Hidden shift of the ionome of plants exposed to elevated CO2 depletes minerals at the base of human nutrition

eLife. Free air CO₂ enrichment (FACE) has been used to surround plants with an elevated concentration of CO₂ (eCO₂) during growth, and has consistently conferred an increase in carbon assimilation and plant productivity.  However, the effect of eCO₂ on nutrient status of the plant is unclear due to the difficulties in accurately measuring low-abundance compounds and minerals, and mis-interpretation of data due to lack of statistical power. Loladze used only data with a statistical power >0.4 to demonstrate that the clear majority of elements assayed (except carbon and manganese) showed a decline at eCO₂ (between 6.5 and 10%), a pattern repeated when restricting samples to foliar or edible tissues. The same effect is seen for both FACE and non-FACE studies, and appears consistent across various geographical sites. It is also consistent across different plant groups, including cereals like wheat and rice, which together provide 40% of the global daily calorie intake. This insight raises important questions for the future of crop production in a changing climate, and provides additional challenges for crop breeders and biotechnologists. (Summary by Mike Page) eLife. 10.7554/eLife.02245