What was done
The authors grew yellow and primrose pansies (Viola x wittrockiana) in greenhouses subjected to various environmental combinations of atmospheric CO2 concentration, air temperature and light irradiance to determine the interactive effects of these variables on vegetative growth and flower production.

What was learned
A 600-ppm increase in the air's CO2 concentration led to increases in total vegetative dry weights ranging from 10 to 30%, depending upon other environmental conditions.  Although elevated CO2 did not affect the time to flowering, it increased flower size by 4 to 10% in a manner dependent upon other environmental conditions.

What it means
As the CO2 content of the air continues to rise, it is likely that pansies will exhibit more robust growth, leading to the production of larger flowers under environmental conditions normally conducive to their growth.  Moreover, it is likely that such increases in growth and flower size will even occur in the face of moderate air temperature and light intensity changes.