What was done
Sunflowers (Helianthus annus cv. Johnny's Albin) were planted and grown in large environmentally-controlled chambers receiving atmospheric CO2 concentrations of 400 and 750 ppm to determine the effects of elevated CO2 on canopy light utilization and photosynthetic carbon uptake in this important agronomic crop.

What was learned
Elevated CO2 increased canopy quantum yield by 32%; and this enhancement of plant light utilization increased canopy carbon uptake by fully 53%.

What it means
As the CO2 content of the air increases, sunflowers should become more efficient at absorbing sunlight and using its energy to convert CO2 into carbohydrates; and as the efficiencies of these processes increase, net photosynthetic rates and biomass production should also increase.  Thus, sunflower yield - including those seeds we all love when roasted and salted - will likely rise right along with future increases in the air's CO2 content.  Yum!