Influence of elevated [CO₂] on elemental content in crops.

(a) Comparison of changes in the content of all tested elements under elevated [CO₂] between brown rice (black circles) and polished grains (red diamonds). Data are presented as the mean and one side of 95% confidence intervals (bars) of nine varieties. Red and blue backgrounds denote a significant difference (P < 0.05), where previous work on brown grain has under- or overestimated, respectively, elemental changes in polished grains. For Al, Si, and Br, the values were off the scale of the y axis, as indicated by the wavy line. (b) Time-dependent changes in the elemental content of each part of the rice plant under elevated [CO₂]. Data are presented as the mean. (c) Percentage change in the elemental content of polished grains and plant body (“straw”) of rice (“Koshihikari”). (d) Estimated change in elemental content in feed crops under elevated [CO₂]. (e) Estimated change in elemental content in leaf vegetables under elevated [CO₂]. The raw data are provided in Table 1 and S4 Table. In (c)-(e), essential elements are arranged in decreasing order of intake requirement. Elements that decreased significantly (P < 0.05) under elevated [CO₂] are shown in red.