TITLE

Impairment of C4 photosynthesis by drought is exacerbated by limiting nitrogen and ameliorated by elevated [CO2] in maize

AUTHOR(S)
Markelz, R. J. Cody; Strellner, Reid S.; Leakey, Andrew D. B.
PUB. DATE
June 2011
SOURCE
Journal of Experimental Botany;Jun2011, Vol. 62 Issue 9, p3235
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Predictions of future ecosystem function and food supply from staple C4 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 [CO2], drought, and nitrogen (N) supply on net photosynthetic CO2 uptake (A) in the world's most important C4 crop, maize (Zea mays) was grown at ambient [CO2] (∼385 ppm) and elevated [CO2] (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 [CO2] when water availability was high, irrespective of N availability. Elevated [CO2] 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 [CO2] were additive, so amelioration of stress by elevated [CO2] did not differ in magnitude between high N and limiting N supply. These findings provide new understanding of the limitations to C4 photosynthesis that will occur under future field conditions of the primary region of maize production in the world.
ACCESSION #
74440695

 

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