Short-term exposure to elevated CO2 stimulates growth and metabolic responses that alleviate early-stage iron deficiency symptoms in soybean

Elevated CO2 (eCO(2)) increase plant biomass and might lead to nutritional losses. The results showed that eCO(2) under Fe-deficiency stimulates root dry weight from 0.37-0.80 g plant(-1) and shoot dry weight from 0.82-2.10 g plant(-1), without compromising root/shoot ratio. Besides, eCO(2) improved the chlorophyl content of Fe-deficient plants. However, downregulation of photosynthesis, reduction in stomatal conductance and transpiration rate, and an increase in water-use efficiency was observed due to eCO(2). Moreover, under Fe-deficiency, eCO(2) decreased K and Mg in roots, and Mg in leaves, whereas increased P and Zn in roots and leaves. In Fe-sufficient plants, eCO(2) increased K, P, Mn, Zn and Fe in leaves and did not change the concentration in roots. The Fe-deficiency-induced responses in roots, including the increase in FCR activity, and the expression of Fe-uptake genes were stimulated by eCO(2), but were not sufficient to increase Fe concentration in Fe-deficient plants.