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Granados and Korner (2002)1 grew three tropical understory vines (Gonolobus cteniophorus, Ceratophytum tetragonolobum and Thinouia tomocarpa) for seven months in controlled environment chambers maintained at atmospheric CO2 concentrations of 280, 420, 560 and 700 ppm in combination with low and high light intensities to study the interactive effects of the two parameters on the vines’ growth. On average, they found that plant biomass was 61% greater at high light than it was at low light. However, the greatest CO2-induced growth response in each species occurred in the low light environment. Increasing the atmospheric CO2 concentration from 280 to 420 ppm, for example, increased Gonolobus biomass by 86 and 32% in low and high light environments, respectively, Ceratophytum biomass by 249 and 24% in low and high light environments, respectively, and Thinouia biomass by 65% in low light, while it actually decreased plant biomass by 1% in the high light environment.