CO2-induced changes in wheat grain composition: meta-analysis and response functions

Publication Type

Journal contribution (peer reviewed)

Authors

Broberg, M., Högy, P., Pleijel, H.

Year of publication

2017

Published in

Agronomy

Band/Volume

7/2

DOI

10.3390/agronomy7020032

Page (from - to)

32

Elevated carbon dioxide (eCO₂) stimulates wheat grain yield, but simultaneously reduces protein/nitrogen (N) concentration. Also, other essential nutrients are subject to change. This study is a synthesis of wheat experiments with eCO₂, estimating the effects on N, minerals (B, Ca, Cd, Fe, K, Mg, Mn, Na, P, S, Zn), and starch. The analysis was performed by (i) deriving response functions to assess the gradual change in element concentration with increasing CO₂ concentration, (ii) meta-analysis to test the average magnitude and significance of observed effects, and (iii) relating CO₂ effects on minerals to effects on N and grain yield. Responses ranged from zero to strong negative effects of eCO₂ on mineral concentration, with the largest reductions for the nutritionally important elements of N, Fe, S, Zn, and Mg. Together with the positive but small and non-significant effect on starch concentration, the large variation in effects suggests that CO₂-induced responses cannot be explained only by a simple dilution model. To explain the observed pattern, uptake and transport mechanisms may have to be considered, along with the link of different elements to N uptake. Our study shows that eCO₂ has a significant effect on wheat grain stoichiometry, with implications for human nutrition in a world of rising CO₂. © 2017 by the authors.