season drought was not sufficiently severe to reduce yields, but caused significant physiological stress, with reductions in stomatal conductance (up to 57%), A (up to 44%), and the in vivo capacity of phosphoenolpyruvate carboxylase (up to 58%). There was no stimulation of A by elevated [CO 2] when water availability was high, irrespective of N availability. Elevated [CO 2] delayed and relieved both stomatal and non-stomatal limitations to A during the drought. Limiting N supply exacerbated stomatal and non-stomatal limitation to A during drought. However, the effects of limiting N and elevated [CO 2] were additive, so amelioration of stress by elevated [CO 2] did not differ in magnitude between high N and limiting N supply. These findings provide new understanding of the limitations to C 4 photosynthesis that will occur under future field conditions of the primary region of maize production in the world.

Original languageEnglish (US)
Pages (from-to)3235-3246
Number of pages12
JournalJournal of experimental botany
Volume62
Issue number9
DOIs
StatePublished - May 2011

Keywords

  • Climate change
  • Zea mays
  • stomata
  • stress

ASJC Scopus subject areas

  • Physiology
  • Plant Science

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