What was done
The authors grew mungbean (Vigna radiata L. Wilczek cv. PS 16) and wheat (Triticum aestivum L. cv. HD 2285) in pots placed within open-top chambers maintained at atmospheric CO2 concentrations of 350 and 600 ppm for several months to study the effects of elevated CO2 on photosynthesis in these important crops.

What was learned
Elevated CO2 increased rates of net photosynthesis throughout the day in both species in both vegetative and reproductive growth stages.  In mungbean, the 250-ppm increase in the air's CO2 content boosted net photosynthesis rates during the vegetative growth stage by 185, 73 and 100% at 9:30, 13:30 and 17:30 local time, respectively.  Similarly, it increased net photosynthesis rates in wheat during the vegetative growth stage by 125, 27 and 33% at 9:00, 13:00 and 16:00 local time, respectively.  Then, during the flowering growth stage, elevated CO2 increased net photosynthetic rates in mungbean by 117, 31 and 80%, and in wheat by 108, 23 and 0% at the same times of day that measurements were made in the vegetative growth stage.

What it means
As the air's CO2 content continues to rise, it will likely stimulate photosynthetic rates in both mungbean and wheat, with greater stimulations occurring during the vegetative growth stage than in the reproductive growth stage.  Both phenomena should help to increase crop yields.