Crops have the potential to exploit
the predicted increase in atmospheric carbon dioxide concentration ([CO2]). Growth is typically stimulated at elevated
[CO2], but a sustained and maximal exploitation of rising [CO2]
is dependent on an adequate supply of nutrients, principally nitrogen, and
sufficient sink capacity to utilize the additional carbon fixed at elevated [CO2]. We have examined the effect of elevated [CO2]
on carbon and nitrogen metabolism in soybean grown in the field using Free Air
CO2 Enrichment (FACE) technology where soybean is able to complete
it's entire life cycle at an elevated concentration of CO2 under
fully open air conditions. In both
fully expanded and developing leaves we have shown that increased carbon
availability at elevated [CO2] improved nitrogen assimilation. The additional carbon available at elevated
[CO2] allowed soybeans to overcome an early season nitrogen
limitation and suggests that soybeans were able to acclimate to the increased
nitrogen demand at elevated [CO2].